DETERMINATION OF CYANIDE BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY USING POSTCOLUMN DERIVATIZATION WITH O-PHTHALALDEHYDE

A simple, highly sensitive and selective method for the determination of cyanide ion by high-performance liquid chromatography (HPLC) with p ostcolumn fluorescence derivatization is described. Cyanide ion was se parated on an ion-exclusion chromatographic column and derivatized wit h two reagents, ammonium ion in the mobile phase and o-phthalaldehyde in the postcolumn reagent solution at pH 9.5. Sulfite ion, 2-mercaptoe thanol and 3-mercaptopropionic acid did not interfere with the analysi s. The average recovery of cyanide from spiked environmental water sam ples (river water) was 99.0% (n = 6). The relative standard deviation was 2.5% (based on peak area) for cyanide standard solutions (0.1 mu g /ml, n = 10). The linear determination range was from 2.5 ng/ml to 1 m u g/ml. The detection limit was 0.1 ng/ml (signal-to-noise ratio = 3, injection volume 200 mu l).