Electrochemical oxidation and electroanalytical determination of xylitol at a boron-doped diamond electrode

Abstract

Xylitol is a reduced sugar with anticariogenic properties used by insulin-dependent diabetics, and which has attracted great attention of the pharmaceutical, cosmetics, food and dental industries. The detection of xylitol in different matrices is generally based on separation techniques. Alternatively, in this paper, the application of a boron-doped diamond (BDD) electrode allied to differing voltammetric techniques is presented to study the electrochemical behavior of xylitol, and to develop an analytical methodology for its determination in mouthwash. Xylitol undergoes two oxidation steps in an irreversible diffusion-controlled process (D=5.05 × 10(-5)cm(2)s(-1)). Differential pulse voltammetry studies revealed that the oxidation mechanism for peaks P1 (3.4 ≤ pH ≤ 8.0), and P2 (6.0 ≤ pH ≤ 9.0) involves transfer of 1H(+)/1e(-), and 1e(-) alone, respectively. The oxidation process P1 is mediated by the (•)OH generated at the BDD hydrogen-terminated surface. The maximum peak current was obtained at a pH of 7.0, and the electroanalytical method developed, (employing square wave voltammetry) yielded low detection (1.3 × 10(-6) mol L(-1)), and quantification (4.5 × 10(-6) mol L(-1)) limits, associated with good levels of repeatability (4.7%), and reproducibility (5.3%); thus demonstrating the viability of the methodology for detection of xylitol in biological samples containing low concentrations.

Chlorpromazine Electro‐oxidation at BDD Electrode Modified with nZVI Nanoparticles Impregnated NiAl LDH

“…where S d is the standard deviation of the blank signal and B is the slope of the calibration curve . LOD and LOQ were estimated to be 0.005 and 0.016 μM, respectively.…”

Determination of triclocarban by direct and adsorptive stripping voltammetric methods on a glassy carbon electrode

“…1A) was due to TCC adsorption and/or its non-electroactive oxidation products, and/or to competitive supercial reactions at the electrode surface in the potential range studied, which may have caused fouling and inactivation of the available electrode surface area. 30 According to Masek et al, 35 two approaches (one using I p vs. v 1/2 curve analysis) to study the reversibility of electrochemical reactions and (another using I p vs. v 1/2 and ln I p vs. ln v curve analyses) to determine whether a reaction rate is controlled by adsorption or diffusion are widely used. The effect of scan rate on the potentials and currents of both peaks P 1 and P 2 was investigated by increasing the scan rate from 25 to 200 mV s À1 by LSV in a potential range of +1.0 to +1.4 V (vs. E Ag/AgCl ), see LS voltammograms obtained in acetate buffer pH 4.2 (Fig.…”

“…25 Square wave adsorptive stripping voltammetry (SWAdSV) is the best electroanalytical method for the determination of electroactive organic molecules that are adsorbed on the working electrode surfaces, 24 such as mesotrione (organoclay modied GCE), 26 halosulfuron-methyl (GCE), 27 nitroxynil (mercury electrode), 28 carbendazim (carbon nanotube modied electrode) 29 and xylitol (boron-doped diamond electrode). 30 The analyte in this method is concentrated by adsorption on the electrode surface and subsequently stripped off in reduction or oxidation scans. 31…”

Remoção eletroquímica dos inseticidas organofosforados metil paration e clorpirifós utilizando eletrodos de diamante dopado com boro

“…Nesse contexto, um dos grandes desafios é o desenvolvimento de materiais anódicos, que ofereçam eficiência na mineralização com baixo consumo de energia ou formação de compostos alifáticos. Diferentemente desses materiais, os ânodos contendo filme de diamante dopado com boro (DDB) vêm sendo cada vez mais estudados devido à alta eficiência na remoção de compostos orgânicos tais como corantes têxteis 36,37 , corantes alimentícios 38 , fármacos [39][40][41][42] e pesticidas 43-47 sem a necessidade de adição de agentes oxidantes e com aplicação de densidades de correntes relativamente baixas (≤ 100 mA cm -2 ) .  Alta estabilidade corrosiva em soluções ácidas; 52  Sua superfície possui baixa propriedade de adsorção e resistência à desativação; 50  Baixa corrente capacitiva.…”