Analysis & Testing Center, Chinese Academy of Tropical Agricultural Sciences, Hainan Provincial Key Laboratory of Quality and Safety for Tropical Fruits and Vegetables, Haikou, 571101, China.
Analyst. 2018 Jun 11;143(12):2790-2798. doi: 10.1039/c8an00613j.
A novel detector for liquid chromatography (LC) for the determination of dithiocarbamate (DTC) fungicides is presented with a miniaturized dielectric barrier discharge-microplasma molecular emission spectrometer and an online microwave-assisted hydrolysis reactor. DTCs in the sample/standard solutions together with SnCl2 were pumped to the reactor to be converted to CS2 with high efficiency, which was then separated from the liquid phase and transformed for the detection of the specific molecular emission at 257.49 nm by the spectrometer. Under optimized conditions, the performance of this new detector was evaluated by its determination of different types of DTC including mancozeb, thiram, zineb, propineb, and metiram, and the limit of detection (LOD) values were found to be in the range 0.1-1.0 μg mL-1. The results from 20 test vegetable and fruit samples determined with the proposed method agreed well with those obtained using the standard headspace gas chromatography-electron capture detector (GC-ECD) method. Preliminary experimental results showed that the proposed method provided slightly higher LOD values than those obtained using GC-ECD. Most importantly, the new LC detector could detect each DTC chemical, whereas the traditional method could not distinguish between analytes of different subclasses of DTC.
一种用于液相色谱（LC）的新型检测器，用于测定二硫代氨基甲酸盐（DTC）杀菌剂，该检测器结合了小型化介电屏蔽放电微等离子体分子发射光谱仪和在线微波辅助水解反应器。将样品/标准溶液中的 DTC 与 SnCl2 一起泵入到反应器中，以高效率转化为 CS2，然后将其与液相分离，并通过光谱仪检测到特定的分子发射在 257.49nm 处。在优化条件下，通过测定不同类型的 DTC（包括代森锰锌、福美双、代森锌、丙森锌和甲基托布津）来评估该新型检测器的性能，其检出限（LOD）值在 0.1-1.0μg·mL-1范围内。用所提出的方法测定 20 个蔬菜和水果测试样品的结果与使用标准顶空气相色谱-电子俘获检测器（GC-ECD）方法获得的结果非常吻合。初步实验结果表明，与 GC-ECD 相比，所提出的方法提供的 LOD 值略高。最重要的是，新型 LC 检测器可以检测每种 DTC 化学物质，而传统方法则无法区分不同亚类 DTC 的分析物。
