The colorimetric analysis of sialic acid in human saliva and bovine salivary mucin.

Three colorimetric methods were compared for their suitability for the analysis of sialic acid in human mixed saliva and bovine submaxillary gland mucin. The thiobarbituric acid method was most precise with human saliva, appeared to be subject to the least interference and is therefore the method of choice for these samples. However, it is not possible to use this method for the analysis of bovine mucins. With these samples the resorcinol method was most suitable, being subject to the least interference and relatively precise. The direct Ehrlich method was least precise overall and gave high values with human whole saliva.