Continuous colorimetric monitoring of vapour-phase urea and cyanates

Abstract

A method is described for continuously monitoring the concentrations of urea and cyanates in gases, based on a modification of a colorimetric method used for urea in human serum. The method was calibrated with standard solutions of urea and potassium cyanate. The reproducibility was ±2% throughout. Using this method, the vapour pressure of urea was measured from 58 to 113 °C. The vapour pressure results have an estimated accuracy of 10% in the range 3 × 10^–4 to 5 × 10^–2 mmHg.