High precision spectrophotometry. Part II. The determination of ammelide, ammeline and melamine in the thermal decomposition products of urea

Abstract

An automatic ultraviolet spectrophotometric method is described for the determination of ammelide, ammeline and melamine in the thermal decomposition products of urea; prior separation of the components is unnecessary. A Unicam SP3000 spectrophotometer is used to make absorbance measurements at several different wavelengths and at two pH values. From the absorbance values obtained the concentrations of the amino-s-triazines are calculated by using a computer to solve the appropriate simultaneous equations. The constants required in these equations are obtained by calibration of the spectrophotometer with solutions of the pure compounds. A semi-quantitative estimation of triuret is also possible. Interferences caused by biuret and cyanuric acid can normally be ignored, but corrections are required if large amounts are present.