Magnetic hydrophilic–lipophilic balance sorbent for efficient extraction of chemical warfare agents from water samples

• Magnetic hydrophilic–lipophilic Balance (MHLB) resins were synthesised and characterized.
• MDSPE method was developed by utilizing synthesized sorbent.
• CWAs and CRCs were extracted from different water samples.
• LODs with GC–MS were in the range of 0.5–1.0 ng mL−1.

Magnetic hydrophilic–lipophilic balance (MHLB) hybrid resin was prepared by precipitation polymerization using N-vinylpyrrolidone (PVP) and divinylbenzene (DVB) as monomers and Fe2O3 nanoparticles as magnetic material. These resins were successfully applied for the extraction of chemical warfare agents (CWAs) and their markers from water samples through magnetic dispersive solid-phase extraction (MDSPE). By varying the ratios of monomers, resin with desired hydrophilic–lipophilic balance was prepared for the extraction of CWAs and related esters of varying polarities. Amongst different composites Fe2O3 nanoparticles coated with 10% PVP + 90% DVB exhibited the best recoveries varying between 70.32 and 97.67%. Parameters affecting the extraction efficiencies, such as extraction time, desorption time, nature and volume of desorption solvent, amount of extraction sorbent and the effect of salts on extraction were investigated. Under the optimized conditions, linearity was obtained in the range of 0.5–500 ng mL−1 with correlation ranging from 0.9911–0.9980. Limits of detection and limits of quantification were 0.5–1.0 and 3.0–5.0 ng mL−1 respectively with RSDs varying from 4.88–11.32% for markers of CWAs. Finally, the developed MDSPE method was employed for extraction of analytes from water samples of various sources and the OPCW proficiency test samples.