Determination of Trihalomethanes and Halogenated Acetic Acids in Urine with Microwave-Assisted Solid-Phase Microextraction
Date Issued
2009
Date
2009
Author(s)
Chen, Ying-Hsun
Abstract
Trihalomethanes(THMs) and haloacetic acids(HAAs) are well known disinfection-by products (DBPs). DBPs can be formed by the reaction between the residual chlorine and the humic acids in raw water. People expose to DBPs through various daily activities, including swimming, for example. Due to poor ventilation and continuing adding organic matter from the swimmers, the concentrations of DBPs in swimming pools are usually higher than what was found in tap water.he concentrations of DBPs in water as well as in air can be determined through environmental assessment. However, there are variations with human activities, rate of absorption, distribution, metabolism, and excretion. Therefore, it is difficult to assess the actual exposure through environmental monitoring. On the other hand, biological monitoring can be applied to evaluate the amounts human body absorbed, while blood, urine and expired breath were common specimens for biomonitoring. Among them, urine sample is favored because the procedure for sample taking is invasive, easily operated with convenience.urrent analytical method utilized different techniques to determine THMs and HAAs in urine, respectively. The procedures were cumbersome and time consuming. Therefore, the purpose of this study was to develop a co-analyzed method for THMs and HAAs in urin. The analytical procedure involved derivatization and extraction of THMs and HAAs simultaneously in urine with microwave assisted headspace solid phase microextraction(MAE-HS-SPME). Gas chromatography with electron capture detector (GC/ECD) was used for the determination. Parameters that might affect the derivatization and the extraction efficiency were optimized. The Carboxen/Polydimethylsiloxane (CAR/PDMS) fiber appeared to be most suitable for the analysis of THMs and HAAs. Besides, the efficiencies of the derivatization and extraction were increased by adding the same volume of acidic methanol as the sample for the derivatization. The esterification/extraction temperature was set at 45°C for 40 min with low stirring rate and without salt addition. For the desosrption and analysis, GC/ECD was used and the temperature of the injection port was set at 250°C and the SPME fiber was desorbed for 2 min. The matrix effect was observed in this study, hence the standard addition method is recommended to be applied. The relative standard deviations (RSDs) for the analysis were between 3.333%-24.052% and 3.615%-15.914% for THMs and HAAs, respectively. The accuracies were between 100±2.53% ~ 100±18.97% and 100±1.19% ~ 100±16.66% for THMs and HAAs, respectively. The method detection limits ranged from 0.043 to 30.33 ng/mL.he effects of decomposition from trihaloacetic acids on the determination of THMs were also investigated.
Subjects
THMs
HAAs
microwave assisted
SPME
urine
Type
thesis
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