Differential Pulse Polarographic Method Research Articles

Furosemide Determination in Pharmaceutical Samples Using Differential Pulse Polarographic method

The research includes the development of a simple, sensitive and accurate differential pulse polarography method for the quantitative determination of furosemide drugs in pharmaceutical preparations and in their pure and commercial forms, the electrochemical behavior using the dropping mercury electrode DME, as well as finding the values of the half-wave potential (E1/2) as a qualitative value, the number of electrons that were transferred and participating in the reduction process. The furosemide drug showed a clear reduction peak at a voltage of (-0.24) volts under optimal conditions. The correlation coefficient for furosemide at a concentration range of (2–24) µg.ml-1 was 0.9969, the LOD and LOQ of the drug were 2.139 and 7.129, respectively, and the average relative standard deviation (RSD) of the drug was 1.41%, with recovery of the f drug 97.58% and (n =5).

Determination of hydrogen peroxide by differential pulse polarography in advanced oxidation processes for water treatment

Knowing the concentration of hydrogen peroxide (H2O2) is crucial for the monitoring and optimizing the Fenton reaction in advanced oxidation processes. Several analytical methods exist to determine these concentrations, but their applications can be difficult because of low selectivity (interaction with other metals), the use of toxic compounds, or low concentrations (μmol LmmolL-1). To overcome these problems, we developed a differential pulse polarographic (DPP) method at the dropping mercury electrode (DME) with the following conditions: tg=1.0s, ΔE=−100mV and v=10mVs−1. Calibration curves had very high correlation coefficients (R2>0.999). The limits of detection and quantification were evaluated respectively at 13 and 21μmolL−1 with peak area measurements of hydrogen peroxide reduction (Ap). The DPP method was compared with other analytical methods (iodometric titration and spectrophotometry) for determining at low concentrations of H2O2 (in the order of mmolL−1 to μmol L−1) in Fenton and electro-Fenton processes. The method developed here allows measure low concentrations of hydrogen peroxide in Fenton and electro-Fenton processes in acidic solutions (∼3) and the presence of interfering species such as Fe3+ and dissolved oxygen.

Determination of Lead and Cadmium Concentrations in the Blood of Workers at the Liquid Battery Factory in Baghdad,Applying Differential Pulse Polarography Method.

The concentrations of Pb2+ and Cd2+ in the blood of 30 persons working in the Liquid Battery Factory in Baghdad were measured applying the Differential Pulse Polarography (DPP) method. It was found that for the majority of the blood samples, the Pb2+ concentration valueswere acceptable and within the acceptable natural limits(10-20µg/100ml).Exceptionsare 4 samples which showed higher lead ion concentrations. The infected persons worked at a location with high lead presence in the factory. As for the measured Cd2+ concentrations, the results for all the blood samples showed normal values, within the defined acceptable concentration (5.4µg/100ml). However, onconsidering the other defined acceptableconcentration, as reported in the literature, (3µg/100ml), three workmen were found, to have higher Cadmium ion concentration in their blood. It was also found that, compared with the calibrated DPP results, themeasured Atomic Absorption Spectroscopic (AAS) results showed much higher concentration values and should therefore be not acceptable. The measured concentrationsofboth ionswere independent from the age of the workers. Inspections for the presence of Cu2+ ions in the blood samples failed in detecting any traces of it.

Electroanalytical Investigation of Nimesulide by Differential Pulse Polarography: Method Validation

Nimesulide is a new non-steroidal anti-inflammatory analgesic drug. In the last eight decades, voltammetric methods has become a popular tool for the study of electrochemical reactions. the electroanalytical behavior of nimesulide using differential pulse polarography techniques. Using this technique, the effect of increasing concentration of nimesulide, scan rate and repetitive scanning on the peak height (Ip) and peak potential (Ep) of each compound will be investigated. The general procedure can be used to obtain DPP Polarogram of nimesulide. A study was carried out using optimum parameters to observe a relationship between Ip and concentration of nimesulide. Precision and accuracy of the method is studied. The developed differential pulse polarography method can be applied for calibration and determination of nimesulide in tablets.

