vii
TABLE OF CONTENTS
CHAPTER TITLE PAGE i
DECLARATION
DEDICATION ii iii
ACKNOWLEDGEMENTS
ABSTRACT
ABSTRAK
TABLE OF CONTENTS iv v vi vii
LIST OF TABLES
LIST OF FIGURES
LIST OF SYMBOLS/ABBREVIATIONS/
NOTATION/TERMINOLOGY
1 INTRODUCTION
LIST OF APPENDICES
1.1
1.2
Food Packaging
Research Background
1.3
1.4
1.5
Statement of Hypothesis
Research Aim
Research Objectives
1
3
4
1
2
4 xiii xvi xviii xxi
1.6
1.7
Scope of Study
Outline of the Thesis
4
5

viii
6
2.6
2.7
2.4
2.5
2.1
2.2
2.3
2.8
2.9
2.10
2.11
2.12
2.13
Styrene
Physical and Chemical properties
Sources
Routes of Exposure
2.4.1
Styrene in Food
Uses of styrene
2.5.1
General Purpose Grade Polystyrene (GPPS)
2.5.2
Expandable Polystyrene (EPS)
2.5.3
High Impact Grade Polystyrene (HIPS)
2.5.4
Glass Reinforced Plastic (GRP)
2.5.5
Styrene Copolymers
Additives Used in Polystyrene Food Packaging
Health Effects
2.7.1
Styrene and Its Metabolite
2.7.2
Other Volatile Organic Compounds (VOCs)
Chemical Residues in Food Packaging Materials
Migration Studies
Legislation Control for Polystyrene Food Packaging
2.10.1
European Food Contact Regulations
2.10.2
U.S. Food and Drugs Administration (FDA)
Regulations
2.10.3
Japan Food Sanitation Law
Analytical Methodology
2.11.1
Method Application in Food Packaging
Analysis
Evaluation of Sample Preparation Techniques
Solid-Phase Microextraction (SPME)
2.13.1
SPME Sampling Techniques
12
13
14
15
11
11
11
12
16
17
18
8
9
10
10
7
8
6
6
19
20
21
22
23
25
25

ix
2.13.2
Parameters which Effect the Absorption
Process
2.13.2.1 Selection of Fiber Coatings
2.13.2.2
Time and Temperature of the
Extraction Process
2.13.2.3
pH Modification and Addition of
Salt
2.13.2.4
Addition of Solvent
2.13.2.5
Agitation of the Sample
2.13.2.6
Volume of the Sample
2.13.2.7
Matrix Effects
2.13.2.8
Derivatization
2.13.3
Interfaces to Analytical Instrumentation
2.13.4
SPME Applications
2.13.5
Advantages of SPME
3 EXPERIMENTAL
3.4
3.5
3.6
3.1
3.2
3.3
Experimental Layout
Analytes and Chemicals
Instrumentation
Samples
Identification of Packaging Materials
Material Test Procedure
3.6.1
Standard Preparation
3.6.2
Sample Preparation – Dissolution Technique
3.6.2.1 Material Test
3.6.2.2 Migration Test
3.6.3 Gas Chromatographic Conditions
3.6.4 Analysis and Quantification
3.6.5 Quality Control Measures
28
28
28
29
29
30
26
26
27
27
27
31
32
35
35
35
36
36
32
32
34
34
36
37
37
38

4 x
3.8
3.7 HS-SPME Method
3.7.1
3.7.2
3.7.3
3.7.4
3.7.5
3.7.6
3.7.7
Method Validation
3.8.1
Standard Preparation
Food Simulant and Leaching Conditions
Sample Preparation
HS-SPME Extraction
Instrumental Conditions
Analysis and Quantification
Optimization of SPME parameters
Specificity
3.8.2
Limit of Detection (LOD) and Limit of
Quantification (LOQ)
3.8.2.1 Signal-to-noise (S/N)
3.8.2.2 Blank Determination
3.8.2.3 Linear Regression
3.8.2.4 Checking a Predetermined Limit of
Quantification (LOQ)
3.8.3 Linearity Study
3.8.4 Accuracy
3.8.5 Precision
3.8.5.1 Instrument Precision
3.8.5.2 Method Precision
3.9 Data Analysis
METHOD DEVELOPMENT IN THE
DETERMINATION OF VOLATILE ORGANIC
COMPOUNDS IN POLYSTYRENE FOOD
PACKAGING BY DISSOLUTION METHOD
4.1
4.2
Identification of Packaging Materials
Material Test
4.2.1
Sample Preparation
4.2.2
Chromatographic Conditions
4.2.3
Quantification Method
49
50
52
54
55
41
41
41
42
39
39
39
40
42
42
43
44
44
46
47
47
47
44
45
46
48
49

