To minimize the impact of pesticide residues in food on human health, it is necessary to enhance their detection. Recently, many nanozyme-based colorimetric methods for pesticides detection have been developed, however, they often required the assistance of natural enzymes, which made the process and result of methods susceptible to the stability and activity of natural enzymes. To overcome these drawbacks, methods for direct detection of pesticides using nanozymes have been developed, and there are few studies in this field currently. Thus, it is of great research and practical significance to develop more nanozymes-based colorimetric methods for direct detection of pesticides. Dual colorimetric platforms based on Os-Rh nanozyme with excellent peroxidase-like activity were constructed for directly detection of glyphosate in this work. Results showed that glyphosate was able to sensitively and selectively inhibit the peroxidase-like activity of Os-Rh nanozyme through hindering the decomposition of HO by Os-Rh nanozyme to produce HO∙. Based on this, the dual colorimetric platforms achieved highly sensitive detection for glyphosate over a wide linear concentration range (50–1000 μg L in solution platform and 200–1000 μg L in paper platform), with the detection limits of 28.37 μg L in solution platform and 400 μg L (naked-eye detection limit)/123.25 μg L (gray scale detection limit) in paper platform, respectively. Moreover, the dual colorimetric platforms possessed satisfactory reliability and accuracy for practical applications, and has been successfully applied to the detection of real samples with the spiked recoveries of 92.78–102.75 % and RSD of 1.17–3.88 %. The dual colorimetric platforms for glyphosate direct detection based on Os-Rh nanozyme developed in this work not only owned considerable practical application potential, but also could provide more inspirations and ideas for the rational design and development of colorimetric sensing methods for the rapid detection of pesticides based on nanozymes.

中文翻译：

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基于具有类过氧化物酶活性的 Os-Rh 纳米酶的双比色平台直接检测草甘膦


为了最大限度地减少食品中农药残留对人体健康的影响，有必要加强其检测。近年来，人们开发了许多基于纳米酶的农药检测比色方法，但它们往往需要天然酶的辅助，这使得方法的过程和结果容易受到天然酶的稳定性和活性的影响。为了克服这些缺点，已经开发了利用纳米酶直接检测农药的方法，但目前该领域的研究很少。因此，开发更多基于纳米酶的比色法直接检测农药具有重要的研究和实际意义。本工作构建了基于具有优异的过氧化物酶样活性的Os-Rh纳米酶的双比色平台，用于直接检测草甘膦。结果表明，草甘膦通过阻碍 Os-Rh 纳米酶分解 H2O2 生成 H2O·2，能够灵敏、选择性地抑制 Os-Rh 纳米酶的类过氧化物酶活性。在此基础上，双比色平台实现了较宽线性浓度范围（溶液平台50~1000 μg·L，纸质平台200~1000 μg·L）对草甘膦的高灵敏度检测，溶液中检出限为28.37 μg·L平台和纸质平台分别为400 μg·L（肉眼检测限）/123.25 μg·L（灰度检测限）。此外，双比色平台在实际应用中具有令人满意的可靠性和准确性，并已成功应用于实际样品的检测，加标回收率为92.78%~102.75%，RSD为1.17%~3.88%。 本工作开发的基于Os-Rh纳米酶的草甘膦直接检测双比色平台不仅具有相当大的实际应用潜力，而且可以为农药快速检测比色传感方法的合理设计和开发提供更多的启发和思路基于纳米酶。