Buffers, as supporting electrolytes

Figure 2, Cyclic voltammogram of TcO/ on bare ITO electrode, 5.0 x 1(T M Tc04 in pH 7 phosphate buffer as supporting electrolyte, 25 mV/s scan rate, Ag/AgCl reference electrode, solution deoxygenated for 30 min prior to scan.

NADH and DCE containing 10 M chloranil, CQ. As supporting electrolytes, 0.5 M 02804 and 0.05 M TPenA+TFPB were added in W and DCE, respectively. The buffer solution used was the same as that in Fig. 5. 

TABLE 2 Concentrations of Redox Products After the Electrolysis for 4 h by Applying a Definite E appi at the Stationary Interface Between W Containing 10 M H2O2 and DCE containing 10 M Tetrachlorohydroquinone, CQH2, Under the Deaerated Condition. As Supporting Electrolytes, 0.5 M Li2SO and 0.05 M TPenA+TEPB Were Added in W and DCE, Respectively. The pH of W Was Adjusted with the Aid of 0.1 M Phosphate Buffer to be 7.0... 

I. 4-methoxyacetophenone (30 //moles) was added as an internal standard. The reaction was stopped after 2 hours by partitioning the mixture between methylene chloride and saturated sodium bicarbonate solution. The aqueous layer was twice extracted with methylene chloride and the extracts combined. The products were analyzed by GC after acetylation with excess 1 1 acetic anhydride/pyridine for 24 hours at room temperature. The oxidations of anisyl alcohol, in the presence of veratryl alcohol or 1,4-dimethoxybenzene, were performed as indicated in Table III and IV in 6 ml of phosphate buffer (pH 3.0). Other conditions were the same as for the oxidation of veratryl alcohol described above. TDCSPPFeCl remaining after the reaction was estimated from its Soret band absorption before and after the reaction. For the decolorization of Poly B-411 (IV) by TDCSPPFeCl and mCPBA, 25 //moles of mCPBA were added to 25 ml 0.05% Poly B-411 containing 0.01 //moles TDCSPPFeCl, 25 //moles of manganese sulfate and 1.5 mmoles of lactic acid buffered at pH 4.5. The decolorization of Poly B-411 was followed by the decrease in absorption at 596 nm. For the electrochemical decolorization of Poly B-411 in the presence of veratryl alcohol, a two-compartment cell was used. A glassy carbon plate was used as the anode, a platinum plate as the auxiliary electrode, and a silver wire as the reference electrode. The potential was controlled at 0.900 V. Poly B-411 (50 ml, 0.005%) in pH 3 buffer was added to the anode compartment and pH 3 buffer was added to the cathode compartment to the same level. The decolorization of Poly B-411 was followed by the change in absorbance at 596 nm and the simultaneous oxidation of veratryl alcohol was followed at 310 nm. The same electrochemical apparatus was used for the decolorization of Poly B-411 adsorbed onto filter paper. Tetrabutylammonium perchlorate (TBAP) was used as supporting electrolyte when methylene chloride was the solvent. 

Bismuth nitrate (analytical grade) lppm high-purity standard solutions of the nitrate salts of Pb and Cd prepared using supporting electrolyte solutions and acetate buffer (0.1 M, pH 4.5) as supporting electrolyte prepared in Milli-Q water. 

Stock 0.1M sodium gluconate (Sigma) solutions prepared in 0.05 M phosphate buffer of pH 6.0, which was used as supporting electrolyte. 

Acetate buffer (0.1M, pH 4) as supporting electrolyte prepared in Milli-Q water. 

Phase Diagram. We will treat protein-water systems as two-component systems although many preparations contain buffer or supporting electrolytes that formally require three (or more) components. These additional components can always be expected to influence a number of measurements and will alter the entire phase diagram, including the bulk melting behavior, in complex ways. We will call attention to such effects where appropriate. 

