The Adsorptive Stripping Indirect Tensammetric Technique

Abstract

A new tensammetric technique for the determination of trace concentrations of non‐ionic surfactants (NS) has been developed. The adsorptive stripping indirect tensammetric technique (AdS‐ITT) combines an adsorptive preconcentration of a substance‐to‐be‐determined with the indirect tensammetric technique (ITT). The lowering of the tensammetric peak of the monitoring substance – ethyl acetate, is the analytical signal in the AdST‐ITT, as it is in the ITT. The dynamic response range can be shifted towards a lower concentration range by one to three orders of magnitude by the selection of an adequate preconcentration time. However, the dispersion of calibration plots of different NS is larger in the AdS‐ITT than in the ITT. The detection limit (at 60 seconds of preconcentration) is approximately 0.1 μg in the sample, i.e., more than one order of magnitude better than that without preconcentration. The ‘zero signal' of ethyl acetate is considerably lower in the AdS‐ITT than in the ITT due to adsorption of impurities of the base electrolyte.