Determination of morpholine residues in allopurinol by ion chromatography
Objective To establish an ion chromatographic method for the determination of morpholine residues in allopurinol.Methods IonPac CS12 column(250 mm×4.0 mm)was used,and 8~40 mmol·L-1 methanesulfonic acid was used as the mobile phases in gradient elution.The flow rate was 1.0 mL·min-1.The injection volume was 500 μL.The column temperature was 30 ℃.The analyte was detected conductively with a CERS 300(4 mm),and the current of inhibitor was 161 mA.External standard method was used to determine the content of morpholine.Results The blank solvent and allopurinol caused no interference.The calibration curve had good linearity for morpholine at 0.001 487~0.014 87 μg·mL-1(r=0.9991).The recoveries of morpholine ranged at 89.99%~118.00%(n=3),and the limit of quantitation(LOQ)was 1.487 ng·mL-1 The control solution and the labeled sample solution of morpholine were stable at room temperature within 46.5 h and 38 h,respectively.Conclusion The method is sensitive,and accurate with good specialization and durability,which can be used to determine morpholine residues in allopurinol.