Differential Pulse Polarographic Technique Research Articles

Electro-chemical and Bacteriological Study of Anti Aids Drug with Fe (III)

The anti HIV drug Perfenazine has been qualitatively and quantitatively analyzed by direct current polarographic (DCP), differential pulse polarographic(DPP) and amperometric technique. Physicochemical, and microbial studies on Fe (III)-Perfenazine complex have been done in solid and aqueous phase. On the basis of elemental analysis, polarographic studies and amperometric titrations, the metal: drug ratio has been worked out to be 1: 1. The metal ligand interaction has been studied using polarographic method at 25±1°C and at ionic strength of μ = 1.0 (KCI). IR spectral studies have been used to ascertain metal:ligand binding site which speaks of the complex formation between the metal and the Perfenazine ligand through the primary -0H group. Microbial studies on the complex was done against various pathogenic bacteria viz. Escherichia coli, Salmonella typhi, Vibrio cholerae and Diplococcus pneumoniae. The results of the microbial studies with the metal: drug complex revealed that the drug: metal complex was more potent against the pathogenic bacteria as compared to the pure drug, Perfenazine. As such Fe (III)-Perfenazine complex may be recommended to the therapeutic experts for its possible use as more potent anti-Aids drugs.

Determination of molybdenum(VI) by differential pulse polarographic technique using 4-(2-hydroxy phenyl ethaminodiol), benzene-1,3-diol(4-2-HPEDB-1,3,D)

A novel analytical reagent 4-(2-hydroxy phenyl ethaminodiol), benzene-1,3-diol(4-2-HPEDB-1,3,D) was synthesized for the determination of molybdenum(VI). The present paper reveals the detailed study of electroanalytical behaviour for [Mo-(4-2-HPEDB-1,3,D)] complex under optimized conditions. The peak obtained for [Mo-(4-2-HPEDB-1,3,D)] prevent the interference of foreign ions which shows the sensitivity of the proposed method. The linearity was maintained at the concentration range of 0.5–200μg/mL at pH 4.5 with correlation factor 0.9997. The present method was successfully applied for the analysis of molybdenum(VI) in biological fluids and plant material. The results obtained from the proposed method show good agreement with reference method.

Determination of the Fungicide Anilazine in Soil and River Water by Differential Pulse Polarography

AbstractThe electrochemical behavior of anilazine (4,6‐dichloro‐N‐(2‐chlorophenyl)‐1,3,5‐triazin‐2‐amine) fungicide has been studied at a dropping mercury electrode. The differential pulse polarographic technique was used to establish an electroanalytical procedure for the determination of the anilazine levels in natural water and soil samples. Three reduction peaks were observed as a function of pH. The polarographic reduction that exhibited only a single well‐defined peak in the pH range from 1.0 to 5.0, was chosen for the analytical determination. The variation of pH and polarographic parameters indicated that the optimum conditions under which anilazine could be reduced were pH = 2.0, Britton‐Robinson (B‐R) buffer solution, a reduction peak potential of –795 mV (vs. SCE), scan rate of 5 mV s–1, pulse amplitude of –50 mV with a pulse duration of 50 ms at an ambient temperature of 20 ± 3°C. A linear relationship between the first peak height and the concentration of anilazine was obtained in the range of 0.497 to 64.800 μM, with a detection limit of 0.128 μM. The mean recoveries of the 10.0 μM anilazine spiked to soil and river water were 9.8 ± 0.1 and 9.6 ± 0.5 μM at the 95% confidence level, respectively. The sufficiently good recoveries and low relative standard deviation (RSD) data reflects the high accuracy and precision of the proposed pulse polarographic method. The interferences with the reduction peak of anilazine peak observed with several commonly used pesticides and inorganic species were also tested. Some interfering species were eliminated either by providing selectivity with pH changes or using complexing agents, e. g., EDTA.

