Rapid and Simple Identification and Quantification of Components in Detergent Formulations by Nuclear Magnetic Resonance Spectroscopy

Abstract

AbstractA rapid, inexpensive, and simple high‐resolution NMR spectroscopic method is outlined for determining the content of surfactants and other low‐molecular‐weight organic compounds in detergent formulations. With simple sample preparation, quantitative results can be obtained from an internal standard and/or the method can be used as a fingerprint analysis of the surfactant composition. The NMR sample is prepared by suspending the detergent sample in deuterated acetic acid and thus dissolving surfactants and other organic compounds. Any content of carbonate will be liberated as CO2, whereas other inorganic materials are removed by centrifugation. From one‐dimensional 1H and two‐dimensional HSQC NMR spectra, the surfactant components and low‐molecular‐weight organic compounds can be identified from reference spectra. Intensities of signature signals in the one‐dimensional 1H NMR spectrum are used for quantification by comparing with an internal standard. Furthermore, it is demonstrated how 31P NMR can be used to identify and quantify phosphonate‐type chelators.