Application of a Picrolonate Ion-Selective Electrode to the Assay of Calcium and Piperazine in Pharmaceuticals and Serum
(EN)
Veltsistas, P. G.
(EN)
Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας
(EL)
Veltsistas, P. G.
(EN)
The construction and some analytical applications of a liquid picrolonate (Picrl(-)) ion-selective electrode based on the tris(phenanthrolinato)iron(II) (ferroin) picrolonate salt, dissolved in 2-nitrotoluene, are described. The liquid membrane electrode exhibits a rapid and almost Nernstian response to picrolonate anions in the concentration range from 5 X 10(-2) to 5 X 10(-2) mol l(-1). The response is virtually unaffected by pH changes ih the range 3-10. Major interferents are picrates, 4-nitrophenolates, 3,5-dinitrosalicylates and 2,4-dinitrophenolates. In analytical applications direct potentiomctric methods for the determination of picrolonates and indirect methods for the determination of calcium and piperazine are described. calcium in the ranges 4-24 and 50-90 mg l(-1), under specified experimental conditions,can be determined with mean relative errors of 1.1 and 1.4%, respectively. The method is applicable to soluble samples, pharmaceuticals and industrial and real human serum. Piperazine in the ranges 1-10 and 13-20 mg can be determined with a mean relative error of 1.2% in soluble salts and pharmaceutical formulations, respectively. An accuracy of better than 1.5% and a reproducibility (relative standard deviation) of 0.1.% mere achieved in the analysis of pharmaceutical products.
(EN)
