Semi-automatic silicon rubber based multi-vial microextraction for determination and removal of pesticides from waters and tea

Abstract

Water resources are increasingly contaminated by industrial and agricultural pollutants, with pesticide residues posing a persistent challenge. Most existing methods were designed for a single purpose of either measuring or eliminating water pollutants, while integrated strategies containing both functions remain scarce. Here we reported a novel semi-automatic silicone rubber (SR) based multi-vial microextraction technique for the simultaneous determination and removal of fifteen pesticides from aqueous matrices. An integrated adsorption-desorption platform enabled effective in-situ extraction of the target pesticides via hydrophobic effects. Key parameters including ultrasonication extraction for 45 min and two sequential 5-min desorption with 5 mL of hexane/ethyl acetate (1:1, v/v) were employed. The quantitative analysis was validated in real waters of the Nanfei River, Chao Lake, and tap water with good recoveries (72.8–112.6 %) and relative standard deviations (0.1–7.5 %), superior limits of detection (0.0020–0.20 μg/L) and quantification (0.006 to 0.50 µg/L), and free matrix effects (87.5–102.1 %) by gas chromatography equipped with electron capture detector. Focusing on its selectivity and recyclability, the proposed approach was further applied to purifying green tea and chrysanthmum tea infusions, achieving over 90 % removal efficiency for most pesticides. These results demonstrated that the semi-automatic SR-based multi-vial microextraction is a robust and effective method for both quantifying and eliminating target pesticides from waters and tea infusions. The high throughput and low cost encourage its potential for customized commercial application in monitoring and remediating emerging pesticides in environment and food fields.