MODIFIED PICRATE METHOD FOR DETERMINATION OF CYANIDE IN BLOOD

Cyanide (CN^- ) is widely distributed in the ecosystem and has been associated with toxic effects in humans and animals. Most outbreaks of CN^- poisoning in animals result from ingestion of plants containing cyanogenic glycosides. Various analytical techniques for estimating cyanide in blood are available. A simple picrate method was developed to determine blood CN^- in goats. This assay is a modification of commonly available methods using picrate paper and those using Conway diffusion cells. Cyanide in blood was measured during and after IV administration of KCN at 0.6 mg/min for 1 h. Blood CN^- levels in rabbits were determined after oral administration of KCN for 10, 20, 30 and 40 days. The CN^- concentration in blood of goats was time-dependent and continued rising during infusion followed by gradual decline after infusion stopped. A calibration curve set by dissolving various concentrations of KCN in distilled water showed a linear relationship between CN^- concentration and absorbance (R=0.995) ranging from 0.3-120 mg CN^- /L. Blood CN^- levels in rabbits showed time-dependent increase with maximum concentration (1.34 mg/L) at 40 days. This is a simple and inexpensive tool for the determination of blood CN^- in the laboratory and under field conditions as well.