In this work, a new colorimetric biosensor for the assay of paraoxon was developed via the conventional iodine-starch color reaction and multi-enzyme cascade catalytic reactions. In the presence of acetylcholine chloride, acetylcholinesterase (AChE) and choline oxidase (ChO) catalyzed the formation of H₂O₂, which then activated horseradish peroxidase (HRP) to catalyze the oxidation of KI to produce an iodine-starch color reaction. Upon exposure to paraoxon, the catalytic activity of AChE was inhibited and less H₂O₂ generated, resulting in a decrease in the production of I₂ and a drop in the intensity of solution color. This colorimetric biosensor showed high sensitivity for the assay of paraoxon with a limit of detection 4.7 ppb and was applied for the assay of paraoxon in spiked real samples. By employing the conventional iodine-starch color reaction, this biosensor has the potential of on-site assay of OPs residues in environmental samples.

中文翻译：

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基于碘-淀粉显色反应的比色生物传感器，用于环境水样中对氧磷的测定

在这项工作中，通过常规的碘-淀粉显色反应和多酶级联催化反应，开发了一种用于测定对氧磷的比色生物传感器。在存在乙酰胆碱氯化物的情况下，乙酰胆碱酯酶（AChE）和胆碱氧化酶（ChO）催化H ₂ O ₂的形成，然后激活辣根过氧化物酶（HRP）催化KI的氧化，从而产生碘-淀粉显色反应。当暴露于对氧磷，乙酰胆碱酯酶的催化活性被抑制，减少ħ ₂ ö ₂产生的，导致在生产的我的减少₂溶液颜色的强度下降。该比色生物传感器对对氧磷的检测显示出高灵敏度，检出限为4.7 ppb，适用于加标的真实样品中对氧磷的检测。通过使用常规的碘-淀粉显色反应，该生物传感器具有现场分析环境样品中OPs残留物的潜力。