POLY(PYROGALLOL) FILM ON GLASSY-CARBON ELECTRODE FOR SELECTIVE PRECONCENTRATION AND STRIPPING VOLTAMMETRIC DETERMINATION OF SB(III)

Oxidative electropolymerization of pyrogallol at the glassy carbon ele ctrode in phosphate buffer (pH 7.00) gave a stable, water-insoluble fi lm, adherent on the electrode surface. This poly(pyrogallol) film modi fied glassy carbon electrode was exploited for the selective preconcen tration of Sb(III) at an open circuit, followed by its determination b y differential pulse anodic stripping voltammetry both in batch and co ntinuous flow regimes. Factors affecting the accumulation, reduction, stripping and removal steps were investigated and an optimized procedu re was then developed. Under optimized conditions, for batch determina tion, the calibration curve was linear in the range 5.00 x 10(-9) to 1 .00 x 10(-7) M Sb(III) (10 min accumulation). A detection limit of 4.1 x 10(-10) M Sb(III) (0.050 ppb) (S/N = 3) was found for a 10 min accu mulation. For eight successive determinations of Sb(III) at concentrat ions of 1.00 x 10(-8) and 5.00 x 10(-9) M, relative standard deviation s were 2.4% and 6.0%, respectively. Similar results were obtained for continuous dow determination. Interferences from selected metals and o ther inorganic ions and organic substances were examined. The develope d method was applied to Sb determinations in human hair and seawater s amples, both in batch and continuous flow systems. (C) 1998 Elsevier S cience B.V. All rights reserved.