A new electrochemical sensor based on carbon paste electrode/Ru(III) complex for determination of nitrite: Electrochemical impedance and cyclic voltammetry measurements

Abstract

International audienceThe modified carbon paste electrode with Ru(III) complex was studied as a novel sensor for the determination of nitrite. The behavior of NO2− at the electrode surface was investigated using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). EIS provided useful information on the charge transfer resistance (R) at the electrode/solution. The EIS measurements showed that R is low at oxidation potentials, and decreases with increasing temperature. The increase of the constant phase element with temperature is due to the accumulation of nitrite on the electrode, thus, facilitating the electron transfer between electrode and NO2−. CV was used to study the effect of pH on the electro-catalytic oxidation of NO2− and to determine the limit of detection (LOD). CV measurements showed a good linear relationship between the oxidation current and the concentration of NO2− over a wide concentration range 0–1.38 × 10−2 mol L−1. Low detection limit of 1.39 × 10−6 mol L−1 toward NO2− was obtained. LOD decreased by 23.2% compared to that determined using cavity microelectrode. © 2016 Elsevier Lt

A Flexible Nafion Coated Enzyme‐free Glucose Sensor Based on Au‐dimpled Ti Structures

“…This can be also confirmed by a simple observation that for the scan rates below 100 mV/s, the oxidation peak potential stays almost constant at +0.34 V whereas for the higher scan rates i. e. 120–300 mV peak shifts towards the higher potential values because of an increasing polarization at high scan rate . Nevertheless, regardless of the scan rate the value of correlation coefficient is close to 1, indicating that the electrochemical kinetics were controlled by both diffusion and adsorption . As the scan rate increases, the diffusion layer is going thinner and the current increases, but at the certain scan rate value of 100 mV/s the growth rate of current value is hampered and the direction factor of the relation j vs .…”

Voltammetric sensor for electrochemical determination of the floral origin of honey based on a zinc oxide nanoparticle modified carbon paste electrode

“…The chemically modified electrodes are widely used as voltammetric sensors due to versatility and unique electrochemical and electro-catalytic properties. Past studies report that various types of modifiers (Skrzypczynska et al, 2016;Terbouche et al, 2016) are available among which nanocrystalline materials are more advantageous because of their large surface area and high thermal and chemical stability. The additions of nanomaterials with common CPs electrodes are useful for catalysis and are advantageous in making sensors.…”

Non-Enzymatic Impedimetric Sensor Based on 3-Aminophenylboronic Acid Functionalized Screen-Printed Carbon Electrode for Highly Sensitive Glucose Detection

“…The Warburg impedance is due to the diffusion of the ions Fe(CN) 6 3-/4- from the bulk electrolyte to the electrode and it appears as a 45° straight line at low frequencies [33]. The CPE element represents a non-ideal capacitor and replaces the capacitance due to its roughness and heterogeneous surface [34]. The impedance associated to this parameter is described by Equation (1), where “Q” is a constant that describes the magnitude of CPE, “ω” is the angular frequency (ω = 2πf), “j” is an imaginary number (j = √−1) and “n” is an exponent related to the heterogeneity of the surface (0 < n < 1) [35].…”