Determination of degree of ethoxylation of fatty alcohol ethoxylates by FTIR/ATR spectroscopy and multivalibrate calibration

Abstract

Abstract The aim of the present work is to develop a fast and simple methodology of analysis of the degree of ethoxylation (ethylene oxide content – EO) of linear C12–C15 fatty alcohol ethoxylates using Fourier transform infrared spectroscopy with attenuated total reflectance accessory. The spectra were recorded in the range of 2000 cm−1 to 600 cm−1, with 64 scans and a resolution of 4 cm−1. The calibration of a linear model using the partial least square regression method applied to the spectral data allowed determination of the ethylene oxide content of the samples. The regression coefficient obtained for the model was R 2 = 0.9948 and the precision of the model was 0.014. The methodology is an important tool for quality control of non-ionic surfactants used in manufacturing of a broad range of final products in the chemical industry.