Gas Chromatography-flame
ionization detection of 1,4-dioxane in
palm oil-based fatty alcohol
ethoxylates
Bonnie Tay-Jones Yen Ping
Principal Research Officer
Quality and Environment Assessment Unit
Malaysian Palm Oil Board
6th International Conference and Exhibition on
Analytical & Bioanalytical Techniques
MALAYSIAN PALM OIL BOARD
Malaysian Palm Oil Board
Vision
To become the premier, research and development institution
providing leadership and impetus for the development of a highly
diversified, value-added, globally competitive and sustainable oil
palm industry.
Mission
To enhance the well-being of the Malaysian oil palm industry
through research, development and excellent services.
ABBREVIATIONS
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GC-FID – Gas Chromatography-flame ionization
detector
FAEO – fatty alcohol ethoxylate
I & I – industrial and institutional
EO – ethylene oxide
S/N – signal-to-noise ratio
LOD- limit of detection
LOQ – limit of quantification
RSD – relative standard deviation
AOAC – Association of Official Analytical Chemists
FDA – Food & Drug Administration (USA)
NIST – National Institute of Standards and
Technology
OVERVIEW
Introduction
Methodology
Validation of
method
Confirmation of 1,4Dioxane
• 1,4-dioxane the issue
• 1,4-dioxane origin
• Fatty alcohol ethoxylate and
its applications
• 1,4-dioxane toxicity
• Regulatory Limit
• Sample preparation
• Instrumentation
• Validation Parameters
• LOD, LOQ, Precision, Accuracy, Specificity
• Identification of 1,4-dioxane in fatty
alcohol ethoxylate by GC-MSD
INTRODUCTION
1,4-DIOXANE : THE ISSUE
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Production of oleochemical derivatives :current developing
industry in Malaysia
Local oleochemical companies: setting up of new commercial
plant to produce palm-based fatty alcohol ethoxylates (FAEO).
Research group in AOTD,MPOB currently setting a pilot plant
producing ethoxylates.
1,4-dioxane presence : levels up to 279 ppm*** in personal care
products formulated with ethoxylated products e.g alcohol
ethoxylate, alcohol ethoxy sulfates, polyethylene glycol and
polysorbates (Black, 2001***).
FDA,USA (2001) : detected up to 1410 ppm in cosmetic raw
materials
***Black RE, Hurley FJ, Havery DC. 2001.
Occurrence of 1,4-dioxane in cosmetic raw materials and finished cosmetic products.
Journal of AOAC International 84(3): 666-670.
1,4-DIOXANE :
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THE ISSUE
1,4-dioxane : recognized as a toxic substance,
need to be controlled. (realised by local
manufacturer)
A request for method to be developed by Quality
and Environment Unit, Advanced Oleochemical
Technology Division
Method for detection of 1,4-dioxane in palmbased FAEO not available. Local industry and
MPOB research unit need to perform quality
control of products for customer requirements.
1,4-DIOXANE ORIGIN
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A by-product that can be produced during the
manufacturing of fatty alcohol ethoxylates.
Ethoxylation Process: Addition of ethylene oxide
to a linear alkyl fatty alcohol (carbon chains
,C12-C14) normally derived from palm kernel
oil/coconut oil.
1,4-dioxane may be formed due to dimerization of
ethylene oxide (under certain reaction
conditions).
Continue…
CHEMICAL STRUCTURES
1,4-dioxane
Fatty alcohol ethoxylate
n = number of moles EO
COMMERCIAL PALM-BASED ALCOHOL ETHOXLYATES
WITH DIFFERENT EO COMPOSITIONS
FAEO 20
FAEO 12
FAEO 2
FAEO 1
FAEO 3
FAEO 4
FATTY ALCOHOL ETHOXYLATE
APPLICATIONS
Home Care
1
2
3
4
5
6
Source: Thai Ethoxylate Co. Ltd, Thailand
Textile
Degreasing agent
Wetting agent
fertilizer
inseciticide
Agrochemicals
Scouring agent
Paint
and
rubber
Herbicide/fungicide
Emulsion
polymerization
I & I cleaners
Household cleaner
Dishwash detergent
Hard surface cleaners
Laundry detergent
(liquid)
Personal care
Laundry dtergent
(powder)
Hand cleaner
Mole
Shower cream/gel
shampoo
FATTY ALCOHOL (C12-C14) ETHOXYLATES WITH
1 – 6 MOLES ETHYLENE OXIDE APPLICATIONS
Metal
working
7
8
9
10
11
12
15
Home Care
Textile
Degreasing agent
Wetting agent
fertilizer
inseciticide
Agrochemicals
Scouring agent
Paint
and
rubber
Herbicide/fungicide
Emulsion polymerization
I & I cleaners
Household cleaner
Dishwash detergent
Hard surface (cleaners)
Laundry detergent
(liquid)
Personal care
Laundry detergent
(powder)
Hand cleaner
Moles
Shower cream/gel
shampoo
Fatty alcohol (C12-C14) ethoxylates with 1 – 6 moles
ethylene oxide applications
Metal
working
TOXICITY OF 1,4-DIOXANE
International Agency for Research on Cancer (IARC)
Section 5, pg.595, Vol.71, 1999
5.1 Exposure data
Exposure to 1,4-dioxane may occur during its manufacture and its use as
a solvent in a wide range of organic products. It has been detected in
ambient air.
5.2 Human carcinogenicity data
Deaths from cancer were not elevated in a single, small prospective study
of workers exposed to low concentrations of dioxane.
5.3 Animal carcinogenicity data
Oral administration and inhalation exposure study in mice, rats and
guinea-pigs: increased incidence of tumour occurrence in the tested
animals.
Continue…..
Continue…
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5.5 Evaluation
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There is inadequate evidence in humans for the
carcinogenicity of 1,4-dioxane.
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There is sufficient evidence in experimental
animals for the carcinogenicity of 1,4-dioxane.
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Overall evaluation
1,4-Dioxane is possibly carcinogenic to humans
(Group 2B).
REGULATORY LIMIT
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No regulatory limit for 1,4-dioxane in palm-based
fatty alcohol ethoxylate produced in Malaysia
International cooperation on cosmetics regulation
(ICCR) , an international group of regulatory
authorities for cosmetics (Japan, United States,
Canada and European Union) : proposal to set
exposure level limits in cosmetic and personal care
products.
•8th ICCR meeting held on the July, 2014: the
reports on 1,4-dioxane in cosmetic products are
undergoing final review
METHOD DEVELOPMENT
METHOD AND PERFORMANCE EVALUATION
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Method Name:
Determination of 1,4-Dioxane in fatty alcohol
ethoxylates by using GC-FID
Method performance: assessed by doing a method
validation based on International Committee on
Harmonization (ICH) /AOAC guidelines
Matrices for spiking/recovery: palm-based fatty
alcohol ethoxylates with different EO composition
SAMPLE PREPARATION FOR ANALYSES
(DIRECT INJECTION )
0.5 g of FAEO sample weigh into volumetric flask (5 ml)
reconstitute with acetonitrile
Inject into GC-FID
Note: Fast sample preparation and no clean up
of matrices required (cost saving method)
AGILENT
TECHNOLOGIES
GC-FLAME IONISATION DETECTOR
7890
GC-FID CONDITIONS FOR DETECTION OF
1,4-DIOXANE
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GC oven temperature program :
initial temperature was (50oC) held for 4 min, then
increased at 10oC/ min to 110oC (held 20 min). Post
Run , 300oC held for 10 min. Total run time was 34
minutes.
Carrier gas: helium (set at constant flow of 0.8 mL/
min)
Inlet temp, Pressure: 200oC; 4.47 psi
Detector temp : 310oC
Split ratio: 10:1
Column: HP-5 column (30 m length x 0.32 mm
internal diameter (i.d.); Agilent Technologies)
GC-FID SAMPLING CONDITIONS
OPTIMIZATION FOR DIRECT INJECTION
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A split focus liner with deactivated glass wool was used
at the inlet port, and replaced if contaminated over time.
The glass wool in the liner is able to trap the heavier
ethoxylates and only allow the volatiles through (prevent
matrix interference).
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Additional post run for 10 mins at 300oC was included
after every analysis to remove other volatile residues
(arising from solvent and matrixs) from the column.
INSTRUMENTATION – STRUCTURE
CONFIRMATION
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GC conditions from GC-FID method was
transferred to an Agilent Technologies 7890A GC
fitted with 5975 C Mass spectrometric detector
Data handling and system operations controlled
by GC-MS NISTO5 software .
Mass spectra obtained were obtained for 1,4dioxane spiked in FAEO.
