Determination of trace levels of thiazopyr residues in oolong tea samples using metal sieve-linked double syringe based liquid-phase microextraction coupled with gas chromatography-mass spectrometry

Abstract

Thiazopyr has raised concerns about its potential impact on human health. Hence, detection of trace levels of thiazopyr herbicide has become critically important. This study presents a highly precise and accurate method to determine thiazopyr at trace levels using a combination of metal sieve-linked double syringe based liquid-phase microextraction (MSLDS-LPME) and Gas Chromatography-Mass Spectrometry (GC-MS) system. A thorough optimization of all parameters affecting the method's efficiency was performed using a univariate optimization approach, followed by an evaluation of the system's analytical performance. Employing the developed method in conjunction with the MSLDS-LPME-GC-MS system yielded a limit of detection (LOD) of 2.73 µg/kg and a limit of quantification (LOQ) of 9.11 µg/kg. To assess the method's applicability, a recovery study was conducted using oolong tea as a real sample matrix, employing a matrix-matching calibration approach. The results of recovery studies demonstrated acceptable recoveries ranging from 87.5 % to 101.9 %.