Comparison study on extraction techniques used to assess S‐phenylmercapturic acid as low benzene exposure biomarker based on gas chromatography coupled with mass spectrometry

The risk assessment of benzene exposure can be performed based on the analysis of biomarkers in biological monitoring processes. S‐phenylmercapturic acid is a specific benzene biomarker, and its analysis challenges the sensitivity of several analytical methods. The present study aims to develop and standardize an analytic procedure to determine this biomarker through gas chromatography–mass spectrometry, based on different extraction methods, to increase the sensitivity and specificity of the studied analytical method. Liquid–liquid extraction, solid‐phase extraction, liquid‐phase microextraction, and low‐temperature partitioning extraction were tested. The last one was the selected extraction method, which was validated to ensure their quality and reliability. The method above has shown linear correlation to benzene concentrations ranging from 5 to 60 μg L−1 and presented detection and quantification limits of 0.95 and 3.18 μg L−1, respectively. Intra and inter‐assay accuracy recorded variation coefficients equal 3.63% and 8.67%, respectively. The mean accuracy value was 98.72%. This procedure presented linearity, accuracy, and detection and quantification limits within the range of interest adopted to assess occupational and environmental exposure to benzene based on biomonitoring processes.