Optimal separation was obtained using mobile phases consisting of 1% (v/v) aqueous acetic acid (solvent A) and 100% acetonitrite (solvent B).
HPLC analyses of model chiral drugs were performed using hydro-organic mobile phases consisting of an organic solvent (acetonitrile or methanol) and aqueous solutions of ammonium acetate (0.020 M) or ammonium formate (0.0025 0.0050 M).
In current article, several aqueous mobile phases, consisting of methanol, water or acetonitrile and water (with or without adjusting pH value), or different buffers (such as ammonium acetate, ammonium formate and formic acid), with altered flow rates, and different gradient compositions, were used to optimize HPLC chromatographic conditions.
A gradient elution was used, with mobile phases consisting of A (water with 1 g/L ammonium acetate and 0.1% formic acid) and B (acetonitrile with 1 g/L ammonium acetate and 0.1% formic acid).
The separation was executed with mobile phases consisting of A; formic acid/water (5/95, v/v) and B; formic acid/acetonitrile (5/95, v/v) with the following gradient elution: 0-2 min 10% B, 2-17 min 10-20% B, 17-21 min 20-60% B, 21-25 min 60% B, 25-27 min 60-10% B. The column was allowed to equilibrate for 5 min between injections (10 μL).
The separation of phenolic compounds was executed with mobile phases consisting of A; acetic acid/water (2/98, v/v) and B; acetic acid/acetonitrile (2/98, v/v) with the following gradient: 0-5 min 0% B, 5-44 min 0-250-25%44-47 min 25-60% B, 47-56 min 60% B, 56-58 min 60-100% B, 58-61 min 100% B, 61-64 min 100-0% B. The column was allowed to equilibrate for 7 min between injections (10 μL).
