Analytical strategies of sample preparation for determination of mercury in
food matrices - A review
Sergio L.C. Ferreira, Valfredo A. Lemos, Laiana O.B. Silva, Antonio
F.S. Queiroz, Anderson S. Souza, Erik G.P. da Silva, Walter N.L. dos Santos,
Cesário F. das Virgens
PII:
DOI:
Reference:
S0026-265X(15)00037-5
doi: 10.1016/j.microc.2015.02.012
MICROC 2095
To appear in:
Microchemical Journal
Received date:
Revised date:
Accepted date:
16 January 2015
2 February 2015
25 February 2015
Please cite this article as: Sergio L.C. Ferreira, Valfredo A. Lemos, Laiana O.B. Silva,
Antonio F.S. Queiroz, Anderson S. Souza, Erik G.P. da Silva, Walter N.L. dos Santos, Cesário F. das Virgens, Analytical strategies of sample preparation for determination of mercury in food matrices - A review, Microchemical Journal (2015), doi:
10.1016/j.microc.2015.02.012
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Analytical strategies of sample preparation for determination of mercury in food matrices -
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A review
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Sergio L. C. Ferreira1,2, Valfredo A. Lemos3, Laiana O. B. Silva1,2, Antonio F. S. Queiroz4,
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Anderson S. Souza1,2, Erik G. P. da Silva5, Walter N. L. dos Santos6,
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Cesário F. das Virgens6
1- Universidade Federal da Bahia, Grupo de Pesquisa em Química e Quimiometria, 40170-
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270, Salvador - Bahia, Brazil.
2- Instituto Nacional de Ciência e Tecnologia, INCT, de Energia e Ambiente, Universidade
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Federal da Bahia, 40170-290, Salvador - Bahia, Brazil.
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Jequié - Bahia, Brazil.
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3- Universidade Estadual Sudoeste Bahia, Laboratório de Química Analítica LQA, 45206-510,
4- Universidade Federal da Bahia, Instituto de Geociencias, 40170-290, Salvador - Bahia,
Brazil.
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5- Universidade Estadual Santa Cruz, Departamento de Ciências Exatas e Tecnologia, 45662900, Ilheus, - Bahia, Brazil.
6- Universidade do Estado da Bahia, Departamento de Ciências Exatas e da Terra, 41150000, Salvador - Bahia, Brazil.
Author correspondence
S.L.C. Ferreira
E-mail: slcf@ufba.br
Tel/Fax: 55-71-32355166
Abstract
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The present paper reports advantages, drawbacks and applications of the main
techniques of sample preparation employed during determinations of total mercury and
methylmercury in food matrices employing analytical methods such as: cold vapor atomic
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absorption spectrometry (CV AAS), cold vapor atomic fluorescence spectrometry (CV AFS),
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inductively coupled plasma mass spectrometry (ICP-MS), voltammetry, neutron activation
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analysis and others. The use of slurry sampling, solid sampling, microwave assisted
extraction, reflux system by cold finger and Vigreux column were discussed. Also a brief text
on use of chromatographic techniques for speciation analysis of mercury is presented. A list
of 134 references is cited and analytical characteristics of some these procedures proposed
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are showed as tables.
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Keywords: Mercury; Food samples; Slurry sampling; Solid sampling; Direct Mercury Analyzer:
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Cold finger; Vigreux column; CV AAS; CV AFS; CV ICP-MS.
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Contents
1. Introduction
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1.1. Toxicity of mercury and its compounds
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1.2. Analytical methods
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2. Determination of mercury in food matrices employing direct analysis
2.1. Direct Mercury Analyzer (DMA)
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2.2. Slurry sampling
2.3. Solid sampling
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3. Strategies involving sample digestion for determination of mercury in food matrices
3.1. Acid digestion bombs
3.4. Vigreux column
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4. Other procedures
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3.3. Microwave digestion
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3.2. Cold finger
5. Speciation analysis of mercury in food samples
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Conclusions
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1. Introduction
1.1. Human exposure to mercury and its compounds
Mercury and its organic and inorganic species are toxic to the central and peripheral
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nervous system, however, this toxicity depends of this chemical form, among which organic
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mercury compounds are the most toxic. The principal chemical forms of mercury are:
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elemental mercury (Hgo), divalent inorganic mercury (Hg2+), methyl mercury (CH3Hg+) and
dimethylmercury ((CH3)2Hg) [1]. The biomonitoring of mercury exposure depends of the
chemical form. So, blood and urinary mercury are used to assess occupational exposure in
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case of contamination by elemental mercury. For exposure by methylmercury, the
bioindicators used are blood and hair samples [1]. The mercury species are volatile and this
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is worrying because the inhalation of mercury vapor and its compounds produce harmful
effects on the nervous, digestive and immune systems and the lungs and kidneys. Children
and babies are most affected by mercury toxicity. Mercury releases in the environment are
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originated from natural sources as such volcanoes and or human activity as production of
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non-ferrous metal (smelters), cement, caustic soda and also waste disposal. For humans, the
main contamination by mercury comes from foods, especially fish and seafood. In fishes,
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elemental mercury is naturally transformed into methylmercury, compound of great toxicity
[2,3,4]. Plant foods may also be contaminated by mercury due to use of phosphate fertilizers
in agricultural processing [5]. These inputs often contain appreciable amounts of toxic
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elements such as: mercury, cadmium, lead and others. Jesus et al. determined mercury in six
phosphate fertilizer samples [5]. The mercury content found varied from 34 to 210 µg kg-1.
This way, several plant foods can contain mercury as contaminant. Rice grown in
contaminated regions accumulates mercury. It is concerned because mercury can be
methylated by bacteria to produce methylmercury. So, many methods have been published
for determination of methylmercury in rice [6,7,8,9]. The World Health Organization (WHO)
recommends a maximum intake of methylmercury of 1.6 μg kg−1 per week [10].
1.2. Analytical methods
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The determination of mercury in food samples can be established in two steps: firstly, a
sample preparation procedure is required and afterward the quantification step. The sample
preparation step is complicated because of the volatile character of mercury and its species
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[11]. However, the mercury determination step is relatively simple and it has been often
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performed using the vapor generation technique coupled to atomic absorption spectrometry
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(CV AAS), fluorescence spectrometry (CV AFS), inductively coupled plasma optical emission
spectrometry (CV ICP OES) and inductively coupled plasma mass spectrometry (CV ICP-MS)
[12,13,14,15,16]. The vapor generation reaction can be performed employing NaBH4 or SnCl2
in acid medium as reducing agent [17,18,19]. NaBH4 promotes faster and more effective
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reduction so that it is preferred to SnCl2. However, the use of NaBH4 promotes the
formation of an excess of H2 resulting in spectral interferences.
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Some problems and interference are encountered in the determination of mercury
species by ICP-MS [20]. For example, a significant memory effect is observed in the sample
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introduction system, resulting in long washing times and poor accuracy and reliability.
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It is suggested that this problem is caused by adherence of mercury to the walls of
the spray chamber and the transfer tubing of the introduction system [21]. The mercury
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vapor builds up slowly in the spray chamber, due to the volatility of the element increased
by large pressure during the pneumatic nebulization. This effect has been eliminated by
some different approaches, such as adding gold to the samples and standards as a stabilizing
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agent and using a combination of flow injection sample introduction [22]. Additionally,
procedures utilizing isotope dilution inductively coupled plasma mass spectrometry (IDA ICPMS) have been very proposed in recent years [23,24,25,26]. Clémens et al. published a
review paper about speciation analysis of mercury in seafood using this technique. Several
methods proposed were discussed [2].
Mercury has been determined also using electrothermal atomization atomic
absorption spectrometry (ET AAS) [27,28]. Alternatively, voltammetric methods have been
also proposed for determination of mercury in several matrices. These are suitable for
determination of mercury in food samples because they are simple, fast, inexpensive and
involve an instrumentation that can easily be operated. Further, the voltammetric methods
have low limits of quantification because these are established having a pre-concentration
step of mercury on the working electrode and subsequent stripping. A review recently
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published summarizes methods proposed for the determination of mercury employing
electroanalytical techniques including applications for analyze of food samples [29].
The neutron activation analysis (NAA) is a direct analysis technique employed for
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many matrices including foods, which have advantages such as: non-destructive character of
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the samples, good accuracy, ability to multi-elemental determinations and high selectivity
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and sensitivity. This is a good alternative for the determination of mercury considering the
volatile nature of this element and the lower limits of quantification that can be obtained
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[30,31].
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2. Determination of mercury in food matrices employing direct analysis
2.1. Direct Mercury Analyzer (DMA)
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The use of the Direct Mercury Analyzer (DMA) is one of the good alternatives that have been
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proposed for determination of trace amounts of mercury in complex matrices, including
foods [21 - 30]. This equipment can be employed for analyses in solid and liquid samples and
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it does not require any pre-treatment of these. It operates on a basis of sample thermal
decomposition, followed of mercury catalytic reduction and amalgamation on a gold system
for vapor mercury trapping and, subsequently mercury desorption and analytical measured
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by atomic absorption spectrometry. The efficiency of a chemical analysis using DMA
depends strongly of the sample homogeneity which is being processed. Generally, the
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calibration curves are established using certified reference materials but, eventually can be
performed also by external calibration technique employing aqueous standard solutions
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[26,29]. This way, DMA has been used for determination of mercury traces in several
matrices [8,32,33]. Ipolyi et al. proposed a method for determination of total mercury and
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methylmercury in mussel samples. Total mercury was quantified using DMA and
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methylmercury by gas chromatography – mass spectrometry after acid extraction. Two
certified reference materials were analyzed and confirmed the accuracy of the method
performed for determination of total mercury [34]. Ikem and Egiebor used DMA for
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determination of trace amount of mercury in canned fishes (mackerel, tuna, salmon,
sardines and herring). The calibration of the equipment was performed using a certified
reference material of dogfish muscle. The analysis of two certified reference materials
demonstrated accuracy of this method [35]. Carbonell et al. employed DMA in method
proposed for quantification of total mercury and methylmercury content in muscle of
seawater fish. Total mercury content is determined directly in the fish muscle and
methylmercury after an extraction step using microwave assisted extraction in acidic
conditions with toluene [36]. Tsaiab et al determined the total mercury content in 69 red
mould rice (Monascus) food samples purchased in Taipei, Taiwan using DMA. During the
validation studies the accuracy was confirmed by analysis of a certified reference material of
apple leaves. Addition/recovery tests were also performed and the average recovery was
95% [37]. Martin et al. established a method employing DMA for quantification of total
mercury content in 87 infant food samples purchased in Lisbon City, Portugal. The accuracy
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evaluation involved analysis of certified reference materials of skimmed milk powder, rice,
spinach, chicken, strawberry leaves and oyster tissue [38]. A method proposed by Torres et
al. determined total mercury content in two types of fresh fish samples employing DMA. In
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it, analytical curves were performed using external calibration with aqueous standard
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solutions [39]. Vieira et al proposed and compared two methods for determination of
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mercury in honey samples. A method using CV AAS and the other employing DMA. The
principal drawback of the DMA method is the sample amount that is limited at 100 mg,
however the DMA method provides limits of detection and quantification lower than CV AAS
method [40]. The Table 1 shows analytical parameters of methods proposed for
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determination of mercury in food samples employing DMA.
