Automated headspace solid-phase microextraction-gas chromatography-mass spectrometry of trihalomethane and typical nitrogenous disinfection by-products in water

Disinfection by-products (DBPs) are detrimental to public health owing to their carcinogenicity and mutagenesis. Fast and reliable determination of DBPs is essential for ascertaining their formation, characteristics, and occurrence. This study reported an automated headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) method for quantifying typical nitrogenous-DBPs, including haloacetonitriles (HANs), trichloronitromethane, and trihalomethanes (THMs). The analysis was further optimized by selecting SPME fiber coatings, extraction/desorption time and temperature, and salt addition. The optimized method examined the occurrence and stability of the selected DBPs in aqueous samples under different preservation conditions and showed good sensitivity (limit of detection: 0.010-0.320 µg/L) and precision. Most THMs and HANs with high recovery were preserved in ultrapure water under dark and low-temperature conditions. However, real samples exhibited greater analytical biases due to comprehensive effects of photochemistry, biochemistry, and physiochemistry. Based on the findings of this study, we recommend that tested samples should be preserved in a frozen state and analyzed within three days.