A Rapid Method for the Determination of Urinary Creatinine by the Picric Acid Spectrophotometry

Objective  To establish a rapid method for the determination of creatinine in urine samples.

Methods  A volume of 20.0 μL urine sample in a 10 mL centrifuge tube was diluted with 3.02 mL pure water. After adding 500 μL chromogenic agent and standing for 15 min, the content of creatinine was measured by the absorbance at 490 nm with a blank for zero adjustment.

Results  The linear range of this method was 0 g/L~2.00 g/L. The regression equation was C=1.5857*A-0.0112 and the correlation coefficient was 0.9998. The detection limit, recovery and relative standard deviation was 0.005 g/L, 96.9%~104% and 1.6%~2.5%, respectively. The content of creatinine in 613 urine samples tested by this method was in the range of 0.08 g/L~4.44 g/L.

Conclusion  The method was rapid, accurate, sensitive, easier to operate and could be used for the determination of urinary creatinine in the field for health checkup.