Abstract
A new validated potentiometric method was described for static and hydrodynamic monitoring of pyrdinium ions (Py+) as an organic pollutant. The method implied the development of a potentiometric sensors responsive to Py+ based on the use of pyridnium tetraphenyl borate [Py+][TPB-] ion-association complex and/or synthesized beta-cyclodextrine (beta-CD) polymer as an electro-active material, in a poly(vinyl chloride) matrix membrane plasticized with dioctyl phthalate (DOP). Optimization of the performance characteristics of the sensors was described. Under static mode of operation, the sensors revealed a near Nernstain response over a wide Py+ concentration range 5.0x10(-6) and 5.0 x 10(-5) to 1.0 x 10(-2) mol L-1 with a detection limit of 3.1x10(-6) and 3.5x10(-5) mol L-1, respectively. In flow injection potentiometry, excellent reproducibility (RSD %+/-0.9%), fast response, high sensitivity with a near-Nernstian 67.2+/-0.8 and 72.8+/-1.1 mV decade(-1), linear range 1.0x10(-4)-1.0x10(-2) mol L-1, detection limit 6.0x10(-5) and 1.0x10(-4) mol L-1, high sampling rate (35-40 and 30-35 sample h(-1)) and stable baseline was observed in the presence of 0.01 mol L-1 acetate solution, pH 3.0 as a carrier for ([Py+][TPB-] and (beta-CD) polymer membrane based sensors, respectively. Validation of the assay method is tested by measuring the lower detection limit, range, linearity, trueness, accuracy, precision, selectivity and ruggedness (robustness). The results reveal good potentiometric performance of the proposed sensor for determination of Py+ in spiked water and soil samples.