An in-tube SPME–based analytical strategy for simultaneous determination of multi-residue pesticides in environmental water samples using a MWCNTs-COOH/Polypyrrole nanocomposite coating

Currently, the application of SPME techniques for multi-residue pesticide analysis is highly limited. In this study, a polypyrrole (PPy) doped with carboxylated multi-walled carbon nanotubes (MWCNTs-COOH) in-tube solid-phase microextraction (IT-SPME) nanocomposite was designed and fabricated by the electrodeposition method. The preparation parameters, such as Py concentration and MWCNTs-COOH content, were optimized. The morphology and structure of the coating were evaluated using SEM and FT-IR which revealed a distributed coating with a coarse and fine grid-like structure, achieving the desired structural integration. Additionally, experimental factors affecting extraction efficiency were optimized, such as sample volume, eluent type, etc. This method indicated a great linear range of 1–500 μg L −1 and high correlation coefficients (R 2 ) above 0.9971. The limit of detection (S/N = 3) and quantification (S/ N  = 10) were 0.12–1.27 μg L −1 and 0.41–4.22 μg L −1 . The relative standard deviations (RSDs) for intra-day and inter-day analyses were in the ranges of 1.02–12.17% and 3.10–13.15%, respectively. The method achieved satisfactory spiked recovery rates ranging from 80.34% to 103.23%. Furthermore, MWCNTs-COOH/PPy coating holds outstanding stability and selectivity. Therefore, the developed IT-SPME approach was successfully used in the analysis of actual environmental water samples.