Simple and Efficient Simultaneous Determination of Six Haloacetic Acid Disinfection Byproducts in Serum: liquid–Liquid Extraction Combined with Acidified Methanol Derivatization and Gas Chromatography

As a major category of disinfection byproducts (DBPs) generated during water chlorination, haloacetic acids (HAAs) pose considerable health risks, including carcinogenic and potential reproductive toxicity, which have raised substantial public health concerns. Nevertheless, information regarding internal HAA exposure in humans, especially in serum, is still scarce. Building upon the USEPA Method 552.3, this study established and verified a robust procedure for quantifying six HAAs in human serum. This method uses fusion liquid–liquid extraction (LLE) as a pretreatment step, followed by acidified methanol derivatization, and finally uses a gas chromatograph (GC) equipped with an electron capture detector (ECD) to complete quantitative analysis. This streamlined protocol requires merely 500 μL of serum and allows for efficient qualitative and quantitative measurement. After systematic optimization, the method achieved enhanced recovery rates and lower detection limits. It demonstrated a linear range of 0.2–100 μg/L, with the following validated parameters: spiked recoveries of 85.112–111.645%, relative standard deviations (RSDs) of 2.092–13.568%, limits of detection (LODs) between 0.007 and 0.923 μg/L, and limits of quantification (LOQs) from 0.022 to 3.076 μg/L. The method’s practicality was confirmed by analyzing 100 human serum samples, in which all six target HAAs were identified, displaying geometric mean concentrations spanning 0.82 up to 2.94 μg/L. These outcomes indicate that the newly developed assay is reliable and well-suited for the large-scale biomonitoring of HAA exposure in population-based studies.