Potentiometric sensor for chromium(VI) using a composite of diphenylcarbazide-natural zeolite-modified membrane electrodes Budi R. Putra (a), Rudi Heryanto (b,c), Eti Rohaeti (b), Laela Wulansari (c), Wulan T. Wahyuni (b,c)
(a) National Research and Innovation Agency (BRIN), Gedung BJ Habibie, DKI Jakarta, 10340, Indonesia
(b) Analytical Chemistry Division, Department of Chemistry, Faculty of Mathematics and Natural Sciences, Kampus IPB Dramaga, Bogor 16680, Indonesia
(c) Tropical Biopharmaca Research Center, Institute of Research and Community Empowerment, IPB University, Bogor 16680, Indonesia
Abstract
The construction and performance of ion selective electrodes (ISEs) for the determination of chromium(VI) based on PVC membranes modified with 1,5-diphenylcarbazide (DPC) and natural zeolite as ionophores are reported in this study. ISE was fabricated in an optimum composition of chromium(VI)-selective membrane consisting of 29 mol% DPC, 43.6 mol% natural zeolite, 25 mol% plasticizer, and 2.2 mol% PVC. The investigation of the performance of the proposed ISE was evaluated in terms of the Nernstian response, range of concentration, limit of detection, response time, and selectivity coefficient. The proposed ISE displayed a linear potential response over a concentration range of 10-1 - 10-6 M K2Cr2O7 with a Nernstian response of -28.8 mV/decade. Adequate sensitivity for chromium(VI) was offered by the proposed ISE, with a limit of detection of 2.14 x 10-6 M and a response time of ~250 seconds. The fabricated ISE has also been investigated in selectivity studies in the presence of Cu2+ and Fe3+ and was found to be more selective in the concentration range of 10-1 - 10-6 M. Therefore, a novel membrane electrode using a composite of DPC and natural zeolite as an ionophore has shown a satisfactory result for the direct potentiometric measurement of chromium(VI) in the presence of Cu2+ and Fe3+, which may have the potential to be used in real sample analysis.
Keywords: ion selective electrode, 1,5-diphenylcarbazide, zeolite, chromium(VI), PVC-based membrane, potentiometry
