Permanganate In Acid Medium Research Articles

Indirect Spectrophotometric Determination of Furosemide using Eriochrome Black-T Dye

A simple, economical and sensitive indirect spectrophotometric method for the determination of furosemide in its pure form and in pharmaceutical preparations is described. The method is based on the oxidation of furosemide by permanganate in acidic medium, then the reaction of the remaining potassium permanganate to oxidize the dye Eriochrome Black-T at a wavelength of 535 nm. The method follows Beer's law within the range (0.25-10) μg mL-1 and the molar absorbance is 1.5×104 L mol-1 cm-1. The value of the determination coefficient was 0.9984, the recovery rate was 100.53 % and the relative error value was 1.12 %, while the value of the limit of detection (LOD) and limit of quantification was (LOQ) 0.118 and 0.395 μg mL-1 respectively. It was found that the method does not suffer from interactions, and the method can be applied to pharmaceutical preparations (ampoules and tablets).

Salt-Assisted Bulk Liquid Membrane and Flame Atomic Absorption Spectrometry for the Separation and Determination of Chromium(VI)

Due to the common use of chromium in many industrial applications, as well as its potential release into water sources, the quantification of chromium in environmental samples has great importance. In this work, a novel and fast salt-assisted bulk membrane extraction (SA-BME) combination with flame atomic absorption spectrometry (FAAS) was proposed for the separation and preconcentration of Cr(VI) in water samples. The transport of Cr(VI) was performed using cetyltrimethylammonium bromide (CTAB) as the mobile carrier dissolved in kerosene/chlorofrom organic membrane at room temperature. After this process, Cr(VI) was reduced to Cr(III) in a receiving phase using an acidified iron(II) sulfate. In aqeous solutions, total chromium was determined as Cr(VI) after the oxidizing Cr(III) to Cr(VI) using potassium permanganate in acid medium and finally total chromium was measured by FAAS. The analytical parameters affecting the separation and mass transfer of Cr(VI) were optimized. With 20 µg L−1 of Cr(VI) in the feed phase, the extraction efficiency was quantitative using a 50 minute extraction time. Under the optimum conditions, the linearity (R2 = 0.9994) was from 7 to 290 µg L−1, the limit of detection 2.3 µg L−1 and the enrichment factor 35 for Cr(VI). Common cation and ions in water samples did not interfere with the separation and determination of Cr(VI). The developed SA-BME method has been successfully applied for the determination of Cr(VI) in stream, sea and waste water with good recoveries.

VALIDATED KINETIC SPECTROPHOTOMETRIC DETERMINATION OF PITAVASTATIN CALCIUM USING ACIDIC PERMANGANATE OXIDATION

Objective: Development and validation of a sensitive, indirect spectrophotometric kinetic method, based on oxidation-reduction reaction, using potassium permanganate, for the quantitative assay of pitavastatin calcium, a cardiovascular drug used for the treatment of hyperlipidemia.
 Methods: The developed spectrophotometric kinetic method is based on the ability of potassium permanganate to oxidize Pitavastatin, where, the drug solution is treated with a fixed concentration of permanganate in acidic medium, and after a specified time, the unreacted permanganate is measured at 525 nm. All variables affecting the color development have been investigated and the conditions were optimized. Different kinetic methods, including initial rate, rate constant, fixed time and fixed concentration, were applied for the determination Pitavastatin.
 Results: During the course of the reaction, the absorbance values, at 525 nm, related to KMnO4, decreased linearly with increasing the concentration of the drug. The reaction rate obeyed was found to be pseudo-first-order and the kinetic method used was the fixed-time method. The assay of PITA in the concentration range of 16-80 μg/ml, using the fixed time method was successfully determined with a correlation coefficient value of 0.9999. The applicability of the developed method was also demonstrated by the determination of pitavastatin in its pure form and in its pharmaceutical formulation, where, the effect of excipients has also been studied and found to have no effect.
 Conclusion: The developed indirect spectrophotometric kinetic method, using the fixed time method, was used for the determination of Pitavastatin in pharmaceutical tablets. This method was simple, accurate and easy to apply for routine assay and in quality control laboratories.

Vortex-assisted supramolecular solvent microextraction based on solidification of floating drop for preconcentration and speciation of inorganic arsenic species in water samples by molybdenum blue method

A new vortex-assisted supramolecular solvent microextraction based on solidification of floating drop (VA-SSM-SFD) has been developed for preconsentration and spectrophotometric determination of inorganic arsenic (iAs) species in various water samples. The method is based on the formation of arsenomolybdenium blue complex followed by VA-SSM-SFD procedure and subsequent spectrophotometric determination in a microcell. The supramolecular solvents consisted of reverse micelles of 1-dodecanol in tetrahydrofuran (THF) which were formed by in-situ coacervation of 1-dodecanol micelles in aqueous samples. Under optimized conditions, iAs (V) formed hetroploy blue complex and was directly determined. The concentration of iAs (III) was determined by subtracting iAs (III) from the total iAs following the oxidation of iAs (III) to iAs (V) by permanganate in acidic medium. Under optimal conditions, the calibration curve for iAs determination showed good linearity in the range of 5.0–140.0 μg L−1(R2 = 0.9988) and detection limit was found to be 0.4 μg L−1, which is much lower than WHO guideline of 10 μg L−1 for iAs in drinking water. The repeatability and reproducibility for 20 μg L−1 were found to be 2.47 and 3.9%, respectively. The proposed method was successfully applied to speciation of iAs species in real water samples.

