The novel anionic surfactant selective sensors based on newly synthesized quaternary ammonium salts as ionophores

Abstract

A series of nitrogen heterocycles containing long alkyl and polyalkyl chains were prepared in the form of quaternary ammonium salts using the one-step procedure in good to excellent yields. The method generally gives rise to exclusive N-alkylation. The newly synthesized quaternary alkylammonium compounds (QAC) characterized by standard analytical methods including IR, 1H- and 13C-NMR, MS and elemental analysis, were theoretically studied and tested as ionophores for surfactant selective sensors. A selective and highly sensitive potentiometric sensors for anionic surfactants (ASs) determination were prepared by using a new QAC-tetraphenylborate (TPB) ion pairs as sensing elements. For each QAC-TPB sensor the response time, selectivity and influence of pH were determined. The electrode with the best response characteristics showed Nernstian response towards dodecyl sulfate (DDS) in the concentration range from 1.5 ∙ 10−7 to 5.0 ∙ 10−3 M and limit of detection of 7.5 ∙ 10−8 M. Also, they were successfully used for ASs determination in pure and real systems.