Use of fluorine-doped tin oxide electrodes for lipoic acid determination in dietary supplements

Miranda, Miguel; Rio, Rodrigo Del; Valle, M. A. del; Faúndez, Mario; Armijo, Francisco

doi:10.1016/j.jelechem.2011.12.022

Cited by 48 publications

(31 citation statements)

References 39 publications

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“…In the present case, LipS 2 , alone, suffers oxidation, via 2 electrons, leading probably to the sulfoxide (represented as LipSSO) and other products, as well reported in the literature , (Eq. 2).…”

Section: Resultssupporting

confidence: 78%

Sensitive Electroanalytical Detection on GCE: the Case of Lipoic Acid and its Interaction with N‐acetylcysteine and Glutathione

Santos

Moura

Tanaka³

et al. 2016

Electroanalysis

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A simple and sensitive electrochemical method was developed for the determination of N‐Acetylcysteine (NAC) and Glutathione (GSH), on glassy carbon electrode. The results indicate that α‐lipoic acid (LipS2) is oxidized at the electrode, but is regenerated by thiols, suggesting a redox catalytic effect. Under optimized conditions, the analytical curves for NAC and GSH were obtained in the range of 1 up to 10 µM and 1 up to 60 µM, respectively. The quantification can be performed in a single assay with high sensitivity, reproducibility and low detection limit of 0.27 and 0.67 µM for NAC and GSH, respectively. This method was successfully applied to the determination of NAC and GSH in artificial saliva and human urine samples, with excellent recovery results.

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Section: Resultssupporting

confidence: 78%

Sensitive Electroanalytical Detection on GCE: the Case of Lipoic Acid and its Interaction with N‐acetylcysteine and Glutathione

Santos

Moura

Tanaka³

et al. 2016

Electroanalysis

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“…Namely, the fluorescence "turn-on" sensing systems have better selectivity than "turn-off" sensors [39,40]. Namely, the fluorescence "turn-on" sensing systems have better selectivity than "turn-off" sensors [39,40].…”

Section: Effect Of Analytical Conditionsmentioning

confidence: 98%

Detection of glutathione with an “off–on” fluorescent biosensor based on N-acetyl-l-cysteine capped CdTe quantum dots

Tan

Yang

Li³

et al. 2015

Analyst

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This paper reports a quantum dot (QD)-based "off-on" fluorescent biosensor specifically for the determination of glutathione (GSH) with high sensitivity. The biosensor was based on the following two properties. Firstly, the high fluorescence of N-acetyl-L-cysteine (NALC) capped CdTe QDs could be effectively quenched by Hg(2+) due to the binding of Hg(2+) to the NALC on the surface of the QDs and the electron transfer from the photoexcited NALC-capped CdTe QDs to Hg(2+). Secondly, in the presence of GSH, the fluorescence intensity of NALC-capped CdTe QDs was found to be efficiently recovered. Under some optimized conditions, the relatively restored fluorescence intensity was proportional to the concentration of GSH in the range of 4-64 μg mL(-1), with a correlation coefficient of 0.9980 and a limit of detection of 2.49 ng mL(-1). In addition, the established method shows a high selectivity for some amino acids except cysteine. Moreover, to further investigate its performance, the biosensor was applied to the determination of GSH in human serum samples through a standard addition method and determination of normal GSH concentration in original human serum samples with satisfactory results.

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“…The developed method was validated for linearity, limit of detection (LOD), limit of quantification (LOQ), precision, repeatability, accuracy, ruggedness and robustness to verify the suitablity for the extended purposes according to the approach proposed by Miranda et al [17]. The LOD and LOQ were calculated by the equations; LOD = 3 SD/m and LOQ = 10 SD/m, where SD is the standard deviation of the three replicate determinations of the RB5 dye at the lowest concentration on the calibration curve and m is the slope of the regression equation [18].…”

Section: Voltammetric Measurementmentioning

confidence: 99%

Voltammetric Determination of Reactive Black 5 (Rb5) in Waste Water Samples From the Batik Industry

