QUANTITATIVE FOURIER TRANSFORM-INFRARED INTERNAL-REFLECTION SPECTROSCOPY (FT-IR-IRS) FOR ADSORPTION DENSITY-MEASUREMENTS

Use of the FT-IR/IRS adsorption density equation or any other equation based on the Beer-Lambert law can result in incorrect quantitative values when applied to cases where only part of the internal reflection element (IRE) is coated. Experimental methods that can lead to incorrect quantitative analyses are identified as well as methods to correct such problems. The validity of the (FT-IR/IRS) adsorption density equation is demonstrated using transferred Langmuir-Blodgett films of stearic and oleic acids with proper consideration of coated and uncoated dimensions of the IRE. Results from this study clearly show the FT-IR/IRS adsorption density equation can be used with confidence for quantitative analyses of surfactant adsorption phenomena.