Comparison of four different methods for the determination of sulfites in foods marketed in South Korea.

Sulfites in foods were analysed using four methods: optimised Monier-Williams (official method), modified Rankine, HPLC and ion-exchange chromatography (IEC). The modified Rankine and HPLC methods were performed according to the previously reported methods but with some modifications. The IEC method was carried out through a combination of a modified Rankine apparatus and an anion-exchange column for the first time. In false-positive response tests, false-positive results with acetic acid and propionic acid were not observed in the modified Rankine, HPLC or IEC methods, unlike the optimised Monier-Williams method. All methods were evaluated for accuracy, precision and simple correlations. Modified Rankine, HPLC and IEC methods were determined to be suitable for foods with less than 10 mg kg(-1) of sulfur dioxide (SO₂). The modified Rankine and HPLC methods were suggested to be the most appropriate for the determination of sulfites in foods due to their high correlation coefficient with the optimised Monier-Williams method (R(2) = 0.9138 and 0.9011, respectively).