English version
Chemical speciation in natural waters and biological fluids
Natural waters and biological fluids can be considered as multi-component solutions where a network of
interactions is established leading to the formation of chemical species with different thermodynamic
stability.
The different chemical behaviour of ions or molecules in the medium where other components are
present leads to a different quantitative distribution of species depending on the kinetics of process and
strength of interaction between the ion or molecule and the ionic medium components.
The way and the rate according to which a chemical species participates to biological and geological
processes depend on the chemical form assumed by the chemical species as a consequence of reactions
occurring in the aquatic ecosystems
Biological Processes
Bio-accumulation
Bio-availability
Bio-transformation
Toxicity
Bio-remediation
Geological Processes
Adsorption/release
Precipitation/dissolution
Mass transport
Oxidation/reduction
Complexation
The term “Chemical speciation” is generally used to assess the “distribution of a certain
chemical species (ion, molecole) under different chemical forms and oxidation states” as
consequence of various reactions and processes (electrostatic interactions, complexation,
oxidation/reduction, precipitation/dissolution) depending on both the reactivity of the
chemical species and the physico-chemical and environmental conditions of the medium
(temperature, pH, salinità, pE, oxidation, surface properties) where reactions and processes
occur.
The IUPAC commissions for Analytical and Environmental Chemistry suggested the Guide4-lines for terms
related to Chemical Speciation and element fractionation.
(Guidelines For Terms Related To Chemical Speciation And Fractionation Of Elements. Definitions, structural aspects
and methodological approaches. IUPAC Recommendations 2000. D.M. Templeton, F. Ariese, R. Cornelis, L.G.
Danielsson, H. Muntau, H. Van Leeuwen, R. Lobinski)
1. Chemical species: specific form of an element defined as to isotopic composition, electronic or
oxidation state, and/or complex or molecular structure
2. Speciation analysis: analytical activities of indentifying and/or measuring the quantities of one or
more individual chemical species in a sample
3. Speciation of an element: distribution of an element amongst defined chemical species in a system
4. Fractionation: process of classification of an analyte or a group of analytes from a certain sample
according to physical (e.g. size, solubility) or chemical (e.g. bonding, reactivity) properties
For Chemical speciation studies the following instrumental techniques can be used
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Electrochemical techniques: potentiometry (ISE-H, ISE-Me), polarography, voltammetry
Spectroscopic techniques: UV-Vis., IR, NMR, ICP-MS
Separation Techniques: HPLC, HPLC-MS
Fields of interest for Chemical Speciation studies [Refs. 1-6]
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Biogeochemical cycles of chemical compounds
Evaluating of toxicity of elements and compounds
Detoxification mechanisms
Quality control for foods
Quality control for medical and pharmaceutical products
Control of technological processes
Application for new environmental technologies and biotechnologies
Clinical analysis
● Environmental decontamination processes
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Refs:
1) Douglas M. Templeton. Biomedical aspects of trace element speciation. Fresenius J Anal Chem (1999)
363 :505–511.
2) Bernhard Michalke. Quality control and reference materials in speciation analysis. Fresenius J Anal Chem
(1999) 363 :439–445
3) Torsten Berg and Erik H. Larsen. Speciation and legislation – Where are we today and what do we need
for tomorrow? Fresenius J Anal Chem (1999) 363 :431–434
4) Graeme E. Batley, A Kevin, A. Francesconi and William A. Maher. The role of speciation in
environmental chemistry and the case for quality criteria. Environ. Chem. 2009, 6, 273–274.
5) Susan J. Fairweather-Tait. The importance of trace element speciation in nutritional sciences. Fresenius J
Anal Chem (1999) 363 :536–540
6) Pietro Apostoli. The role of element speciation in environmental and occupational medicine. Fresenius J
Anal Chem (1999) 363 :499–504
Some articles published in this topic
1)
A. Gianguzza et al. The Speciation of (CH3)2Sn2+ in electrolyte solution containing the major components
of natural waters. Aquatic Geochem., 5, pp. 381-398 (1999).
