Miniaturized dielectric barrier discharge-molecular emission spectrometer for determination of total sulfur dioxide in food.

SO2 is a type of additive widely used in the food processing industry as preservative and anti-browning, bleaching, or effective antibacterial agent. However, the SO2 residue can have adverse effects on human health. In this work, a low-temperature microplasma generated by dielectric barrier discharge was used for the direct, in situ excitation of the molecular emission of SO2 in food samples. The food samples were acidified and heated to release SO2 and a miniaturized charge-coupled device spectrometer recorded the characteristic emission line at 301.9 nm. The linear correlation coefficient of the method was greater than 0.99 in the range of 10 to 100 mg L-1. Moreover, the limit of detection was 0.01 mg L-1, with recoveries between 72% and 108% and relative standard deviations of 1.5%-7.6%. The method is simple, accurate, low-cost, involves miniaturized and compact equipment and is suitable for the determination of total SO2 in food samples.