1. Introduction
The general trend of the modern analytical chemistry is
the elaboration of simple, ecologically safe, sensitive, and
selective methods for microcomponents determination combining
previous concentration and further determination by
physical or physico-chemical methods [1]. Micellar extraction
with non-ionic surfactants (NS) at cloud point (CP) is
a high effective, ecologically safe method for microcomponents
preconcentration which has been developed intensively
recent years [2,3]. High concentration coefficients, selectivity,
simple combination with spectral, atomic absorption,
chromatographic, and electrochemical analysis allow to use
extraction with NS phases for elaborating high-sensitive and
convenient analytical methods [4–7].