FIG. 6 Ratios of NADH reacted (curve 1) and CQ- produced (curve 2) after the electrolysis for 4 h by applying a constant potential difference, appl at the interface between W containing 10-3 M NADH and DCE containing 1CT3 M chloranil, CQ. As supporting electrolytes, 0.5 M Li2S04 and 0.05 M TPenA+TFPB- were added in W and DCE, respectively. The buffer solution used was the same as that in Fig. 5. 

If instead of 10-3 M KC1 citrate-phosphate buffer solutions (2 x 10 3 M) or Tris-buffer (2 x 10-3 Af) was used as supporting electrolyte no generation of a transmembrane potential was observed (points A and Bl9 Fig. 15). 

It has been demonstrated that the half-wave potential for the reduction of Ti(IV) to Ti(III) is -0.81 V (against the standard calomel electrode) in 0.1 M HCl [27]. The further reduction of Ti(III) to Ti(ll) can be observed in alkaline media, but this reaction has no useful analytical significance. In these methods, oxalate, tartrate, or citrate buffer systems are used as supporting electrolytes to prevent the hydrolytic precipitation of hydrated titanium oxides. In the presence of tartrate buffer, well defined waves are obtained only at pH values less than 2, or between 6 and 7. The Ti(lV)-Ti(III) couple is reversible only in tartrate buffer at pH values less than 1. 

Amperometric responses of GOD-PBT electrode to glucose were made in a three-electrode flow cell with 0.1 mol dm 3 phosphate buffer, pH 7.0 solution as supporting electrolyte. The schematic description of the amperometric glucose sensor is depicted in Figure 1. The flow rate was controlled at 1 ml min l by a Atto Coporation model SH-121IH perista pump. All supporting electrolyte solutions and glucose solutions were air-saturated prior to experiment. 

All chemicals used were of analytical grade. 0.01 M stock solution of TeO , VO3, BrO, 10 and 10 were prepared by dissolving the accurate weight of the solid potassium or ammonium salt in twice distilled deionized water. The modified universal buffer series of Britton and Robinson (pH 2 - 12) was used as supporting electrolyte and prepared as given by Britton. ... 

The purity of the compounds was checked by elemental analysis and m.p. determination. Stock 0.01 M solutions were prepared in absolute ethanol. The modified universal buffer series of Britton and Robinson was used as supporting electrolyte. The pH was checked using a digital Radiometer pH-meter, Model PH M64, accurate to 0.05 unit. 

For voltammetric study of the total antioxidant activity of the samples automated voltammetric analyzer Analyzer of TAA (Ltd. Polyant Tomsk, Russia) was used. As supporting electrolyte the 10 ml of phosphate buffer (pH = 6.76) with known initial concentration of molecular oxygen was used [7]. The electrochemical cell (V = 20 ml) was connected to the analyzer and consisted of a working MFE, a silver-silver chloride reference electrode with KCl saturated (Ag AgCl KCl J and a silver-silver chloride auxiliary electrode. The investigated samples (10-500 ml) were added in cell. 

For voltammetric study of the total antioxidant activity of the samples automated voltammetric analyzer Analyzer of TAA (Ltd. Polyant Tomsk, Russia) was used. As supporting electrolyte the 10 ml of phosphate buffer (pH = 6.76) with... 

Rochester, N.Y.) as supporting electrolyte. Aqueous samples were run in phosphate buffered saline pH 7.5 (PBS), Hank s balanced salt solution (HESS) pH 7.5 or unbuffered water adjusted to pH 7.5. The electrolyte was 0.05 M KCl. 

Other investigators have also observed similar waves in buffered solutions of benzalazine [106]. With quaternary ammonium salts as supporting electrolyte in unbuffered solutions benzalazine and naphthalazine each form two waves of approximately equal height [106, 107], and according to the Ilkovic equation each wave corresponds to the addition of two electrons, i. e., reduction probably gives 1, 2-dibenzylhydrazine, like reduction with sodium amalgam in alkaline solution. 

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