Spectrophotometric Determination of Urea in Urine Samples by using Bispyrazolone Method

Accurate quantization of urea is very essential for precise dialysis therapy in the case of kidney failure. In the present paper we report a new colorimetric method for urea quantification using urease as a probe. The method is based on the reaction between bispyrazolone and ammonia released by the urease catalyzed hydrolysis of urea. A linear relationship of the absorbance at 540 nm of the product was observed with urea concentration in the range of 1.5 μg-20 μg (slope = 0.0439; R2 = 0.998). The present method was also analyzed for potential interferences and results obtained were compared with other popular methods of urea quantitation. Urine samples were analyzed by two existing methods namely diacetyl monoxime method and indophenol method, and their results were compared with that obtained by the newly developed bispyrazolone method. Results by this method and by other known methods were in good agreement. The present method has the potential for automation for high throughput screening of urine samples.