Quantitative analysis of hydroxyurea and urea by proton nuclear magnetic resonance (NMR) spectroscopy

Quantitative 1H-nuclear magnetic resonance (NMR) procedures are described for measuring hydroxyurea and urea. Dimethylsulfoxide-d6 is used as the solvent for both assays; the internal standards employed are urea and p-dichlorobenzene for hydroxyurea and urea, respectively. The analysis for hydroxyurea is based on the comparison of the area of the -NH2 peak of hydroxyurea with the area of the urea -NH2 peak area. The analysis of urea is based on the comparison of the -NH2 peak of urea with the area of the p-dichlorobenzene singlet. The 1H-NMR assays yield results that are precise and agree well with results of the more cumbersome and less specific USP procedures.