FT-IR quantitative analysis of solvent mixtures by the constant ratio method

An analytical methodology to quantify compounds in complex mixtures by FTIR spectroscopy is proposed and the "Constant Ratio Method" (CRM) was develop ed. The addition of a standard to the sample allows us to establish a const ant K-MS characteristic of the Analyte/Standard system which can be employe d as a quantification factor of the analyte in different samples. In the pr oposed method the measurements are independent of optical path length. This method has been successfully applied to quantify butylacetate and toluene in binary and tertiary samples and tertiary mixtures. Butylacetate/toluene/ nujol have been resolved employing valeronitrile as standard, obtaining val ues for relative error between 1% and 3%. (C) 1999 Elsevier Science B.V. Al l rights reserved.