Wave Cathodic Stripping Voltammetry Research Articles

Electrochemical studies and square wave adsorptive stripping voltammetry of the antidepressant fluoxetine

The electrochemical reduction of the antidepressant drug fluoxetine was investigated by cyclic, linear sweep, differential pulse and square wave voltammetry using a hanging mercury drop electrode in alkaline buffer solution in water and in a water/acetonitrile mixed solvent. Cyclic voltammograms in aqueous solution showed very strong adsorption of fluoxetine on the electrode with formation of a compact film. The effect of addition of different percentages of acetonitrile on the voltammetric response was evaluated. It is shown that acetonitrile protects the electrode surface, thus preventing the adsorption of fluoxetine as a compact film, although reduction occurs at more negative potentials. Adsorption was used to accumulate the drug onto the electrode surface. The adsorbed species were measured voltammetrically by reduction at −1.3 V in an aqueous 0.05 M Ringer buffer, pH 12, 20% acetonitrile v/v. Linear calibration graphs were obtained in the range 0.52–5.2 M. The quantification of fluoxetine in pharmacological formulations existing in the market was performed using adsorptive square wave cathodic stripping voltammetry. and compared with data from UV spectrophotometry. The method is simple and not time-consuming. A comparative high performance liquid chromatography assay with UV detection was performed. Recovery data for both methods are reported.

Determination of sub-nanomolar concentration of arsenic(III) in natural waters by square wave cathodic stripping voltammetry

A method is presented for the measurement of arsenic(III) in natural waters using square wave cathodic stripping voltammetry at a hanging mercury drop electrode. Pre-concentration was carried out in 2 M HC1 in, the presence of 0.8 mM CuCl 2 at a potential of −0.4 V vs. Ag AgCl . The deposited intermetallic compound was reduced at a potential of about − 0.8 V vs. Ag AgCl . The square wave frequency was 70 Hz with a staircase step of 2 mV and a pulse height of 25 mV. The peak current decreased with scan number, however, this effect can be minimized by the addition of hydrazine. The detection limit is approximately 0.06 nM (5 parts per trillion) when a 10 min deposition time was used. The relative standard deviation was calculated as 8% ( n = 11) at 1 × 10 −9 M arsenic for l min period of deposition. The method was tested by the measurement of arsenic(III) in both river and sea water.

Square wave cathodic stripping voltammetric determination of selenium in small quantities of biological tissues

AbstractA sensitive procedure for the determination of selenium in small quantities of biological tissues (5 to 10 mg), using square wave cathodic stripping voltammetry with an in situ formation of Cu2Se on the HMDE, is described. Microwave digestion and clean‐room facilities have been used to prevent the loss of analyte and sample contamination. The method has been standardized through the analysis of NIST SRM 1577 bovine liver. The method offers a detection limit of 1 pg/mL. The average precision of determination at 150 pg/mL of Se is 1.8% RSD. This method is highly suitable for the determination of biopsy samples where the quantity available for the analysis is very limited.