2 ) A. Gianguzza, D. Piazzese et al. Speciation of low molecular weight carboxylic ligands: protonation
constants and association with major components of seawater of oxydiacetic and citric acids. Anal.
Chim. Acta, 398, 103-110, (1999).
3)
A. Gianguzza et al. Speciation of low molecular weight ligands in natural fluids: protonation constants
and association of open chain polyamines with major components of seawater. Anal. Chim. Acta, 418,
pp. 43-51, (2000)
4)
A. Gianguzza, D. Piazzese et al. Inorganic Speciation of Organotin(IV) cations in natural waters with
particular reference to seawater. Chem. Spec. Bioavailab., 12(2), 41-52, (2000).
5)
A. Gianguzza, D. Piazzese et al. Chemical Speciation of Nucleotide 5’-Monophosphates in the presence
of Biogenic Amines. Chem. Spec. Bioavailab., 13(4), (2001), pp. 1-9.
6)
A. Gianguzza, D. Piazzese et al.. Speciation of polyelectrolytes in natural fluids. Protonation and
interaction 0f polymethacrylates with major components of seawater. Talanta, 58 (2002), pp. 405-417.
7)
A. Gianguzza, D. Piazzese et al. Speciation of poly-amino carboxylic compounds in seawater. Chem.
Spec. Bioavailab., 15(3), 75-86 (2003).
8)
A. Gianguzza et al. Speciation of trialkyltin(IV) cations in natural fluids. Mar. Chem., 85, (2004), 157167.
9)
A. Gianguzza, D. Piazzese et al. Speciation of organic matter in natural waters. Interaction of
polyacrylates with the major cation components of seawater. Mar. Chem., 86,(2004), pp. 33-44.
10) A. Gianguzza, D. Piazzese et al. Chemical speciation of organic matter in natural waters. Interaction of
nucleotides 5’ mono- di- and tri-phosphates with major components of seawater. Chem. Spec.
Bioavailab. Vol. 16 (1/2) (2004), 1-8. Special issue devoted to the Italian-Spanish congress on
Themodynamics of Metal Complexes “ISMEC 2003”, A. Gianguzza and S. Sammartano eds.
11) A. Gianguzza, D. Piazzese et al. Speciation of organotin compounds in NaCl aqueous solution.
Interaction of mono-, di- and triorganotin(IV) cations with nucleotides 5’ monophosphates. Applied
Organomet. Chem., 18, (2004), pp. 653-661.
12) A. Gianguzza, D. Piazzese et al. Metals distribution in organic and inorganic fractions of soils from Sicily.
Chem. Spec. Bioavailab., 3, 83-93, (2005).
13) A. Gianguzza et al. Speciation of dimethyltin(IV)- and trimethyltin(IV)-carbocysteinate and -glutamate
systems in aqueous media. Chem. Spec. Bioavailab., 20(3), (2008), 137-148.
14) A. Gianguzza, D. Piazzese et al. Speciation of chitosan-phosphate and chitosan-nucleotide systems in
NaCl aqueous solution. Chem. Spec. Bioavailab. (2010), 22(2), 99-107.
15) A. Gianguzza, D. Piazzese et al. Aqueous solution chemistry of alkyltin(IV) compounds for speciation
studies in biological fluids and natural waters. Coord. Chem. Rev. 256 (2012) 222– 239.
16) A. Gianguzza, A. Pettignano et al. Advances in the investigation of dioxouranium(VI) complexes of
interest for natural fluids. Coord. Chem. Rev. 256 (2012) 63– 81.
17) A. Gianguzza et al. Speciation of Al3+ in fairly concentrated solutions (20 –200 mmol L-1) at I = 1 mol L-1
(NaNO3), in the acidic pH range, at different temperatures. Chem. Spec. Bioavailab. (2011), 23, 33-37.