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

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.