An optical material for the detection of trace S2O3 2− in milk based on a copper complex

A novel S2O3 2− luminescent sensor (Cu2+-p-CPIP) was developed and the presence of S2O3 2− caused an obvious fluorescence enhancement at 420 nm upon excitation at 330 nm, which could be distinguished with the naked eye under a UV lamp. Remarkably, the compound exhibited excellent selective and sensitive response to S2O3 2− over other common anions with a micromolar limit of detection (0.442 μM) in DMSO/H2O (v/v, 1:1) buffer. The absorbance intensity and the color of Cu2+-p -CPIP solution changed gradually with the increase of S2O3 2− concentration. The proposed method was applied to the determination of S2O3 2− in milk samples and the recoveries were 97.5–105%. The preparation of Cu2+-p -CPIP exhibited the quick, simple and facile advantages. The results showed that Cu2+-p -CPIP can be a good candidate for simple, rapid and sensitive colorimetric detection of S2O3 2− in aqueous solution.