Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, USA.
U.S. Army Combat Capabilities Development Command (DEVCOM)-Soldier Center, 10 General Greene Avenue, Natick, Massachusetts 01760, USA.
Analyst. 2024 Nov 18;149(23):5684-5692. doi: 10.1039/d4an01203h.
Pesticides are primarily used in agriculture to protect crops and extend their longevity. However, pesticide exposure has been linked to various acute and chronic health effects, raising significant environmental concerns. Current detection methods are often expensive and time-consuming, relying on complex instruments. Although enzyme-inhibition-based microfluidic paper-based analytical device (mPAD) platforms offer an easier alternative, they suffer from slow analyte transport and analyte adsorption issues in microchannels. Consequently, there is a need for a fast, simple, and cost-effective point-of-need platform for pesticide sensing. In this study, we present a rapid microfluidic platform for on-site pesticide residue detection. Unlike traditional mPAD platforms, our system transports pesticide samples through hollow capillary channels within seconds without adsorption of pesticides in the microchannels. While much research has focused on acetylcholinesterase inhibition on paper, this study is the first to introduce a tyrosinase inhibition-based assay on a paper platform for pesticide detection. Ziram, a representative dithiocarbamate pesticide, was detected using a colorimetric enzymatic inhibition assay. A limit of detection (LoD) of 1.5 ppm was obtained. In this study, we optimized the fast-flow device, assessed its stability and susceptibility to various interferences, and conducted real-sample tests using glove extraction to evaluate its capability in real-world settings. Spike recovery analysis revealed an extraction efficiency of 82.5% to 87.5% for leather gloves and 68.9% to 71.9% for nitrile gloves. This platform demonstrates strong selectivity against interferences, with the enzyme retaining 90% activity even after a week under the established storage protocols with room for further investigation. While primarily a proof of concept, this device shows promise as an additional tool for pesticide detection, with potential future integration into multiplexed devices.
农药主要用于农业保护作物并延长其寿命。然而，农药暴露已与各种急性和慢性健康影响有关，引起了重大的环境问题。目前的检测方法通常昂贵且耗时，依赖于复杂的仪器。尽管基于酶抑制的微流控纸基分析器件 (mPAD) 平台提供了一种更容易的替代方法，但它们在微通道中存在分析物传输缓慢和分析物吸附问题。因此，需要一种快速、简单且具有成本效益的现场农药传感平台。在本研究中，我们提出了一种用于现场农药残留检测的快速微流控平台。与传统的 mPAD 平台不同，我们的系统在几秒钟内通过空心毛细管通道输送农药样品，而不会在微通道中吸附农药。虽然许多研究都集中在纸上的乙酰胆碱酯酶抑制上，但本研究首次在纸平台上引入了基于酪氨酸酶抑制的农药检测分析。使用比色酶抑制测定法检测代表性的二硫代氨基甲酸盐农药福美锌。得到了 1.5 ppm 的检测限 (LoD)。在本研究中，我们优化了快速流动装置，评估了其稳定性和对各种干扰的敏感性，并使用手套提取进行了实际样品测试，以评估其在实际环境中的能力。加标回收分析表明，皮革手套的提取效率为 82.5%至 87.5%，丁腈手套的提取效率为 68.9%至 71.9%。该平台对干扰具有很强的选择性，即使在根据既定储存方案储存一周后，酶仍保留 90%的活性，还有进一步研究的空间。虽然这主要是一个概念验证，但该设备作为农药检测的附加工具具有很大的潜力，未来可能会集成到多路复用设备中。
