Graphitic disc

S.A. Jaffari and A.P.F. Turner, Novel hexacyanoferrate(III) modified graphite disc electrodes and their application in enzyme electrodes.1. Biosens. Bioelectr. 12,1—9 (1997). 

Kleinmann and Svoboda [42] reported direct vaporization of samples into a low-power ICP source from a graphite disc support mounted directly within the body of the plasma torch. Nixon et al. [43] described the use of a tantalum filament electrothermal... 

MPG mercury-plated graphite disc SSCE sodium saturated calomel... 

Fig. 2.3 Experimental current-time curve (a) and logarithmic curves (b) for the application of a constant potential to a graphite disc electrode of radius 0.5 mm (planar electrode) for the reduction of Fe(CN)g. ...

Acetylcholineesterase and choline oxidase A rotating graphite-disc electrode was polished, defatted, cleaned and oxidized by immersion in 10% HN03/2.5%, K2Cr207 at 2.2 V versus SCE for 10 s. AChE was covalently immobilized on to the electrode using a standard method. Measurements were made in 0.1 M-universal buffer of pH 7 at 0.8 V versus SCE. Calibration graphs were linear from 0.6-10 pM substrate. RSD were 5% (n = 10). The detection limit was 10 pM acetylthiocholine, electrode response time was 15 s. [89]... 

Fig. 9.6. Schematic diagram of the experimental system for laser ablation-assisted radio-frequency atomization excitation. (I) Sample holder, (2) tantalum lid, (3) graphite cup, (4) graphite disc, (5) rf power source, (6) different types of sample holder for sintered ceramics, (7) NdiYAG laser, (8) laser beam-focusing lens, (9) spectrometer, (10) quartz window for laser irradiation, (11) central electrode, (12) discharge chamber, (13) quartz window for optical observation. (Reproduced with permission of the Royal Society of Chemistry.)...

The same authors also studied the polarization behavior of a rotating-disc electrode and the chronopotentiometry of a graphite disc electrode. Figure 15.11 illustrates the situation in the vicinity of the cathode. A cupric chloride ion, CUCI3, moves to the cathode through its diffusion layer (Step 1) and is electrochemically reduced to CuClg (Step 2). 

Differential calorimeters consisting of two graphite discs (with separate thermocouples each) have been designed and used mainly for cahbration of routine dosimeters (Janovsky 1985). During irradiation, only one of the two graphite discs is irradiated, while the other one is used as reference. The temperature difference measured between the two discs serves to calculate the dose. Radak et al. (1973) designed similar instrument for calibration at low electron energies (400 keV). 

Hastings, I.J. and R.D. MacDonald. 1984. High Burnup Performance of Annular UO2 Fuel with Inter-Pellet Graphite Discs, Atomic Energy of Canada Limited Report, AECL-8510, January. 

Fig. 81. Reduction of 0.28 mM O2 in 0.1 M NaCl 4- 0.1 M acetate buffer at a rotating graphite electrode. pH 5.3, disc potential scan 0.02 V s rotation rate 100 rev.min" Current responses (1) at freshly polished graphite (dashed curve) (2) at the graphite disc with 3.1 x 10" mol m of adsorbed Fe(III)-alizarine complexone (full curve). Adapted according to [214].

Recently, two additional large three-fold symmetric graphitic discs, one containing 150 carbon atoms 45 and another containing 90 carbon atoms 46 at the core, were prepared (Scheme 3.15) [52]. The former is the largest disc with three-fold... 

Scheme 3.15. Synthesis of two three-fold symmetric graphitic discs.

Scheme 3.16. Synthesis of giant graphitic discs containing 132 and 222 carbons.

The above results show that the standard synthetic concept for HBCs can also be applied in the synthesis of larger graphitic discs and ribbons, thus opening the door to a broad range of versatile electronic materials with different functions. 

Strong van der Waals interactions bettveen the HOPG substrate and graphitic discs as well as alkyl chains induce ordered monolayer or bilayers at the solid/liquid interface. 

---