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Table 1
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2.2. Slurry sampling
Slurry sampling is a good alternative that has been often employed in recent times for
sample preparation during determination of mercury employing spectrometric methods
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[41]. In these procedures, the samples are handled with diluted acid solutions under room
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temperature or eventually under temperature conditions that are not critical to loss of
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volatile elements. The main advantages are: allows frequently use of the external calibration
technique, lower risk of contamination by reagents, sample masses and reagent volumes are
not parameters critical, such as occur in microwave-assisted digestion with pressurized
closed-vessel methods. Additionally, slurry sampling allows also the development of
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procedures for speciation analysis of mercury [42]. Silva et al propose a method for analysis
of rice samples. Firstly, the samples are heated at 60 oC for 20 min in closed system and,
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afterward the suspension obtained is sonicated for 30 min at 60 oC in the presence of 6 mol
L-1 hydrochloric acid and thiourea. Under these conditions, mercury is quantitatively
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transferred from solid phase to liquid phase of the suspension and it is determinate by CV
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AAS [9]. Several analytical techniques have been employed for determination of mercury in
food matrices using slurry sampling, however the procedures which used ETV ICP-MS
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[43,44,45,46] and CV ICP-MS [47] provided have lower limit of quantification. During the
determination of mercury in cereals using slurry sampling and flow injection chemical vapor
generation as the sample introduction system in ICP-MS, mercury was quantified by isotope
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dilution technique because the external calibration technique cannot be used [38]. CavaMontesinos et al proposed a method employing cold vapour atomic fluorescence for
determination of mercury in milk by slurry sampling using multicommutation. Several
chemical reagents were used for slurry preparation including potassium bromide and
potassium bromate [48]. Segade and Tyson proposed two simple flow injection (FI) systems
for mercury speciation analysis in fish tissue samples by slurry sampling cold vapor atomic
absorption spectrometry [49]. Chen and Jiang developed a method employing slurry
sampling electrothermal vaporization inductively coupled plasma mass spectrometry for
determination of arsenic, selenium and mercury in fish samples. Palladium and
thioacetamide were used as modifiers. The quantification of the elements was performed
using analyte addition technique [50]. The Table 2 shows analytical parameters of methods
developed for determination of mercury in food matrices using slurry sampling.
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Table 2
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2.3. Solid sampling
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Direct analysis employing the solid sampling technique has great advantages over sample
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digestion procedures especially for determination of mercury because of the volatile
character this element and its species. Solid sampling allows acceleration and simplification
of the analytical procedures of sample preparation with sensitivity due to the absence of any
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dilution, it avoids use of chemical reagents and frequently allows quantifications employing
the external calibration technique using aqueous standards. However, the drawbacks of this
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technique are: the accuracy is very influenced by sample homogeneity and low
reproducibility. The solid sampling has been utilized for determination of mercury in several
matrices as: contaminated soils [51], airborne particulate matter [52], polymers [53],
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biological samples [54,55], but its application for food analysis has been limited. Methods
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have been established for determination of mercury in fish [56], tuna fish [50], milk powder
[50], spinach [57], seafood [58] and fish [59]. The Table 3 shows analytical parameters of
Table 3
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methods proposed for determination of mercury in food samples.
3. Strategies involving sample digestion for determination of mercury in food matrices
3.1. Closed vessels and thermal heating
Acid digestion bombs are closed systems that are heated by convection using conventional
oven. In this, the sample amount used for digestion is rigorously controlled because of risk of
explosions. In the past, this digester system were widely recommended for sample
mineralization during the determination of volatile species including mercury [60,61].
3.2. Cold finger
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The sample mineralization utilizing the reflux system "cold finger" [62] is one of the
strategies that have been recently employed for sample preparation during the
determination of volatile chemical elements such as: lead [63,64],arsenic [,65], and others
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[66,67]. The “cold finger” is a glass tube in the shape of finger, which is placed over the
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digester tube during the acid digestion by conventional heating using block digester [55].
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This system causes reflux and condensation of the volatile species, avoiding the loss by
evaporation. Advantages, drawbacks and use of this reflux system during digestion of
inorganic and organic matrices are summarized in review paper [55]. The "cold finger"
system has been used in sample preparation procedures for determination of mercury in
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sediment samples [68, biological matrices [69], crude oil and related products [70]. However,
it has not reported any work involving digestion of food samples for the determination of
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mercury.
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3.3. Microwave heating
Microwave heating enables a rapid decomposition of samples due a control over the time
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and heating power. Microwave digestion can be performed in open, closed, and flow
systems. Open microwave systems have the risk of escape of volatile components of the
sample, which may influence greatly the results. However, this type of system allows
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removal of gaseous products of the reactions and also the addition of reagents during the
digestion process. Closed microwave systems are simpler and faster than open systems and
their use reduces the risk of contamination. However, this type of device allows the use of
only small amounts of sample, due to the large amount of gases released and the
consequent risk of explosion. In microwave assisted extraction, the critical experimental
factors are the concentration and volume of the extractor reagent, irradiation temperature,
extraction time, sample mass and stability of the species [71,72]. Extraction procedures
using dilute acid combined with solvent extraction have been proposed solid samples such
as food, soil and sediments. Nitric acid, hydrochloric acid and hydrogen peroxide reagents
have been used in the digestion procedures.
Alkaline solution of tetramethylammonium hydroxide was used in digestion procedure of a
method proposed for determination of methylmercury in fish
employing gas
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chromatography-mass spectrometry. Digestion conditions were optimized and the results
obtained demonstrated that the analytical signals were strongly dependent of the heating
time and irradiating power. Long heating times or high irradiating power resulted in low
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content of methylmercury [73]. Tuzen used nitric acid and hydrogen peroxide in a
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microwave digestion system for determination of mercury and other trace elements in fish
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samples [74]. De Paz et al. also employed hydrogen peroxide and nitric acid in a digestion
procedure of fish samples using microwave oven for determination of mercury by flow
injection analysis system cold vapor atomic absorption spectrometry [75]. Hight and Cheng
used a mixture of nitric acid and sodium chloride in microwave oven during digestion of
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seafood samples for determination of total mercury by CV AAS [76]. Drennan-Harris et al.
established comparison between microwave digestion and acid extraction procedures
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proposed for determination of mercury in rice samples using ICP-MS. They concluded that
both procedures are effective for rice digestion [77]. Carrasco and Vassileva proposed an
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analytical procedure for the determination of methylmercury in marine biota samples using
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gas chromatography coupled to atomic fluorescence spectrometry. Five different extraction
procedures were tested, including acid and alkaline leaching assisted by microwave and
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conventional oven heating and also enzymatic digestion. The highest extraction recoveries
were obtained using alkaline extraction (potassium hydroxide in methanol), microwaveassisted extraction employing hydrochloric acid and enzymatic digestion with protease XIV
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[78]. A method was proposed for determination of arsenic, cadmium, chromium, lead and
mercury in seafood species used for sashimi. The mineralization procedure of the samples
was performed in a closed microwave digestion system utilizing 7 mL of concentrated nitric
acid and 3 mL of hydrogen peroxide. The elements were determined by ICP OES [79].
Kosanovic et al. quantified cadmium, mercury, lead, arsenic, copper, and zinc in human
breast milk by ICP‐MS. The sample mineralization procedure involved use of microwave oven
[80]. A sample preparation procedure for the determination of mercury in breast milk was
established using a 1 mL of homogenized milk sample, 2 mL suprapur nitric acid and a closed
microwave oven. The digested obtained was transferred to a 25 mL volumetric flask utilizing
ultrapure water and the total mercury was determined by AFS using stannous chloride as
reduction agent [81]. Koplik et al. proposed a method for the determination of
methylmercury and inorganic divalent mercury in fish, vegetables, herbs and cereals using
reversed-phase liquid chromatography hyphenated with inductively coupled plasma mass
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spectrometry. A procedure involving an extraction step of the mercury species using a
mercaptoethanol acid solution was efficient for quantification of methylmercury and
inorganic divalent mercury in fish muscle and vegetable tissues [82]. Qin el al. determined
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total mercury in fishes employing ICP-MS. The sample mineralization was performed using
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nitric acid and hydrogen peroxide in microwave oven [83]. Zhao et al. proposed a method for
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speciation analysis of mercury in fish samples by using capillary electrophoresis-inductively
coupled plasma mass spectrometry. The mercury species were extracted using a 1 M
hydrochloric acid solution in a microwave digester [84]. The efficiency of eight different
analytical procedures commonly used for extraction of mercury species in biological samples
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was evaluated by analysis of a certified reference material of fish used for determination of
total mercury and methylmercury [85]. The extraction procedures tested were: alkaline
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extraction with KOH or tetramethylammonium hydroxide; acid leaching with hydrochloric,
nitric or acetic; extraction using L-cysteine hydrochloride; and enzymatic digestion with
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protease XIV. Total mercury and mercury species from all extractions were determined using
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ICP-MS and HPLC-ICP-MS, respectively. Procedures using alkaline digestion with microwave
assisted extraction and ultrasonic assisted extraction were the most efficient, where levels of
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transformation of mercury species were the lowest (6% or less). Extraction using 5.0 mol L-1
hydrochloric acid and/or enzymatic digestion with protease also showed good results. The
authors warn that despite the frequent use of acid leaching for the extraction of mercury
species in fish samples, the lowest extraction efficiencies and greater transformation
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between mercury species were obtained when microwave assisted extraction with 4.0 mol Lnitric acid or acetic acid were used [84]. An efficient method was proposed for speciation
analysis of mercury in fish tissue using microwave assisted extraction in a closed system.