Polarographic Behavior of Nicotinamide in Surfactant Media and Its Determination in Cetyltrimethylammonium Bromide Surfactant System

The behavior of nicotinamide has been studied by differential pulse polarography and cyclic voltammetry in the presence of certain ionic and nonionic surfactants, viz. cetyltrimethylammonium bromide (CTAB), sodium dodecylsulfate (SDS) and Triton X-100 (TX-100). The cathodic peak potential (E(p(c))) and peak current (I(p(c))) of nicotinamide were found to be remarkably dependent on the charge and concentration of the surfactant. The presence of SDS and that of TX-100 cause a shift in peak potential and a change in peak current of nicotinamide. In the presence of the cationic surfactant, CTAB, an enhancement in the sensitivity of nicotinamide was observed. A sharp peak with more than two-fold increase in current was used to determine the limit of detection and linear working range using the differential pulse polarographic technique. The present method was successfully used for the simultaneous determination of nicotinamide and pyridoxine hydrochloride, and for the determination of nicotinamide in multivitamin pharmaceutical preparations.

Enhancement of uranyl ion uptake by the prestructuring of poly(2‐hydroxyethyl methacrylate itaconic acid) hydrogels in the presence of lead and cadmium ions/polarographic determination

AbstractPoly(2‐hydroxyethyl methacrylate/itaconic acid) [P(HEMA/IA)] hydrogels were prepared by the γ‐ray irradiation of aqueous solutions. In the presence of lead and cadmium ions, the UO ion uptake on P(HEMA/IA) hydrogels was investigated with two types of hydrogel systems prepared by nonprestructuring and prestructuring methods. A differential pulse polarographic technique was used for the determination of trace quantities of uptake elements by the measurement of the reduction peak currents at −200, −410, and −580 mV for UO, Pb(II), and Cd(II) ions, respectively. Hydrogels prestructured with UO ions took up approximately 45% more UO ions than hydrogels prepared by the usual procedure. The UO ion uptake capacity of the hydrogels increased with an increasing percentage of itaconic acid in the hydrogel systems and an increasing concentration of UO ions in the presence of Pb(II) and Cd(II) ions. Uptake studies showed that other stimuli, such as the temperature and ionic strength of the solutions, also influenced the UO ion uptake capacity of the P(HEMA/IA) hydrogels. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2385–2390, 2003

Voltammetric determination of nilvadipine in dosage forms and spiked human urine.

The voltammetric behaviour of nilvadipine was studied adopting direct-current, differential-pulse and alternating current polarography. Nilvadipine-being nitroderivative-exhibited well-defined cathodic waves over the whole pH range in Britton-Robinson buffers. At pH 5, the diffusion-current constant, (Id) was 4.78. The current-concentration plots are rectilinear over the range 1.5-20 and 0.2-10 microg/ml using the direct current and differential pulse-polarographic techniques with minimum detectability of 0.05 microg/ml (1.3 x 10(-7) M) using the latter technique. The proposed method was applied to commercial capsules containing the drug. The percentage recoveries were in agreement with those obtained by a reference method. Furthermore, the method was applied to spiked human urine, the percentage recovery was 95.54+/-2.137.

A Polarographic Study of Tl+, Pb2+ and Cd2+ Complexes with Aza-18-crown-6 and Dibenzopyridino-18-crown-6 in some Binary Mixed Non-aqueous Solvents

The complexation of Tl+, Pb2+and Cd2+ cations by macrocyclic ligands, aza-18-crown-6 (L1) and dibenzopyridino-18-crown-6 (L2) was studied in some binary mixtures of methanol (MeOH), n-propanol (n-PrOH), nitromethane (NM) and acetonitrile (AN) with dimethylformamide (DMF) at 22 °C using DC (direct current) and differential pulse polarographic techniques (DPP). The stoichiometry and stability constants of the complexes were determined by monitoring the shifts in half-waves or peak potentials of the polarographic waves of metal ions against the ligand concentration. In all of the solvent systems, the stability of the resulting 1:1 complexes was found to be L1 > L2. The selectivity order of the L2 ligand for the cations was found to be Pb2+ > Tl+ > Cd2+ and the selectivity of the L1 ligand for Pb2+ ion was greater than that of Tl+ ion. The results show that the stability of the complexes depends on the nature and composition of the mixed solvents. There is an inverse relationship between the stability constants of the complexes and the amount of dimethylformamide in the mixed solvent systems.

