Urea was quantified by the Diacetylmonoxime method . To 1 ml of the electrolyte sample, 1 ml of acid-ferric solution and 2 ml of monoxime-carbazide solution are added. The resulting sample is heated at 100 °C with constant stirring for 5 mins followed by cooling at room temperature for 5 mins. The sample changes color from colorless to pink. The sample was scanned for absorbance as a function of wavelengths from 400 to 800 nm using a visible spectrometer. The maximum absorbance was observed at 525 nm and hence 525 nm was chosen to measure absorbances to quantify urea. Calibration graphs (Absorbances Vs Concentration of urea) were prepared for different concentrations of urea in the electrolyte. Separate calibration graphs were prepared when the concentration of the electrolyte was changed for improved accuracy, as it was observed that the absorbances are sensitive to the electrolyte solution. The urea calibration graphs for different electrolyte compositions is provided in Figure of the supporting information.