Quantitative extraction of mercury species were obtained by leaching using 5.0 mol L-1
hydrochloric acid and 0.25 mol L-1 sodium chloride for 10 min at 60 oC. Total mercury and
mercury species were determined using ICP-MS and HPLC-ICP-MS, respectively [86]. An
alternative procedure using a vessel that allows partial release of gases was reported. This
device enabled an increase of sample mass, the completeness of oxidation, and the
retention of volatile elements in solution [87]. The Table 4 summarizes analytical parameters
of procedures proposed for the determination of mercury in food samples employing
microwave assisted digestion. 88,899091929394
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Table 4
3.4. Vigreux column
In 1990, Landi et al. used the Fricdrichs and Vigreux condensers in sample preparation
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procedures during the determination of mercury in vegetable matrices employing CV AAS
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[95]. In another method, these authors employed potassium dichromate, diluted sulphuric
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acid and a reflux system using a condenser for determination of total mercury in seafood
and other protein-rich products by CV AAS [96]. Subsequentially, a sample digestion
procedure using the Vigreux column was proposed for the determination of mercury in core
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sediments by cold vapour atomic fluorescence spectroscopy [97]. In the last times, this same
research group has established sample preparation procedures using Vigreux column and
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oxidant acid mixtures for determination of mercury in foods as: vegetables [98], teas [99],
meals [100] and other matrices [101,102] employing square wave anodic stripping
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voltammetry (SW ASV) using a gold electrode.
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4. Other sample preparation procedures for determination of mercury in food samples
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Although NAA presents great advantages for the determination of mercury, the employ this
technique for analysis of food is relatively low. Singh and Garg determined the content of 16
trace elements in Indian cereals, vegetables and spices employing NAA. The sample
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preparation procedure for neutron irradiation of the seed matrices (rice, wheat fenugreek
and black pepper) involved cleaned with tissue paper, followed by drying using an IR lamp at
80°C. Afterward, grinding to powder using a food processor/mixer and an agate mortar. The
vegetable samples were washed distilled water and dried in oven <80°C for overnight. Then,
these matrices were grinding to powder in an agate mortar [103]. Rizzo et al determined
total mercury in muscle and liver of four fish species by NAA. For irradiation, the samples
were dried, homogenized and sealed in quartz ampoules. These authors warn that the limits
of detection and quantification for mercury in NAA determinations depend strongly of the
analytical conditions of the analyzed sample, particularly the gamma-ray spectral
background generated by other elements contained in the sample [104]. Anderson
evaluated the effect of L-cysteine on drying and neutron irradiation loss of mercury and
other elements from fish tissue. During the experiments some tissue samples were dried and
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analyzed by NAA. Other samples were treated with L-cysteine followed by freeze drying and
also analyzed by NAA. The results for the untreated tissues showed that mercury may be
largely lost (23–49%) by volatilization during irradiation. Treatment with L-cysteine reduced
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significantly these losses, however, these reductions were highly dependent of the drying
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procedure used. Freeze drying of treated tissues at - 50 oC and 1.3 – 2.7 Pa was most
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efficient (1.0 – 3.5%) [105]. Antoine et al. determined mercury and several other elements in
twenty-five rice brands originated from Jamaican using NAA. For neutron irradiation the rice
samples were weighed out into pre-cleaned double polyethylene bags and heat sealed in
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pre-cleaned polyethylene vials [106].
Analytical strategies involving microwave-induced combustion (MIC) have been considered
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as a good alternative for sample preparation during determination of metals and non-metals
in complex matrices [107, ,108]. This technique has as advantage the possibility to digest
relatively large amounts of sample (up to 500 mg) using low volumes of acids, allowing a
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final solution with a low residual carbon content. So, MIC has been also employed for sample
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digestion during determination of mercury in fish [109], soil [110] and coal [111].
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Schmidt et al. evaluated the influence of drying conditions on the behavior of mercury
species (inorganic mercury and methylmercury) present in six different fish species. The
drying conditions studied were as follow: air circulation drying oven in different
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temperatures (50 to 175 oC) and lyophilization (0.25 mm Hg, -2 oC). The evaluation of the
results was based on losses and conversions of original Hg species after each drying
condition. The determination of total mercury and its species were performed employing
CVG ICP-MS) and LC-CVG-ICP-MS, respectively. The results demonstrated that for drying
temperatures above 100 oC, losses and conversions of methylmercury to inorganic mercury
can occur for some fish species [112].
Mashhadizadeh et al proposed a pre-concentration procedure by magnetic solid phase
extraction using Fe3O4 nanoparticles coated with 3-(trimethoxysilyl)-1-propanethiol and
modified with ethylene glycol bis-mercaptoacetate for determination of mercury in food
samples (rice, tuna fish and tea leaves) employing CV AAS as analytical technique [113].
Lemos et al employed a pre-concentration system containing a mini-column packed with the
Amberlite XAD-4 sorbent functionalised with 2-(2'-benzothiazolylazo)-p-cresol (BTAC) for
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determination of mercury in fish, shellfish and saliva using CV AAS [114]. An enrichment
procedure employing Fe3O4 magnetic nanoparticles functionalized with dithizone was
investigated for extraction and determination of ultra-trace amounts of mercury in table
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salt, green tea, vegetables, toothpaste, and water samples using CV AAS [115]. A pre-
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concentration procedure for determination of amount trace of mercury in sea and river fish
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samples was proposed using dispersive liquid-liquid micro-extraction [116]. A procedure for
determination of total mercury in muscle tissue of fish was developed using GF AAS. Copper
nitrate and sodium tungstate were tested as chemical modifier and permanent modifier,
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respectively. A limit of quantification of 0.047 mg kg-1 was obtained [117].
A multisyringe flow injection system was established for determination of total mercury in
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rice samples using cold vapour atomic fluorescence spectrometry (CV AFS). The limits of
detection and quantification obtained were 0.48 and 1.61 ng g-1, respectively [92].
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A non-chromatographic method was developed for determination of methylmercury and
inorganic mercury in muscles tissues of ten freshwater fish species employing CV AAS as
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analytical technique. For speciation, the digested samples in alkaline conditions were
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reduced sequentially with stannous chloride and sodium tetrahydroborate for quantification
of inorganic mercury and methylmercury, respectively [118]. A procedure involving sample
thermal decomposition followed by mercury amalgamation and atomic absorption has been
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performed for determination of methylmercury in fish. An extraction step with toluene and
back-extraction into an aqueous L-cysteine solution allows the separation for speciation
analysis [119]. An on-line pre-concentration system with valves electronically controlled
using a minicolumn packed with polytetrafluoroethylene was developed for determination
of mercury in water samples employing CV AAS. In it, mercury(II) ions as
pyrrolidinedithiocarbamate complexes are firstly pre-concentrated on the minicolumn and
afterward these complexes are eluted and reduced using a solution sodium
tetrahydroborate(III). A pre-concentration factor of 35 and a limit of detection of 0.02 µg L-1
was obtained [120]. Goudarzi et al. determined Mercury, lead and cadmium in breast milk of
healthy lactating women from Iran. The sample preparation step involved a volume of 25 mL
of milk sample and digestion in semi-closed glass apparatus in presence of 7 mL
concentrated nitric acid and 3 mL of hydrogen peroxide. After cooling, the volume was
adjusted to 50 mL using ultrapure water and mercury as quantified employing CV AAS [121].
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Procedures involving amalgamation in gold traps or Pd-based substrates have been
described for the preconcentration of mercury after cold vapor generation [122,123]. Pdbased substrates, such as a Pd wire, Pd-coated SiO2 fiber and Pd-coated stainless steel wire
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have also been applied for preconcentration of Hg using solid-phase microextraction
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methodology. Hg vapor generation is carried out in a vial and the volatile Hg formed is then
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amalgamated onto the Pd-based materials. The preconcentration procedures based on the
trapping of mercury on a gold filament preconcentrator are followed by rapid thermal
desorption and detection. The absorption of mercury in a gold surface is highly effective and
well known [124, 125]. This phenomenon usually generates selective procedures because
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mercury is the only species absorbed if gases acids are removed. Preconcentration using
mercury amalgamation in gold trap has been applied to the determination of the element in
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fish tissues [126], water [127] and biological matrices [128].
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5. Sample preparation for speciation analysis of mercury in food samples
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The determination of organic mercury in food has been frequently reported in the
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literature, due to the high toxicity of these species [129]. Various chromatographic
techniques have been employed for the quantification of mercury species, including the gas
chromatography (GC) and high-performance liquid chromatography (HPLC) [130]. The
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hyphenation with spectrometric detection techniques, such as atomic fluorescence
spectrometry (AFS), atomic emission spectrometry (AES), atomic absorption spectrometry
(AAS) and mass spectrometry (MS) have resulted in powerful tools for speciation of organic
mercury species in various samples such as red wine [131], fish [132,133,134], rice [135] and
seafood [136]. Capillary electrophoresis has also been used in some applications. The
determination of methylmercury in fish was performed by leaching with HBr analyte
extraction with toluene and back-extraction with aqueous L-cysteine [119]. MeHg was
determined using sample thermal decomposition followed by mercury amalgamation and
atomic absorption. A method for the speciation of mercury in seafood used the hyphenation
LC-ICP-MS and a fast sample preparation procedure [128]. Mercaptoethanol, L-cysteine and
HCl were used to extract the mercury species, with the aid of sonication for 15.0 minutes. A
C8 reverse phase column has been used for separation of mercury species. Organic and
inorganic mercury were determined in fresh and canned fish and in blood using a method
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based on ICP-MS coupled with high performance liquid chromatography (HPLC) [137]. Gas
chromatography with atomic emission detection has been used in a simple method for
speciation of mercury species in fish and seafood [138]. Methylmercury was measured in
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rice (Oryza sativa L.) using gas chromatography (GC)-CVAFS detection. The cereal grown in
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soils from areas of abandoned mercury mines [116]. Flow injection cold vapour generation-
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inductively coupled plasma mass spectrometry (FI-CVG-ICP-MS) and gas chromatographyICP-MS (GC-ICP-MS) have been applied to determination of total Hg, inorganic Hg and
methylmercury in red wine [112]. Hight and Cheng proposed a method for determination of
methylmercury and total mercury in seafood samples [139]. In it, mercury compounds are
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extracted of the samples using 50 mL of an aqueous solution containing V L-cysteine and
hydrochloric acid followed of heating by 120 min at 60 oC. Afterward, the mercury
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compounds containing in the aqueous extracts are separated by reversed-phase high
performance liquid chromatography using a C-18 column and detected employing
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inductively coupled plasma-mass spectrometry at mass-to-charge ratio 202. Methyl and
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inorganic mercury are determined in extracts. Montero-Alvarez et al. developed a method
for speciation analysis of mercury in edible fish samples employing HPLC-ICP-MS and isotope
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dilution analysis. The extraction of the mercury species was performed mercaptoethanol, Lcysteine, hidrochloric acid and sonication for 30 min [140]. Huang et al. proposed a
procedure for determination of methylmercury and total mercury in marine fish samples
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(five species). Methylmercury was quantified employing HPLC -AFS and total mercury using a
direct mercury analyzer. The methylmercury was extracted using microwave radiation [141].
