This work introduces the concept of a counting-based measurement on paper analytical devices (cPADs) to improve the utilization of numerous reactions. The design of cPADs consists of two layers of paper substrates; the first layer contains a central sample zone combined with a radial surrounded by 12 detection zones that are predeposited with the various reagents, and the second layer acts as a connection channel between the sample zone and each detection zone. The solution can vertically flow from the first to the second layer and then move through the area to each subsequent detection zone. The analyte level can be evaluated by counting the number of detection zones that change color from a blank signal. Furthermore, our cPADs exhibit a capability of implementation for a broad series of reactions. Compared to the dPAD technique, some reactions that are possibly difficult to apply in such devices can be wholly enabled in our devices. The final color reaction on cPADs can apparently occur due to its identity. We applied this technique to the monitoring of carbaryl (CBR) and copper ions (Cu²⁺) using different reactions, including azo-coupling and complexation, respectively. Accordingly, this indicates an excellent result validated using the more traditional methods. Our cPADs can be applied for rapid screening of both CBR and Cu²⁺ in water samples with outstanding accuracy and precision using a naked-eye measurement by a relatively unskilled person. We offer a simple platform on PADs for rapid screening, combining high cost-effectiveness within a miniaturized platform designed for use with onsite applications, which is thus suitable for several different reactions.

中文翻译：

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一种基于简单计数的纸张分析设备测量方法及其应用

这项工作引入了基于计数的纸分析设备 (cPAD) 测量的概念，以提高众多反应的利用率。cPAD 的设计由两层纸基材组成；第一层包含一个中心样品区和一个由12个检测区包围的径向组合，这些检测区预先沉积了各种试剂，第二层作为样品区和每个检测区之间的连接通道。溶液可以从第一层垂直流到第二层，然后通过该区域到达每个后续检测区。分析物水平可以通过计算从空白信号改变颜色的检测区域的数量来评估。此外，我们的 cPAD 表现出执行一系列广泛反应的能力。与 dPAD 技术相比，一些可能难以在此类设备中应用的反应可以在我们的设备中完全启用。cPAD 上的最终颜色反应显然是由于其特性而发生的。我们将该技术应用于监测西维因 (CBR) 和铜离子 (Cu²⁺) using different reactions, including azo-coupling and complexation, respectively. Accordingly, this indicates an excellent result validated using the more traditional methods. Our cPADs can be applied for rapid screening of both CBR and Cu²⁺ in water samples with outstanding accuracy and precision using a naked-eye measurement by a relatively unskilled person. We offer a simple platform on PADs for rapid screening, combining high cost-effectiveness within a miniaturized platform designed for use with onsite applications, which is thus suitable for several different reactions.