Introducing absorptive stripping voltammetry: wide concentration range voltammetric phenol detection

Nissim, Rita; Compton, Richard G.

doi:10.1039/c4an01417k

Cited by 24 publications

(15 citation statements)

References 32 publications

(41 reference statements)

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“…It is likely that the electrochemical reaction occurs at the triple phase boundary that exists at the carbon-oil (binder)-water triple interface [ 22 ], as the analyte diffuses out of the paste. By using the bulk-paste of an optimised carbon paste electrode to pre-concentrate THC and subsequently “stripping” that target, the effect of fouling in the less dilute samples can be overcome [ 20 ]. The pre-concentration of the target also ensures low limits of detection.…”

Section: Introductionmentioning

confidence: 99%

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Absorptive stripping voltammetry for cannabis detection

Nissim

Compton

2015

Chemistry Central Journal

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BackgroundGiven that Δ9-tetrahydrocannabinol, the active constituent of cannabis, has been shown to greatly reduce driving ability, thus being linked to many drug driving accidents, its reliable detection is of great importance.ResultsAn optimised carbon paste electrode, fabricated from graphite powder and mineral oil, is utilised for the sensitive detection of Δ9-tetrahydrocannabinol (THC) in both aqueous solutions of pH 10.0 and in synthetic saliva solutions. “Absorptive Stripping Voltammetry” is exploited to that effect and the paste is used to pre-concentrate the carbon paste electrode with the target molecule. Practical limits of detection of 0.50 μM and 0.10 μM are determined for THC in stationary and stirred aqueous borate buffer solutions, respectively. Theoretical limits of detection are also calculated; values of 0.48 nM and 0.41 nM are determined for stationary and stirred THC aqueous borate buffer solutions, respectively. THC concentrations as low as 0.50 μM are detected in synthetic saliva solutions. The sensitivity of the sensor was 0.12 μA μM−1, 0.84 μA μM−1 and 0.067 μA μM−1 for the stationary buffer, the stirred buffer and the saliva matrix, respectively.Conclusions“Absorptive Stripping Voltammetry” can be reliably applied to the detection of Δ9-tetrahydrocannabinol, after suitable optimisation of the assay. Usefully low practical limits of detection can be achieved.

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Section: Introductionmentioning

confidence: 99%

“…The pre-concentration of the target also ensures low limits of detection. This electroanalytical approach has been termed “absorptive stripping voltammetry”, with concentration in the electrode bulk [ 20 ], as opposed to “adsorptive stripping voltammetry” where the target is allowed to adsorb on the electrode surface.…”

Section: Introductionmentioning

confidence: 99%

Absorptive stripping voltammetry for cannabis detection

Nissim

Compton

2015

Chemistry Central Journal

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“…Oil analysis based on electroanalytical techniques can be performed (i)w ith samples diluted in organic solvent media [1],( ii)i ns urfactant solubilised samples [2],( iii) inverse micro-emulsions [3],o r( iv) employing the oil phase dispersed in am esoporous carbon/conductor substrate [4,5] to provide an enhanced electrochemically active oil j electrode j aqueous electrolyte three-phase boundary interface [6].Aconsiderable area of development of closely related oil-carbon composite electrodes is in electroanalytical paste electrodes [7].A reas of application are particularly in anti-oxidant content monitoring [8],i no il quality monitoring [9],b iofuel testing [10],a nd in the quantitative detection of impurities or dye additives such as quinizarin. Quinizarin (see molecular structure and redox processes in Scheme 1) is water-insoluble in the ambient pH range and has been shown to be electrochemically active.…”

