Figure 6: Typical HPLC chromatograms obtained from 20 μl injections of Amlodipine Besylate Amlodipine impurity A, B, Atorvastatin Calcium, Atorvastatin impurity A and C under chromatographic conditions of mobile phase consisted of acetonitrile: phosphate buffer (PH = 6.5) was pumped on columns at a flow rate 1.2 ml/min and detected at 240 nm at constant temperature 40°C. (Ascending order)
1- Agilent eclipse plus C18 (3.5 um, 4.6 x 100 mm) and acetonitrile 30%
2- Agilent eclipse plus C18 (3.5 um, 4.6 x 100 mm) and acetonitrile 35%
3- Thermo BDS HYPERSIL C18 (5um, 150 X 4.6 mm) and acetonitrile 30%
4- Thermo BDS HYPERSIL C18 (5um, 150 X 4.6 mm) and acetonitrile 35%