Simple Method for Determination of Thiocyanate in Urine

• Published in: Clinical chemistry (Baltimore, Md.) Vol. 45; no. 9; pp. 1459 - 1464
• Main Authors: Haque, M. Rezaul, Bradbury, J. Howard
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Washington, DC Am Assoc Clin Chem 01.09.1999; American Association for Clinical Chemistry
• Subjects: Adult; Biological and medical sciences; Child; Colorimetry; Cyanides - analysis; Female; Food toxicology; Humans; Male; Medical sciences; Oxidation-Reduction; Picrates; Potassium Permanganate; Reagent Kits, Diagnostic; Sulfates - analysis; Thiocyanates - chemistry; Thiocyanates - urine; Toxicology; Tropical medicine; Human; Urine; Biochemical analysis; Toxicity; Semi quantitative analysis; Cyanides; Foodstuff; Ion exchange chromatography; Analysis method; Surveillance; Reagent strip; Clinical biology; Thiocyanates; Tropical medicine; Picric acid; Spectrophotometry; Cassava
• DOI: 10.1093/clinchem/45.9.1459
• ISSN: 0009-9147

It would be useful to develop a simple kit method for determination of thiocyanate in urine, which could be used to monitor cyanide overload in cassava-consuming populations. The method was based on the quantitative oxidation of thiocyanate in acid permanganate at room temperature in a closed vial with liberation of HCN, which reacted with a picrate paper. For semiquantitative analysis in the field, the colored picrate paper was matched with a color chart prepared using known amounts of KSCN. In the laboratory, a more accurate result was obtained by elution of the colored complex in water and measurement of the absorbance at 510 nm. Over the range 0-100 mg/L, there was a linear relationship given by the equation: thiocyanate content (mg/L) = 78 x absorbance. The picrate thiocyanate method gave no interference with urine samples containing protein at less than 7 g/L, 21 amino acids, histamine, glucose, NaCl, urea, blood, and linamarin. For 53 urine samples analyzed by an accurate column method and the thiocyanate picrate method, a regression line gave very good agreement (r(2) = 1. 000). Quantitative recoveries of thiocyanate added to urine samples were obtained with the picrate method. A simple picrate kit for determination of thiocyanate in urine was developed and is available free of charge for workers in developing countries.