Potentiometric Sensors Based on Various Active Components for the Multisensor Determination of Anionic and Nonionic Surfactants

Unmodified and modified solid-contact potentiometric sensors based on associates of alkyl sulfates with copper(II)-organic reagent complex compounds and alkylpyridinium alkyl sulfates for the determination of synthetic anionic surfactants are considered. The electroanalytical properties of the sensors are compared. The introduction of compounds of alkyl sulfates with cationic complexes of copper(II) with pyridine, 2,2'-dipyridyl, 1,10-phenanthroline, N,N '-bis(salicylidene)ethylenediamine (ionophores) into the composition of plasticized polyvinyl chloride membranes made it possible to create sensors for anionic surfactants (ASs) with improved electroanalytical characteristics (analytical range 1 x 10(-2)-2 x 10(-7) \M, c(min) = 1 x 10(-7) \M, response time 8-9 s, potential drift 2-3 mV/day in solutions with concentrations of at least 1 x 10(-4) \M, service life 12 months). The considered compounds are poorly soluble (K-s = n x 10(-22)-n x 10(-20)) and thermally stable (80-90 degrees C). As ionophores of membranes for sensors for nonionic surfactants (NSs), tetraphenylborate associates with barium(II)-polyethoxylate complexes with different numbers of oxyethyl groups (n = 10-100). On the basis of electrode, dynamic, transport, selective properties, cross-sensitivity parameters of AS and NS sensors, their use in the multisensor determination of homologous sodium alkyl sulfates, polyoxyethylated nonylphenols in model mixtures, natural waters, and technical preparations is justified.