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Conclusions
The development of methods for the determination of trace amounts of mercury in
food samples has been still important and timely considering the high toxicity of this
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element and its compounds.
During the determination of mercury in food samples the quantification step is very
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simple and can be done using CV AFS or CV AAS, which are analytical techniques highly
sensitive for mercury with low cost. The ICP-MS and CV ICP-MS techniques are also often
used but the analytical cost is very high. However, the sample preparation step is very
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critical because of the volatile character of mercury and its compounds. Thus, further studies
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should be made considering the variety of food matrices that may contain this element.
The employ of the Direct Mercury Analyzer (DMA) has been a good option for direct
determination of mercury in samples of solid and liquid foods. This enables the analysis
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without the use of chemical reagents and it allows the use of external calibration technique
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using certified reference materials or aqueous standards.
Slurry sampling is a sample preparation technique that has been also very employed
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for determination of mercury in food samples. In this, the sample amount is not limited as
DMA and/or solid sampling technique and the calibration can be performed eventually by
external calibration technique using aqueous standards. Procedures have been established
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by chemical vapor generation as: CV AAS, CV AFS, CV ICP-MS and also using electrothermal
vaporization-inductively coupled plasma mass spectrometry (ETV-ICP-MS), which allows low
limits of detection and quantification. Foods of animal and vegetable origin have been
analyzed by this technique.
The reflux system using "cold finger" has been often employed for sample
preparation during the determination of volatile elements. Several methods for
determination of mercury in complex matrices as: crude oil, sediment and biological samples
have been developed using this digestion strategy. However, there is no a work involving
sample preparation using cold finger for determination of mercury in food samples. Studies
carried out with other volatile elements in food matrices and the works established for
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mercury, suggest that this technique of reflux may be used for mineralization of food
samples for determination of mercury.
Microwave assisted digestion (MAD) in closed vessels has been widely applied for the
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digestion of many food matrices during determination of mercury, due to its high efficiency
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and reduced risks of losses and contamination in comparison with conventional digestion
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procedures using open vessels. For determination of total mercury, the reagents most often
used are: nitric acid, hydrochloric acid and hydrogen peroxide. Alkaline digestions using
tetramethylammonium or potassium hydroxide have been recommended by several authors
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for determination of methylmercury.
The speciation analysis of mercury in food samples has been performed employing
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gas chromatography (GC) and high-performance liquid chromatography (HPLC) as separation
techniques, being the detection established by several spectroanalytical techniques such as:
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atomic fluorescence spectrometry (AFS), atomic absorption spectrometry (AAS) and
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inductively coupled plasma mass spectrometry (ICP-MS).
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Acknowledgements
The authors are grateful to Conselho Nacional de Desenvolvimento Científico e
Tecnológico (CNPq), Fundação de Amparo a Pesquisa do Estado da Bahia (FAPESB) and
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for providing grants
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NU
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and fellowships and for the financial support.
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References
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Table 1. Analytical parameters of methods developed for determination of mercury in food
samples using DMA
Sample
LOD
LOQ
RSD
strategy
(g)
Kg-1
Canned
1
35
0.02 ng
<1.5%
36
0.24 µg
Kg-1
-
0.1
1.0 ng
4.1%
38
< 1.0%
39
< 4.4%
ECT
40
1
2.5 ng g-1
2.7–3.4%
g-1
ECT - External calibration technique.
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37
Kg-1
3.0 µg Kg-
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Honey
0.1
0.29 µg
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Kg-1
foods
Fishes
0.10 µg
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0.1 – 0.5
ECT
Kg-1
*Rice
Infant
< 14.79%
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0.05 – 0.10 0.6 µg
muscle
34
<1.5%
fishes
Fish
ECT
0.01 ng
NU
0.1
2 - 14%
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0.08 µg 0.3 µg Kg-
Nuts
Mussel
References
T
mass
Calibration
IP
Sample
*- Foods from Taiwan containing red mould rice (Monascus)
41
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Table 2. Analytical characteristics of methods developed for determination of mercury in
Sampl
e
Homogenizati
e
mass
on
Size
(µm
)
Analytic
Precisio
generatio
al
n
LO
Referenc
n
techniqu
Q
es
e
AC
CE
P
TE
D
MA
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(g)
Vapor
T
Sampl
IP
food samples using slurry sampling
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Herbs
0.5
Ultrasonic bath
150
-
ETV-ICP-MS
4.0
0.3 ng g-1
44
150
-
ETV-ICP-MS
< 10
2.6 ng g-1
45
ETV-ICP-MS
2.6 ng g-1
46
ETV-ICP-MS
1.75 ng g-1
47
microcarpa
1.0
Ultrasonic bath
and Vortex mixer
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Ficus
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Rice and
Rice and
Wheat flour
Ultrasonic bath
100
-
0.2
Ultrasonic bath
100
-
0.6
Ultrasonic bath
2
Ultrasonic bath
-
Fish
0.25
Magnetic stirrer
100
NaBH4
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Milk
Fish
2.25% (w/v)
-
heated (85°C)
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Rice flour
0.1
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N
Wheat flour
3 mol L-1 HCl
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D
Rice and
CR
Leaves
2.5% (w/v) SnCl2
0.75% (w/v)
NaBH4
CV-ICP-MS
-
0.23 ng g-1
48
CV AFS
3.4
0.036 ng g−1
49
FI-CV AAS
2.49
221 ng g-1
50
ETV-ICP-MS
< 11%
112 ng g-1
51
AC
CE
P
TE
D
MA
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IP
T
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Table 3. Analytical characteristics of methods developed for determination of total mercury
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in food samples using direct solid sampling (SS).
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None
ETV-ICPMS
Several
matrices
Up to 35
None
GF AAS
Seafood
-
None
GF AAS
0.2 - 0.4
Ir permanent + Pd + Mg
LOQ
6 ng g-1
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D
CE
P
AC
Fish
Ir permanent + Pd + Mg
+ Triton X-100
GF AAS
Remarks
References
Wet fish; drying step in
the temperature
program
59
<3
(0.5 - 50
ng)
8 ng g-1
Zeeman-effect
background correction;
Ni–Cr tube with Pt
platform;
one-step temperature
program
60
1.5 (5
ng)
0.04 ng
Special Ni tube furnace;
Zeeman-effect
background correction
61
-
0.789 µg g-1
Speciation analysis
62
MA
N
Fish
Precision
% R.S.D
7.2
(wet
fish)
T
Detection
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Chemical modifier
CR
Sample
mass (mg)
~1
US
Sample
0.623 µg g-1
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ETV-ICP-MS electrothermal vaporization inductively coupled plasma mass
spectrometry, GFAAS graphite furnace atomic absorption spectrometry, LOQ limit of
quantification, ZAAS zeeman atomic absorption spectrometry.
29
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Table 4. Characteristics of procedures for microwave digestion of food samples for determination of total
mercury.
Time of
Sample amount
Reagent for digestion
Power (W)
samples) or 0.5
nd foodstuffs of
and 1.0g (wet
animal origin
samples)
1.0g
3.0 mL of concentrated HNO3 (65%),
6.0 mL of concentrated HNO3 (65%), 2.0 mL of
concentrated H2O2 (30%)and 2.0 mL of H2O
D
0.5g
10.0 mL of concentrated HNO3 (65%)
0.1-0.4g
Seafood
0.1 mg
Rice
0.50g
Breast milk
1.0 mL
Rice
0.5g
Fish
0.25
Rice
0.5g
a
b
b
irradiation
(min)
10.0
20.0
250
2.0
0
2.0
250
6.0
400
5.0
c
technique
ICP-MS
97, 98
CV AAS
83
8.0
d
100 , 50 ,
15.0
c
100 ,100
d
20.0
100 ,150
c
d
20.0
c
d
10.0
c
d
0.0
100 ,175
100 , 20
Hg
analyser
300
4.0
FIAS-CV
mL of concentrated H2O2 (30%)
600
2.0
AAS
1.0 mL of 1.0 % w/v NaCl and 5.0 mL of
300
5.0
concentrated HNO3 (65%)
1200
20.0
5.0
800
2.0
800
2.0 mL of concentrated HNO3 (65%), 1.0 mL of
4.0
900
concentrated H2O2 (30%)and 5.0 mL of H2O
2.0
900
10.0
1000
10.0
1000
----400
2.0 mL of concentrated HNO3 (65%)
200 mg of L-cysteine, 3.0 mL of H2O and 3.0
mL of concentrated HNO3 (65%)
e
99
84
CV AAS
85
CV AFS
102
-----
CV AFS
100
20.0
ICP-MS
86
ICP-MS
101
CV AFS
103
5.0 mL of concentrated HNO3 (65%) and 0.5
75
mL of concentrated H2O2 (30%)
180
15
4.0 mL of concentrated HNO3 (69%), 2.0 mL of
RT-85
3.0
e
Referenc
20.0
0 ,0
550
Detection
4.0 mL of concentrated HNO3 (65%) and 0.2
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Fish
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etary supplements
b
800 ,1000
a
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Fish
500 , 800
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eakfast and lunch)
a
0.2 and 0.5g (dry
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Duplicate meals
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Sample
1
30
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85-145
9.0
145-180
4.0
180
15.0
180-30
25.0
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concentrated H2O2 (35%)and 4.0 mL of H2O
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a: inicial; b: final; c: 100% power; d: pression, psi; e: ventilation; TMAH: tetramethylammonium hydroxide; GCMS: gas chromatography–mass spectrometry; ICP-MS: inductively coupled plasma mass spectrometry; CV AAS:
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cold vapor atomic absorption spectrometry; FIAS-CV-AAS: flow injection analysis system cold vapor atomic
absorption spectrometry; AFS: cold vapor atomic fluorescence spectrometry
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[1] R. Cornelis, J.A. Caruso, H. Crews, K.G. Heumann (Eds.), Handbook of Elemental
Speciation, Handbook of Elemental Speciation II: Species in the Environment, Food, Medicine
MA
and Occupational Health. John Wiley & Sons, Chichester, England, 2005.
