Properties of thiolate monolayers formed on different amalgam electrodes

Yosypchuk, Bogdan; Mareček, Vladimı́r

doi:10.1016/j.jelechem.2011.01.017

Cited by 21 publications

(9 citation statements)

References 65 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The most suitable for electroreduction processes, particularly at high negative potentials, are mercury and amalgam electrodes. Construction of non‐toxic solid amalgam electrodes and paste amalgam electrodes is similar to electrodes of other materials suitable for analysis in flow systems. The very useful advantage of solid amalgams is the possibility to prepare electrodes of required size and shape .…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Biosensors Based on Enzymatic Reactors Filled by Various Types of Silica and Amalgam Powders for Measurements in Flow Systems

2016

View full text Add to dashboard Cite

Two enzymatic biosensors with amalgam powder reactors and twelve enzymatic biosensors with various silica powder reactors were fabricated and tested in this work. The enzymatic reactors based on silver amalgam powder provide high sensitivity and they are convenient for faster flow rates. Experiments with six silica materials showed that mesoporous silica SBA‐15 was the best one in terms of covering by enzymes, sensitivity and lifetime of biosensors. The current response of the SBA15‐glucose oxidase (GOx) sensor started to decrease only after 200 day testing and after 406 days the peak current was still 35.9 % of the initial value. The used amalgam tubular detector in a flow system allowed working at highly negative potentials, which significantly increased the sensitivity of determinations. Statistical results of parallel measurement of model solutions with the fabricated biosensors show their high accuracy (RSD=0.28–1.81 %) and sensitivity (6.2–14.3 µmol L−1). The proposed SBA15‐GOx biosensor was successfully used for determination of glucose in commercial honey.

show abstract

Section: Introductionmentioning

confidence: 99%

Electrochemical Biosensors Based on Enzymatic Reactors Filled by Various Types of Silica and Amalgam Powders for Measurements in Flow Systems

2016

View full text Add to dashboard Cite

show abstract

“…A protein was adsorbed on the working electrode from the 5 % L drop of the sample solution in PBS at open current potentials for the accumulation time of 120 s, followed by the transfer of the modified electrode to the background electrolyte (50 mM Na‐phosphate buffer, pH 7) and by the SW voltammogram recording: initial potential −1 V, end potential −2 V, amplitude 10 mV, step 1 mV, frequency 95 Hz. Preparation of the meniscus‐modified SAE and its electrochemical activation and regeneration was earlier described in detail in .…”

Section: Methodsmentioning

confidence: 99%

“…Diagram of the pneumatic valve. A piston actuated by the pressurized air pushes a thin carbon fiber rod through a PDMS membrane into the microchannel and blocks it. and its electrochemical activation and regeneration was earlier described in detail in [28,29].…”

Section: Methodsmentioning

confidence: 99%

Electrochemical Analysis of Glycoprotein Samples Prepared on a Pneumatically‐controlled Microfluidic Device

2019

View full text Add to dashboard Cite

In this work, we designed and manufactured a microfluidic device for isolation and purification of glycoprotein samples. The conceived sample preparation device was fabricated in polycarbonate by micro‐milling. The flow control and the fluid dosage into the micro‐channels was solved by equipping the device with integrated pneumatic valves. The biochemical functionality was provided by beaded support modified by molecules with affinity to glycoproteins which was stacked inside the micro‐channel reminiscent of packed affinity columns used in glycoprotein lectin assays. Unlabeled glycoproteins, namely fetuin, asialofetuin, and prostate‐specific antigen, were voltammetrically analyzed using catalytic peak H at silver amalgam electrode.

show abstract

“…Chronopotentiograms were recorded from an initial potential ( E i ) of −1.4 V at a stripping current ( I str ) of −25 or −40 µA at HMDE or SAE, respectively; if not stated otherwise. Preparation of the SAE and its electrochemical activation and regeneration was earlier described in detail 36, 37.…”

Section: Methodsmentioning

confidence: 99%

Lysine, Arginine, and Histidine Residues in Peptide‐Catalyzed Hydrogen Evolution at Mercury Electrodes

et al. 2015

View full text Add to dashboard Cite

Dedicated to Professor R. G. Compton on the Occasion of his 60 th Birthday 1IntroductionNucleic acids are electroactive species undergoing reduction and oxidation of their base residues at various types of electrodes.E lectrochemistry of nucleic acids embraces aw ide variety of natural and synthetic molecules including DNAand RNA [1][2][3].Incontrast, electrochemistry of proteins was concentrated mostly on the fast reversible electrode processes of non-protein redox centers in conjugated proteins [4][5][6][7][8].Recently,w eh ave shown that using constant-current chronopotentiometric stripping (CPS) in combination with mercury and amalgam electrodes,p ractically all proteins and many peptides produce the so-called peak H due to catalytic hydrogen evolution reaction (CHER,). Thep osition, height, shape,and area of this peak are sensitive to the analyte concentration and allow the detection of proteins in the nanomolar range. Application of CPS peak Hw as useful in the analysis of proteins such as determination of metalloproteins in tissues [12] and solubility of transmembrane proteins [13,14],m onitoring of protein aggregation [15,16] and denaturation [15,[17][18][19] [17,23].C PS peak Hi s ap owerful label-free electroanalytical signal useful in the contemporary protein research.To take full advantage of application of CPS peak Hi n the protein analysis,i ti se ssential to understand different parameters influencing the CHER. Modelp eptides [24,25] and polyamino acids [26,27] were used to explore the role of their amino acid (aa) composition [25] or interfacial organization of the adsorbed peptide layer on the CHER [28].I np eptides and proteins,o nly aa residues bearing functional groups with exchangeable protons should play the active role.W eh ave already shown that cysteine (Cys) thiol [20,24,28],l ysine (Lys) e-ammonium [27],a rginine (Arg) guanidinium or histidine (His) imidazolium groups [25] transfer the protons from the acid constituent of the buffer (proton donor) onto highly negatively charged surface of the electrode where they subsequently combine in more stable molecules of the gaseous hydrogen (H 2 ); for more details about the mechanism of the catalytic hydrogen evolution see e.g. [9].Thea bility of proteins to catalyze hydrogen evolution from aqueous solutions was discovered [29] soon after invention of polarography.T he so-called presodium wave on DC polarograms was too close to the background discharge and was considered of little analytical use.I tw as shown that the catalytic process is better developed in buffered media and application of polarography in studying the catalytic process was restricted to neutral or weakly alkaline media;a tp H < 7t his wave was masked by hydrogen evolution from the buffer [30].C ompared to DC polarography,c hronopotentiometry is highly sensitive to the catalysis of hydrogen evolution and CPS peak Hi s well separated from the background discharge even below pH 7[ 31].T his peak can be considered as as econd generation of the presodium wave [32,33].Recently,w e...

show abstract

Properties of thiolate monolayers formed on different amalgam electrodes

Cited by 21 publications

References 65 publications

Electrochemical Biosensors Based on Enzymatic Reactors Filled by Various Types of Silica and Amalgam Powders for Measurements in Flow Systems

Electrochemical Biosensors Based on Enzymatic Reactors Filled by Various Types of Silica and Amalgam Powders for Measurements in Flow Systems

Electrochemical Analysis of Glycoprotein Samples Prepared on a Pneumatically‐controlled Microfluidic Device

Lysine, Arginine, and Histidine Residues in Peptide‐Catalyzed Hydrogen Evolution at Mercury Electrodes

Contact Info

Product

Resources

About