Biochar/sodium alginate mixed matrix membrane as adsorbent for in‐syringe solid‐phase extraction towards trace nitroimidazoles in water samples prior to ultra‐high‐performance liquid chromatography‐tandem mass spectrometry analysis

In the present work, the herb (Poria cocos (Schw.) Wolf) residue, as an environmentally friendly and renewable biomass source, was converted into novel biochar. Biochar/sodium alginate mixed matrix membrane was fabricated. On this basis, a biochar/sodium alginate mixed matrix membrane‐based in‐syringe solid‐phase extraction was developed combined with ultra‐high performance liquid chromatography‐tandem mass spectrometry to determine nitroimidazoles in water samples. The factors including times of exaction, type, and volume of elution solvent, and sample solution pH were thoroughly optimized. Then the correlation coefficient was 0.9995–0.9997. The limit of detection of four analytes was between 0.006 and 0.014 ng/mL, and the recovery was between 79.02% and 99.1%. Consequently, the established method would provide a new perspective on monitoring nitroimidazoles in water samples. [ABSTRACT FROM AUTHOR]