Determination of Methimazole in Pharmaceutical Preparation and Human Serum by Square Wave and Differential Pulse Polarographic Methods

Objectives: In this study, the polarographic behaviour of methimazole was studied using cyclic, square wave and differential pulse polarographic methods. Methods: The influence of several variables (including nature of the buffer, concentration, scan rate, drop size, etc.) was examined in square wave and differential pulse polarographic methods for methimazole. The best square wave and differential pulse polarographic responses were obtained in 0.1 M sulfuric acid. The peak currents were measured with a static mercury drop electrode at 0.10 V versus Ag/AgCl. Results: The linearity was established over the concentration range of 5-80 mg/mLfor both methods in supporting electrolyte and human serum. The methods were validated and applied to the determination of methimazole in a commercial tablet. There was no significant differences between the results obtained by square wave and differential pulse polarographic methods. Square wave and differential pulse polarographic methods are also available and applicable for the determination of mentioned substance in human serum. No electroactive interferences from the endogenous substances were found in the serum samples. Mean recovery was 99.9%. Conclusion: They were concluded that the developed methods were accurate, sensitive, precise, reproducible and useful for the quality control of methimazole in pharmaceuticals and spiked serum.

Differential Pulse Polarography Method for the Determination of Trace Fe, Ni, Pb, Zn, Se and Cu in Black Tea Leaves

In this work a new and simple polarographic method has been established for the determination of trace elements present in tea. After digestion with acids, tea samples were analyzed using various electrolytes such as acetate and ammonia at different pH values in the presence or absence of EDTA. Thus, it was possible tochoosethe best medium for the determination of6 trace elements in one tea sample. Polarographic peaks of copper and iron could be separated in HAc at about pH =7 in the presence of EDTA and their quantities were determined. Ni and Zn peaks could be separated and determined in ammonia buffer at about pH= 10. Lead could be determined at pH= 2HAc electrolyte. Selenite, was determined from its hydrogen catalytic peak in KCl, pH= 2 medium in the presence of Mo (VI). The LOD was found as 2.4x10-7 for instead of (S/N=3).The trace element ranges in black tea were found as, Fe 35 μg/g, Cu 45 μg/g, Ni 19 μg/g, Zn 22 μg/g, Pb 28 μg/g and Se 77 μg/g.

Development and validation of a differential pulse polarography method for determination of total vitamin C and dehydroascorbic acid contents in foods

The objective of the study was to develop a new method for the determination of total vitamin C and dehydroascorbic acid contents in food using the differential pulse polarography technique, and to compare achieved results to those obtained with the proposed reference method applying HPLC with spectrophotometric detection. Dithiothreitol was used to reduce dehydroascorbic acid into l-ascorbic acid. Interference due to the presence of dithiothreitol during polarographic determination of l-ascorbic acid was efficiently eliminated by clarification of the sample solution with Carrez reagent. Validation of the polarographic method indicates its usefulness for the analysis of foods products that do not contain isoascorbic acid. The coefficient of variation for the analysis of l-ascorbic acid and total vitamin C content ranges from 1.86% to 6.98%, Horrat values from 0.41 to 0.89 and average recovery of l-ascorbic acid ranges from 98% to 104%. Results obtained using the developed method are characterised by high compatibility with those obtained with the HPLC reference method, indicating equivalence of both methods, and in conclusion, the method was deemed fit for purpose for measuring total vitamin C and dehydroascorbic acid in foods.

Determination of Ibuprofen in Pharmaceutical Formulations Using Differential Pulse Polarography

A reliable differential pulse polarographic (DPP) method has been developed and applied for the determination of ibuprofen IBU in dosage form with dropping mercury electrode (DME) versus Ag/AgCl. The best peak was found at cathodic peak of -1.18 V in phosphate buffer at pH=4 and 0.025M of KNO3 as supporting electrolyte. In order to obtaine the highest sensitivity, instrumental and experimental parameters were examined including the type and concentration of supporting electrolyte, pH of buffer solution, pulse amplitude and voltage step time. Diffusion current showed a direct linear relationship to ibuprofen concentration in the range of (5 – 30) μg. mL-1 (2.43× 10-5 – 1.45 × 10-4 mol·L–1) with correlation coefficient r= 0.9999, detection limit (S/N = 3) =3.40 μg. mL-1 (1.65 × 10-5 mol·L–1) and the value of precision in terms of relative standard deviation RSD%, ranged between 0.374-0.5176 %. The established DPP method offers an excellent analytical figure of merits as well as its successful applicability to examine two commercial drug forms (tablet and suspension) for the determination of ibuprofen.

