Department of Analytical Chemistry, Institute of Chemistry, University of Campinas, Campinas, SP, 13083-970, Brazil.
PPG-SEA and NEEA/CRHEA/SHS, São Carlos Engineering School, University of São Paulo, São Carlos, SP, 13.560-970, Brazil.
Environ Monit Assess. 2020 Nov 27;192(12):797. doi: 10.1007/s10661-020-08776-3.
Fipronil and 2,4-D are two main pesticides of sugarcane cultivation in Brazil. While pesticides have helped to improve food quality and quantity, the continuous increase in usage has raised concerns over the unintended negative environmental impacts they introduce. Mesocosm systems are used as surrogate ecosystems to evaluate the fate, transport, and transformation of pesticides. Controlled experimental manipulations on mesocosms simulate the effects of stressors on the environment, in which the studies to evaluate effects on the living organisms and assess pesticide dynamics produce more realistic data than those obtained in the laboratory. However, analytical methods that follow mesocosm studies shall be robust enough towards sensitive variations in analyte concentration and matrix-induced effects of suppression or enhancement of analytical response. An analytical method using solid-phase extraction (SPE) along with liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed for simultaneous determination of fipronil, 2,4-D, and their respective transformation products in aquatic systems. The method presented instrument quantification limits from 0.1 to 10.0 ng mL and recovery values from 14 to 101%, with a maximum relative standard deviation (RSD) value of 12%. In the matrix effect assessment, the majority of matrix proportions showed a statistically relevant matrix effect for all compounds (p < 0.05). The method was further applied to over 500 different samples from mesocosm systems during controlled pesticide application and conversion of pastureland into sugarcane cropland. 2,4-D and fipronil mesocosm concentrations varied from 5 ng L to 1.6 mg L and 0.3 ng L to 56 μg L, respectively.
氟虫腈和 2,4-D 是巴西甘蔗种植的两种主要农药。虽然农药有助于提高食品的质量和数量，但使用量的持续增加引起了人们对其引入的意外环境负面影响的担忧。中宇宙系统被用作替代生态系统来评估农药的归宿、迁移和转化。在中宇宙系统中进行受控实验操作可以模拟环境胁迫因素对环境的影响，其中评估对生物的影响和评估农药动态的研究比在实验室中获得的数据更真实。然而，用于中宇宙研究的分析方法应足够稳健，以应对分析物浓度的敏感变化和基质对分析响应的抑制或增强的影响。本研究开发了一种使用固相萃取（SPE）和液相色谱串联质谱（LC-MS/MS）的分析方法，用于同时测定水生系统中的氟虫腈、2,4-D 及其各自的转化产物。该方法的仪器检测限为 0.1-10.0ng/mL，回收率为 14-101%，最大相对标准偏差（RSD）值为 12%。在基质效应评估中，大多数基质比例对所有化合物均表现出统计学上显著的基质效应（p<0.05）。该方法进一步应用于控制农药应用和牧场转化为甘蔗种植园期间中宇宙系统的 500 多个不同样本。中宇宙系统中的 2,4-D 和氟虫腈浓度分别为 5ng/L 至 1.6mg/L 和 0.3ng/L 至 56μg/L。
