Identification of unknown surfactants using electrospray mass spectrometry and NMR spectroscopy preceded by liquid ionization mass spectrometry

Abstract

Commercially available but completely unknown surfactants used in the tin–lead plating industry were successfully identified by using electrospray mass spectrometry and NMR spectroscopy techniques, preceded by liquid ionization mass spectrometry used to obtain the preliminary information. The mass spectral data suggested that ethoxylated nonionic surfactants having a homologous distribution of molecular weights like 520, 564, 608, 652, 696, etc. were present. The NMR data suggested the presence of two aromatic rings and a quaternary carbon for the hydrophobe moiety instead of the well-known alkyl chains or alkylphenols. The unknown surfactants were finally concluded to be novel nonionic 4-(α,α-dimethylbenzyl)-phenol ethoxylates.