Sensitive Differential Pulse Polarographic Method Research Articles

Pulse polarographic determination of thiophanate methyl fungicide in relation to its soil adsorption study

Abstract Background The environmental pollution caused by the extensive use of the pesticide thiophanate methyl is of great concern, because it is a category III acute toxicant and a suspected carcinogen. Method A remarkably sensitive differential pulse polarographic method for the determination of thiophanate methyl has been developed. The method is based on the reaction of the fungicide with copper(II) perchlorate in the presence of butylmethylimidazolium bromide (ionic liquid) in acetonitrile. Results The reaction product exhibits an analytical useful diffusion controlled peak at −180 mV (vs SCE), and the thiophanate methyl has been determined in the linearity range 1.25 × 10−6 to 12.5 × 10−6 mol L−1 with a correlation coefficient of 0.997. To study the fate of this pesticide in soil and extent of surface and groundwater contamination, its adsorption on four soils of different soil characteristics has been studied using batch equilibrium technique. Conclusion The leaching potential, a measure of ground and surface water contamination, has been evaluated in terms of groundwater ubiquity score (GUS) and the value obtained is in the range 0.87 to 0.97, classifying it as non-leaching pesticide.

Estimation of tegaserod maleate by differential pulse polarography

A highly sensitive differential pulse polarographic method has been developed for the estimation of tegaserod maleate after treating it with hydrogen peroxide solution. The oxidation of tegaserod maleate is a reversible process as the oxidized product could be reduced at hanging mercury drop electrode in a quantitative manner using differential pulse polarography mode. The limit of quantification was 0.1ng/ml. The voltametric peak was obtained at -1.05 volts in presence of 0.1M potassium chloride as supporting electrolyte. The technique could be used successfully to analyze tegaserod maleate in its tablet formulation.

A new simple sensitive differential pulse polarographic method for the determination of acrylamide in aqueous solution

A new simple sensitive differential pulse polarographic (DPP) method was investigated for the determination of acrylamide (AA) directly in a neutral aqueous solution. The AA showed a well-defined and well-resolved peak in pure aqueous LiCl at −1.84 V in the potential range from −1.6 V to −1.97 V at nitrogen pressure of 0.5 kg cm −2. Among the various electrolytes studied, the AA showed good DPP response in the presence of LiCl and tetra methyl ammonium iodide, while it showed poor response in the presence of tetra butyl ammonium hydroxide and tetra butyl ammonium bromide due to their strong adsorption on the surface of electrode which hindered its reduction. The effect of LiCl concentration, the cyclic voltammetric response and the drop time study showed that AA exhibited an irreversible adsorptive electrochemical behavior. The good electrochemical response in pure aqueous medium suggested that hydrogen bonding might be involved which may favor the electrode reaction. Under optimized conditions, the peak current was linear in the entire concentration range from 0.2 mg L −1 to 20 mg L −1 with the correlation coefficient of R 2 = 0.9998. The method showed good reproducible results with R.S.D. of 0.3% ( n = 16). The detection limit (LOD) was 27 μg L −1. The influence of various interfering agents was also studied. The method was applied successfully for the quantification of AA in water samples without any interference effect from alkali metals.

Voltammetric studies of copper(II)-dithiocarbamate reaction and a differential pulse polarographic method for the determination of dithiocarbamates

The electrochemical behaviour of the reactions of dithiocarbamates with copper(II) in acetonitrile has been studied by both cyclic voltammetry and pulse polarography. The observations/data resulting from above studies has been found extremely useful not only in arriving out at a convincing mechanism for this analytically useful reaction, but also in evolving a remarkably sensitive differential pulse polarographic method for the determination of dithiocarbamates.

Determination of insecticide pymetrozine by differential pulse polarography/application to lake water and orange juice

A simple, fast and sensitive differential pulse polarographic method (DPP) for the determination of pymetrozine insecticide in pure form, agrochemical formulation, natural water and orange juice samples is proposed. The polarographic behavior of pymetrozine exhibited a double well-defined polarographic peaks at −580 and 950 mV (versus SCE), respectively. The peak potentials were strongly pH-dependent in that they shifted to more negative values with increasing pH. The polarographic reduction corresponding to the first peak at pH 2.0 (B–R buffer solution) showed quantitative increments with the additions of standard pymetrozine solution under the optimal conditions and the corresponding peak current was linearly proportional to pymetrozine concentration in the range of 4.97 × 10 −7 to 7.35 × 10 −5 mol L −1. The limit of detection (LOD) and limit of quantification (LOQ) were obtained as 1.48 × 10 −7 and 4.93 × 10 −7 mol L −1, respectively. The mean recoveries of the 5.0 × 10 −6 mol L −1 pymetrozine spiked to lake water and orange juice were (4.89 ± 0.23) × 10 −6 and (4.97 ± 0.19) × 10 −6 mol L −1 at 95% confidence level, respectively. The method was extended to the determination of pymetrozine in agrochemical insecticide formulation Plenum ® and accuracy was in agreement with that obtained by HPLC comparison method. Influences of some interfering ions and some other pesticides were also investigated. The mechanistic study was not pursued.

Stability Prediction of cefazolin sodium and Cephaloridine in solid state

The stability of commercially-available solid pharmaceutical preparations containing cephaloridine and cefazolin sodium was evaluated with an accelerated isothermal degradation method at three different temperatures (37°, 45° and 60°C). A specific and sensitive differential pulse polarographic method was used for cephalosporin determination. Data obtained from high-temperature studies were processed using Arrhenius relation to predict shelf-life. The greater thermal stability of cephaloridine than cefazolin sodium was found, in contrast to what can be deduced from official monographs. Differential scanning calorimetry and X-ray diffraction were used to characterize the solid state of cephalosporin antibiotics.

Differential Pulse Polarographic Analysis of Adriamycin in Plasma

Abstract A sensitive differential pulse polarographic method is described for the determination of adriamycin in plasma. No sample preparation or manipulation is required; polarograms are recorded after direct introduction of a dropping mercury electrode into a degassed, untreated plasma sample. The method does not distinguish between parent drug and its metabolites. The minimum detectable concentration of adriamycin is 400 ng of drug/ml of plasma. Eleven anti-neoplastic agents, often used therapeutically in combination with adriamycin, were evaluated with respect to their possible interference with this method.