Determination of Total Cyanide in Drugs by Ion Chromatography Combined with Phosphoric Acid Distillation

A method was developed for the determination of total cyanide in drugs by ion chromatography combined with phosphoric acid distillation. The samples were heated and distilled in a phosphoric acid solution, and the hydrogen cyanide evaporated was absorbed by the sodium hydroxide solution. The cyanide (CN^-) in the solution was determinated by ion chromatography with amperometric detector. Ion chromatographic condition:IonPac AS11-HC chromatographic column (250 mm×4 mm) and IonPac AG11-HC protect column (50 mm×4 mm) were used with the mobile phase of 4 mmol·L^-1 NaOH solution, and the flow rate was 1.0 mL·min^-1. Linear relationship between values of peak area and the mass concentration of CN^- was found in the range of 0.02-1.0 mg·L^-1 with correlation coefficient of 0.999 7. Values of detection limit (3S/N) for CN^- was 0.004 mg·L^-1. The recovery of sample ranged from 100% to 102%, and the RSDs (n=6) ranged from 1.0% to 2.1%. The method is sensitive, high precision and good repeatability. The method avoids the interference of matrix in drugs to the determination of cyanide,which is successfully used for the determination of cyanide in drugs.