pH 4.5 Phosphate buffer(0.05M)- Dissolve 6.805g of monobasic potassium phosphate in1000ml of water.
Mobile phase -prepare a filtered and degassed mixture of acetonitrile and pH 4.5 phosphate buffer(0.05M)(65:35).adjust with phosphoric acid to a pH of 4.7,and mix.
chromatographic system chromatograph is equipped with a 205nm detector and a 3.9-mm*30-cm column that contains 10-um packing L8. the flow rate is maintained at about 1ml per minute. then change the composition linearly over the next 20 minutes to a mixture of 65% acetonitrile and 35% water. elute 100ml of this mixture,then change the composition liinearly over th following 20 minutes to 100% mobile phase, and allow chromatography to proceed for about 3 hours.chromatograph the resolution solution, and record the peak responses as directed for procedure: the resolution, R,between crotonoylbetaine(levocarnitine related compound A)and levocarnitine is not less than 1.0