Spectrophotometric determination of urea in urine stains on foods and containers.
Urea is extracted from rodent urine-contaminated material with hot acetone. After the extract is evaporated to dryness, aqueous urease solution is added to produce ammonia and carbon dioxide. A blue product, indophenol, is formed by the reaction of ammonia with phenol in the presence of hypochlorite. Absorbance is maximum at 625 nm. Presence of urea is easily detected at 4 microgram. Detection of urine contamination in various materials is compared with detection by the AOAC urease-H2PtCl6 test.
D000818:Animals; D005506:Food Contamination / Q000032:analysis*; D012377:Rodentia; D013053:Spectrophotometry; D014508:Urea / Q000032:analysis* / Q000652:urine
D014508:Urea