[2] S. Clemens, M. Monperrus, O.F.X. Donard, D. Amouroux, T. Guerin, Mercury speciation in
TE
D
seafood using isotope dilution analysis: A review, Talanta, 89 (2012) 12-20.
[3] L. Carrasco, E. Vassileva, Determination of methylmercury in marine biota samples:
CE
P
Method validation, Talanta, 122 (2014) 106-114.
[4] T.F. Shen, Q.L. Yue, X.X. Jiang, L. Wang, S.L. Xu, H.B. Li, X.H. Gu, S.Q. Zhang, J.F. Liu, A
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reusable and sensitive biosensor for total mercury in canned fish based on fluorescence
polarization, Talanta, 117 (2013) 81-86.
[5] R.M. de Jesus, L.O.B. Silva, J.T. Castro, A.D.A. Neto, R.M. de Jesus, Sergio L.C. Ferreira,
Determination of mercury in phosphate fertilizers by cold vapor atomic absorption
spectrometry, Talanta 16 (2013) 293–297.
[6] X. Feng, P. Li, G. Qiu, S. Wang, G. Li, L. Shang, B. Meng, H. Jiang, W. Bai, Z. Li, X. Fu, Human
exposure to methylmercury through rice intake in mercury mining areas, Guizhou province,
China, Environ. Sci. Technol. 42 (2008) 326-32.
31
ACCEPTED MANUSCRIPT
[7] G. Qiu, X. Feng, P. Li, S. Wang, G. Li, L. Shang, X. Fu, Methylmercury accumulation in rice
(Oryza sativa L.) grown at abandoned mercury mines in Guizhou, China, J. Agric. Food Chem,
IP
T
56 (2008) 2465-2468.
[8] H. Zhang, D.M. Wang, J.L. Zhang, X.H. Shang, Y.F. Zhao, Y.N. Wu, Total mercury in milled
SC
R
rice and brown rice from China and health risk evaluation, Food Addit. Contam. B, 7 (2014)
141-146.
NU
[9] L.O.B. Silva, D.G. da Silva, D.J. Leao, G.D. Matos, S.L.C. Ferreira, Slurry sampling for the
determination of mercury in rice using cold vapor atomic absorption spectrometry, Food.
MA
Anal. Method. 5 (2012) 1289-1295.
[10] FAO/WHO Expert Committee on Food Additives. Evaluation of certain food additives
D
and contaminants: sixty-first report of the joint FAO/WHO expert committee on food
TE
additives. Ed. World Health Organization. V. 61. World Health Organization, 2004.
CE
P
[11] H. Matusiewicz, R.E. Sturgeon, Chemical vapor generation with slurry sampling: a review
of applications to atomic and mass spectrometry, Appl. Spectrosc. Rev. 47 (2012) 41-82.
AC
[12] W. Maher, F. Krikowa, M. Ellwood, S. Foster, R. Jagtap, G. Raber, Overview of
hyphenated techniques using an ICP-MS detector with an emphasis on extraction techniques
for measurement of metalloids by HPLC-ICPMS, Microchem. J. 105 (2012) 15-31 SI.
[13] Z. Long, C. Chen, X.D. Hou, C.B. Zheng, Recent Advance of Hydride Generation-Analytical
Atomic Spectrometry: Part II-Analysis of Real Samples, Appl. Spectrosc. Rev. 47 (2012) 495517.
[14] M. Slachcinski, Recent Achievements in Sample Introduction Systems for Use in
Chemical Vapor Generation Plasma Optical Emission and Mass Spectrometry: From Macroto Microanalytics, Appl. Spectrosc. Rev., 49 (2014) 271-321.
32
ACCEPTED MANUSCRIPT
[15] A. Ohki, M. Taira, S. Hirakawa, K. Haraguchi, F. Kanechika, T. Nakajima, H. Takanashi,
T
Determination of mercury in various coals from different countries by heat-vaporization
IP
atomic absorption spectrometry: Influence of particle size distribution of coal, Microchem.
J., 114 (2014) 119-124
SC
R
[16] E. Stanisz, J. Werner, H. Matusiewicz, Task specific ionic liquid-coated PTFE tube for
solid-phase microextraction prior to chemical and photo-induced mercury cold vapour
NU
generation, Microchem. J., 114 (2014) 229-237
[17] L.B. Escudero, R.A. Olsina, R.G. Wuilloud, Polymer-supported ionic liquid solid phase
MA
extraction for trace inorganic and organic mercury determination in water samples by flow
injection-cold vapor atomic absorption spectrometry, Talanta 116 (2013) 133-140.
D
[18] P. Pohl, I.J. Zapata, E. Voges, N.H. Bings, J.A.C. Broekaert, Comparison of the cold vapor
TE
generation using NaBH4 and SnCl2 as reducing agents and atomic emission spectrometry for
the determination of Hg with a microstrip microwave induced argon plasma exiting from the
CE
P
wafer, Microchim. Acta, 161 (2008) 175-184
[19] N. Bansal, J. Vaughan, A. Boullemant, T. Leong, Determination of total mercury in
AC
bauxite and bauxite residue by flow injection cold vapour atomic absorption spectrometry,
Microchem. J., 113 (2014) 36-41
[20] C.F. Harrington, S.A. Merson, T.M.D. D' Silva, Method to reduce the memory effect of
mercury in the analysis of fish tissue using inductively coupled plasma mass spectrometry,
Anal. Chim. Acta, 505 (2004) 247-254
[21] A. Woller, H. Garraud, F. Martin, O.F.X. Donard, P. Fodor, Determination of total
mercury in sediments by microwave-assisted digestion-flow injection-inductively coupled
plasma mass spectrometry, J. Anal. Atom. Spectrom., 12 (1997) 53-56
33
ACCEPTED MANUSCRIPT
[22] J. Allibone, E. Fatemian, P.J. Walker, Determination of mercury in potable water by ICP-
T
MS using gold as a stabilising agent, J. Anal. Atom. Spectrom., 14 (1999) 235-239
IP
[23] R. Liu, M. Xu, Z. Shi, J. Zhang, Y. Gao, L. Yang, Determination of total mercury in
biological tissue by isotope dilution ICP-MS after UV photochemical vapor generation,
SC
R
Talanta, 117 (2013) 371-375.
[24] H. Pietila, P. Peramaki, J. Piispanen, L. Majuri, M. Starr, T. Nieminen, M. Kantola, L.
NU
Ukonmaanaho, Determination of methylmercury in humic-rich natural water samples using
N2-distillation with isotope dilution and on-line purge and trap GC-ICP-MS, Microchem. J.,
MA
112 (2014) 113-118.
[25] E. Vassileva, I. Wysocka, M. Betti, Reference measurements for cadmium, copper,
D
mercury, lead, zinc and methylmercury mass fractions in scallop sample by isotope dilution
TE
inductively coupled plasma mass spectrometry, Microchem. J., 116 (2014) 197-205.
CE
P
[26] H. Pietila, P. Peramaki, J. Piispanen, L. Majuri, M. Starr, T. Nieminen, M. Kantola, L.
Ukonmaanaho, Determination of methyl mercury in humic-rich natural water samples using
N-2-distillation with isotope dilution and on-line purge and trap GC-ICP-MS, Microchem. J.,
AC
112 (2014) 113-118
[27] C.P. Braga, A.C. Bittarello, C.C.F. Padilha, A.L. Leite, P.M. Moraes, M.A.R. Buzalaf, L.F.
Zara, P.M. Padilha, Mercury fractionation in dourada (Brachyplatystoma rousseauxii) of the
Madeira River in Brazil using metalloproteomic strategies, Talanta, 132 (2015) 239–244.
[28] A. de Jesus, R.E. Sturgeon, J.X. Liu, M.M. Silva, Determination of mercury in gasoline by
photochemical vapor generation coupled to graphite furnace atomic absorption
spectrometry, Microchem. J., 117 (2014) 100-105
34
ACCEPTED MANUSCRIPT
[29] D. Martín-Yerga, M.B. González-García, A. Costa-García, Electrochemical determination
T
of mercury: A review, Talanta, 116 (2013) 1091-1104.
IP
[30] E. Witkowska, K. Szczepaniak, M. Biziuk, Some applications of neutron activation
SC
R
analysis: A review, J. Radioanal. Nucl. Ch., 265 (2005) 141 – 150.
[31] R.R. Greenberg, P. Bode, E.A.D.N. Fernandes, Neutron activation analysis: A primary
NU
method of measurement, Spectrochim. Acta, B 66 (2011) 193 – 241.
[32] S.J.M. Butala, L.P. Scanlan, S.N. Chaudhuri, A detailed study of thermal decomposition,
MA
amalgamation/atomic absorption spectrophotometry methodology for the quantitative
analysis of mercury in fish and hair, J. Food Protect. 69 (2006) 2720-2728.
D
[33] M.J. da Silva, A.P.S. Paim, M.F. Pimentel, M.L. Cervera, M. de la Guardia, Determination
TE
of total mercury in nuts at ultratrace level, Anal. Chim. Acta, 838 (2014) 13-19.
CE
P
[34] I. Ipolyi, P. Massanisso, S. Sposato, P. Fodor, R. Morabito, Concentration levels of total
and methylmercury in mussel samples collected along the coasts of Sardinia Island (Italy),
AC
Anal. Chim. Acta, 505 (2004) 145–151.
[35] A. Ikem, N.O. Egiebor, Assessment of trace elements in canned fishes (mackerel, tuna,
salmon, sardines and herrings) marketed in Georgia and Alabama (United States of America),
J. Food Compos. Anal., 18 (2005) 771-787.
[36] G. Carbonell, J.C. Bravo, C. Fernandez, J.V. Tarazona, A New Method for Total Mercury
and Methyl Mercury Analysis in Muscle of Seawater Fish, Bull. Environ. Contam. Toxicol. 83
(2009) 210-213.
