Application of multi-factorial experimental design to successfully model and optimize inorganic chromium speciation by square wave voltammetry

MARIELA CUELLAR; VALERIA PFAFFEN; PATRICIA I. ORTIZ

JOURNAL OF ELECTROANALYTICAL CHEMISTRY

ELSEVIER

Lugar: Amsterdam; Año: 2016 vol. 765 p. 37 - 37

0022-0728

esponse surface methodology (RSM) was used to optimize voltammetric signal of hanging mercury dropelectrode (HMDE) for inorganic chromium determination and speciation. Initial solution pH, DTPA(Diethylenetriaminepentaacetic acid) concentration, SWV frequency, pulse height, step potential, accumulationtime and accumulation potential were considered as important operating factors through experimental designmethodology for Cr(VI) quantification. The central composite and a Box?Behnken designs as response surface designcoupled with numerical optimization technique was applied for obtaining the optimum chemical and SWVinstrumental conditions as well as the maximum height of chromium reduction peak. Optimum conditions wereset as follow: pH 6.5, DTPA concentration 5.5 mmol L−1, SWV parameters: frequency 500 Hz, step potential0.005 V, pulse height 0.1 V, accumulation time 120 s and accumulation potential −1.10 V. Speciation is performedin two separate samples, in the first one Cr(