Laboratory for Assessment of Organic Contaminants (LACOr), Institute of Marine Sciences-Federal University of Ceará (LABOMAR-UFC), Av. Abolição, 3207-Meireles, CEP: 60165-081, Fortaleza, CE, Brazil.
Talanta. 2012 May 15;93:212-8. doi: 10.1016/j.talanta.2012.02.015. Epub 2012 Feb 13.
The effects promoted by environmental aqueous matrices on pesticide determinations have been assessed, and for the first time, a simple, low-cost and efficient strategy for the correction of analytical results has been determined. This method can be useful as a parameter of quality control in a quality assurance programs. Evaluation of the matrix effect showed that environmental aqueous matrices, e.g., estuarine water, promote a distinctive and significant effect on the determination of pesticides. The picloram, atrazine and methyl parathion pesticides suffered the smallest effects promoted by the estuarine matrix, whereas chlorpyrifos and cypermethrin suffer a significant effect. For picloram, the matrix effect was a function of its physiochemical properties. However, for atrazine, methyl parathion, chlorpyrifos and cypermethrin, the matrix effect was promoted by environmental matrix components. As strategy for analytical quality control, it has been determined that there are relation factors (RFs) between pesticides and the selected surrogates standards. These RFs are not altered by the complexities and compositions of simple and complex aqueous matrices. Predetermined RFs was applied to the picloram, atrazine and methyl parathion assessment in a real sample from the estuary of the Jaguaribe River, and the results showed that when no quality control was applied, the concentration levels would be underestimated, leading to incorrect results and inaccurate conclusions.
环境水基质对农药测定的影响已得到评估，并且首次确定了一种简单、低成本且高效的校正分析结果的策略。该方法可用作质量保证计划中质量控制的参数。基质效应的评估表明，环境水基质（如河口水）对农药的测定有显著影响。百草枯、莠去津和甲基对硫磷等农药受河口基质促进的影响最小，而氯菊酯和氯氰菊酯则受到显著影响。对于百草枯，基质效应是其物理化学性质的函数。然而，对于莠去津、甲基对硫磷、氯菊酯和氯氰菊酯，基质效应是由环境基质成分促进的。作为分析质量控制策略，已确定在简单和复杂水基质中，农药与所选替代标准品之间存在相关因子（RFs）。这些 RFs 不受简单和复杂水基质的复杂性和组成的影响。在来自 Jaguaribe 河口的实际样本中，已应用预定的 RFs 对百草枯、莠去津和甲基对硫磷进行评估，结果表明，如果不进行质量控制，浓度水平将会被低估，导致结果错误和结论不准确。
