2024 年 31 巻 2 号 p. 84-89
In this study, we validate the use of a HPLC method, which is listed as the confirmation test for sulfur dioxide (SO2) and sulfites in the notification, “Analytical Methods for Food Additives in Foods” by the Ministry of Health, Labour and Welfare in Japan, as a quantitative method. Moreover, the stability of aqueous 1% triethanolamine (tris(2-hydroxyethyl)amine: TEA) SO2 solution with several concentrations was tested. The results revealed that the long-term (1 year) stability at 5℃ was favorable under the concentration of 1,000 µg/mL with the range of 0.1-20 µg/mL, which are normally used for standard stock and calibration solutions, respectively. Conversely, the high-concentration standard solutions (10,000 and 20,000 µg/mL), usually used in spike tests around the upper acceptable limit, are unstable even after 3 days of storage at 5℃, suggesting that such solutions must be prepared at the time of their use. Furthermore, recovery tests conducted by spiking an SO2 solution equivalent to the upper acceptable limits to eight types of food showed the HPLC method was applicable for quantification. Thus, their recovery range was 86.9%-95.6% and their RSD of repeatability and intra-laboratory reproducibility were 1.7%-4.6% and 2.4%-6.9%, respectively. These results suggest that the HPLC method is useful for quantitative analysis of SO2 in foods during daily inspections.