xi
4.3
4.2.4 Method Validation
4.2.4.1 Specificity
4.2.4.2 LOD and LOQ
(a) Signal-to-noise (S/N)
(b) Blank Determination
(c) Linear Regression
(d) Comparison of LOD and LOQ of
Different Approaches
(e) Checking a Predetermined Limit of Quantification (LOQ)
4.2.4.3
Linearity Test
(a) Inspection of y-Residual Plot
(b) Validation of Assumption
4.2.4.4
Accuracy
4.2.4.5
Precision
(a) Instrument Precision
(b) Method Precision
4.2.5
Application of Method to the Analysis of
Polystyrene Food Packaging
4.2.5.1 Quality Assurance
4.2.5.2 Analyte Concentration in Samples
Migration Test
4.3.1
Selection of Control Sample
4.3.2
Sample Homogeneity
4.3.3
Migration of Analyte at Different
Temperature
61
62
64
65
67
57
57
59
60
67
69
70
72
72
73
74
75
75
76
77
78
79

xii
5
5.4
APPLICATION OF SOLID-PHASE
MICROEXTRACTION TO THE STUDY OF THE
MIGRATION OF VOCs FROM POLYSTYRENE
FOOD PACKAGING INTO WATER AS FOOD
SIMULANT
5.1 Preamble
5.2
5.3
Instrumental Conditions
Optimization of SPME Parameters
5.3.1
5.3.2
5.3.3
5.3.4
Fiber Coating Selection
Sample Volume Studies
Elutropic Strength Studies
Extraction Temperature Studies
5.5
5.3.5
5.3.6
5.3.7
5.3.8
5.4.1
5.4.2
Extraction Time Studies
Desorption Time Studies
Sample Agitation
Addition of Salt
Performance of the Method
LOD and LOQ
Linearity
5.4.3
Precision
5.4.4
Accuracy
Application of the Method
6
REFERENCES
Appendix A
CONCLUSIONS AND SUGGESTIONS FOR FURTHER
STUDIES
6.1 Conclusions
6.2 Suggestions for Further Studies
81
101
103
104
115
91
93
95
96
88
89
90
91
83
84
85
87
81
81
82
83
97
101

xiii
4.6
4.7
4.8
4.3
4.4
4.5
3.3
3.4
3.5
4.1
4.2
2.1
2.2
3.1
3.2
TABLE NO.
LIST OF TABLES
TITLE
Four common classes of food simulants
Japanese specification for polystyrene food contact materials: (a) Material test; and (b) Migration test
Description of analytes and internal standard
Description of chemicals
Migration conditions used for testing of polystyrene cups
Preparation of calibration standard for migration test
Evaluation of SPME parameters
Characteristic wave numbers obtained from polystyrene samples
Comparison of the extraction efficiencies for different sample extraction techniques
Mean concentration of analytes in samples obtained by internal standard method and standard addition method
Comparison of precision and accuracy using internal standard and sample addition method
Concentration recovered from ten different types of spiked samples
Evaluation of specificity for the targeted analytes
Concentration of analytes and number of replicates used for determination of LOD and LOQ
Data obtained for each test compound based on signal-tonoise approach
PAGE
59
59
60
53
56
56
58
37
39
42
50
17
21
33
33

4.18
4.19
4.20
4.21
4.14
4.15
4.16
4.17
4.9
4.10
4.11
4.12
4.13
4.22
4.23
4.24
4.25
5.1
5.2 xiv
The mean concentration and standard deviation of blank obtained using blank determination approach
Parameters of linear ordinary least-squares regression for the five test compounds at seven different levels of concentration
Results of the statistical evaluation of the linear regression curve
Summary of estimated LOD by different approaches
Summary of estimated LOQ by different approaches
Check for predetermined LOQ of 0.2 µg/mL
Check for predetermined LOQ of 0.4 µg/mL
Results of regression test and lack-of-fit test
Summary of findings of linearity tests for the five analytes
% recovery of the analytes at different spiking levels: (a) 10 mg/kg; (b) 200 mg/kg; and (c) 400 mg/kg
Intra-day and inter-day precisions for the five analytes
Precision of method based on different sample matrices
Categories of PS samples and number of replicates used for the analysis
Concentrations of the five analytes found in different PS samples
Concentration of ethylbenzene and styrene in control samples
Concentration of ethylbenzene and styrene in samples
Estimation of ethylbenzene and styrene migrated from polystyrene cup using dissolution method
Data obtained for each test compound based on signal-tonoise approach
Results for regression test and lack-of-fit test
62
63
61
64
64
65
78
80
92
95
76
77
71
73
74
75
66
69
70

5.3
5.4
5.5
5.6
5.7
Summary of findings for linearity testing using HS-SPME
Three different concentration levels applied for precision testing
Intra-day and inter-day precision for migration test method
Evaluation of method accuracy by extraction recovery, p
=3
Mean concentration of analytes migrated from samples into water solution xv
96
97
95
95
99

