VOLTAMMETRIC BEHAVIORS OF ADRENALINE AND ITS Be(Ⅱ)COMPLEX

The electrochemical oxidation behaviors of adrenaline(AD)and its Be(Ⅱ)complex have been studied by voltammetric method with a carbon paste working electrode.On the bases of calculation of the atomic net electronic charges of AD molecule by INDO approximate method and results of comparative experiment with dopamine the possible coordination site of Be(Ⅱ)-AD complex is proposed.

A STUDY ON VOLTAMMETRIC BEHAVIOR OF INDIGO CARMINE AND ITS MIXTURE WITH AMARANTH AT MERCURY FILM ELECTRODE ON SILVER SUBSTRATE

The voltammetric behavior of indigo carmine at mercury film electrode on a silver substrate (MFES) was studied in this paper. It was found that indigo carmine gave a sensitive reduction peak at a potential (Vp) of -0.11 V at pH 4.0 in aqueous solution. The MFES gave good reproducibility and life time. The peak currents (ip) depended lipearly on the concentrations of indigo carmine free 0 to 100 ng/ml. The Vp and Ip of indigo carmine at MFES were independent of the concentrations of amaranth at pH 4.0, the Vp of amaranth was -0.24 V at this pH. The differences of Vp between both colorants enabled to distinguish indigo carmine free amaranth.

Studies on the Voltammetric Behaviors of Rare Earth Ions-Amino Acids

The voltammetric behaviors of rare earth ions-amino acids were studied.The reduction potential of Eu^(3+) was shifted positively and the peak separation of the cathodic and anodic peaks in cyclic voltammogram de- creased when a certain amino acid was added to Eu^(3+) solution.Experimental results showed that Eu^(3+) was re- duced by way of forming complexes with amino acids which were adsorbed on mercury electrode surface.When histidine and formaldehyde existed simultaneously in the solution containing Eu^(3+),a well-defined reversible catalytic prewave of Eu^(3+) was obtained.Meanwhile,the reduction current of formaldehyde increased greatly with the addition of histidine.The mechanism was studied.Several other rare earth ions and amino acids were also studied preliminarily.

Study of the Voltammetric Behavior of Heme and Its Direct Analysis Application

The electroanalytical method of ferriheme was studied by linear sweep voltammetry in medium of 0.05 mol/L Tris+0.05 mol/L NH3?NH4Cl buffer at hang mercury drop electrodes (HMDE). Heme exhibits two pair reversible redox peaks and one irreversible peak. The cathodic peak potentials are?;0.236 V, ?0.422 V and ?1.408 V respectively. The first and the third peaks can be used for directly quantitative determination of heme concentrations. The peak currents are good linear relationship with heme concentration in ranges of 3×10?6–6×10?5 mol/L and 3×10?7–1.5×10?5 mol/L respectively.

STUDIES ON THE VOLTAMMETRIC BEHAVIOR OF EU(Ⅲ)-ALDOPENTOSE AND EU(Ⅲ)-D-RIBOSE-L-AMINO ACIDS COMPLEXES

The rate of voltammetric reduction of Eu(Ⅲ)in acetate solution was increased by the formation of a complex with ribose,lyxose or arabinose.If a ternary complex of Eu(Ⅲ)-D-ribose-L-phenylanaline formed on the surface of mercury electrode,the redox process of Eu(Ⅲ)became more reversible than that of Eu(Ⅲ)-D-ribose in solution phase.

Voltammetric Behavior of Tembotrione Using Silver/Amalgam Electrode

Tembotrione is herbicide which belongs to the triketone group of herbicides. It’s registered as a selective, post-emergence herbicide developed for the control of a broad spectrum broadleaf and grassy weeds in corn. There is little information about tembotrione because of his short presence in the market. Due to its ever wider application, it is important to know the details of its chemical characteristics and redox processes, including biogeochemical transformation and migration after application to agricultural land, which could contribute to its efficient and safer application. In this paper we examined voltammetric behavior of tembotrione using Silver/Amalgam (Ag/Hg) electrode. For the investigation of electrochemical behavior we used the cyclic voltammetry technique, with conventional three-electrode cell and electrochemical workstation. During the experiment pH values of solution varieties while constant concentration of tembotrione was maintained. Cyclic voltammograms were recorded at pH values 6, 8, 10 and 12, at which tembotrione was electrochemically active. At this pH values two signals were observed. Optimum pH value, at which the current intensity was greatest, was 12. Obtained results provide relevant information on the electrochemical behavior of tembotrione, which can serve as a basis for the development of electrochemical techniques for the removal and degradation of this pesticide in the environment.

Voltammetric Behavior of Sodium 7-Methoxyl-4'-hydroxylisoflavone-3'-sulfonate and Its Application

Voltammetric behavior of sodium 7-methoxyl-4'-hydroxylisoflavone-3'-sulfonate (SMHS) in the aqueous solu-tion from pH 1 to 5 was studied by linear sweep voltammetry, cyclic voltammetry and normal pulse voltammetry. Experimental results showed that in 0.2 molL-1 sodium citrate-hydrochloric acid buffer solution (pH=4.65), SMHS caused only one reduction wave at -1.34 V (vs. saturated calomel electrode, SCE), which was an irreversi-ble adsorptive wave of SMHS protonized involving one electron and one proton. The peak current of SMHS on lin-ear sweep voltammogram was proportional to its concentration in the range of 8.0×10-6—8.0×10-5 molL-1 (r=0.995), and the detection limit was 5.0×10-6 mol昄-1. The method was applied to determination of SMHS in syn-thetic samples. In addition, its scavenging effect on superoxide anion radical was studied by the auto-oxidation of pyrogallol in HCl-tris buffer solution (pH=8.2) in order to explain its peculiar biological effects. The experimental results proved that SMHS has antioxidant quality, and it is an efficient free radical scavenger of superoxide anion radical.

Effect of Caffeic acid on the Tumor Cells U937 Evaluated by an Electrochemical Voltammetric Method

Electrochemical voltammetric method can;be used to monitor cell health state during its growth. Here we studied the effect of caffeic acid on leukemia cells U937 by the voltammetric behavior of the cells. The result showed that this drug had a negative influence on cell health. which suggests that caffeic acid may be used in inhibition of tumor cells.