DETERMINATION OF ALKYLBENZENESULFONATES AND ALKYLSULFATES AS ANIONIC SURFACTANTS BY C-13 NUCLEAR MAGNETIC-RESONANCE SPECTROMETRY

13C NMR has been used for analysis of anionic surfactants. Using spectral peaks at both aromatic and aliphatic regions, the biodegradable soft type of alkylbenzenesulfonate is easily discernible from the hard type. The purity of the soft type is also deducible by the relative peak intensities of the aromatic carbons (C4 or C2 and C3). Qualitative and quantitative analyses of dodecyl, tetradecyl, and cetyl sulfates are possible at resonance signals of their terminal methyl carbons whose chemical shifts are more than 2 Hz apart from each other. Standard deviations in quantitation are less than 1.6. Applications of the 13C NMR method for commercially available detergents are exemplified. © 1979, American Chemical Society. All rights reserved.