Abstract: An efficient detection method for thiophanate methyl residue in plant-derived foods was established by combing a high-throughput automated homogenizer, an automatic online purification and concentration system and a liquid chromatography-tandem mass spectrometry. Samples were homogenized with acetonitrile on a high-throughput automated homogenizer, purified using an automatic online purification (gel chromatographic and solid phase extraction column) system, online concentrated and detected using a liquid chromatography-tandem mass spectrometer. The quantification of thiophanate methyl was carried out using the external standard method. The detection conditions were: acetonitrile-water (gradient) as mobile phase, ESI as ionization method, qualitative ion pairs of m/z 343.0＞151.1 and 343.0＞192.1, quantitative ion pairs of m/z 343.0＞151.1. With the addition of 0.01 to 10.0 mg/kg of thiophanate standard to samples, the recovery rate was between 88.4% and 97.9% and the relative standard deviations (RSDs) varied from 1.3% to 2.9%. The detection limit of the established method was 0.01 mg/kg.

Key words: high-throughput automated system, plant-derived foods, thiophanate-methyl residue