Yaacob¹

2016

MJAS

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A cyclic voltammetry (CV) and differential pulse cathodic stripping voltammetry (DPCSV) studies of RB5 in Britton-Robinson buffer (BRB) at a hanging mercury dropping electrode (HMDE) are described. CV was carried out by cathodic and anodic potential scan over the range of +200 mV to -800 mV with no accumulation time and three well-defined pH-dependent cathodic peaks were observed. The effects of different scan rates, pH of BRB, repetitive cycle and increasing concentrations on the peak height and peak potential of the analyte were studied. The results showed that RB5 dye was adsorbed and irreversibly reduced at the mercury electrode, mainly under diffusion controlled in the optimum pH 4.0 of BRB. By using DPCSV, pH of BRB and various instrumental parameters such as scan rate, accumulation time, accumulation potential and pulse amplitude that may affect the peak height of RB5 were investigated and optimized for RB5 determination. Under the optimized parameters, the peak height was found to be linear with RB5 concentration in the range from 2.5 x 10 -7 mol L -1 to 2.0 x 10 -6 mol L -1 . A detection limit (3SD/m) of 1.3 x 10 -8 mol L -1 was achieved. The precision of the developed method in terms of RSD was 0.55% for intra-day measurement and 0.55%, 0.24% and 0.40%, for inter-day measurements, respectively. The developed method was successfully applied in the determination of RB5 in batik wastewaters with the mean recovery of 83.97 ± 4.78% to 97.93 ± 5.45% (0.5 x 10 -6 mol L -1 ), 95.91 ± 2.68% to 103.49 ± 1.32% (1.0 x 10 -6 mol L -1 ) and 99.17 ± 0.75% to 105.12 ± 0.28% (2.0 x 10 -6 mol L -1 ). The developed method is considered sensitive, precise, accurate, rugged, robust, fast and low cost for routine analysis of RB5 dye in batik wastewaters over the UV-VIS spectrometry method.Keywords: Reactive Black 5, differential pulse cathodic stripping, Britton-Robinson buffer, hanging mercury dropping electrode, batik wastewater samples Abstrak Kajian voltammetri berkitar (CV) dan voltammetri perlucutan denyut kebezaan (DPCSV) terhadap pewarna RB5 dalam larutan penimbal Britton-Robinson (BRB) menggunakan elektrod jatuhan raksa tergantung (HMDE) dihuraikan. CV dijalankan dengan mengimbas potential kathodik dan anodik dari +200 mV ke -800 mV tanpa masa pengumpulan dan tiga puncak diperhatikan selepas imbasan. Kesan perbezaan kadar imbasan, pH BRB, imbasan berkitar yang berulang dan peningkatan kepekatan RB5 ke atas ketinggian dan nilai keupayaan puncak dikaji. RB5 yang dijerap dan diturunkan secara tidak berbalik pada permukaan elektrod merkuri adalah dibawah kawalan difusi pada pH BRB yang optimum iaitu 4.0. Dengan menggunakan DPCSV, pH BRB dan parameter-parameter peralatan yang memberi kesan kepada ketinggian puncak seperti kadar imbasan, masa pengumpulan, keupayaan pengumpulan dan amplitud denyut telah dioptimumkan untuk analisis RB5. Ketinggian puncak berkadar terus dengan kepekatan RB5 dalam julat dari 2.5 x 10 -7 mol L -1 hingga 2.0 x 10 -6 mol L -1 . Had pengesanan adalah 1.3 x 10 -8 mol L -1 . Ketepatan (RSD...

show abstract

Use of fluorine-doped tin oxide electrodes for lipoic acid determination in dietary supplements

Cited by 48 publications

References 39 publications

Sensitive Electroanalytical Detection on GCE: the Case of Lipoic Acid and its Interaction with N‐acetylcysteine and Glutathione

Sensitive Electroanalytical Detection on GCE: the Case of Lipoic Acid and its Interaction with N‐acetylcysteine and Glutathione

Detection of glutathione with an “off–on” fluorescent biosensor based on N-acetyl-l-cysteine capped CdTe quantum dots

Voltammetric Determination of Reactive Black 5 (Rb5) in Waste Water Samples From the Batik Industry

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