Electrochemical detection of lipophilic antioxidants with high sensitivity at boron-doped diamond electrode

Abstract

a b s t r a c tThe electrochemical detection of lipophilic antioxidants, ␣-tocopherol (vitamin E, VE) and ubiquinone (coenzyme Q 10 , CoQ 10 ), in methanol and in methanol/hexane mixture solutions, respectively, at borondoped diamond (BDD) electrodes was investigated by cyclic voltammetry (CV) and flow-injection electrochemical measurements. CV measurements revealed that the overpotential for electrochemical reaction of VE and CoQ 10 was larger at an oxidized BDD electrode surface than at that of a hydrogenated BDD (H-BDD) electrode. The slope of the CV calibration curve used to determine the VE and CoQ 10 concentrations was larger at a glassy carbon (GC) electrode than at the H-BDD electrode; however, the signal-to-background ratio was larger at the H-BDD electrode than at the GC electrode, due to the low background feature of the H-BDD electrode. The limit of detection (LOD), defined by a signal-to-noise ratio of three for flow-injection electrochemical detection, was much smaller at the H-BDD electrode (VE: 41 nM and CoQ 10 : 17 nM) than at the GC electrode (VE: 263 nM and CoQ 10 : 71 nM). These results confirm that the H-BDD electrode is reliable for the electrochemical detection of lipophilic antioxidants, especially at low concentrations.

Electrochemical Methods for Total Antioxidant Capacity and its Main Contributors Determination: A review

“…A stipulated reason could be the electrostatic interaction between the phenolic -OH group of the vitamin E molecule and the electrode surface functional groups. The signalto-background ratio was greater at the hydrogenated boron-doped diamond electrode than at the glassy carbon electrode due to the lower background characteristics of the hydrogenated boron-doped diamond electrode [78].…”

Electroanalysis of Pharmaceuticals on Boron‐Doped Diamond Electrodes: A Review

“…Lipophilic antioxidants such as α‐tocopherol (vitamin E, VE) and ubiquinone (coenzyme Q10, CoQ10) are indispensable micronutrients used to protect humans against diseases related to oxidative stress, including cardiovascular disease, cancer, cataracts, and age‐related problem. Considering the importance of these micronutrients to human, Kondo and coauthors, developed a methodology by CV and flow‐injection electrochemical measurements. Although the proposed methodology was not applied in a real sample, during the development, modifications were made to the BDD electrode with UV/ozone treatment where it was observed that the hydrogenated surface improved the electrochemical response of both analytes, thus obtaining a linearity of 5×10 −7 to 1×10 −4 mol L −1 .…”

“…Industrial foods may contain the most diverse compounds. In the work developed by Alpar and coauthors, a method was developed to detect 5‐O‐caffeoylquinic acid, vanillin and caffeine in commercial samples . The authors used anodic and cathodic pretreatments of the BDD electrode were carried out in 0.5 mol L −1 H 2 SO 4 for 180 s, by applying activation potential of 1.7 and −1.7 V, respectively.…”

Electrolytic Treatment Characteristics of Boron-doped Nanocrystalline Diamond/Amorphous Carbon Composite Films Prepared by Coaxial Arc Plasma Deposition

“…Aqueous waste containing various persistent substances is reported to be decomposed by BDD films used as anode electrodes (3) . BDD electrodes have also been used as electrodes for electrosynthesis (4) and electrochemical sensors (5) ; thus, BDD is an electrode material with numerous potential electrochemical applications. Diamond films are usually fabricated by chemical vapor deposition (CVD); they are promising for various engineering applications as electrochemical, electronic device, and hard coating materials (6,7) .…”