Determination of Nitrite and Nitrogen Oxides by Anodic Voltammetry at Conductive Diamond Electrodes

Abstract

The oxidation of nitrite at boron-doped diamond ͑BDD͒ electrode was investigated by use of anodic voltammetry. The voltammetric curves exhibit well-defined anodic peaks, with response that is superior to that obtained with glassy carbon electrodes. The influence of pH, nitrite concentration, and potential sweep rate on the electrode response was thoroughly investigated. The results show that the measurement of the oxidation peak current can be used as the basis for a simple, accurate, rapid method for the determination of NO 2 Ϫ , within a concentration range of 0.002-1 mM. Flow injection analysis with amperometric detection was also examined and improved sensitivity was observed, with analytical useful signals being obtained at 50 nM. The possibility of using anodic voltammetry for the determination of nitrogen oxides ͑NO and NO 2 ͒ was also assessed. It is shown that BDD is a very promising electrode material for the detection of nitrogen oxides (NO,NO 2 ) in gases and the determination of NO in aqueous solution.The important role that the nitrite ion (NO 2 Ϫ ) plays in environmental chemistry and public health was recognized long ago. 1-3 Although naturally occurring concentrations of nitrites are usually of no health significance, wastes from fertilizers or intentional additions of nitrites for corrosion control are potential sources of NO 2 Ϫ contamination. Nitrite is often used as an additive for meat products, because it provides effective protection against microorganisms that cause food poisoning. 4 For these reasons, it has become increasingly important to monitor nitrite. In addition, it has also been shown that the analysis of NO 2 Ϫ derived from the metabolism of nitric oxide ͑NO͒ is a convenient approach in studying the metabolism of NO in tissues. 5,6 Most of the methods developed for the determination of nitrite are spectrophotometric, and many of them involve complicated, time-consuming procedures. 7,8 High-performance liquid chromatography ͑HPLC͒ has also been used extensively, and several analytical procedures were described for NO 2 Ϫ detection, e.g., conductometry, UV adsorption, fluorometry, and electrochemical detection ͑see Ref.6, and references therein͒.One of the most attractive features of the use of anodic voltammetry in general for nitrite determination is the lack of nitrate interference. 9 However, the use of noble metals is limited by the presence of oxides on the electrode surface, which cause decreased sensitivity for NO 2 Ϫ determination. 10,11 The use of glassy carbon ͑GC͒ for the oxidative detection of nitrite is rendered difficult by the passivation of the surface as a result of irreversible adsorption of reaction products and intermediates. 9 Nevertheless, GC electrodes have been used for the detection of nitrite, within the concentration range 7.0 ϫ 10 Ϫ5 to 7.0 ϫ 10 Ϫ4 M, by anodic voltammetry, 12 and promising results were also obtained by use of chemically modified electrodes with both voltammetric 9 and amperometric methods. 13

Novel Nitrite Sensing Using a Palladium-polyphenosafranine Nano-composite

“…Results show that the peak current (ipa) was a linear function of the square root of scan rate over the range peak potential (Epa) was affected significantly by the variation of pH. This is in agreement with the observations reported; 45,46 the process is different from the mechanism in acidic media. 47 This was explained by the reaction route of NO2 formation followed by a homogeneous disproportionation reaction to NO3 -.…”

Electroanalysis at Diamond‐Like and Doped‐Diamond Electrodes

“…Also beneficial effects for the electrochemical detection of N-methylcarbamate pesticides at boron-doped diamond electrodes were reported [112]. Due to the high positive potentials accessible at boron-doped diamond electrodes, hitherto difficult to detect species such as nitrite and nitrogen oxides are readily detected at boron-doped diamond electrodes [113]. A flow injection analysis procedure has been proposed with a diamond electrode detector.…”

Boron doped diamond electrode for the wastewater treatment

“…A total region of around four volts is available within which rather low background currents are recorded. [29][30][31][32][33] With its combination of a low background current, an extremely high overvoltage for oxygen and hydrogen evolution, and an extremely high stability, diamond is a suitable material for some industrial applications.…”