An ultra-sensitive colorimetric sensor based on smartphone for pyrophosphate determination

Monitoring pyrophosphate (PPi) in food is still a challenge due to lack of ultrasensitive, rapid, and selective analysis techniques. Herein, a smartphone-based colorimetric sensor based on anti-aggregation of polyvinylpyrrolidone (PVP) modified silver nanoparticles caused by Pb2+ is reported, which lead to a color change from blue to yellow for accurate and reliable detection of PPi in water and canned meat. The smartphone-based colorimetric sensor exhibits high sensitivity with detection limits of 1.0 μM by naked-eyes and 0.2 μM by smartphone analysis. Confirmatory analysis indicates that the proposed smartphone-based colorimetric sensor exhibits feasibility and real time performance for PPi detection in real food samples. The first-principles calculations at the PBE/DNP + level indicate that the Gibbs free energy (ΔG) of the interaction between PPi and Pb2+ is much higher than that between PVP and Pb2+, which effectively verified the anti-aggregation detection mechanism. This study provides a meaningful design strategy for the development of novel colorimetric sensors in the future.