Detection of Organochlorine Pesticides in Environmental Water Samples Using Effervescent Assisted Magnetic Micro Solid‐Phase Extraction Combined With Gas Chromatography

ABSTRACT In this study, a novel effervescent‐assisted magnetic micro solid‐phase extraction (EA‐MSPE) method was developed for the detection of four organochlorine pesticides (OCPs) in water samples. The adsorbent for this method consisted of magnetic biochar particles, which were created by loading Fe 3 O 4 onto pomelo peel biochar. It combined effervescent compression technology to complete the automatic extraction process and utilized an applied magnetic field to achieve solid‐liquid separation, thereby establishing the EA‐MSPE method. Several experimental parameters that affect the extraction efficiency, including biochar dosage, acid‐base conditions, pH, eluting solvent, and salt content, were investigated. The results indicated that the optimal conditions were as follows: a biochar dosage of 0.06 g, a ratio of sodium dihydrogen phosphate to sodium bicarbonate of 1:3, a pH of 10, an elution solvent composed of ethyl acetate and n ‐hexane (2:1), and 10% NaCl. The recoveries of the four OCPs ranged from 63.56% to 87.52%. The limits of detection varied between 0.17 and 0.95 µg/L. The relative standard deviations ranged from 6.0% to 9.2%. This method was based on effervescent technology and magnetic particles to achieve an automatic extraction and separation process, saving time, energy, and being environmentally friendly. The produced magnetic effervescent tablet was easy to carry, more suitable for field sampling and extraction, and has strong practicability.