Capillary Electrophoresis Assisted Flow System for In Situ Analysis of Products of Heterogeneous Electrocatalytic and Catalytic Processes: Application to the Oxidation of Glycerol

Lopes, Fernando Silva; Nogueira, Thiago Assis Rodrigues; Lago, Claudimir Lúcio do; Gutz, Ivano Gebhardt Rolf

doi:10.1002/elan.201100321

Cited by 19 publications

(19 citation statements)

References 17 publications

(16 reference statements)

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“…The two methods of anodic stripping voltammetry and CE‐C 4 D are thus highly complementary in that each method defeats a shortcoming of the other. The same system was subsequently employed for a study of the electrochemical oxidation of glycerol on different electrode materials . The group also reported the on‐line coupling of the air sampling system mentioned above to CE‐C 4 D and demonstrated the determination of formic and acetic acid .…”

Section: New and Extended Instrumentationmentioning

confidence: 99%

Contactless conductivity detection for analytical techniques: Developments from 2010 to 2012

Kubáň

Hauser

2012

Electrophoresis

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The developments in the field of capacitively coupled contactless conductivity detection in the approximate period from July 2010 to June 2012 are traced. Few reports concerning fundamental studies or new detector designs have appeared. On the other hand, applications in standard CZE are flourishing and contactless conductivity measurements are increasingly being employed as part of novel or more sophisticated experimental systems. Work on the lab-on-chip devices integrating contactless conductivity detection is continuing. A range of reports on the use of the simple yet powerful detection technique of contactless conductivity measurements in chromatographic separation as well as for analytical methods not including a separation step have also appeared.

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Section: New and Extended Instrumentationmentioning

confidence: 99%

Contactless conductivity detection for analytical techniques: Developments from 2010 to 2012

Kubáň

Hauser

2012

Electrophoresis

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“…The coupling of voltammetry with liquid chromatography has allowed the monitoring of non‐volatile products and stable intermediates from electro‐oxidation processes . Capillary electrophoresis has also been coupled to an electrochemical cell and was successfully used to monitor the products from electrocatalytic oxidation of glycerol using an EC‐CE‐C 4 D (Electrochemical Conversion ‐ Capillary Electrophoresis ‐ Capacitively Coupled Contactless Conductivity Detection) online flow system. In a previous application of CE , the possibility to carry out the quantification of ethanol by monitoring ethanoate generated electrochemically on platinum working electrode in acidic medium by using EC‐CE‐C 4 D was demonstrated.…”

Section: Introductionmentioning

confidence: 99%

Online monitoring of electrocatalytic reactions of alcohols at platinum and gold electrodes in acidic, neutral and alkaline media by capillary electrophoresis with contactless conductivity detection (EC‐CE‐C⁴D)

2017

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An EC-CE-C D flow system was applied to the investigation of electrocatalytic processes by monitoring carboxylic acids formed during the electro-oxidation at various potentials of primary alcohols (mixture of 1 mmol/L of ethanol, n-propanol, n-butanol and n-pentanol) in acidic, neutral and alkaline media. The electro-oxidation was carried out on gold and platinum disk electrodes (3 mm of diameter) in a thin-layer electrochemical flow cell. Products were sampled 50 μm apart from the electrode directly into the capillary. All the generated carboxylates were determined in near real time (less than 2 min) by CE-C D in counter-flow mode, with Tris/HCl buffer solution (pH 8.6) as BGE. Long sequences of 5-min experiments were run automatically, exploring the applied potential, electrolysis time and solution composition. Electro-oxidation at 1.5 V (versus Ag/AgCl quasi-reference) during 50 s in acidic medium was found appropriate for both Pt and Au electrodes when the determination of alcohols after derivatization is intended. A noteworthy selectivity effect was observed on the Au electrode. The signal corresponding to pentanoate is similar on both electrodes while the signal of ethanoate (acetate) is four times larger on gold than on platinum. The carboxylate signals were lower in alkaline medium (below the determination limit on Pt) than in acidic and neutral media. On gold, the formation of carboxylates was anticipated (0.85 V in alkaline medium versus 1.40 V in neutral medium). The automatic online monitoring of electrochemical processes by EC-CE-C D holds great potential to investigate ionic/ionizable intermediates/products of new electrocatalysts and/or alternative fuels.

