Rapid microfluidic paper-based platform for low concentration formaldehyde detection

Abstract

Abstract An integrated platform consisting of a microfluidic paper-based analytical device (μPAD) and a portable detection system is proposed for low concentration formaldehyde (CH 2 O) 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 CH 2 O concentration is derived using self-written RGB color analysis mobile software implemented on the phone. The experimental results obtained using control samples with known CH 2 O 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 R 2 = 0.9937. The real-world applicability of the proposed detection platform is demonstrated by measuring the CH 2 O 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 CH 2 O measurement purposes.