Determination of potassium ferrocyanide in table salt and salted food using a water-soluble fluorescent silicon quantum dots.

The addition of potassium ferrocyanide (K[Fe(CN)]) in table salt as anti-caking agent has a crucial role in preventing the formation of lumps. However, the excess of K[Fe(CN)] and its decomposers are harmful to both human health and environment. To date, there are still lack of suitable methods for simple and rapid analysis of K[Fe(CN)] in table salt and salted food. Herein, a novel fluorescent Si QDs probe for sensitive, selective and rapid detection of K[Fe(CN)] was synthesized by facile one-step strategy. Notably, the fluorescence of Si QDs could be remarkably quenched by K[Fe(CN)] via electrostatic interaction. Based on this phenomenon, a new method of determination of K[Fe(CN)] was established. A wide linear range was obtained from 0.05 to 8.0 µg/mL with a detection limit of 30 ng/mL. The established fluorescent new method was suitable for detecting K[Fe(CN)] in table salt and salted food samples with satisfactory results.