This work presents an alternative method to determine the concentration of silicone (polydimethylsiloxane) in antifoaming products using Fourier Transformed Infrared Spectroscopy (FT-IR) with the attenuated total reflectance (ATR) accessory. The spectra were recorded in the range from 2500 to 780 cm-1, with a resolution of 4 cm-1 and 128 scans. With calibration of a linear model using PLS regression method applied to spectral data we were able to determine the silicone concentration in the samples. This method may be useful for antifoaming producers since the performance of such products generally is evaluated as a function of their viscosity. Moreover, during manufacturing an incomplete homogenization of silicone in the solvent may occur, in which case the viscosity results are not representative of the samples. The determination of the silicone weight percentage is important to avoid losses in the production process and to help the Statistical Process Control.
Antifoaming; FT-IR; silicone; multivariate calibration