Complexes of Vitamin B6. 23. Interaction of Some Tertiary Ligating Amino Acids with the Binary Complexes of Ni(II) or Cu(II) and Pyridoxamine

Binary and ternary complexes involved in the systems pyridoxamine (PM), glutamic acid (Glu), or aspartic acid (Asp) plus Ni(II) or Cu(II) were studied in solution at 0.15 M ionic strength and 25 °C by pH-metric, absorpiometric, and polarographic techniques. The differential pulse polarographic technique was used to study the reduction properties of these complexes. EPR was used to confirm the presence of binary and ternary complex species in the Cu(II) systems. The stoichiometry and formation constants of the binary and ternary complex species were determined by the SUPERQUAD program. Ternary species of the types 1:1:1:r and 1:2:1:r (PM/Glu or Asp/M/H) were found to exist in the pH range ∼3 to ∼10.

Polarographic and Voltammetric Determination of Some Toxic Heavy Metal Ions in the Treated Wastewater at Abu-Dhabi, U.A.E.

Differential pulse polarographic (DPP) and anodic stripping voltammetric (DP-ASV) techniques were employed for determination of Zn, Cu, Pb and Cd in the treated wastewater at Abu-Dhabi, U.A.E. Four samples were collected from two different treated wastewater plants at Al-Ain and Abu-Dhabi cities during the period of May-Nov, 1996. The collected samples were subjected to UV-irradiation, before the direct analysis, to eliminate the interference effect of the organic compounds on the determination of the metal ions. Double step solvent extraction was used to minimize the effect of interference of the organic compounds on the methods of analysis. Also, the solvent extraction techniques was used for preconcentration of the four metal ions from the collected samples. The pre-treated samples with UV-irradiation and/or solvent extraction techniques were subjected to full analysis using DPP and DP-ASV methods in order to determine the operational and solution parameters for trace determination of the metal ions. A multi-step standard addition method was applied on the polarographic and voltammetric peaks of the four metal ions for calculation of the concentration level of each metal ion in the collected samples. the results indicated that the concentration range of the four metal ions in the investigated samples were 0.11-0.16, 0.020-0.025, 0.01-0.02 and 0.008-0.012 ppm for Zn(II), Cu(II), Pb(II) and Cd(II), respectively. It should be mentioned that the treated wastewater in Abu-Dhabi was used for irrigation of ornamental plants.

Study of the complex formation between 18C6 crown ether and Tl +, Pb 2+ and Cd 2+ in binary non-aqueous solvents using differential pulse polarography

Complexation of the Tl +, Pb 2+ and Cd 2+ ions with macrocyclic ligand 18-crown-6 (18C6) was studied in various binary solvent mixtures of propylencarbonate (PC)/dimethylformamide (DMF) and acetonitrile (AN)/dimethylsulfoxide (DMSO) systems at 22 °C using the differential pulse polarographic technique. The stoichiometry of the complexes was found to be 1:1 and the complexation constants increased with decreasing amounts of dimethylsulfoxide and dimethylformamide in these binary systems. In all cases, the variation of the stability constant with composition of the solvents was monotonic and showed good correlation with the inherent solvation ability of the neat solvents which form the mixture. In all of the solvent systems, the selectivity order for 18C6 complexes is Tl + > Pb 2+ > Cd 2+.

Polarographic Studies on Se(IV) in Absence and Presence of Pb(II), Zn(II) and Sb(III) Ions in Aqueous N-(2-ACETAMIDO) Imino Diacetate Buffer Solutions

Abstract The polarographic reduction and determination of selenite ions in absence and presence of a mixture of some cationic species such as, Pb(II), Zn(II) and Sb(III) in N-(2-acetamido) imino diacetate solutions, at constants of ionic strength 0.1 mol dm−3 (KNO3) and temperature 25°C was studied using direct current and differential pulse polarographic (DPP) techniques. It was shown that reduction of Se(IV) takes place along one, two or three waves depending on the pH value of the solution using the direct current polarographic measurements. The reduction of Se(IV) in N-(2-acetamido) imino diacetate buffer solutions was found to be reversible and involving six electron transfer process. Microcoulometric experiments was performed at the limiting current region of the different waves and at various pH values. Kinetic parameters and wave characteristics for the reduction of selenite ions have been calculated. A method for the analytical determination of selenite ions in either simple or quadruple mixture ...

Spectrophotometric and Polarographic Studies of Di-2-pyridyl ketone 2-thienoylhydrazone.