35
ACCEPTED MANUSCRIPT
[37] C.F. Tsaiab, D.Y.C. Shiha, Y.T. Shyub, Survey of total mercury in foods from Taiwan
containing red mould rice (Monascus) using a direct mercury analyser (DMA), Food Addit.
IP
T
Contam. B, 3 (2010) 84-89.
[38] C. Martins, E. Vasco, E. Paixao, P. Alvito, Total mercury in infant food, occurrence and
SC
R
exposure assessment in Portugal, Food Addit. Contam., B 6 (2013) 151-157.
[39] D.P. Torres, M.B. Martins-Teixeira, Method development for the control determination
NU
of mercury in seafood by solid-sampling thermal decomposition amalgamation atomic
MA
absorption spectrometry (TDA AAS), Food Addit. Contam., B 29 (2012) 625-632.
[40] H.P. Vieira, C.C. Nascentes, C.C. Windmoller, Development and comparison of two
analytical methods to quantify the mercury content in honey, J. Food Compos. Anal., 34
TE
D
(2014) 1-6.
[41] S.L.C. Ferreira, M. Miro, E.G.P. da Silva, G.D. Matos, P.S. dos Reis, G.C. Brandao, W.N.L.
CE
P
dos Santos, A.T. Duarte, M.G.R. Vale, R.G.O. Araujo, Slurry sampling—An analytical strategy
for the determination of metals and metalloids by spectroanalytical techniques, Appl.
AC
Spectrosc. Rev., 45 (2010) 44 – 62.
[42] S.R. Segade, J.F. Tyson, Determination of methylmercury and inorganic mercury in water
samples by slurry sampling cold vapor atomic absorption spectrometry in a flow injection
system after preconcentration on silica C18 modified, Talanta, 71 (2007) 1696-1702.
[43] M.L. Lin, Determination of As, Cd, Hg and Pb in herbs using slurry sampling
electrothermal vaporization inductively coupled plasma mass spectrometry, Food Chem.,
141 (2013) 2158-2162.
36
ACCEPTED MANUSCRIPT
[44] Y.Z. Yi, S.J. Jiang, A.C. Sahayam, Palladium nanoparticles as the modifier for the
determination of Zn, As, Cd, Sb, Hg and Pb in biological samples by ultrasonic slurry sampling
T
electrothermal vaporization inductively coupled plasma mass spectrometry. J. Anal. At.
IP
Spectrom., 27 (2012) 426-431.
SC
R
[45] S.Y. Huang, S.J. Jiang, 8-Hydroxyquinoline-5-sulfonic acid as the modifier for the
determination of trace elements in cereals by slurry sampling electrothermal vaporization
NU
ICP-MS, Anal. Methods., 2 (2010) 1310-1315.
[46] P.C. Li, S.J. Jiang, Electrothermal vaporization inductively coupled plasma-mass
MA
spectrometry for the determination of Cr, Cu, Cd, Hg and Pb in rice flour, Anal. Chim. Acta,
495 (2003) 143-150.
D
[47] F.Y. Chen, S.J. Jiang, Slurry Sampling Flow Injection Chemical Vapor Generation
TE
Inductively Coupled Plasma Mass Spectrometry for the Determination of As, Cd, and Hg in
CE
P
Cereals, J. Agr. Food Chem., 57 (2009) 6564-6569.
[48] P. Cava-Montesinos, E. Rodenes-Torralba, A. Morales-Rubio, M.L. Cervera, M. de la
Guardia, Cold vapour atomic fluorescence determination of mercury in milk by slurry
AC
sampling using multicommutation, Anal. Chim. Acta, 506 (2004) 145-153.
[49] S.R. Segade, J.F. Tyson, Evaluation of two flow injection systems for mercury speciation
analysis in fish tissue samples by slurry sampling cold vapor atomic absorption spectrometry
J. Anal. At. Spectrom., 18 (2003) 268-273.
[50] S.F. Chen, S.J. Jiang, Determination of arsenic, selenium and mercury in fish samples by
slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry,
J. Anal. At. Spectrom., 13 (1998) 673-677.
[51] J. Sysalova, J. Kucera, M. Fikrle, B. Drtinova, Determination of the total mercury in
contaminated soils by direct solid sampling atomic absorption spectrometry using an AMA37
ACCEPTED MANUSCRIPT
254 device and radiochemical neutron activation analysis, Microchem. J., 110 (2013) 691-
T
694.
IP
[52] H. Zelinkova, R. Cervenka, J. Komarek, Stabilizing Agents for Calibration in the
Determination of Mercury Using Solid Sampling Electrothermal Atomic Absorption
SC
R
Spectrometry, Sci. World J. Article ID 439875 (2012) 1-7.
[53] R.G.O. Araujo, F. Vignola, I.N.B. Castilho, D.L.G. Borges, B. Welz, M.G.R. Vale, P.
NU
Smichowski, S.L.C. Ferreira, H. Becker-Ross, Determination of mercury in airborne particulate
matter collected on glass fiber filters using high-resolution continuum source graphite
MA
furnace atomic absorption spectrometry and direct solid sampling, Spectrochim. Acta B, 66
(2011) 378-382.
D
[54] M. Resano, J. Briceno, M.A. Belarra, Direct determination of Hg in polymers by solid
TE
sampling-graphite furnace atomic absorption spectrometry: A comparison of the
performance of line source and continuum source instrumentation, Spectrochim. Acta B, 64
CE
P
(2009) 520-529 SI.
[55] A.F. da Silva, F.G. Lepri, D.L.G. Borges, B. Welz, A.J. Curtius, U. Heitmann, Determination
AC
of mercury in biological samples using solid sampling high-resolution continuum source
electrothermal atomization atomic absorption spectrometry with calibration against
aqueous standards, J. Anal. At. Spectrom., 21 (2006) 1321-1326.
[56] M. Resano, I. Gelaude, R. Dams, F. Vanhaecke, Solid sampling–electrothermal
vaporization–inductively coupled plasma mass spectrometry for the direct determination of
Hg in different materials using isotope dilution with a gaseous phase for calibration,
Spectrochim. Acta B, 60 (2005) 319-326.
38
ACCEPTED MANUSCRIPT
[57] K.H. Grobecker, A. Detcheva, Validation of mercury determination by solid sampling
Zeeman atomic absorption spectrometry and a specially designed furnace, Talanta, 70
IP
T
(2006) 962-965.
[58] A. Detcheva K.H. Grobecker, Determination of Hg, Cd, Mn, Pb and Sn in seafood by solid
SC
R
sampling Zeeman atomic absorption spectrometry, Spectrochim. Acta B, 61 (2006) 454-459.
[59] J. Naozuka C.S. Nomura, Total determination and direct chemical speciation of Hg in fish
NU
by solid sampling GF AAS, J. Anal. At. Spectrom., 26 (2011) 2257-2262.
MA
[60] S.C. Foo, T.C. Tan, Elements in the hair of South-east Asian islanders, Sci. Total Envirom.,
209 (1998) 185-192.
D
[61] K. Araujo, M. Colina, R. Mazurek, J. Delgado, H. Ledo, E. Gutierrez, L. Herrera, Mercury
TE
determination by CV-AAS in wastewater and sewage sludge from a stabilization pond
CE
P
system, Fresenius J. Anal. Chem., 355 (1996) 319-320.
[62] S.L.C. Ferreira, L.O.B. Silva, F.A. de Santana, M.M.S. Junior, G.D. Matos, W.N.L. dos
Santos, A review of reflux systems using cold finger for sample preparation in the
AC
determination of volatile elements, Microchem. J., 106 (2013) 307-310.
[63] R.M. de Jesus, M.M.S. Junior, G.D. Matos, A.M.P. dos Santos, S.L.C. Ferreira, Validation
of a digestion system using a digester block/cold finger system for the determination of lead
in vegetable foods by electrothermal atomic absorption spectrometry, J. AOAC Int., 94
(2011) 942-946.
[64] M.B. Dessuy, R.M. de Jesus, G.C. Brandao, S.L.C. Ferreira, M.G.R. Vale, B. Welz, Food
Addit. Contam. A, 30 (2013) 202-207.
39
ACCEPTED MANUSCRIPT
[65] E.V. Silva, S.M. Sella, E.C. Spinola, I.R. Santos, W. Machado, L.D. Lacerda, Mercury, zinc,
manganese, and iron accumulation in leachate pond sediments from a refuse tip in
IP
T
Southeastern Brazil, Microchem. J., 82 (2006) 196-200.
[66] E.Q. Oreste, R.M. de Oliveira, A.M. Nunes, M.A. Vieira, A.S. Ribeiro, Sample preparation
SC
R
methods for determination of Cd, Pb and Sn in meat samples by GFAAS: use of acid digestion
associated with a cold finger apparatus versus solubilization methods, Anal. Methods, 5
NU
(2013) 1590-1595.
[67] A.C.D. Pinheiro, M.T. Lisboa, A.S. Ribeiro, A.M. Nunes, A. Yamasaki, Evaluation of rice
MA
sample mineralization using a reflux system for determination of Cu, Fe, Mn and Zn by FAAS,
Quim. Nova, 37 (2014) 6-9.
D
[68] E.V. Silva-Filho, S.M. Sella, E.C. Spinola, I.R. Santos, W. Machado, L.D. Lacerda, Mercury,
TE
zinc, manganese, and iron accumulation in leachate pond sediments from a refuse tip in
CE
P
Southeastern Brazil, Microchem. J., 82 (2006) 196-200.
[69] E.Q. Oreste, A. de Jesus, R.M. de Oliveira, M.M. da Silva, M.A. Vieira, A.S. Ribeiro, New
design of cold finger for sample preparation in open system: Determination of Hg in
AC
biological samples by CV-AAS, Microchem. J., 109 (2013) 5-9 SI.
[70] F.V.M. Pontes, M.C. Carneiro, D.S Vaitsman, M.I.C. Monteiro, A.A. Neto, M.L.B. Tristao,
M.F. Guerrante, Comparative study of sample decomposition methods for the determination
of total Hg in crude oil and related products, Fuel Process. Technol., 106 (2013) 122-126.
