Determination of Trifluoroacetic Acid£¨TFA£© Residues in Linagliptin Drugs by Ion Chromatography with Direct Conductance

KeyWord:ion chromatography with direct conductance  trifluoroacetic acid£¨TFA£©  linagliptin

Abstract:

      An ion chromatographic method was developed for the determination of trifluoroacetic acid£¨TFA£© residues in linagliptin drugs.After dissolved with dichlomethane and extracted with water£¬the samples were loaded onto the instument.The determination was performed on an Ionpac AS11-HC£¨4 mm¡Á25 cm£© column with an IonpacAG11-HC£¨4 mm¡Á5 cm£© guard column.The eluent was 20 mmol/L potassium hydroxide solution produced on-line with EG¢ó KOH at a flow rate of 1ª±2 mL/min.TFA was detected by suppressed conductivity with an ASRS 500-4 mm suppressor at a current of 60 mA.The column temperature was set at 30 ¡æ and the injection volume was 25 ¦ÌL.There was a good resolution between trifluoroacetic acid and other components.The calibration curve showed a good linearity£¨r=0.999 4£© in the range of 0.848-6.46 ¦Ìg/mL.The limit of detection£¨LOD£© was 0.031 8 ¦Ìg/mL and the limit of quantitation£¨LOQ£© was 0.106 ¦Ìg/mL.The method has the advantages of simple operation,high sensitivity and good reproducibility,and could be used for the detection of trifluoroacetic acid£¨TFA£© residues in linagliptin drugs.