Rapid microfluidic analysis detection system for sodium dehydroacetate in foods

Sodium dehydroacetate (NADH) has good antibacterial effects and is widely used as a preservative in dairy products. However, NADH is toxic in large amounts, so it must be added to food in accordance with regulations. Accordingly, the current study has developed a microfluidic analysis detection (MAD) system for the determination of NADH in foods incorporating a microfluidic PMMA-paper chip and a smart analysis device. In this system, the extracted NADH sample is dropped into the sample chamber of the microfluidic PMMA-paper chip and is then wicking/filtering through paper strips and transferred to a detection zone embedded with Fe-Alum reagent. The chip is heated at 35 °C for 5 min to produce a compound reaction and the color compound image acquired by a camera is then transmitted wirelessly to a smartphone, where the NADH concentration is obtained by the intensity inversion of RGB analysis. A standard calibration curve is determined using NADH control samples with concentrations in the range of 30–5000 ppm. The feasibility of the proposed MAD system is then evaluated by analyzing the NADH concentrations of 15 commercial dairy products. It is shown that the measured values deviate from those obtained using an official high performance liquid chromatography (HPLC) method by no more than 5.0%.