Abstract The spectral and differential pulse polarographic (DPP) behaviour of di-2-pyridyl ketone 2-thienoylhydrazone (DPKTH) has been investigated in 30% (v/v) ethanol-buffer mixtures over a wide range of pH (2.0-12.0). The spectral bands located at 325, 276, 230 and 208 nm of the DPKTH in ethanol are assigned to the possible electronic transitions of the molecule. The spectral data at various pH values indicates that the molecule characterized by the keto = enol tautomerization and the pKa value for the enolic form of the compound is determined in aqueous ethanol and was found to be 10.6. The effect of various operational parameters on the reduction current and the mechanism of the electrode reaction of DPKTH at the DME are discussed. The main reduction peaks are attributed to the reduction of C=N centre of both the keto and enol forms. This behaviour is compared with the DPP behaviour of the other related acid hydrazone compounds. The applicability of DPP technique for the trace determination of DPKTH ...

Voltammetric determination of As(III) in an aqueous zwitterionic complexing medium

The polarographic behaviour and determination of As(III) in aqueous complexing electrolytes (bicine buffer solutions) ofpH values varying from 1.13–11.96 have been investigated at 25°C (direct current and differential pulse polarographic techniques). Using DC polarographic measurements, it was shown that reduction of As(III) takes place along one or three waves depending upon thepH value of the solution. Microcoulometric experiments have been performed at the limiting region of the different waves obtained at differentpH values. Cyclic voltammograms were recorded using a HDME to investigate the nature of reduction. Schemes for the mechanism of reduction occurring at the DME have been deduced. Kinetic parameters and wave characteristics for the reduction of As(III) have been calculated. A method for DPP determination of As(III) in bicine buffer solution ofpH 1.41 is reported. The detection limit of the method is 6.60×10−8M As(III).

Voltammetric studies on composition and stabilities of complexes of tetracycline and oxytetracycline with some metal ions in aqueous medium

The composition and stability of complexes of tetracycline and oxytetracycline with Cu(II), Cd(II), Pb(II) and UO2(II) have been studied polarographically (direct current and differential pulse polarographic techniques) at 25±0.1°C. Differential pulse polarographic studies have been particularly helpful in deciding the nature of metal-drug interactions at low concentrations. The reduction of Cu(II)-tetracycline has been found to be irreversible and diffusion controlled with the presence of an adsorption component. In the system uranyl(II)-tetracycline the complex formed has a stoichiometry of 1:1 and logKox=4.04 which is very close to that obtained by potentiometric measurements. The peak half widthW1/2 of the Pb(II)-OTC system is 60 – 70mV indicating that the process is reversible and two electrons are consumed. The log β′ is 10.30 in 0.1 mol dm−3 NaClO4. In the Cu(II)-OTC system two complexes were formed with log β1′=8.50 and log β2′=14.10. Cyclic voltammograms were recorded using a hanging dropping mercury electrode for the systems Cu(II), Cd(II), Pb(II) and UO2(II)-OTC to examine the irregularities in both peak potentials and peak currents during the polarographic investigations.

Polarographic study of the interaction between heavy metal ions and some macrocyclic ligands in binary Acctonitrile + water mixtures

The complexation reactions between TI +, Cd 2+, Hg 2+ and Pd 2+ ions and 18-crown-6 (18C6), 1,10-diaza-18-crown-6 (C22) and cryptand C222 were studied in various CH 3CN + H 2O mixtures at 22°C using dc and differential pulse polarographic techniques. The stoichiometry and stability of the complexes were determined by monitoring the shift in half-wave or peak potential of the polarographic waves of metal ions against the ligand concentration. In the cases where irreversible polarograms were observed for M 2+/M(Hg) systems, the reversible Hg 2+/Hg amalgam couple was used as an electrochemical probe for the study of M 2+ - ligand interactions. In all the solvent mixtures used, the stability of the resulting 1:1 complexes was found to vary in the order C222 > C22 > 18C6. The selectivity order for 18C6 complexes is Pb 2+ > Cd 2+ > Hg 2+ > Tl + while for the C22 and C222 complexes it is Hg 2+⪢ Pb 2+ > Cd 2+ > Tl +. There is an inverse relationship between the complex formation constants and the amount of water in the mixed solvent. In all cases, a linear relation was observed between log K f and the mole fraction of acetonitrile.

