Content area
Full Text
Acetone and Ethyl Acetate in Commercial Nail Polish Removers: A Quantitative NMR Experiment Using an Internal Standard
While the use of proton nuclear magnetic resonance (1H NMR) to elucidate the structure of organic compounds is widespread, its potential as a quantitative technique is largely ignored in instrumental analysis textbooks. Several experiments for use with continuous wave instruments that demonstrate the ease with which it can be used quantitatively have appeared in this Journal (1-5), but only one applies the technique to a commercial product (1). This experiment provides an opportunity for students to use an NMR spectrometer and an internal standard to determine the concentration of the primary ingredient in commercial nail polish removers. The major ingredients in the two nail polish removers used in this experiment, as listed on the bottle, are acetone/water and ethyl acetate/alcohol (the identity of the alcohol is not listed).
The unique feature of NMR that allows its straightforward application to quantitative problems is the signal intensity's direct proportionality to the number of nuclei producing the signal. Unlike in other spectroscopies (IR and UV-vis), this is true regardless of the molecule containing the nuclei. An internal standard can be substituted for calibration curves that require analyzing a series of samples containing...