METHOD VALIDATION
Limit of detection
 Limit of quantification
 Precision
 Linearity and working range
 Accuracy
 Selectivity
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GC-FID chromatograms of 1,4-dioxane, blank FAEO &
spiked FAEO
1 ug/ml 1,4-dioxane
RT : 8.589 mins
FAEO (blank)
FAEO ( spiked at 1 ug/ml)
RT 1,4-dioxane : 8.583 mins
LOD /LOQ
 LOD
& LOQ : based on S/N ratio approach
 Acceptable
S/N ratio for LOD was 3:1 and
10:1 for LOQ (ICH guideline)
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this method:
LOD : 10 µg/g of FAEO
LOQ : 30 µg/g of FAEO
PRECISION (INTRA DAY)
Concentration of
1,4-dioxane
(μg/g)*
n= 4
Percentage
Recovery (%)
RSD (%)
15.5 (low)
99.4
0.4
77.5 (medium)
100.6
0.4
505.0(high)
101.4
0.2
* Same analyst, same instrument
Evaluation Criterion: AOAC Guidelines at ppm level,
acceptable RSD for ppm : < 6%
INTERMEDIATE PRECISION
2 conditions: same analyst on different days; different
analyst on different days n= 6 replicates
Inter-day and intermediate precision RSD (%)
for 1,4-dioxane at 100 µg/g
n=6
Day 1
0.5
Day 2
0.4
Analyst 1
0.5
Analyst 2
0.4
Evaluation Criterion: AOAC Guidelines
at ppm level, acceptable RSD for ppm :
< 6%
LINEARITY AND WORKING RANGE
A series of 6 calibration solution were prepared at the LOD
up to the highest expected working concentration. These
standards were run for 6 different batches.
Linear Regression
1,4-dioxane working
Data
range (5.0 – 700 µg/g)
n=6
Slope
0.6524
Intercept
0rigin
Standard error
0.05
R2 value
0.9999
ACCURACY
o Accuracy estimated by using recovery studies (spiking 1,4-dioxane in FAEO)
o Evaluation criterion for accuracy : 80 – 115% (AOAC Guidelines)
1,4-dioxane
(μg/g)
FAEO
FAEO
FAEO
(3 moles EO)
(7 moles EO)
(9 moles EO)
Recovery RSD
Recovery
RSD
Recovery
RSD
(%)
(%)
(%)
(%)
(%)
(%)
N= 6
N=6
N =6
30
103.5
1.5
99.9
2.4
96.8
2.3
60
101.4
2.5
100.0
2.4
98.4
2.9
100
99.9
1.3
98.0
1.5
96.9
3.3
200
101.8
2.2
97.3
2.9
96.2
1.9
500
104.3
3.0
96.5
3.8
97.2
2.1
MONITORING OF COMMERCIAL FAEO
WITH DIFFERENT ETHYLENE OXIDE
COMPOSITIONS
• 22 types of commercial FAEO samples
from local and overseas manufacturing
companies with various ethylene oxide
compositions (1,2, 3, 5,7, 9,12 and 20)
were found to be free from 1,4-dioxane.
MASS SPECTRUM OF SPIKED FATTY ALCOHOL
ETHOXYLATE OBTAINED FROM 7890 AGILENT
TECHNOLOGIES GC-5975C TRIPLE AXIS MSD
Mw: 88.1 (for 1,4-dioxane)
Spectrum matching from experiment
(spiked at 500 µg/g ) and NIST library GC-MSD:
94%
CONCLUSIONS
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Method is fit for the detection of 1,4-dioxane in palmbased fatty alcohol ethoxylate with different moles
ethylene oxide at LOD of 10 µg/g of FAEO within the
range of 5 µg/g to 700 µg/g with precision < 6%, and
accuracy within 80 - 115%
Method will be useful for routine monitoring of 1,4Dioxane ,due to its simple preparation ,and the use of
a commonly available instrument (GC-FID) at the
Quality control laboratory of local FAEOs producers.
Local and overseas commercial FAEOs were found to
be free from 1,4-dioxane.
FURTHER INFORMATION
Gas Chromatography with flame ionization
detection of 1,4-dioxane in palm-based fatty
alcohol ethoyxlates
Bonnie Tay Yen Ping ; Zulina A Maurad and
Halimah Muhammad
JAOCS, 2014, 91, 1103 – 1110.
ACKNOWLEDGEMENT
Committee Members of 6th Bioanalytical
conference –for their kind invitation to present at
this conference
 Director General of Malaysian Palm Oil Board
for permission to present this work
 Malaysian Palm Oil Board – for funding this
research
 Thai Ethoxylate Ltd, Bangkok, Thailand –
providing fatty alcohol ethoxylates samples for
spiking/recovery work
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Thank you