[71]. L.H. Reyes, J.L.G. Mar, A. Hernández-Ramírez, J.M. Peralta-Hernández, J.M.A. Barbosa,
H.M.S. Kingston, Microwave assited extraction for mercury speciation analysis. Microchim.
Acta, 172 (2011) 3-14.
40
ACCEPTED MANUSCRIPT
[72]. Y. Gao, Z.M. Shi, Z. Long, P. Wu, C.B. Zheng, X.D. Hou, Determination and speciation of
mercury in environmental and biological samples by analytical atomic spectrometry,
IP
T
Microchem. J., 103 (2012) 1-14.
[73] S.S. Chen, S.S. Chou, D.F. Hwang, Determination of methylmercury in fish using focused
SC
R
microwave digestion following by Cu2+ addition, sodium tetrapropylborate derivatization, nheptane extraction, and gas chromatography-mass spectrometry, J. Chromatogr. A, 1024
NU
(2004) 209 - 215.
[74] M. Tuzen, Toxic and essential trace elemental contents in fish species from the Black
MA
Sea, Turkey, Food Chem. Toxicol., 47 (2009) 1785 - 1790
[75] L.A. de Paz, A. Alegria, R. Barbera, R. Farre, M.J. Lagarda, Determination of mercury in
D
dry fish samples by microwave digestion and flow injection analysis system cold vapor
TE
atomic absorption spectrometry, Food Chem., 58 (1997) 169-172.
CE
P
[76] S.C. Hight, J. Cheng, Determination of total mercury in seafood by cold vapor-atomic
absorption spectroscopy (CVAAS) after microwave decomposition, Food Chem., 91 (2005)
AC
557–570.
[77] L.R. Drennan-Harris, S. Wongwilawan, J.F. Tyson, Trace determination of total mercury
in rice by conventional inductively coupled plasma mass spectrometry, J. Anal. At.
Spectrom., 28 (2013) 259-265.
[78]. L. Carrasco, E. Vassileva, Determination of methylmercury in marine biota samples:
Method validation, Talanta, 122 (2014) 106 - 114.
[79] M.A. Morgano, L.C. Rabonato, R.F. Milani, L. Miyagusku, K.D. Quintaes, As, Cd, Cr, Pb
and Hg in seafood species used for sashimi and evaluation of dietary exposure, Food control,
36 (2014) 24 – 29.
41
ACCEPTED MANUSCRIPT
[80] M. Kosanovic, A. Adem, M. Jokanovic, Y. M. Abdulrazzaq, Simultaneous Determination
of Cadmium, Mercury, Lead, Arsenic, Copper, and Zinc in Human Breast Milk by
IP
T
ICP‐MS/Microwave Digestion, Anal. Lett., 41 (2008) 406 – 416.
SC
R
[81] L.R. da Cunha, T.H.M. da Costa, E.D. Caldas, Mercury Concentration in Breast Milk and
Infant Exposure Assessment During the First 90 Days of Lactation in a Midwestern Region of
NU
Brazil, Biol. Trace Elem. Res., 151 (2013) 30 – 37.
[82] R. Koplik, I. Klimesova, K. Malisova, O. Mestek, Determination of Mercury Species in
MA
Foodstuffs using LC-ICP-MS: the Applicability and Limitations of the Method, Czech. J. Food
Sci., 32 (2014) 249 -259.
[83] D.L. Qin, Dongli, Z.X. Chen, H.T. Wang, J.W. Zhao, Z.B. Mou, Determination of Total
D
Mercury in Fish from Amur and Ussuri River of China by Microwave Digestion-ICP/MS
TE
Method, Asian J. Chem. , 25 (2013) 3665 - 3667.
CE
P
[84] Y.Q. Zhao, J.P. Zheng, L. Fang, Q. Lin, Y.N. Wu, Z.M. Xue, F.F. Fu, Speciation analysis of
mercury in natural water and fish samples by using capillary electrophoresis-inductively
AC
coupled plasma mass spectrometry, Talanta, 89 (2012) 280 - 285.
[85] L.H. Reyes, G.M.M. Rahman, T. Fahrenholz, H.M.S. Kingston, Comparison of methods
with respect to efficiencies, recoveries, and quantitation of mercury species interconversions
in food demonstrated using tuna fish, Anal. Bioanal. Chem., 390 (2008) 2123-2132.
[86]. L.H. Reyes, G.M.M. Rahman, H.M.S. Kingston, Robust microwave-assisted extraction
protocol for determination of total mercury and methylmercury in fish tissues, Anal. Chim.
Acta, 631 (2009) 121-128.
42
ACCEPTED MANUSCRIPT
[87] O.A. Tyutyunnik, M.L. Getsina, E.S. Toropchenova, I.V. Kubrakova, Microwave
preparation of natural samples to the determination of mercury and other toxic elements by
IP
T
atomic absorption spectrometry, J. Anal. Chem., 68 (2013) 377-385
[88] L. Noel, J.C. Leblanc, T. Guerin, Determination of several elements in duplicate meals
SC
R
from catering establishments using closed vessel microwave digestion with inductively
coupled plasma mass spectrometry detection: estimation of daily dietary intake, Food Addit.
NU
Contam., 20 (2003) 44-56
[89] L. Noel, V. Dufailly, N. Lemahieu, C. Vastel, T. Guerin, Simultaneous analysis of cadmium,
MA
lead, mercury, and arsenic content in foodstuffs of animal origin by inductively coupled
plasma/mass spectrometry after closed vessel microwave digestion: Method validation, J.
D
AOAC Int., 88 (2005) 1811-1821.
TE
[90] M. Kim, Mercury, cadmium and arsenic contents of calcium dietary supplements, Food
CE
P
Addit. Contam., 21 (2004) 763-767
[91] L.R. da Cunha, T.H.M. da Costa, E.D. Caldas, Mercury Concentration in Breast Milk and
Infant Exposure Assessment During the First 90 Days of Lactation in a Midwestern Region of
AC
Brazil, Biol. Trace Elem. Res., 151 (2013) 30-37.
[92] J. Djedjibegovic, T. Larssen, A. Skrbo, A. Marjanovic, M. Sober, Contents of cadmium,
copper, mercury and lead in fish from the Neretva river (Bosnia and Herzegovina)
determined by inductively coupled plasma mass spectrometry (ICP-MS), Food Chem., 131
(2012) 469-476.
[93] D.G. da Silva, L.A. Portugal, A.M. Serra, S.L.C. Ferreira, V. Cerda, Determination of
mercury in rice by MSFIA and cold vapour atomic fluorescence spectrometry, Food Chem.,
137 (2013) 159-163.
43
ACCEPTED MANUSCRIPT
[94] M.J. da Silva, A.P.S. Palm, M.F. Pimentel, M.L. Cervera, M. de la Guardia, Determination
of mercury in rice by cold vapor atomic fluorescence spectrometry after microwave-assisted
IP
T
digestion, Anal. Chim. Acta, 667 (2010) 43-48.
[95] S. Landi, F. Fagioli, C. Locatelli, R. Vecchietti, Digestion method for the determination of
SC
R
mercury in vegetable matrices by cold vapour atomic absorption spectrometry, Analyst, 115
(1990) 173 - 177.
NU
[96]S. Landi, F. Fagioli, C. Locatelli, Determination of total mercury in seafood and other
MA
protein-rich products, J. AOAC Int., 75 (1992) 1023 - 1028.
[97] D. Fabbri, G. Gabbianelli, C. Locatelli, D. Lubrano, C. Trombini, I. Vassura, Distribution of
TE
Soil Pol, 129 (2001) 143 – 153.
D
mercury and other heavy metals in core sediments of the northern Adriatic sea, Water Air
[98] C. Locatelli, D. Melucci, Voltammetric method for ultra-trace determination of total
CE
P
mercury and toxic metals in vegetables. Comparison with spectroscopy, Cent. Eur. J. Chem.
11 (2013) 790 - 800.
AC
[99] D. Melucci, M. Locatelli, C. Locatelli, Trace level voltammetric determination of heavy
metals and total mercury in tea matrices (Camellia sinensis), Food Chem. Toxicol. 62 (2013)
901 – 907.
[100] C. Locatelli, D. Melucci, Voltammetric determination of ultra-trace total mercury and
toxic metals in meals, Food Chem., 130 (2012) 460 – 466.
[101] C. Locatelli, Mutual interference problems in the simultaneous voltammetric
determination of trace total mercury(II) in presence of copper(II) at gold electrode.
Applications to environmental matrices, Anal. Methods, 2 (2010) 1784 – 1791.
44
ACCEPTED MANUSCRIPT
[102] D. Melucci, S. Montalbani, C. Locatelli, Optimization of analytical procedures for the
simultaneous voltammetric determination of total Hg(II) in presence of Cu(II) in
IP
T
environmental matrices, Cent. Eur. J. Chem., 10 (2012) 267 - 276.
[103] V. Singh, A.N. Garg, Availability of essential trace elements in Indian cereals, vegetables
SC
R
and spices using INAA and the contribution of spices to daily dietary intake, Food Chem., 94
(2006) 81 - 89.
NU
[104] A. Rizzo, M. Arcagni, M.A. Arribere, D. Bubach, S. Ribeiro Guevara, Mercury in the
biotic compartments of Northwest Patagonia lakes, Argentina, Chemosphere, 84 (2011) 70 –
MA
79.
[105] D.L. Anderson, Effect of L-cysteine on drying and neutron irradiation loss of Hg, Se, As,
TE
D
and Br from fish tissue, J. Food Compos. Anal., 28 (2012) 88 – 98.
[106] J.M.R. Antoine, L.A.H. Fung, C. N. Grant, H.T. Dennis, G.C. Lalor, Dietary intake of
(2012) 111 – 121.
CE
P
minerals and trace elements in rice on the Jamaican market, J. Food Compos. Anal., 26
AC
[107] C.C. Muller, A.L.H. Muller, C. Pirola, F.A. Duarte, E.M.M. Flores, E.I. Muller, Feasibility
of nut digestion using single reaction chamber for further trace element determination by
ICP-OES, Microchem. J., 116 (2014) 255 - 260.
[108] J.S. Barin, J.S.F. Pereira, P.A. Mello, C.L. Knorr, D.P. Moraes, M.F. Mesko, J.A. Nobrega,
M.G.A. Korn, E.M.M. Flores, Focused microwave-induced combustion for digestion of
botanical samples and metals determination by ICP OES and ICP-MS, Talanta, 94 (2012) 308314.
