Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.
Analyst. 2021 Sep 13;146(18):5592-5600. doi: 10.1039/d1an00651g.
Determination of pesticide residues in a wide variety of matrices is an ongoing challenge due to low concentration and substantial amounts of interfering endogenous compounds that can be coextracted with the analytes. Herein, we describe the use of cellulose thread both as a suitable sampling medium for various matrices and as a direct analysis platform through an improved thread spray mass spectrometry (MS) approach. Enhanced extraction and the subsequent generation of tiny nanodroplets, after the application of DC potential to the wet thread, enabled ultra-sensitive detection of pesticides without prior sample treatment. This methodology was applied to quantify glyphosate and its metabolite, aminomethylphosphonic acid, in surface water at 12.2 μg mL limit of detection (LOD) standard addition calibration. The method was also used for an internal standard calibration for the analysis of atrazine, which resulted in a LOD of 0.74 ng mL. The enhanced thread spray MS platform also proved effective when applied for direct analysis of diphenylamine and thiabendazole, which enabled the evaluation of post-harvest pesticide treatment of fruits (surface and interior) without complete destruction of the fruits.
由于低浓度和大量可能与分析物一起共提取的内源性干扰化合物，对各种基质中的农药残留进行测定一直是一个挑战。在此，我们描述了纤维素线的用途，它既可以作为各种基质的合适采样介质，也可以通过改进的线喷雾质谱（MS）方法直接作为分析平台。通过对湿线施加直流电势，增强了提取效果，并随后生成微小的纳米液滴，从而实现了无需样品预处理的超灵敏农药检测。该方法应用于定量检测地表水 中的草甘膦及其代谢物氨甲基膦酸，检测限（LOD）为 12.2μg mL-1（标准添加校准）。该方法还用于分析莠去津的内标校准，其检测限为 0.74ng mL-1。增强型线喷雾 MS 平台在直接分析二苯胺和噻菌灵时也非常有效，这使得可以在不破坏水果的情况下对水果（表面和内部）进行收获后农药处理的评估。
