Glass-carbon electrode

Tan, X.C.,Tian, Y.X., Cai, P.X. andZou, X.Y. (2005) Glucose biosensor based on glucose oxidase immobilized in sol—gel chitosan/silica hybrid composite film on Prussian blue modified glass carbon electrode. Analytical and Bioanalytical Chemistry, 381, 500-507. 

Qian, D., Nakamura, C., Wenk, S., Wakayama, T., Zorin, N., Miyake, J. (2003). Electrochemical hydrogen evolution by use of a glass carbon electrode sandwiched... 

Lin Z, Chen J, Chen G (2008) An ECL biosensor for glucose based on carbon-nanotube/ Nafion film modified glass carbon electrode. Electrochim Acta 53(5) 2396-2401. doi 10.1016/j. electacta.2007.09.063... 

NH3 ILs-EmimNTF, Glass carbon electrode QH, (hydroquinone)-H2NHj 2NH3 -rQ or 4NH3 3NH/ -h- AN,+3e... 

Using a glass carbon electrode (GCE) modified with MWCNTs, Cai et al. ° observed an enhanced sensitivity for electrochemical DNA biosensor based on CNTs. Figure 6.22 schematically shows the steps for constructing the nanotube-DNA biosensor. To start, carboxylic acid functionalized MWCNTs (COOH-MWCNTs) were dropped on a GCE electrode, single-strand DNA oligonucleotides (ss-DNAs) were then covalently bonded onto the COOH-MWCNTs via amide formation. The hybridization reaction on the electrode was monitored by differential pulse voltammetry (DPV) using an electroactive daunomycin intercalator as the indicator. 

Carbon dioxide devices were originally developed by Severinghaus and Bradley (59) to measure the partial pressure of carbon dioxide in blood. This electrode, still in use today (in various automated systems for blood gas analysis), consists of an ordinary glass pH electrode covered by a carbon dioxide membrane, usually silicone, with an electrolyte (sodium bicarbonate-sodium chloride) solution entrapped between them (Figure 6-17). When carbon dioxide from the outer sample diffuses through the semipermeable membrane, it lowers the pH of the inner solution ... 

Batley [780] examined the techniques available for the in situ electrodeposition of lead and cadmium in seawater. These included anodic scanning voltammetry at a glass carbon thin film electrode and the hanging drop mercury electrode in the presence of oxygen, and in situ electrodeposition on mercury-coated graphite tubes. 

Batley [28] examined the techniques available for the in situ electrodeposition of lead and cadmium in estuary water. These included anodic stripping voltammetry at a glass carbon thin film electrode and the hanging drop mercury electrode in the presence of oxygen and in situ electrodeposition on mercury coated graphite tubes. Batley [28] found that in situ deposition of lead and cadmium on a mercury coated tube was the more versatile technique. The mercury film, deposited in the laboratory, is stable on the dried tubes which are used later for field electrodeposition. The deposited metals were then determined by electrothermal atomic absorption spectrometry, Hasle and Abdullah [29] used differential pulse anodic stripping voltammetry in speciation studies on dissolved copper, lead, and cadmium in coastal sea water. 

The concept of thin films of a molecularly imprinted sol-gel polymer with specific binding sites for a target analyte is general and can be applied also to electrochemical sensors. For example, a sensor to detect parathion in aqueous solutions is based on films cast on glass substrates and on glassy carbon electrodes (Figure 6.14).12... 

A 500-mL, four-necked, reaction flask, equipped with a mechanical stirrer, thermometer, and glass pH electrode combined with an automatic titrator (Note 1), is charged with sodium (meta)periodate (85.5 g, 0.4 mol) (Note 2) and water (200 mL). The suspension is cooled to 0°C in an ice bath and 3 N sodium hydroxide (about 133 mL, 0.4 mol) is added dropwise at a rate such that the temperature does not exceed 7°C. The final pH of the suspension is 5.5. The cooling bath is removed and finely powdered 5,6-0-isopropylidene-L-gulono-1,4-lactone (Note 3) (43.6 g, 0.2 mol) Is added in one portion. The temperature of the mixture is kept below 30°C (Note 4). The pH of the suspension is maintained at 5.5 during the course of the reaction by addition of aqueous 15% sodium carbonate (about 15 mL). The suspension is further stirred at room temperature for 30 min, saturated with sodium chloride (105 g), and filtered by suction using a Buchner funnel. The white solid (Note 5) is washed thoroughly with two, 50-mL portions of brine and the pH of the combined aqueous layers is adjusted to... 

Sometimes, semiconductivity depends on the type of a structural phase that arises from synthesis. Thus, in the case of (TCNQ) Cu the semiconducting phase is thermodynamically disfavored. To prepare this semiconductor, Harris et al. (2005) proposed to perform the reduction of TCNQ in acetonitrile at glass-carbon, gold, or platinum electrode in the presence of Cu. This allows the electrocrystallization of sparingly soluble TCNQCu semiconducting phase to occur by a nucleation... 

Ebel et al. have used a microliter vessel in the voltammetry and polarographic determination of small sample volumes of chlorpromazine [166]. The concentration of cells in glass or PTFE was described for use with a dropping-mercury electrode (sample volume 180 pL), a rotating disc electrode (sample volume 1 mL), or a stationary vitreous-carbon electrode (sample volume 80 pL). Chlorpromazine was determined using oxidative voltammetry at a 3 mm vitreous-carbon or a rotating electrode. 

New polymer membrane-based ISEs for nitrate and carbonate exhibit detection limits and selectivities that may be applicable for ocean measurements. In addition, a number of these ISEs can be used as internal transducers for the design of useful potentiometric gas sensors. For example, dissolved C02 can be detected potentiometrically by using either a glass membrane electrode or a polymer-based carbonate ISE, in conjunction with an appropriate reference electrode, behind an outer gas permeable membrane. Novel differential pC02 sensors based on two polymer membrane-type pH sensors have also been developed recently. 

Add 2 mL of 0 5M sodium carbonate buffer, pH 10 5, and stir slowly. Place in a fume hood and immerse the glass pH electrode in the solution... 

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