Validation of differential pulse polarographic method of ascorbic acid assay in food – Comparison with the chromatographic reference method

The objective of the study was to demonstrate the applicability of differential pulse polarography (DPP) technique of the ascorbic acid (AA) assay for the analysis of food samples with various matrices. The following validation parameters were determined: selectivity, linearity, precision, accuracy, limit of detection, and limit of quantification. The limits of detection and quantification were 0.17 and 0.5 mg ascorbic acid per 100 g food, respectively. The average recovery of added ascorbic acid from all matrices was 96.3–103.6%. The values of the coefficient of variation calculated on the basis of AA contents for food matrices were in the range 2–9.26% and Horrat values were 0.37–1.10. Ascorbic acid values of the samples obtained from the polarographic method were compared with those obtained from high-performance liquid chromatography with diode-array detection (HPLC-DAD) used as the reference method. The analytical parameters determined showed that the polarographic method was equivalent to the chromatographic method. Validation of the polarographic method of ascorbic acid assay indicates that it can be applied for the analysis of ascorbic acid concentration in food products that do not contain isoascorbic acid. This means that the method can be recommended for routine determinations.

Investigation of ecological purity of village pastures in Kakheti Region based on the analysis of toxic metals in grass

Abstract The work is dedicated to the establishment of an ecological condition of the pastures in central mountainous part of Kakheti region located in Eastern Georgia. Namely, studies have been carried out on grass at its various phenological stages from pastures, located near the villages of Akhmeta, Sagarejo and Gurjaani municipalities. Studies of heavy metals content (copper, lead, cadmium and zinc) in grass have been performed through differential-pulse polarographic method. Based on the results obtained, it has been established that the quantitative concentration of heavy metals in grass collected in the above-mentioned municipalities is fully in line with international standards and does not exceed permissible limits thus clearly indicating to soil and overall ecological purity of the region, in general.

Heavy metals and arsenic content in water along the southern Caspian coasts in Iran.

Due to the importance of pollution monitoring in marine ecosystems and lack of a coherent and systematic investigation of heavy metal ions along the southern shores of the Caspian Sea, in the present study, the amount of these metals and As ions in coastal waters along its 780-km-long coast in Iran have been studied. Heavy metals (cobalt, nickel, copper, zinc, cadmium, mercury, lead) and a poisonous metalloid (arsenic) were selected in 59 sampling stations and determined using differential pulse polarography method. The multivariate statistical tools were applied to describe and interpret the experimental data. The overall mean concentrations of studied metals (in microgram per liter; μgL-1) in the samples were found in the order Zn (10.9) > Ni (7.4) > Cu (5.5) > Pb (1.9) > Hg (1.4) > As (1.3) > Co (1.1) > Cd (0.2). The results when compared with reported international standards confirmed that the sampled waters do contain some of these elements above the suggested maximum permissible limits. Hg and Cu were detected in 54.2 and 72.9% of the samples, almost all above the permissible limits. Ni, Zn, Pb, and Co were detected in 100, 96.6, 93.2, and 88.1%, respectively, while 8.5, 22.0, 3.4, and 1.7% were above the permissible limits. Cd and As were present in 61 and 93% of the samples, and their concentrations were higher than the rate presented by Russian System of Management Chemicals (RSMC). In addition, spatial distribution of heavy metal concentrations showed that Gorgan Bay is an ecosystem serving as a filter, trapping natural and anthropogenic materials that are brought from industrial, commercial, and urbanized areas. The multivariate data analysis reveals that Caspian Sea is contaminated by both anthropogenic as well as pedo-geochemical sources.

Rapid and Sensitive Determination of Hg(II) Using Polarographic Technique and Application to Chlorophytum comosum

A differential pulse polarographic (DPP) method has been used for the indirect determination of Hg(II). With a known amount of cyanuric acid (CA) in polarography cell (B–R buffer, pH 10.5) was added an unknown Hg(II) sample and the Hg(II) concentration is calculated simply from the decrease in the CA peak after reaction with Hg(II). The linear concentration range was between 20 and 120 μM and limit of detection was calculated to be 6.7 μM. The proposed method was successfully applied to the dried leave samples belong to C. comosum plant. The method was extended to the indirect determination of mercury(II) in C. comosum plant and results were in agreement with that obtained by a spectrometric comparison method (ICP-MS). The sufficiently good recoveries and low standard deviations reflect the high accuracy of developed method.

