Abstract
Qualitative and quantitative analyses of commercial Nekal-type surfactants, the alkali salts of butyl- and propylnaphthalenesulfonic acids [BNS and PNS, respectively], were investigated by mass spectral pattern analysis, after converting them into their methyl esters quantitatively.
According to mass spectra, measured by In-beam EI method (20eV) and direct inlet method (70eV), each component contained in these samples exhibited a characteristic spectral pattern consisting of both parent ions [M] + and their fragment ions, such as [M-29 (C2H5)] + and [M-15 (CH3)] + pro-duced by the fragmentation of the methyl esters of BNS and PNS, respectively. The fragmentation pattern of the alkyl group attached to the aromatic nuclei indicated each BNS and PNS to be a mixture of the sodium salts of homologous s-butylnaphthalene- and isopropylnaphthalene-monosulfonic acids, respectively. Moreover, each homologous component in the commercial Nekal-type surfactants was determined readily and quantitatively by the In-beam EI method, but only qualitatively by the direct inlet method.