Complexes of vitamin B 6—XXI. The affinity of the binary complexes of the 2,2′-bipyridyl copper(II) system to the vitamin B 6 compounds

The interaction of the vitamin B 6 (VB 6) compounds, pyridoxol (P), pyridoxal (PL) and pyridoxamine (PM), with the binary species 2,2′-bipyridyl (BP) of copper(II) has been studied potentiometrically and polarographically at an ionic strength of 0.15 M Cl −. The potentiometric data at 37°C were assessed by the SUPERQUAD program. The results indicated that BP enhances ternary complex formation with vitamin B 6 compounds, especially with P and PL. The differential pulse polarographic technique further confirmed the formation of ternary species, especially at pHs greater than 5.5. The ternary complex enhancement was discussed in terms of log K 1 (log β 111 i -log β 1010-log β 011 i ) and log K 2 (2 log β 111 i -log β 2010-log β 0211 i ).

Complexes of hydroxamates VI: Binary and ternary complexes involved in the palladium(II) monohydroxamic acids—glycylglycine systems

Binary complexes of dl-serine-, l-histidine-, glycine-, aceto-, methionine- hydroxamic acids as well as glycylglycine (Glygly) with Pd(II) have been studied in solution. Only Pd(II) complexes with methionine hydroxamic (MX) acid were successfully studied potentiometrically because the other hydroxamic acids formed instant black precipitates. The potentiometric data for Pd(II)-MX were assessed by the SUPERQUAD program. The formation constants of only two species were determined in a limited pH range. The ternary complexes of Pd(II) with Glygly and MX were also studied, in which only two species were formed. It has been possible to determine only one species for the binary interaction of Pd(II) with Glygly, which is not usually simple to obtain in the absence of MX. The differential pulse polarographic technique was applied to the binary and ternary complexes involved in the system of Pd(II)-MX-Glygly in a wider pH range than that in the potentiometric study.

An on-line voltammetric analyzer for trace metals in wastewater

Differential-pulse anodic stripping voltammetric and differential pulse polarographic techniques were adapted to an on-line analytical system to measure trace levels of metals in a waste- water stream. Chromium, nickel, zinc, cadmium, lead and copper were determined automatically for several days to characterize a wastewater stream and detection limits were typically near 50 μg l −1.

Determination of N-methyl-N′-nitro-N-nitrosoguanidine in aerosol by differential pulse polarography

The application of a sensitive electroanalytical technique for the analysis of N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) in aerosol was investigated. Cyclic voltammetric studies of the reduction of MNNG in acidic media showed three reduction waves. The first reduction step was assigned to be the reduction of the nitroso group and the second and third steps the reduction of the nitro group. The second peak was selected for the analysis as it was found to give a constant high current at pH below 1 and it was stable up to 40 days under normal daylight exposure and bubbling air at slow flow rate. Optimised parameters for the sensitive differential pulse polarographic technique were determined and the sampling conditions were investigated. The standard addition method was used to reduce the marix interference and the peak current was measured by the difference of current before and after UV irradiation so as to eliminate the interference caused by trace metals and electroactive and UV stable organic compounds present in air. The developed method was used to analyse MNNG aerosol in an animal room. The detection limit was found to be about 3 μg/m3 for a sampling period of 48 h with a flow rate of 100 ml/min for the scrubbing method, whereas for the membrane filter method it was about 0.1 μg/m3 for a sampling period of 8h at a flow rate of 4.9 l/min.

Maxima in pulse polarography

Maxima may occur in pulse polarography under certain circumstances. They have been found in solutions of Zn2+ and Cd2+ ions with very dilute supporting electrolytes. The possibility of adsorption phenomena, which may cause another kind of maxima, has been excluded. Due to the fact that maxima have not yet been systematically studied with the present technique, it is premature to assign them to any particular kind, although they somewhat resemble to classical d.c. polarographic maxima of the first kind. It is shown that larger peak maxima are obtained at short pulse widths and, mainly, at short decay times and that they disappear by increasing either the decay time or the measuring time, or both; by shortening the delay time or by turning to the differential pulse polarographic technique. Some considerations are made on the influence of the double layer and or surface phenomena on the dropping mercury electrode.