Kapok fiber-derived biochar-based pipette-tip solid-phase microextraction for the eco-friendly and rapid extraction and determination of organochlorine pesticides in beverages and herbal extracts

Organochlorine pesticides (OCPs) are known for their environmental persistence and potential health risks through consumption of contaminated agricultural products. The need for their routine monitoring and quantification is thus critically important. This study introduces a novel approach utilizing kapok fiber-derived biochar (KFBC) affixed to the inner wall of pipette tips for solid-phase microextraction (PT-SPME) to detect OCPs in beverages and herbal extracts. The KFBC was prepared through the pyrolysis of natural kapok fibers, chosen for its efficiency, economy, eco-friendliness, and notably its porous structure. The method simplifies handling by integrating the biochar into a pipette-tip extraction device, optimizing key parameters for efficient extraction. This process, requiring only 150 μL of acetonitrile , is completed in about 3 min. Coupled with gas chromatography-electron capture detection, the method demonstrates high linearity (R 2  > 0.995), sensitivity (detection limits: 0.03–0.30 ng/mL), accuracy (relative recoveries: 88.5–117.1%), and precision (relative standard deviations: 2.6–11.8%) for OCPs. Its operational ease and minimal environmental impact highlight its potential as an effective analytical technique for OCPs determination.