UC Irvine

This paper presents a preliminary application of Raman spectroscopy in conjunction with the chemometric method of Partial Least Squares to predict silicone concentrations in homogeneous turbid samples. The chemometric technique is applied to Raman spectra to develop an empirical, linear model relating sample spectra to polydimethysiloxane (silicone) concentration. This is done using a training set of samples having optical properties and known concentrations representative of those unknown samples to be predicted. Partial Least Squares, performed via cross- validation, was able to predict silicone concentrations in good agreement with true values. The detection limit obtained for this preliminary investigation is on par with that of magnetic resonance spectroscopy. The data acquisition time for this Raman based method is 200 seconds, which compares favorably with the 17 hour acquisition required for magnetic resonance spectroscopy to obtain a similar sensitivity. The combination of Raman spectroscopy and chemometrices shows promise as a tool for quantification of silicone concentrations from turbid samples. ©2005 Copyright SPIE - The International Society for Optical Engineering.