engleski

A New Microsensor for the Determination of Anionic Surfactants in Commercial Products

A new potentiometric microsensor for the determination of anionic surfactants (ASs), prepared by the application of a liquid membrane based on the dimethyldioctadecylammonium-tetraphenylborate (DDA-TPB) ion pair as a sensing material on a commercial carbon-based screen-printed electrode (SPE), was developed. The microsensor exhibited sub-Nernstian responses for sodium dodecylbenzene sulfonate (NaDBS, 45.7 mV/decade) and sodium dodecyl sulfate (NaDDS, 50.2 mV/decade) in concentration ranges from 1•10^7 to 2•10^3 M for NaDBS and from 2•10^7 to 7•10^3 M for NaDDS. The detection limit of the new SPE microsensor was 1•10^7 M, which is even lower than the detection limit of a conventional ISE electrode with the same sensor material [1]. The new microsensor is very accurate and selective ; thus, different ionic strengths, nonionic surfactants and potentially interfering anions did not have an influence on its performance. Two-component mixtures of ASs and three commercial detergents with different AS contents were successfully titrated using the new microsensor, which resulted in the accurate quantification of ASs in the samples.

microsensor; anionic surfactant; potentiometric titration; PVC membrane; screen-printed electrode; commercial products

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