engleski

Application of a new sensing material for the construction of surfactant potentiometric sensor

Anionic surfactants (ASs) are commercially the most widely used group of surfactants. They are used in industry, households and research.1 ASs have exceptional cleaning properties, can improve efficiency of active compounds in various commercial products and are biologically active.2-4 Their annual production was 7686 KT in 2014. Due to their widespread use, it is necessary to find simple, rapid and accurate method for monitoring ASs concentrations in commercial products, during the industrial processes and in environmental samples. The two-phase titration is the reference method for ASs determination in products where the higher concentrations of ASs are expected.5 In the effluents and in samples with lower ASs concentration, the standard method for determination is Methylene Blue Active Substances method (MBAS).6 Both of these methods are tedious procedure, time- consuming and require a large consumption of organic solvents. Considering the above, ASs selective electrodes as sensors during the potentiometric titrations represent great alternative to the standard methods.7 In the last years, great efforts are invested in construction of the electrodes having the best analytical and functional properties and finding the new components of the electrode membrane that can improve sensor characteristics. 8, 9 The new electrode for ASs determination was made using tetraoctadecylammonium-tetraphenylborate as sensor material incorporated in liquid type of membrane. The response characteristics of the new sensor material were tested using dodecyl sulfate and dodecylbenzenesulfonate ions. The new sensor responded in approximately 5 s after an abrupt change of AS concentration. The applicability of the new electrode was tested over a wide pH range and there was no significant potential deviations. Finally, the sensor was used for ASs determination in three commercial products with different concentration of ASs and the results were compared with those obtained using the two-phase titration.

anionic surfactants ; potentiometric sensor ; tetraoctadecylammonium -tetraphenylborate ; commercial products

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