A smartphone based-paper test strip chemosensor coupled with gold nanoparticles for the Pb2+ detection in highly contaminated meat samples

Abstract

A rapid and selective colorimetric chemosensor based on a paper test-strip platform and smartphone detection were investigated to determine lead ions (Pb2+) in meat samples. The colorimetric chemosensor for Pb2+ analysis, the rhodamine 6G −1 (RD6G −1 probe), was synthesized through the Schiff base formation of rhodamine 6G hydrazide and 3,4,5-trimethoxybenzaldehyde. The Pb2+ sensing process was accomplished by the color on the detection zone change from colorless to pink within 1 min. The proposed chemosensor strip was functionalized with (3-aminopropyl)triethoxysilane and gold nanoparticles (AuNPs) to enhance the colorimetric response. Under the optimal conditions, the color intensity of the chemosensor strip increased linearly with the Pb2+ concentrations in the range of 0.1–1.0 mg/L. This developed strip allowed low detection limit (0.12 mg/L). The paper test strip modified with AuNPs provided a color response 9-fold higher than the one without AuNPs. Moreover, the paper test strip was successfully applied for Pb2+ analysis in meat samples, consistent with the inductively coupled plasma-mass spectrometry method.This work showed the proposed smartphone-based paper test-strip chemosensor offers a highly selective and accurate quantitative detection of Pb2+ ions without the additional equipment.