NEW METHODS FOR TRACE TITANIUM DETERMINATION BY ADSORPTIVE PRECONCENTRATION VOLTAMMETRY WITH PYROCATECHOL VIOLET

New sensitive stripping voltammetric procedures for trace measurements of titanium in various samples are reported. The first method is base d on the interfacial accumulation of the titanium-pyrocatechol violet complex onto a hanging mercury drop electrode, followed by reduction o f the adsorbed complex. The limit of detection is 0.55 nmol/L titanium after a 30 s collection with a stirred solution at pH 4.9. The proced ure is extremely selective with respect to other metals and has been a pplied in analyzing various samples. Based on this, a catalytic method involving the chlorate ion was developed and the sensitivity was enha nced by more than an order of magnitude. In this way, analysis for Ti in aqueous solutions at the picomolar (part per trillion) level is pos sible.