Flow Control-based 3D μPADs for Organophosphate Pesticide Detection

Abstract

Flow control-based paper devices have recently shown great potential for point-of-need analysis, since they allow for the easy operation of multi-step assays by minimizing user operation. In this work, a wax printing method was evaluated as a means to control liquid flow in 3D microfluidic paper-based analytical devices (μPADs). The resulting flow controlbased 3D μPADs were applied to determine paraoxon-ethyl as a typical organophosphate pesticide model system. The analytical procedure is as simple as applying a 200-μL sample solution, resulting in reproducible (relative standard deviation of colorimetric signals from 6 independently fabricated devices, 2.63%) colorimetric signals within 1 h of the assay time with the limit of detection (LOD) reaching 25.0 μg/L. Finally, results obtained for pesticide-spiked water samples analyzed by flow control-based 3D μPADs showed good agreement with those from a conventional HPLC analysis with UV detection.

Bioactive microfluidic paper device for pesticide determination in waters

“…However, these methods require different operating steps that are performed manually, such as adding external reagents or inverting the device at a given time to produce the colour. To solve these problems, a flow control-based 3D µPAD is proposed in which the flow rate is controlled by modifying the length and width of the channels for an optimum interaction between the pesticide, AChE and chromogen indoxyl acetate, which promotes their hydrolysis and subsequent atmospheric oxidation to blue indigo dye [13]. Alternatively, a dual flow channel design has been proposed in which the fluid moves at different speeds by sandwiching the paper channels between flexible films [14].…”

Paper-Based Analytical Device for the On-Site Detection of Nerve Agents

“…A comparison of our device with other reported paper devices for pesticide and nerve agent testing and with DETEHIT is shown in Table S1. ,− Given the cumbersome procedure, long incubation time, and low robustness of the other devices and the selectivity to nerve agents, the present device is believed to be useful for rapid testing of unknown materials at the scene of a terrorist attack. The good selectivity of the present device is due in part to the short incubation time, which allows for rapid detection.…”

Determination of Phosphorus

“…This method provides the results with high reproducibility (2.63% RSD) regardless of user skills. 18 This highlight introduces recent achievements of concerning the determination of phosphorus, which has been extensively investigated for several decades. The molybdenum blue method has been well established for the determination of orthophosphate, but it has less selectivity for arsenate(V).…”