Highly selective electrochemical quantitation of creatinine based on its chemical reaction with 3,5-dinitrobenzoate.

[Display omitted] • Creatinine can be quantitated though its reaction with an electrochemical probe molecule: 3,5-dinitrobenzoate (3,5-DNB). • Chemical interference of urinary species can be greatly suppressed by 5 min reaction of creatinine with 3,5-DNB at 0.75 M NaOH. • With the use of real human urine samples, reliability of this method was confirmed by comparing the data obtained from this and conventional method. A simple and reliable method for creatinine quantitation was developed for urine-based diagnosis as creatinine is an internal standard molecule for the calibration of fluctuating urinary concentration. Herein, the quantitation of creatinine in artificial urine was performed in the range of 1–30 mM, covering the normal concentration of human urine, using 3,5-dinitrobenzoate (3,5-DNB) as an electrochemical probe molecule. The chemical interference from various urinary species, including urea, uric acid, ammonia, ascorbic acid, alcohol, albumin, bilirubin, acetaminophen, and glucose, is confirmed to be significantly suppressed when the reaction of creatinine and 3,5-DNB is limited to 5 min with an increased OH– concentration. Additionally, the reliability of this method is confirmed for the use of real human urine samples by comparing the data obtained from this and with that of the conventional method. [ABSTRACT FROM AUTHOR]