3.1.5. Effect of mobile phase pH
We studied the effect of varying the pH between 7.57 and 9, using ammonia solution (35%, w/w). We
observed that the best separation results were achieved at pH ¼ 9 (Fig. 6).
3.2. Validation of the method
Identity of each peak was confirmed by the retention time. Method compatibility with the
requirements of system suit- ability according to the standards of U.S. Pharmacopeia [9]
ability according to the standards of U.S. Pharmacopeia [9]