Improved solid-phase microextraction extraction procedure to detect trace-level epichlorohydrin in municipal water systems by HS-SPME-GC/MS

Abstract

Epichlorohydrin (ECH) is toxic to humans via multiple routes and is a potential carcinogen. The accurate measurement of ECH at trace level (<0.1 μg/L) is still an obstacle hindering the monitoring and regulation of municipal water systems. In this study, an improved headspace solid-phase microextraction (HS-SPME) procedure is developed and optimized to extract and enrich ECH with high sensitivity, accuracy, and precision. A total 17.4-time enhancement in extraction efficiency is achieved compared with the default condition. Specifically, the AC/PDMS/DVB fiber offered a 4.4-time enhancement comparing with the PDMS/DVB fiber. The effects of different mineral salts in SPME were studied and it was found that an addition of 3 g Na₂SO₄ in the SPME head achieved an additional 3.3-time increase. The pattern how sodium sulfate enhanced ECH extraction by salting out is discussed. The optimization of extraction conditions (pH = 7, 35°C, and 20 min extraction duration) brought another 1.2 times further. Combined with gas chromatography with mass spectrometry, the optimized method exhibits curve linearity in the range of 0.02–1.00 μg/L with an R2 of 0.998. The limit of detection, precision, and accuracy of the method are 0.006 μg/L, 2.6%–5.3%, and −3.5% to −2.0%, respectively. The recovery of ECH spiking in tap water and surface water was investigated, with recovery rates of 88.0%–116% and 72.5%–108%, respectively. Adhering to the requirements of existing water quality regulations, our method shows a high potential to be applied in drinking water quality monitoring and water treatment process assessment.

A Study of Headspace Solid‐Phase Microextraction in the Analysis of 54 Hydrophobic Pollutants in Remote Alpine Lake Waters with an Emphasis on Analyte Recovery and Storage Time

“…The dependence of water pH on recovery is not suspected to be an important parameter, given the nonpolarizable nature of OCPs, but has been evaluated by Frenich et al (2011) and Qiu & Cai (2009). The addition of salt to the sample ideally to make analytes less soluble and more volatile has been evaluated by Frenich et al (2011), Antelo et al (2007), Mmualefe et al (2009), Qiu & Cai (2009), Holopainen et al (2013), Martínez et al (2013), and Lei et al (2022), with little effect found for OCPs. A variety of fiber coatings and coating thicknesses have been evaluated by Alonso et al (2003), Polo et al (2005), Derouiche et al (2007), Mmualefe et al (2009), Qiu & Cai (2009), and Martínez et al (2013).…”