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 ��m) with mobile phase consisting acetonitrile -20 mmol��L-1 ammonium acetate (adjusted to pH 2.5 with formic acid) (60��40)�� 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 �棬 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.
.The Structure Identification and Screening of Illegal Additive D-(-)- Isoascorbic Acid in Vitamin C Yinqiao Tablets[J] Chinese Pharmaceutical Journal, 2012,V47(4): 300-302
2012, Vol. 47 
