Development of a novel automatic potentiometric system for determination of selenium and its application in pharmaceutical formulations and anodic slime

作者：Kamel Ayman H^*; Elnaby Eman H; Kelany Ali E

来源：Electroanalysis, 2008, 20(9): 1016-1023.

DOI：10.1002/elan.200704138

• selenium
• potentiometry
• tin and cobalt phthalocyanine
• sensors
• ion-ionophore complex formation
• flow injection analysis (FIA)

Poly(vinyl chloride) polymeric membrane sensors containing Sn(IV) phthalocyanine dichloride (SnPC) and Co(II) phthalocyanine (CoPC) as novel electroactive materials dispersed in o-nitrophenyl octylether (o-NPOE) as a plasticizer are examined potentiometrically with respect to their response toward selenite (SeO32-) ions. Fast Nernstian response for SeO32- ions over the concentration ranges 7.0 X 10(-6) - 1.0 X 10(-3) and 8.0 x 10(-6) - 1.0 X 10(-3) Mol L-1 at pH 3.5 - 8.5 with lower detection limit of 5. 0 X 10(-6) and 8.0 x 10(-6) mol L-1 and calibration slopes of - 25.4 and - 29.7 mV decade(-1) are obtained with SnPC and CoPC based membrane sensors, respectively. The proposed sensors reveals by the modified separate solution method (MSSM) a good selectivity over different anions which differ significantly from the classical Hofmeister series. A segmented sandwich membrane method is used to determine complex formation constants of the ionophores in situe in the solvent polymeric sensing membranes. Membrane incorporating CoPC in a tubular flow detector is used in a two channels flow injection set up for continuous monitoring of selenite at a frequency of ca. 50 samples h(-1). Direct determination of selenium in pharmaceutical formulations and anodic slime gives results in good agreement with data obtained using standard ICP method.

• 出版日期2008-5