I. Development of a passive sampler and static sampling chamber to measure personal exposure to gaseous PAHs. II. Method development for determination of current-use and persistent pesticides in cow milk, human breast milk, baby formulas, and human serum using gas chromatography tandem mass spectrometry. Open Access
Chen, Xianyu (Vivian) (2012)
Abstract
Abstract
Exposure to polycyclic aromatic hydrocarbons (PAHs) is regarded as
an important
environmental risk factor for humans. A passive sampler made of 80
sections of 2 cm
long GC columns was tested in our study. The main purpose of this
passive sampler is to
detect the amount of gaseous PAHs people breathe in every day.
Since the sampling
rate is a critical parameter that evaluates how well a passive
sampler works, we
developed a "static chamber" to determine this rate. Ultimately, we
will use these
results to design a sensitive, reliable, simple, economical and
user-friendly passive
sampler to measure personal exposure to gaseous
semi-volatiles.
An analytical method to determine organochlorine (OC),
organophosphate (OP),
carbamate, and pyrethroid insecticide residues in cow milk, human
milk, and baby
formulas was developed. This method involves a liquid-liquid
extraction, freezing-lipid
filtration, and solid-phase extraction procedure followed by gas
chromatography
tandem mass spectrometry (GC-MS/MS) for the identification and
quantification of
targeted pesticides.
The sample preparation method for pesticides analysis in milk
proposed above was
tested and modified to analyze OC, OP, pyrethroid, and carbamate
pesticides in serum.
However, during the method validation process, this method and its
modified ones were
both proved to yield unsatisfying recoveries and fail to clean-up
serum matrices.
Afterwards, a different method was adapted, modified, and validated
for pesticides
analysis in pooled serum samples. This sample preparation method
started with C18 SPE
cartridges and was followed by florisil SPE procedures. Extracted
samples were analyzed
in GC-MS/MS for the identification and quantification of targeted
pesticides.
In the GC-MS/MS analysis, ionization of pesticide molecules was
achieved by electron
ionization in positive mode. Multiple reaction monitoring (MRM) was
the acquisition
mode used for the monitoring of two MS/MS transitions for each
analyte.
Table of Contents
Chapter 1 Exposure, human health, and exposure assessment
1.1 A short history of exposure assessment
1.2 Inhalation route and its exposure assessment
1.3 Pesticides, toxicity, and their exposure routes
1.4 Breast milk
1.5 Serum
1.6 Objective and significance
Chapter 2 Development of a passive sampler and static sampling chamber to measure personal exposure to gaseous PAHs
2.1 Introduction
PAHs and human health concerns
Personal sampling
Active samplers
Passive samplers
A newly developed passive sampler
2.2 Chemicals, standard and internal standard preparation
2.3 Chamber Development and Characterization
2.4 GC Method
2.5 The characterizations of passive samplers made from GC capillary columns
2.6 Results and Discussion
2.7 Conclusions
Chapter 3 Method development for determination of current-use and persistent pesticides in cow milk, human breast milk and baby formulas using gas chromatography tandem mass spectrometry
3.1 Introduction
Organochlorines (OCs), organophosphates (OPs), carbamates, and pyrethroids
Human breast milk, cow milk, and baby formulas
Method development
Purposes of this study
3.2 Materials and methods
Sample Collections
Chemicals
Native Standards and Internal Standards Preparation
Preparation and extraction procedure for milk samples
Instrumental Analysis
Quantification method
Limit of Detection
Extraction efficiency
Accuracy
Precision
3.3 Results
Recoveries
Limits of Detection (LOD)
Precision and Accuracy
Analysis of human breast milk, cow milk and baby formulas
3.4 Discussion
Liquid-liquid extraction
Sample clean-up
Method development for baby formulas
GC-MS and high sensitive electron ionization (EI) MS analysis
Limit of detection (LOD)
3.5 Conclusions
Chapter 4 Method development for determination of current-use and persistent pesticides in human serum using gas chromatography tandem mass spectrometry
4.1 Introduction
4.2 Materials and Methods
Serum Samples
Chemicals
Native Standards and Internal Standards Preparation
Preparation and Extraction Procedure for Serum Samples
Quality Control (QC) Samples
Instrumental Analysis
Quantification Method
Limit of Detection
Extraction Efficiency
Accuracy
Precision
Sample Storage Stability
4.3 Results
Recoveries
Limit of Detection (LOD)
Accuracy and Precision
4.4 Discussions
4.5 Conclusions
Chapter 5 Conclusions and future development
Reference
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