45
ACCEPTED MANUSCRIPT
[109] L. Schmidt, C.A. Bizzi, F.A. Duarte, V.L. Dressler, E.M.M. Flores, Evaluation of drying
conditions of fish tissues for inorganic mercury and methylmercury speciation analysis,
IP
T
Microchem. J., 108 (2013) 53 – 59.
[110] R.S. Picoloto, H. Wiltsche, G. Knapp, J.S. Barin, E.M.M. Flores, Mercury determination
SC
R
in soil by CVG-ICP-MS after volatilization using microwave-induced combustion, Anal.
Methods, 4 (2012) 630-636.
NU
[111] F.G. Antes, F.A. Duarte, M.F. Mesko, M. A. G. Nunes, V. A. Pereira, E. I. Mueller, V. L.
Dressler, E. M.M. Flores, Determination of toxic elements in coal by ICP-MS after digestion
MA
using microwave-induced combustion, Talanta, 83 (2010) 364 - 369.
[112] L. Schmidt, C.A. Bizzi, F.A. Duarte, V.L. Dressler, E.M.M. Flores, Evaluation of drying
TE
Microchem j., 108 (2013) 53 - 59.
D
conditions of fish tissues for inorganic mercury and methylmercury speciation analysis,
CE
P
[113] M.H. Mashhadizadeh, M. Amoli-Diva, M.R. Shapouri, H. Afruzi, Solid phase extraction
of trace amounts of silver, cadmium, copper, mercury, and lead in various food samples
based on ethylene glycol bis-mercaptoacetate modified 3-(trimethoxysilyl)-1-propanethiol
AC
coated Fe3O4 nanoparticles, Food Chem., 151 (2014) 300 - 305.
[114] V.A. Lemos, L.O. dos Santos, A new method for preconcentration and determination of
mercury in fish, shellfish and saliva by cold vapour atomic absorption spectrometry, Food
Chem., 149 (2014) 203 - 207.
[115] L. Adlnasab, H. Ebrahimzadeh, A.A. Asgharinezhad, M.N. Aghdam, A. Dehghani, S.
Esmaeilpour, A Preconcentration Procedure for Determination of Ultra-Trace Mercury (II) in
Environmental Samples Employing Continuous-Flow Cold Vapor Atomic Absorption
Spectrometry, Food Anal. Method, 7 (2014) 616 - 628.
46
ACCEPTED MANUSCRIPT
[116] M. Hossien-poor-Zaryabi, M. Chamsaz, T. Heidari, M.H.A. Zavar, M. Behbahani, M.
Salarian, Application of Dispersive Liquid-Liquid Micro-extraction Using Mean Centering of
T
Ratio Spectra Method for Trace Determination of Mercury in Food and Environmental
IP
Samples, Food Anal. Method, 7 (2014) 352 - 359.
SC
R
[117] P.M. Moraes, F.A. Santos, B. Cavecci, C.C.F. Padilha, J.C.S. Vieira, P.S. Roldan, P.D.M.
Padilha, GFAAS determination of mercury in muscle samples of fish from Amazon, Brazil,
NU
Food Chem., 141 (2013) 2614 - 2617.
[118] A.Q. Shah, T.G. Kazi, J.A. Baig, H.I. Afridi, M.B. Arain, Simultaneously determination of
MA
methyl and inorganic mercury in fish species by cold vapour generation atomic absorption
spectrometry, Food Chem., 134 (2012) 2345 - 2349.
D
[119] M. Ruiz-de-Cenzano, A. Rochina-Marco, M. Luisa Cervera, M. de la Guardia, Speciation
TE
of methylmercury in market seafood by thermal degradation, amalgamation and atomic
CE
P
absorption spectroscopy, Ecotox. Environ. Safe., 107 (2014) 90 - 96.
[120] L.O. Dos Santos, V.A. Lemos, Development of an On-line Preconcentration System for
AC
Determination of Mercury in Environmental Samples, Water air soil poll., 225 (2014) 2086.
[121] M.A. Goudarzi, P. Parsaei, F. Nayebpour, E. Rahimi, Determination of mercury,
cadmium and lead in human milk in Iran, Toxicol. Ind. Health, 29 (2013) 820 – 823.
[122] V. Romero, I. Costas-Mora, I. Lavilla, C. Bendicho, Cold vapor-solid phase
microextraction using amalgamation in different Pd-based substrates combined with direct
thermal desorption in a modified absorption cell for the determination of Hg by atomic
absorption spectrometry, Spectrochim Acta B, 66 (2011) 156-162
[123] X. Yuan, G. Yang, Y. Ding, X.M. Li, X.F. Zhan, Z.J. Zhao, Y.X. Duan, An effective analytical
system based on a pulsed direct current microplasma source for ultra-trace mercury
47
ACCEPTED MANUSCRIPT
determination using gold amalgamation cold vapor atomic emission spectrometry,
Spectrochim Acta B, 93 (2014) 1-7
T
[124] P. Rivaro, C. Ianni, F. Soggia, R. Frache, Mercury speciation in environmental samples
IP
by cold vapour atomic absorption spectrometry with in situ preconcentration on a gold trap,
SC
R
Microchim. Acta, 158 (2007) 345-352
[125] E.L.M. Flores, J.N.G. Paniz, E.M.M. Flores, D. Pozebon, V.L. Dressler, Mercury
NU
Speciation in Urban Landfill Leachate by Cold Vapor Generation Atomic Absorption
Spectrometry using Ion Exchange and Amalgamation, J Brazil Chem Soc, 20 (2009) 1659-
MA
1666
[126] J.V. Cizdziel, T.A. Hinners, E.M. Heithmar, Determination of total mercury in fish tissues
D
using combustion atomic absorption spectrometry with gold amalgamation, Water Air Soil
TE
Poll., 135 (2002) 355-370
CE
P
[127] T. Frentiu, A.I. Mihaltan, E. Darvasi, M. Ponta, C. Roman, M. Frentiu, A novel analytical
system with a capacitively coupled plasma microtorch and a gold filament microcollector for
the determination of total Hg in water by cold vapour atomic emission spectrometry, J. Anal.
AC
Atom. Spectrom., 27 (2012) 1753-1760
[128] S. Halbach, G. Welzl, In-situ measurements of low-level mercury vapor exposure from
dental amalgam with Zeeman atomic absorption spectroscopy, Toxicol. Mech. Method, 14
(2004) 293-299
[129] K. Leopold, M. Foulkes, P.I. Worsfold, Preconcentration techniques for the
determination of mercury species in natural waters, Trac-Trends in Analytical Chemistry, 28
(2009) 426 - 435
48
ACCEPTED MANUSCRIPT
[130] A.M. Carro, M.C. Mejuto, Application of chromatographic and electrophoretic
methodology to the speciation of organomercury compounds in food analysis, J.
IP
T
Chromatogr. A, 882 (2000) 283 - 307.
[131] V.L. Dressler, C.M.M. Santos, F.G. Antes, F.R.S. Bentlin, D. Pozebon, E.M.M. Flores,
SC
R
Total Mercury, Inorganic Mercury and Methyl Mercury Determination in Red Wine, Food
Anal. Meth., 5 (2012) 505 - 511.
NU
[132] M. Ruiz-de-Cenzano, A. Rochina-Marco, M.L. Cervera, M. de la Guardia, Speciation of
methylmercury in market seafood by thermal degradation, amalgamation and atomic
MA
absorption spectroscopy, Ecotox. Environ. Safe., 107 (2014) 90 - 96.
[133] F.A. Duarte, C.A. Bizzi, F.G. Antes, V.L. Dressler, E.M.D. Flores, Organic, inorganic and
D
total mercury determination in fish by chemical vapor generation with collection on a gold
TE
gauze and electrothermal atomic absorption spectrometry, Spectrochim. Acta B, 64 (2009)
CE
P
513 - 519.
[134] L. Schmidt, C.A. Bizzi, F.A. Duarte, V.L. Dressler, E.M.M. Flores, Evaluation of drying
conditions of fish tissues for inorganic mercury and methylmercury speciation analysis,
AC
Microchem. J., 108 (2013) 53 - 59.
[135] G.L. Qiu, X.B. Feng, P. Li, S.F. Wang, G.H. Li, L.H. Shang, X.W. Fu, Methylmercury
accumulation in rice (Oryza sativa L.) grown at abandoned mercury mines in Guizhou, China,
J. Agric. Food Chem., 56 (2008) 2465 - 2468.
[136] B.L. Batista, J.L., Rodrigues, S.S. de Souza, V.C.O. Souza, F. Barbosa, Mercury speciation
in seafood samples by LC-ICP-MS with a rapid ultrasound-assisted extraction procedure:
Application to the determination of mercury in Brazilian seafood samples, Food Chem., 126
(2011) 2000 - 2004.
49
ACCEPTED MANUSCRIPT
[137] M. Prodana, A. Murariu, A. Meghea, I. Demetrescu, Biomonitoring as assessment of
human exposure to heavy metals. Speciation of Hg in fish food and impact on human health,
IP
T
Mater. Res. Innov., 13 (2009) 409 - 412.
[138] T. Kuballa, E. Leonhardt, K. Schoeberl, D.W. Lachenmeier, Determination of
SC
R
methylmercury in fish and seafood using optimized digestion and derivatization followed by
gas chromatography with atomic emission detection, Eur. Food Res. Technol., 228 (2009)
NU
425 - 431.
[139] S.C. Hight, J. Cheng, Determination of methylmercury and estimation of total mercury
MA
in seafood using high performance liquid chromatography (HPLC) and inductively coupled
plasma-mass spectrometry (ICP-MS): Method development and validation, Anal. Chim. Acta,
D
567 (2006) 160 - 172.
TE
[140] A. Montero-Alvarez, M.D.F. de la Campa, A. Sanz-Medel, Mercury speciation in Cuban
commercial edible fish by HPLC-ICP-MS using the double spike isotope dilution analysis
CE
P
strategy, Int. j. Environ. An. Ch., 94 (2014) 36 - 47.
[141] Z. Huang, X.D. Pan, J.L. Han, P.G. Wu, J. Tang, Y. Tan, Determination of methylmercury
187.
AC
in marine fish from coastal areas of Zhejiang, China, Food Addit. Contam. B, 5 (2012) 182 -
50