The structure identification and screening of illegal additive D-(-)-isoascorbic acid in vitamin C Yinqiao tablets / 中国药学杂志

ABSTRACT

OBJECTIVE: To identify the structure of illegal additive D- (-) -isoascorbic acid in vitamin C Yinqiao tablets and to screen for it in different samples. METHODS: The separation of D- (-) - isoascorbic acid in vitamin C Yinqiao tablets was performed on a CAPCELL PAK NH2 column (4.6 mm × 250 mm, 5 μm) with mobile phase consisting acetonitrile -20 mmol · L-1 ammonium acetate (adjusted to pH 2.5 with formic acid) (6040), the flow rate was 1.0 mL · min-1. D-(-)-isoascorbic acid was detected by diode array detector at 246 nm. Electrospray ionization (ESI) source in positive ion mode was applied for the identification with following parameters; nebulizer pressure of 220 kPa, drying gas temperature of 350°C, flow rate of 12 L · min-1, and capillary voltage of 3.5 kV. The additive D-(-)- isoascorbic acid in vitamin C Yinqiao tablets was separated and prepared by HPLC for further structure confirmation by 13C-NMR. RESULTS: The structure of the additive was elucidated by analyzing the fragment of [M + H]+ of the additive and comparing with that the reference substance. The additive was further confirmed as D-(-)- isoascorbic acid by 13C-NMR. D-(-) - isoascorbic acid was detected in 64 of 366 batch samples. CONCLUSION: The LC-MS method is accurate and sensitive, which can be used for rapid screening and identification of the illegal additive D- (-) - isoascorbic acid in vitamin C Yinqiao tablets. Copyright 2012 by the Chinese Pharmaceutical Association.