Determination of Creatinine in Urine by Voltammetry and Glassy Carbon Electrode Modified with Functionalized Multi‐walled Carbon Nanotubes and Copper

Abstract A square‐wave voltammetric method was developed for the determination of creatinine using glassy carbon electrode functionalized multi‐walled carbon nanotubes and doped with copper. Since the creatine‐creatinine balance is dependent on pH, the linear responses at either pH 4.0 or 7.0 were evaluated allowing versatility in application, covering analyte concentration from limit of quantification (0.3 μmol L −1 ) up to 1.200 μmol L −1 (pH 4) or 660 μmol L −1 (pH 7). Electrode is simple to prepare and robust for routine analysis and it was used for the determination of creatinine in urine after simple thin‐layer separation procedure to avoid interference from creatine.