Institut für Energie- und Umwelttechnik e. V. (IUTA, Institute of Energy and Environmental Technology), Bliersheimer Str. 58-60, 47229, Duisburg, Germany.
Instrumental Analytical Chemistry, Faculty of Chemistry, University of Duisburg-Essen, Universitätsstr. 5, 45141, Essen, Germany.
Anal Bioanal Chem. 2022 Jun;414(14):4167-4178. doi: 10.1007/s00216-022-04068-6. Epub 2022 May 18.
Pesticides such as organothiophosphates (OTPs) are neurotoxically active and enter the aquatic environment. Bioassays, using acetylcholinesterase (AChE), a suitable substrate and reactant, can be applied for the photometric detection of AChE-inhibiton (AChE-I) effects. The oxidized forms of OTPs, so-called oxons, have higher inhibition potentials for AChE. Therefore, a higher sensitivity is achieved for application of oxidized samples to the AChE assay. In this study, the oxidation of malathion, parathion, and chlorpyrifos by n-bromosuccinimide (NBS) was investigated in an approach combining high-performance thin-layer chromatography (HPTLC) with an AChE-I assay. Two AChE application approaches, immersion and spraying, were compared regarding sensitivity, precision, and general feasibility of the OTP effect detection. The oxidation by NBS led to an activation of the OTPs and a strong increase in sensitivity similar to the oxons tested. The sensitivity and precision of the two application techniques were similar, although the spray method was slightly more sensitive to the oxidized OTPs. The 10% inhibition concentrations (IC) for the spray approach were 0.26, 0.75, and 0.35 ng/spot for activated malathion, parathion, and chlorpyrifos, respectively. AChE-I effect recoveries in samples from a stormwater retention basin and receiving stream were between 69 and 92% for malathion, parathion, and chlorpyrifos. The overall workflow, including sample enrichment by solid-phase extraction, HPTLC, oxidation of OTPs, and AChE-I assay, was demonstrated to be suitable for the detection of AChE-I effects in native water samples. An effect of unknown origin was found in a sample from a stormwater retention basin.
有机磷杀虫剂（OTPs）具有神经毒性，并会进入水生环境。生物测定法，使用乙酰胆碱酯酶（AChE）作为合适的底物和反应物，可以用于检测 AChE 抑制（AChE-I）效应的光密度。OTPs 的氧化形式，即所谓的氧代物，对 AChE 的抑制潜力更高。因此，对于将氧化后的样品应用于 AChE 测定，灵敏度更高。在这项研究中，采用高效薄层层析法（HPTLC）与 AChE-I 测定相结合的方法，研究了 N-溴代丁二酰亚胺（NBS）对马拉硫磷、对硫磷和毒死蜱的氧化作用。比较了两种 AChE 应用方法，即浸泡和喷雾，在灵敏度、精密度和一般检测 OTP 效应的可行性方面。NBS 的氧化导致 OTPs 被激活，灵敏度显著提高，类似于测试的氧代物。两种应用技术的灵敏度和精密度相似，尽管喷雾方法对氧化的 OTP 略为敏感。喷雾方法的 10%抑制浓度（IC）分别为 0.26、0.75 和 0.35ng/斑点，用于激活的马拉硫磷、对硫磷和毒死蜱。从雨水滞留池和接收溪流中的样品中，AChE-I 效应回收率分别为马拉硫磷、对硫磷和毒死蜱的 69%至 92%。包括固相萃取、HPTLC、OTP 氧化和 AChE-I 测定在内的整个工作流程，被证明适用于检测天然水样中的 AChE-I 效应。在一个雨水滞留池的样品中发现了一种未知来源的效应。
