engleski

Potentiometric determination of low levels of anionic and nonionic surfactants in effluents

The use of potentiometric sensors, commercial and new ones, for determination of anionic and nonionic surfactants in industrial effluents has been presented. The determination was carried out on the modelled effluents formulations as well as on the real industrial effluents. The sensors mentioned served as end-point detector by potentiometric titration of low surfactant concentration levels (down to 10-5 mol dm-3 for anionic surfactants and 10-6 mol dm-3 for nonionic surfactants). No special sample pretreatment was needed, except filtration when necessary. Equivalence point by noisy and flat titration curves was determined using extended least-squares regression formalism of the Savitzky-Golay method. The results for anionic surfactants agree satisfactory with standard extraction-spectrophotometric MBAS method and are comparable with the results obtained using a commercially available surfactant electrode. The accuracy and precision of the nonionic surfactants determination has been evaluated by using standard addition method. Further investigation activities are directed toward increasing of the sensor sensitivity, extending of its linear response range, development of methods for surfactant preconcentration in surface waters.

potentiometric sensors; anionic and nonionic surfactants; potentiometric titration; surface waters

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