| 摘要 |
PROBLEM TO BE SOLVED: To provide a simultaneous analytical method of negative/positive counter ions which are used frequently for drugs. SOLUTION: The method for simultaneously analyzing negative/positive counter ions includes a separation step for applying a counter-ion containing sample of a drug containing positive ions and negative ions to a hydrophilic interaction chromatography, by using a column having an amphoteric ion type functional group and eluents which are mixed solutions of water, acetonitrile and ammonium acetate buffer, wherein the separation step includes, (i) a step of eluting with an eluent the concentration of which is adjusted so that the mixed solution contains 70-90 v/v% of acetonitrile and 10-40 mmol/L of the buffer solution, and (iii) a step of eluting with an eluent, the concentration of which is adjusted so that the mixed solution contains 40-70 v/v% of acetonitrile and 30-100 mmol/L of the buffer solution, and in the separation step the eluent is concentration adjusted by changing the mutual ratio of water, acetonitrile and the buffer solution in the mixed solution. COPYRIGHT: (C)2011,JPO&INPIT
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