A Dual-Channel and Dual-Signal Microfluidic Paper Chip for Simultaneous Rapid Detection of Difenoconazole and Mancozeb

Abstract

Using L-cysteine (L-Cys) modified carbon quantum dots (CQDs) and CdTe quantum dots (CdTe QDs) as fluorescence signals, we developed a novel dual-channel and dual-signal microfluidic paper chip, which enables portable and rapid analysis of difenoconazole and mancozeb by internal filter effect (IFE) and photoinduced electron transfer (PET), respectively. The results indicate that the two single-fluorescence imprinted paper chips have great stability and fluorescence property, and the dual-channel microfluidic paper chip composed of them can achieve simultaneous rapid detection of difenoconazole and mancozeb in a mixed solution. The rapid quantitative detection of two templates were achieved under the same excitation wavelength (360 nm) within 5 min. The limits of detection of difenoconazole and mancozeb were 0.18 μg/mL and 2 μg/mL, respectively. Furthermore, the dual-channel microfluidic paper chip also had good specific recognition for their analogs. Moreover, its recoveries of the actual samples were 102.2-108.8% and 96.0-105.5%, respectively, and the relative standard deviations were all less than 5.6%. In conclusion, this work has successfully prepared a multi-template rapid quantitative pesticide residue detection sensor, which provides a useful exploration for the development of new universal rapid detection technologies and theories and is of great significance for the rapid detection of pesticide residues in export products.

Keywords: pesticide residues, rapid detection, Dual-channel detection, Microfluidic paper chip, Quantum dots