Section: Introductionmentioning

confidence: 99%

Carbon Microsphere – Polystyrene Composite Electrode for Three‐Phase Boundary Oil Analysis: Quinizarin in Methyllaurate

et al. 2015

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Quinizarin (see molecular structure and redox processes in Scheme 1) is water-insoluble in the ambient pH range and has been shown to be electrochemically active. In technical application, quinizarin has been proposed as colorant and anti-corrosion coating for anodised aluminium [11].M olecular quinizarin adsorbed onto carbon has been shown to catalyse the oxygen reduction process [12,13].Q uinizarin has also been shown to act as aM ichael-acceptor when oxidised [14] and this has potential implications in electroanalytical detection of sulphur species.W hen examined as aD NA groove-binding redox reagent, quinizarin has been shown to act as af luorescence reporter in biological samples [15] and it has been investigated as am odel system for anti-cancer drug molecules [16].H owever, the main application of quinizarin is as dye-marker additive in hydrocarbon oils [17,18] for safety and tax reasons.Methyllaurate is am ajor component in bio-fuels [19] and employed here as a" model oil" with quinizarin as a" model redox marker". Then ewly developed electroanalytical method based on ac arbon microsphere composite electrode could be applied to aw ider range of oils containing redox active substances such as anti-oxidants. No electrolyte is added to the oil phase which is deposited directly into ap orous carbon electrode made from ac omposite with glassy carbon microspheres and polystyrene.F igure 1s hows as chematic drawing of the electrode with as mall amount (A) and with ah igher amount (B) of oil deposited. Thee lectrochemical reaction is believed to occur at the three-phase boundary.AFaradaic current is anticipated as long as the electro-analyte (quinizarin in oil) can diffuse towards the three-phase boundary,w here ions (here protons) present in the neighbouring phase can balance the build-up of charge resulting from the electron transfer. From an electroanalytical standpoint, not having to alter or prepare the sample before electrochemical analysis is beneficial and developing as imple "dip-probe" method could be very useful.In this study ac ost efficient and easy-to-make (potentially disposable) porous carbon electrode is fabricated to facilitate three-phase boundary electrochemistry.T he Abstract:O il analysis for the case of quinizarin in methyllaurate is demonstrated with ad isposable carbon microsphere -p olystyrene composite electrode.O xidation and reduction of quinizarin are observed as three-phase boundary processes at the immiscible oil j water j carbon interface.R andomly packed glassy carbon microspheres (2-12 mmd iameter) held together with ap olystyrene binder (ca. 0.1 %b yw eight) are immobilized onto ap encil lead electrode and used for electrochemical oil analysis.P orefilling with oil is optimised for voltammetric detection and fluorescence spectroscopy is employed to support the mechanistic analysis based on voltammetry.F uture applications for aw ider range of oils and additives are proposed.

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“…On the one hand, electrochemistry has emerged as a very promising method to detect and quantify phenols, parabens and its derivatives in different media 11,12 . On the other hand, regarding the use of electrochemical detection systems in enzyme processes, there are three main ways to couple electrodes to enzyme reactions which give rise to the so-called 1 st , 2 nd and 3 rd generation of electrochemical biosensors 13 .…”

Section: Introductionmentioning

confidence: 99%

Using Electrochemical Methods To Study the Kinetics of Laccase-Catalyzed Oxidation of Phenols

Cusola

Valls

Vidal

et al. 2018

Ind. Eng. Chem. Res.

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In the present work the laccase kinetics upon the oxidation process of phenolic compounds was studied using cyclic voltammetry (CV). Several hydroxybenzoic and cinnamic acid compounds were analyzed and the oxidation kinetics were correlated to their chemical structures. Significant differences were observed, and several structural parameters were identified as enhancers of the reaction rate. Folin-Ciocalteau, UV-Vis Spectrophotometry and Thin Layer Chromatography (TLC) methods were also used to assess the laccase-oxidation process. The TLC results correlated well with those from the CV, while the UV-Vis results do so with those from the Folin-Ciocalteau analysis. Results suggest that intermediate adducts, non-detectable by CV, Folin-Ciocalteau, UV-Vis, and TLC analyses, may be formed during the oxidation process. A new approach for using bare glassy carbon electrodes to detect phenolic compounds and monitor their oxidation using laccase enzymes is presented.

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Introducing absorptive stripping voltammetry: wide concentration range voltammetric phenol detection

Cited by 24 publications

References 32 publications

Absorptive stripping voltammetry for cannabis detection

Absorptive stripping voltammetry for cannabis detection

Carbon Microsphere – Polystyrene Composite Electrode for Three‐Phase Boundary Oil Analysis: Quinizarin in Methyllaurate

Using Electrochemical Methods To Study the Kinetics of Laccase-Catalyzed Oxidation of Phenols

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