EPOXY - GRAPHITE TUBE BULK-MODIFIED WITH 2-MERCAPTOBENZOTHIAZOLE AS AROBUST ELECTRODE FOR THE PRECONCENTRATION AND STRIPPING ANALYSIS OF HG(II)

A novel method of fabricating a bulk-modified composite electrode is p roposed. In this method, a preformed, porous graphite tube was impregn ated with a modifier by thorough. soaking in a solution containing the modifier. After drying, the modifier was sealed in place in the pores with epoxy. For the purpose of demonstrating the usefulness of the el ectrode, 2-mercaptobenzothiazole was chosen as the modifier and the mo dified electrode was used to preconcentrate mercury(II), followed by v oltammetric stripping analysis, The fabricated electrode possessed goo d stability and had an extended lifetime, Precision for 10 consecutive differential pulse stripping experiments, for a 2 min preconcentratio n, gave relative standard deviations of 1.9% and 2.6% for Hg(II) conce ntrations of 1.00 x 10(-6) and 1.00 x 10(-8) M, respectively. Detectio n limit was estimated to be 3.0 x 10(-9) M (S/N = 3, 3 min preconcentr ation). A certified aqueous sample, USEPA WP 386, was employed for met hod testing.