Determination of Fe(III) Using Diamond Paste Based Electrodes

• Published in: Instrumentation science & technology Vol. 31; no. 4; pp. 411 - 416
• Main Authors: Stefan, Raluca-Ioana, Bairu, Semere Ghebru, van Staden, Jacobus Frederick
• Format: Journal Article
• Language: English
• Published: Taylor & Francis Group 12.01.2003
• Subjects: Diamond paste electrodes; Fe(III); Monocrystalline diamond
• ISSN: 1073-9149; 1525-6030
• DOI: 10.1081/CI-120025575

Voltammetric characterization of new types of electrochemical sensors, based on diamond paste, was performed for Fe(III). The construction of electrodes was done using monocrystalline diamond [natural diamond 1 µ, synthetic diamond 50 µ (synthetic-1), and synthetic diamond 1 µ (synthetic-2)] powder and paraffin oil. Differential pulse voltammetry (DPV) was used to study the variation of peak height with the concentration of Fe(III), at 300 mV (vs. Ag/AgCl). The linear concentration ranges were between 10 −12 and 10 −9  mol/L for the natural diamond with detection limit of 10 −13  mol/L; between 10 −7 and 10 −5  mol/L for synthetic-1 with a detection limit of 10 −8  mol/L; and between 10 −11 and 10 −5  mol/L for synthetic-2, with a detection limit of 10 −12  mol/L. Fe(III) was determined from four water samples with relative standard deviation values less than 1%. Ions such as, Fe(II), Cr(III), Cr(VI), Mg(II), Mn(II), Cu(II), and Zn(II) do not interfere in the measurements.