Effects of 99mTc on the electrochemical properties of thiamazole in vitro

Thiamazole inhibits the thyroid hormone synthesis and does not inactivate the existing thyroxine and triiodothyronine that circulate in the blood. In this paper Thiamazole electrochemical behavior was monitored by cyclic voltammetry on glassy carbon (GC) electrode in the absence and presence of sodium pertechnetate (99mTc). The influence of different Thiamazole concentrations without and in the presence of radiopharmaceutical 99mTc, the effect of the number of scan cycles, and the effect of 99mTc activity on the appearance of cyclic voltammograms were examined. The results show that there is an observed increase in the reduction peak current with an increase of Thiamazole concentration. It was found that the concentration of the tested drug had a significant effect on its redox characteristics. The results obtained show that the application of different concentrations of sodium pertechnetate exhibits the inhibitory properties of the used radiopharmaceutical on the drug in the treatment of thyroid gland disease.

Polarographic determination of DNA based on its interaction with the phenanthroline-zinc(II) complex

By using the linear sweep voltammetric technique, a phenanthroline (Phen) and zinc(II) (Phen-Zn(II)) complex was used as the electrochemical probe for the determination of double-stranded (ds) DNA. In pH 9.0 Britton- -Robinson (B-R) buffer solution, Phen can interact with Zn(II) to form a stable electroactive [Phen-Zn(II)] complex, which had a sensitive second order derivative polarographic reductive peak at -1.300 V (vs. SCE). After the addition of dsDNA into a solution of Phen-Zn(II) complex, the reduction peak current decreased with a negative shift of the reduction peak potential and without the appearance of new peaks. The results showed that a new supramolecular complex was formed via interaction of the Phen-Zn(II) complex with dsDNA. The conditions of interaction and the electrochemical detection were carefully investigated. Under the optimum conditions, the decrease in the reduction peak current was directly proportional to the dsDNA concentration in the range of 0.4-18.0 mg L-1 with the linear regression equation: ?Ip?/nA = 349.48 + + 84.647(c/mg L-1) (n = 13, ? = 0.991) and a determination limit of 0.20 mg L-1 (3?). The relative standard deviation (RSD) for 10 parallel determinations of 10.0 mg L-1 dsDNA was found to be 2.03 %. The method was successfully applied to the detection of synthetic samples with satisfactory results.

Dedection of Parathion Based on Molecularly Imprinted Polymer of O-Aminothiophenol

A new electrochemical modified electrode for the detection of parathion was constructed based on molecularly imprinted polymer of self-assembled o-aminothiophenol onto gold electrode. Cyclic voltammetry was employed in the process of electropolymerization and electrochemical measurements. The template molecules and the nonbound o-aminothiophenol were removed from the modified electrode surface by washing with 0.5mol/L hydrochloric acid. The effects of the ratio of monomers to templates, pH and incubation time on the reduction peak current of parathion at the imprinted polymer film coated electrodes were demonstrated. Parathion imprinted and nonimprinted polymer films were exposed to a series of closely related compounds and the sensor exhibited good selectivity and sensitivity to parathion. A highly linear response to parathion in the concentration range of 5.0×10-7～1.0×10-4mol/L was observed, with a detection limit of 2.0×10-7mol/L estimated at a signal-to-noise ratio of 3.