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“…An electrochemical injection device was integrated into a flow system and applied to trace determinations of heavy metals. Another report by the same group 9 was concerned with the study of the electrooxidation of glycerol at noble metal electrodes by means of combined CE with contactless conductivity detection.…”

Section: Introductionmentioning

confidence: 99%

Electrochemically Assisted Injection in Combination with Capillary Electrophoresis‐Mass Spectrometry (EAI‐CE‐MS) – Mechanistic and Quantitative Studies of the Reduction of 4‐Nitrotoluene at Various Carbon‐Based Screen‐Printed Electrodes

et al. 2012

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Electrochemically assisted injection (EAI) is a recently introduced injection concept for capillary electrophoresis (CE) enabling the separation of neutral analytes by means of electrochemical generation of charged species during the injection process. EAI‐CE is particularly attractive in combination with mass spectrometry (MS) leading to enhanced performance of MS detection. In this work, a fully automated EAI injection device was developed and applied to mechanistic and quantitative studies of the reduction of 4‐nitrotoluene (4‐NT). Three different carbon‐based screen‐printed electrodes (SPEs) were used including unmodified carbon, carbon nanofiber and reduced graphene oxide SPEs. Under acidic conditions the main products of 4‐NT reduction were 4‐hydroxylaminotoluene (4‐HAT) and 4‐aminotoluene (4‐AT). The EAI‐CE‐MS approach enabled the separation and selective determination of both compounds. On the basis of this methodical concept it was possible to study the formation of reduction products of 4‐NT in dependence on electrode potential and electrode material. In contrast to conventional electrochemical techniques like cyclic voltammetry EAI‐CE‐MS provides detailed information regarding changes of the product composition in dependence on various experimental conditions. Over the complete potential range studied the ratio of 4‐HAT/4‐AT was clearly different for the reduced graphene oxide SPE compared to the unmodified carbon and carbon fiber SPE. The construction of mass voltammograms added considerably to the information content of voltammetric experiments. Another aspect of this work was the reliable quantitative determination of 4‐NT by EAI‐CE‐MS using isotopically labeled 4‐NT as an internal standard. In this way the “classical” problem of changing response characteristics at solid electrodes could be eliminated based on the assumption that the target analyte and its isotopically labeled form behave in the same way. A corresponding protocol for quantitative EAI‐CE‐MS determinations of 4‐NT was elaborated and applied to standard solutions and spiked soil samples.

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Capillary Electrophoresis Assisted Flow System for In Situ Analysis of Products of Heterogeneous Electrocatalytic and Catalytic Processes: Application to the Oxidation of Glycerol

Cited by 19 publications

References 17 publications

Contactless conductivity detection for analytical techniques: Developments from 2010 to 2012

Contactless conductivity detection for analytical techniques: Developments from 2010 to 2012

Online monitoring of electrocatalytic reactions of alcohols at platinum and gold electrodes in acidic, neutral and alkaline media by capillary electrophoresis with contactless conductivity detection (EC‐CE‐C⁴D)

Electrochemically Assisted Injection in Combination with Capillary Electrophoresis‐Mass Spectrometry (EAI‐CE‐MS) – Mechanistic and Quantitative Studies of the Reduction of 4‐Nitrotoluene at Various Carbon‐Based Screen‐Printed Electrodes

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Capillary Electrophoresis Assisted Flow System for In Situ Analysis of Products of Heterogeneous Electrocatalytic and Catalytic Processes: Application to the Oxidation of Glycerol

Cited by 19 publications

References 17 publications

Contactless conductivity detection for analytical techniques: Developments from 2010 to 2012

Contactless conductivity detection for analytical techniques: Developments from 2010 to 2012

Online monitoring of electrocatalytic reactions of alcohols at platinum and gold electrodes in acidic, neutral and alkaline media by capillary electrophoresis with contactless conductivity detection (EC‐CE‐C4D)

Electrochemically Assisted Injection in Combination with Capillary Electrophoresis‐Mass Spectrometry (EAI‐CE‐MS) – Mechanistic and Quantitative Studies of the Reduction of 4‐Nitrotoluene at Various Carbon‐Based Screen‐Printed Electrodes

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Online monitoring of electrocatalytic reactions of alcohols at platinum and gold electrodes in acidic, neutral and alkaline media by capillary electrophoresis with contactless conductivity detection (EC‐CE‐C⁴D)