NMR spectroscopy is currently a premier technique for structural elucidation of organic molecules. Quantitative NMR (qNMR) methodology has developed more slowly but is now widely accepted, especially in the areas of natural product and medicinal chemistry. However, many undergraduate students are not routinely exposed to this important concept. This article describes a simple and practical lab experiment that has been successfully performed by students in a Quantitative Analysis class for several years and is based on a comparison of relative integration areas of species present in spectra of compound mixtures. In this experiment, [superscript 1]H NMR spectroscopy is used to determine the purity of common organic solvents using dimethyl sulfoxide as an internal standard in D[subscript 2]O. Groups of students analyze unknown samples containing one of the following solvents: methanol, ethanol, 2-propanol, tetrahydrofuran, or acetone, to which water has been added as an impurity. Over a period of five years, 54 students analyzed samples ranging from 60% to 99% purity with an average error of 2.64%. This experiment fills a niche in the initial portion of a standard Quantitative Analysis lab sequence by differentiating between qualitative and quantitative analysis, providing exposure to equipment not usually encountered in an introductory analytical lab, and generating numerical data for students to analyze and evaluate.