Comparison Between Dynamic Headspace and Headspace Solid-Phase Microextraction for Gas Chromatography of Btex in Urine

Ljiljana Skender,Irena Karačonji

doi:10.2478/v10004-007-0035-1

Abstract

The aim of this study was to compare two extraction procedures: dynamic headspace-purge and trap (PT) and headspace solid-phase microextraction (HS-SPME) for gas chromatographic determination of benzene, toluene, ethylbenzene, and isomeric xylenes (BTEX) in urine with photoionization (PID) and mass spectrometric (MS) detection, respectively. Both methods showed linearity in the range of interest [(50-2000) ng L-1], good accuracy (80% to 100%), and repeatability (RSD< or =11%). Detection limits were in the low ng L-1 level for both methods, although slightly greater sensitivity was found for the PT method. In comparison with PT, HS-SPME was simpler and required less time for analysis. Although the analytical features of both examined methods are appropriate for biomonitoring of environmental exposure to BTEX, only the HS-SPME-GC-MS method is recommended for routine analysis of BTEX in urine. The method was applied for the quantitative analysis of BTEX in urine samples collected from non-smokers (n=10) and smokers (n=10).

Highlights

The aim of this study was to compare two extraction procedures: dynamic headspace-purge and trap (PT) and headspace solid-phase microextraction (HS-SPME) for gas chromatographic determination of benzene, toluene, ethylbenzene, and isomeric xylenes (BTEX) in urine with photoionization (PID) and mass spectrometric (MS) detection, respectively
At the level of environmental exposure, the concentration of BTEX excreted unmodified in the urine is low; the proportion is usually in the order of 1 % or less of the absorbed dose [9], so the quantification of BTEX in the urine of general population has become possible thanks to the development of the very sensitive analytical techniques which permit determination at levels as low as ng L-1 [1, 5, 10]
The aim of this study was to compare BTEX extraction using PT and Headspace sampling (HS)-SPME, and to find out which of the two procedures could be recommended for routine BTEX analysis in the urine

Summary

Introduction

The aim of this study was to compare two extraction procedures: dynamic headspace-purge and trap (PT) and headspace solid-phase microextraction (HS-SPME) for gas chromatographic determination of benzene, toluene, ethylbenzene, and isomeric xylenes (BTEX) in urine with photoionization (PID) and mass spectrometric (MS) detection, respectively. Several instrumental variations are described for the low level BTEX determinations in the urine These include different sampling techniques such as dynamic headspace (thermal desorption, TD and purge and trap, PT) [10,11,12] and headspace solid-phase microextraction (HS-SPME) [1, 5, 13] followed by gas chromatographic separation and flame ionization [10,11,12] and/or mass spectrometric [1, 5, 10, 13] detection. HS-SPME was applied for the quantitative analysis of BTEX in the urine samples collected from 20 healthy adults without any known occupational BTEX exposure

Objectives

Results

Conclusion