AN IMPROVED METHOD FOR DETERMINATION OF THIOCYANATE IN PLASMA AND URINE

An improved spectrophotometric method is described for the determinati on of thiocyanate in plasma and urine. Thiocyanate is adsorbed on a we ak anion-exchange resin with strong affinity for chaotropic ions, and eluted with perchlorate. Thiocyanate is then chlorinated by hypochlori te and quantified according to the Konig (J Prakt Chem 1904; 69:105-37 ) reaction by use of isonicotinic acid and 1,3-dimethyl-barbituric aci d. The method affords a simple, rapid and sensitive assay for thiocyan ate and has a detection limit of 0.93 mu mol/l. At thiocyanate concent rations of 107.1 and 167.4 mu mol/l in plasma and urine the within-day CVs were 0.69% and 1.1% respectively, and the total imprecision measu red for a period of 65 days was 0.98%. Analytical recoveries were quan titative both with urine and plasma samples.