Kapok-fiber-supported liquid-liquid extraction enables rapid and convenient determination of five phenoxycarboxylic acid herbicide residues in beverages and oral liquids.

In this study, a novel green and miniaturized sample preparation method, named tributyl phosphate (TBP)-based kapok-fiber-supported liquid microextraction (TBP-KF-SLME), was developed to determine five phenoxycarboxylic acid herbicides in beverages and oral liquids. The extraction of phenoxycarboxylic acid herbicides was achieved using natural kapok-fiber and tributyl phosphate. A unique in-syringe platform, in which the kapok fiber was packed within the needle tip, facilitated the integration of extraction and enrichment through straightforward push-pull movements with 6 min. This method demonstrated excellent linearity (R2 ≥ 0.999), sensitivity (limits of detection: 0.006-0.024 μg/mL), recovery (92.3-104.6%), stability (relative standard deviation <6.63%), and enrichment factor (9.36-13.47). The validated in-syringe TBP-KF-SLME method was successfully applied to real samples, showcasing high accuracy and precision. A rigorous evaluation using six green assessment tools revealed that, TBP-KF-SLME offers a sustainable and efficient strategy for the analysis of herbicide residues.