Using FTIR-ATR Spectroscopy To Teach the Internal Standard Method

The internal standard method is widely applied in quantitative analyses. However, most analytical chemistry textbooks either omit this topic or only provide examples of a single-point internal standardization. An experiment designed to teach students how to prepare an internal standard calibration curve is described. The experiment is a modified version of an experiment that uses the internal standard method to quantify the percentage of vinyl acetate in poly(ethylene-co-vinyl acetate). Students gain a good understanding of how to apply the internal standard method as the concentration of internal standard changes throughout the experiment. The experiment also provides students with hands-on experience with the use of Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy.