Analysis of Betaines Using near Infrared Spectroscopy

Abstract

Cocoamidopropyl betaines are becoming increasingly important in cosmetic formulations because of their mild and effective surface active properties. A simple and accurate method is needed for quality control during the production of betaines. The aim of the present study was to determine if near infrared spectroscopy can replace wet methods for routine analysis of betaine. The calibration curve was obtained by partial least squares. The optimisation of calibration factors was guided by coefficient of determination (R²) and the root mean square error of evaluation (RMSEE). R² was 0.99 or higher and RMSEE 0.025, 0.071, 0.03% and 0.007 units for active matter, sodium chloride, solids and pH, respectively. The method was validated with independent samples in the same manner on a different day and true values were obtained with R² of 0.99 or higher and root mean standard error of prediction of 0.060, 0.074, 0.075% and 0.035 units for active matter, sodium chloride, solids and pH, respectively.