Applicability of electrochemical stripping analysis at mercury- and bismuth film-plated carbon paste electrodes to crude oil digests

Abstract

In this article, a combination of electrochemical stripping analysis with mercury- and bismuth-plated carbon paste electrodes (MF- and BiF-CPEs) has been examined for the determination of selected metals in decomposed crude oil samples. Microwave-assisted digestion under temperature- and pressure-controlled conditions was performed with the optimised amount of crude oil samples emulsified in an ultrasonic bath for effective mixing the organic phase of crude oil with aqueous solution of oxidation mixture (65% HNO3+30% H2O2). After buffering, the resultant crude oil digests were analysed using either a MF-CPE in the differential pulse adsorptive stripping voltammetris mode (determination of nickel) or a BiF-CPE coupled with computer-controlled potentiometric stripping analysis (simultaneous detection of lead and cadmium).