Octoxynol 9, often referred to as TritonTM X-100, is a widely used surfactant. Its unique chemical structure, composed of a hydrophilic polyethylene oxide chain and a hydrophobic 4-(1,1,3,3-tetramethylbutyl)-phenyl group, confers to it some desirable solubilizing properties. In this application note, we demonstrate equivalency to the current USP-NF monograph assay method, which requires the use of high-performance liquid chromatography (HPLC). This is done using benchtop quantitative nuclear magnetic resonance (qNMR) spectroscopy, and this technique also allows for the simultaneous determination of the degree of polymerization in these products.