Determination of Ultra Trace Copper in Water Samples by Differential Pulse Polarography after Solid Phase Extraction

A high selective and sensitive anodic stripping differential pulse polarographic method for determination of ultra-trace amounts of Cu 2+ ion in water samples is proposed. The method is based on the separation and preconcentration of Cu 2+ on an octadecyl bonded silica (ODBS) membrane disk modified by a recently synthesized triazene ligand, ([1-(ortoacyl benzene)3-(3,4-dichlorobenzene)triazene]). Various parameters such as, pH of aqueous solution (7-8), flow rates (10 mL min -1 ), the amount of ligand (6.0 mg) and the type of stripping solvent (0.1M nitric acid) have optimized. The breakthrough volume was greater than 500 mL with an enrichment factor of more than 100 and 3.88µg L -1 detection limit. The capacity of the modified disks is 220µg of copper per 6mg of the ligand. The effects of various cationic interferences on the percent recovery of copper ion were studied. The method was successfully applied to the determination of copper ion in different samples. DOI: http://dx.doi.org/10.17807/orbital.v9i5.1093

A new and direct method for the determination of trace elements in spinach using differential pulse polarography

For the trace determination of elements in spinach a new differential pulse polarographic (DPP) method is established. The polarograms were taken in various electrolytes and pH values in the presence of digested spinach sample. Trace element determinations were made in acetate and ammonia electrolytes at various pH values, with or without EDTA. Fe and Cu peaks could be separated and determined at pH7, acetic acid electrolyte in the presence of EDTA. Ni and Zn peaks could be separated and determined in ammonia buffer at pH10. Lead could be determined at pH2 acetic acid and Mo (VI) was determined at pH4 acetate buffer, EDTA medium. Selenite was determined from its hydrogen catalytic peak. The trace element in spinach was found as Fe 15μg/g, Cu 17μg/g, Ni 8μg/g, Zn 27μg/g, Pb 47μg/g, Mo 43μg/g, and Se 762μg/g.

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.

A new sensitive method for the determination of trace mercury by differential pulse polarography: Application to raw salt sample

A new indirect differential pulse polarographic (DPP) method is established for the trace determination of mercury(II). Because of its toxic effects on human health, trace determination of mercury is very important. An indirect method had to be used since no polarographic peak is observed in its direct determination. According to the standard potentials, the reaction between Sn(II) and Hg(II) was found suitable. The peak of Sn(II) at about −0.40 V is sharp, high and very reproducible, which enables the determination of low concentrations of Hg(II). For this purpose, to a known amount of Sn(II) present in the polarographic cell (acetic acid, HAc, pH 1–2), the unknown Hg(II) sample is added and the quantitative reaction takes place directly in the cell. The Hg(II) concentration is calculated simply from the decrease of the Sn(II) peak. The limit of detection (LOD) was found as 2 × 10−7 M for S/N = 3. Interferences of some common cations, such as Fe, Cd, Cu, Zn and Pb and anions have been investigated. Only Pb had an overlapping peak with Sn(II). This peak overlap was eliminated simply by working at pH 2 (HAc electrolyte), because of the shift of the Pb peak in the Ac complex to −0.7 V. This method was successfully applied to synthetic samples and raw salt sample taken from a salt lake in Turkey.

A New and Simple Method for the Simultaneous Determination of Fe, Cu, Pb, Zn, Bi Cr, Mo, Se, and Ni in Dried Red Grapes Using Differential Pulse Polarography

Dried grapes are consumed in Turkey in high quantities. It is a very important fruit because of its high content of vitamins and elements. A new and simple differential pulse polarographic (DPP) method for the trace element determination in dried grapes has been established. With this technique, it is possible to determine very low quantities of elements with high accuracy. The polarograms were taken in various electrolytes and pH values in the presence of digested grape sample. According to these results, nine trace element determinations were made in acetate, potassium carbonate, and ammonia electrolytes at various pH values, with or without EDTA depending to ions under consideration. It was possible to separate and determine Pb, Cu, and Cr simultaneously in potassium carbonate at pH 11 with only one sample addition. For separation and determination of Ni and Zn peaks, ammonia buffer, pH = 9.8, was found suitable. Simultaneous determination of Bi, Mo, and Fe could be made in HAc–NaAc buffer at about pH = 7 and in the presence of EDTA. Selenite could be determined in HAc–NaAc buffer from its hydrogen catalytic peak in the presence of Mo(VI).

