Trace level and highly selective determination of urea in various real samples based upon voltammetric analysis of diacetylmonoxime-urea reaction product on the carbon nanotube/carbon paste electrode

•Diacetylmonoxime reaction with urea led to an electroactive product.•Urea was indirectly determined by square wave voltammetry of the reaction product.•A graphite/MWCNTs paste electrode was used as the electrochemical transducer.•Reaction condition and electrode composition was very effective on the method.•Linear range of 10−7-10−2 mol L−1 and detection limit of 52 nmol L−1 were obtained.

In this study an innovative method was introduced for selective and precise determination of urea in various real samples including urine, blood serum, soil and water. The method was based on the square wave voltammetry determination of an electroactive product, generated during diacetylmonoxime reaction with urea. A carbon paste electrode, modified with multi-walled carbon nanotubes (MWCNTs) was found to be an appropriate electrochemical transducer for recording of the electrochemical signal. It was found that the chemical reaction conditions influenced the analytical signal directly. The calibration graph of the method was linear in the range of 1 × 10−7- 1 × 10−2 mol L−1. The detection limit was calculated to be 52 nmol L−1. Relative standard error of the method was also calculated to be 3.9% (n = 3). The developed determination procedure was applied for urea determination in various real samples including soil, urine, plasma and water samples.

Graphical abstractDownload high-res image (131KB)Download full-size image