xvi
5.1
4.5
4.6
4.7
4.3
4.4
2.1
3.1
4.1
4.2
FIGURE NO.
LIST OF FIGURES
TITLE
Structure of styrene
Polystyrene cup with 1 cm rim mark
Resin identification code for styrene
FTIR spectra of (a) reference styrene; (b) PS bowl; and
(c) PS container
Comparison of the analyte response using different sample extraction techniques, p
=6
GC-FID separation of analytes at 10 µg/mL on a DB-
WAX column, 30 m, 0.25 mm I.D., 0.25 µm film thickness. GC conditions as described in 3.6.3. Peaks: 1
= Toluene; 2 = Ethylbenzene; 3 = iso-Propylbenzene; 4 = n
-Propylbenzene; 5 = Styrene and 6 = 1,4-Diethylbenzene
(ISTD)
GC chromatogram of an expanded polystyrene cup by using GC conditions as described in 3.6.3. Peaks: 1 =
Ethylbenzene; 2 = Styrene and 3 = 1,4-Diethylbenzene
(ISTD)
Residual plots for (a) Styrene; (b) Toluene; (c)
Ethylbenzene; (d) iso-Propylbenzene and (e) n -
Propylbenzene with limits ± t
(0.05, np
-2).
S res
Mean recovery of the analytes based on different concentration levels of spiking
GC chromatogram of analyte mixture using HS-SPME method. Peak: 1 = Toluene (45 ppb); 2 = Ethylbenzene
(15 ppb); 3 = iso-Propylbenzene (5 ppb); 4 = n-
Propylbenzene (5 ppb); 5 = Styrene (10 ppb); and 6 = 1,4diethylbenzene (ISTD, 5 ppb)
PAGE
54
68
72
82
52
54
7
40
49
51

5.2
5.3
5.4
5.5
5.6
5.7
5.8
5.9
5.10 xvii
Effect of sample volume on extraction efficiency of analytes
Studies of elutropic strength effect on the targeted analytes
Effect of extraction temperature on analyte extraction efficiency
Extraction time profile for the five analytes
Desorption time profile for the five analytes
Effect of sample agitation rate on the extraction efficiency of analytes
Salting out effect on the five analytes
Residual plot of the targeted analytes (a) Toluene; (b)
Ethylbenzene; (c) iso-Propylbenzene ; (d) n
-
Propylbenzene; and (e) Styrene with limits ± t
(0.05, np
-
2).
S res
GC chromatogram showing the analytes migrated from a polystyrene cup. Peaks: 1 = Ethylbenzene; 2 = Styrene; and 3 = 1,4-diethylbenzene (ISTD)
86
84
85
87
88
90
91
94
98

xviii a
LIST OF SYMBOLS/ABBREVIAITIONS/NOTATION/TERMINOLOGY
– Intercept of regression line
ABS
ATR
–
–
Acrylonitrile butadiene styrene
Attenuated total reflection b
–
BTEX –
C –
Slope of regression line
Benzene, toluene, ethylbenzene and xylene
Capacity
CFR – Code of Federal Regulations
CS
2
– Carbon Disulphide
CW – Carbowax
CW-TPR –
DCM –
DMA –
DMF –
Carbowax – templated resin
Dichloromethane
Dimethylacetamide
Dimethylformamide
DNA –
DVB –
EB
EC
–
–
EPS
FDA
–
–
FT-IR –
GC –
GC-FID –
GC-MS –
GPPS –
GRP –
HIPS –
Deoxyribonucleic acid
Divinylbenzene
Ethylbenzene
European Commission
Expanded polystyrene
Food and Drug Administration
Fourier transform infrared spectroscopy
Gas chromatography
Gas chromatography - flame ionization detection
Gas chromatography – mass spectrometry
General purpose grade polystyrene
Glass reinforced plastic
High impact grade polystyrene

HPLC –
HS-SPME –
IARC –
ICH –
I.D.
IPB
–
–
ISTD –
IUPAC –
JHOSPA –
KCl –
LC-MS –
LLE –
LOD –
LOQ –
High performance liquid chromatography
Headspace solid-phase microextraction
International Agency on Research for cancer
International Conference on Harmonization
Internal diameter iso-Propylbenzene
Internal standard
International Union of Pure and Applied Chemistry
Japan Hygienic Olefin and Styrene Plastics Association
Potassium chloride
Liquid chromatography - mass spectrometry
Liquid-liquid extraction
Limit of detection
Limit of quantification
MAE –
MEK – n
NPB
–
–
OML –
OLS – p
PA
–
–
Microwave-assisted extraction
Methyl ethyl ketone
Number of samples or levels of standard solutions n -Propylbenzene
Overall migration limit
Ordinary least square regression
Number of replicates
Polyacrylate
PAHs –
PDMS – ppb ppm
–
–
Polycyclic aromatic compounds
Polydimethylsiloxane
Part per billion
Part per million ppt – Part per trillion
PS – Polystyrene
PTFE – Polytetrafluoroethylene
PVC – Polyvinyl chloride
QC – Quality control r
–
RSD
RT
–
–
Relative standard deviation
Retention time xix

SA
SAN
S b
S res
S y0
SBR
–
–
SFE –
SML –
–
–
–
–
S/N
SPE
–
–
SPME –
UV –
VOCs –
Standard addition
Styrene acrylonitrile
Standard deviation of blank
Standard deviation of y-residuals
Standard deviation of y-intercepts
Styrene butadiene rubber
Supercritical fluid extraction
Specific migration limit
Signal-to-noise ratio
Solid-phase extraction
Solid-phase micorextraction
Ultra violet
Volatile organic compounds xx

xxi
A
LIST OF APPENDICES
Presentations and Publications 115