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

The addition of potassium ferrocyanide (K-4[Fe(CN)(6)]) in table salt as anti-caking agent has a crucial role in preventing the formation of lumps. However, the excess of K-4[Fe(CN)(6)] 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-4[Fe(CN)(6)] in table salt and salted food. Herein, a novel fluorescent Si QDs probe for sensitive, selective and rapid detection of K-4[Fe(CN)(6)] was synthesized by facile one-step strategy. Notably, the fluorescence of Si QDs could be remarkably quenched by K-4[Fe(CN)(6)] via electrostatic interaction. Based on this phenomenon, a new method of determination of K-4[Fe(CN)(6)] was established. A wide linear range was obtained from 0.05 to 8.0 mu g/mL with a detection limit of 30 ng/mL. The established fluorescent new method was suitable for detecting K-4[Fe(CN)(6)] in table salt and salted food samples with satisfactory results.