An integrated platform consisting of a microfluidic paper-based analytical device (μPAD) and a portable detection system is proposed for low concentration formaldehyde (CH₂O) detection. In the proposed approach, the reaction zone of the μPAD is coated with ammonium acetate (AA) and acetoacetanilide (AAA) indicator and is dried at 40 °C for 30 min. The formaldehyde sample is then dripped on the reaction zone and the μPAD is transferred to a hot plate in the portable detection system. A Hantzsch reaction is induced by heating the μPAD at 30 °C for 10 min. The resulting fluorescent formaldehyde-Acetoacetanilide complex (dihydropyridine derivative) is observed by a CMOS camera and the color image is transferred to a smartphone by means of a connector. Finally, the CH₂O concentration is derived using self-written RGB color analysis mobile software implemented on the phone. The experimental results obtained using control samples with known CH₂O concentrations in the range of 0.2–2.5 ppm show that the B (blue) fluorescence intensity (Y) and formaldehyde concentration (X) are related as Y = 29.455 X + 117.64. Moreover, the correlation coefficient is equal to R² = 0.9937. The real-world applicability of the proposed detection platform is demonstrated by measuring the CH₂O concentration in twelve commercial food samples. It is shown that the concentration measurements obtained using the proposed system deviate by no more than 6.2% from those obtained using a conventional spectrophotometric technique. Overall, the results presented in this study show that the proposed integrated microfluidic paper-based system provides a compact and reliable tool for low concentration CH₂O measurement purposes.

提出了一个由微流体纸质分析设备（μPAD）和便携式检测系统组成的集成平台，用于低浓度甲醛（CH ₂ O）检测。在提出的方法中，μPAD的反应区涂有乙酸铵（AA）和乙酰乙酰苯胺（AAA）指示剂，并在40°C下干燥30分钟。然后将甲醛样品滴在反应区上，并将μPAD转移到便携式检测系统中的加热板上。通过在30°C下加热μPAD10分钟来诱导Hantzsch反应。用CMOS照相机观察所得的荧光甲醛-乙酰乙酰苯胺络合物（二氢吡啶衍生物），并通过连接器将彩色图像转印至智能手机。最后，CH ₂O浓度是使用在手机上实现的自写RGB颜色分析移动软件得出的。使用已知CH ₂ O浓度在0.2-2.5 ppm范围内的对照样品获得的实验结果表明，B（蓝色）荧光强度（Y）和甲醛浓度（X）的关系为Y = 29.455 X + 117.64。此外，相关系数等于R ²  = 0.9937。通过测量CH ₂证明了所提出的检测平台在现实世界中的适用性十二种商业食品样品中的O浓度。结果表明，使用建议的系统获得的浓度测量值与使用常规分光光度技术获得的浓度测量值相差不超过6.2％。总体而言，本研究中提出的结果表明，所提出的基于微流体纸的集成系统为实现低浓度CH ₂ O测量目的提供了一种紧凑而可靠的工具。