Determination of the food dye carmine in milk and candy products by differential pulse polarography

As a basis for the development of a sensitive analytical method for the determination of carmine food dye, a study of the differential pulse polarographic reduction of carminic acid (CA) on a dropping mercury electrode was performed. For the analytical differential pulse polarographic method running at pH 2.0 Britton–Robinson (B–R) buffer solution (peak at −489 mV), the relationship between the peak current and CA concentration was linear in the range of 1 μM to 90 μM with a detection limit of 0.16 μM. The proposed electrochemical procedure was successfully applied to the determination of carmine food dye in spiked commercially available strawberry flavored milk. The method was extended to the determination of CA in candy and results were in agreement with that obtained by a spectrophotometric comparison method. A cyclic voltammogram of CA in 2.0 B–R buffer electrolyte was obtained on the dropping mercury electrode at pH 2.0 during potential scans from 0.00 mV to 1000 mV versus Ag/AgCl. From repetitive cyclic voltammograms, one cathodic peak at −500 mV and three anodic peaks on the reverse scan between approximately −340 mV and −460 mV were recorded. The influences of some other commonly found inorganic and organic salts on the determination of CA were also examined. The sufficiently good recoveries and low standard deviations for the data reflect the high accuracy and precision of the proposed differential pulse polarographic method.

A new and sensitive method for the determination of trace arsenic using differential pulse polarography

A new and simple differential pulse polarographic method has been developed for the trace determination of arsenic. When selenite was added into solutions of some ions such as copper, lead, cadmium, zinc, and chromium, their differential pulse polarographic peak decreased. A new reduction peak appeared at a more positive potential than the ion present and it was always higher than the corresponding reduction peak of the ion. Thus, we made use of this interference for the trace determination of As(III). By the addition of selenite onto As(III), a new As−Se intermetallic compound peak was formed at about −0.35 V (pH at about 1.0–2.0). The trace arsenic concentration could be determined simply from this peak by the addition of standard arsenic into a polarographic cell. In the presence of large amounts of selenite, 2 × 10−7 mol/L As(III) could be determined from this peak precisely. With the newly established method, the limit of detection was 1 × 10−8 mol/L (S/N = 3). Among the most common cations and anions, only Cd−Se and Pb−Se intermetallic compound peaks had an overlap with the As−Se peak. This interference could be eliminated simply by the addition of EDTA. This method was applied successfully for the determination of arsenic in a digested beer sample.

A new and very simple procedure for the differential pulse polarographic determination of ultra trace quantities of tungsten using catalytic hydrogen wave and application to tobacco sample

In this work a new and very simple differential pulse polarographic method is established for the trace determination of tungsten using catalytic hydrogen peak. For its determination, polarograms have been taken in various electrolytes including Britton–Robinson buffer (pH=2.0, pH=4.0, pH=5.0 and pH=6.0), nitric acid, hydrochloric acid, perchloric acid and phosphoric acid. The highest peak was obtained in the presence of 0.01M H3PO4 +0.1M KCl (pH=2.0–2.5) which appeared at −1.1V. The effects of pH, phosphate concentration, type of electrolyte on this peak have been studied. The height of the hydrogen catalytic peak was increasing with the addition of Mo(VI). Formation of a heteropoly acid was responsible of the catalytic hydrogen peak. The best condition for the determination of 5×10−8MW(VI) was found to be 1×10−5M Mo(VI) and 1×10−2M H3PO4+0.1M KCl (pH=2.0–2.5).The interference effect of Cu(II), Pb(II), Sn(IV), Mo(VI), Se(IV), As(III) and Zn(II) have also been studied. Among these ions only in the presence of As(III), the catalytic hydrogen peak of tungsten (shown as Mo–W) overlapped with the hydrogen catalytic peak of arsenic (Mo–As). This interference could be eliminated by oxidizing As(III) into As(V) using HNO3. With the newly established method the limit of detection (LOD) was 1.3×10−9M (S/N=3). This method was applied successfully for the determination of tungsten in digested tobacco sample.