Redox titration on foldable paper-based analytical devices for the visual determination of alcohol content in whiskey samples

This report describes the development of foldable paper-based analytical devices (PADs) to perform redox titrations. Paper devices were designed to contain three spot tests, which were wax printed and folded to create a three-layer structured platform and to promote the sample transport based on vertical flow. The proposed devices were explored for the visual determination of the alcoholic content in whiskey samples. For this purpose, a classical permanganometry reaction was employed to allow the indirect determination of ethanol based on the required amount of oxalic acid to react with the excess of permanganate in acidic medium. The endpoint of the redox titrations performed in different alcoholic concentrations was measured and revealed a good linear behavior for the ethanol concentration range between 0% and 50% (R2 = 0.992), achieving a limit of detection equal to 2.1%. The alcoholic content was determined in a total of 44 whiskey samples seized by the Brazilian Federal Police. When compared to genuine samples and using an established cut-off limit, 73% of the seized samples were correctly classified as whiskeys containing adulterated alcoholic content. The proposed method was compared to a reference protocol and no difference was observed at the confidence level of 95%. The instrumental simplicity, the low cost, the sample volume requirement, the short analysis time and mainly the inherent portability make these devices quite attractive for on-site forensic applications.

Supramolecular dispersive liquid–liquid microextraction-based solidification of floating organic drops combined with electrothermal atomic absorption spectrometry for determination of chromium species

ABSTRACTA simple, sensitive and reliable method has been developed for separation and preconcentration of chromium (VI) from aqueous samples before determination by electrothermal atomic absorption spectrometry. The method is based on the extraction of the hydrophobic complex of chromium (VI) with ammonium pyrrolidine dithiocarbamate in the coacervates made up of decanoic acid reverse micelles in the water–tetrahydrofuran mixture. Parameters affecting the extraction efficiency of the analyte were studied and optimised. Under the optimum conditions, the linear range, enhancement factor, the limit of detection and limit of quantification were found to be 0.008–0.4 µg L−1, 127, and 1.8 ng L−1 and 6.0 ng L−1, of Cr(VI), respectively. The relative standard deviation at the concentration level of 0.1 µg L−1 Cr(VI) (n = 6) was 4.2%. Total chromium was determined after the oxidation of Cr(III) to Cr(VI) with permanganate in acidic medium. The method was successfully applied to the determination of chromium species in water and human serum samples.

Oxidation of linezolid by permanganate in acidic medium: Pd(II) catalysis, kinetics and pathways

The uncatalysed and Pd(II)-catalysed oxidation of linezolid (LNZ) by permanganate (PMGT) in acidic medium was carried out in the pH range from 3.0 to 6.0. The second order rate constants were found to decrease with increase in pH. The apparent second order rate constants for the uncatalysed reaction were, for example, k″app = 6.32 dm3 mol–1 s–1 at pH 3.0 and k″app. = 2.64 dm3 mol–1 s–1 at pH 6.0 and at 25 ± 0.2 °C and for the Pd(II)-catalysed reaction the total apparent second order rate constants were k″app = 75.5 dm3 mol–1 s–1 at pH 3.0 and k″app. = 45.66 dm3 mol–1 s–1 at pH 6.0 and at 25 ± 0.2 °C. The rate constant of the Pd(II)-catalysed reaction was thus ten times higher than for the uncatalysed reaction. The oxidation products of the reaction were identified using high resolution LC–MS. The reaction progresses via formation of a Pd–LNZ complex, which reacts with acidic PMGT to form an intermediate compound, which then decomposes to give oxidised products. The dependence of the rate of reaction on various parameters, such as pH, temperature, [LNZ], [PMGT], [Pd(II)], dielectric constant and ionic strength were studied and activation parameters for the reaction were evaluated and discussed.

Oxidation kinetics of crystal violet by potassium permanganate in acidic medium

The oxidation kinetics of crystal violet (a triphenylmethane dye) by potassium permanganate was focused in an acidic medium by the spectrophotometric method at 584 nm. The oxidation reaction of crystal violet by potassium permanganate is carried out in an acidic medium at different temperatures ranging within 298–318 K. The kinetic study was carried out to investigate the effect of the concentration, ionic strength and temperature. The reaction followed first order kinetics with respect to potassium permanganate and crystal violet and the overall rate of the reaction was found to be second order. Thermodynamic activation parameters like the activation energy (Ea), enthalpy change (ΔH*), free energy change (ΔG*), and entropy change (ΔS*) have also been evaluated.

Oxidative transformation of antiretroviral drug zidovudine during water treatment with permanganate: reaction kinetics and pathways

The presence of the pharmaceutical substances in the water has been reported by many studies and has attracted attention across the world. The mechanistic insight into oxidation of antiretroviral drug zidovudine (ZDV) by potassium permanganate was investigated between the pH values 3.0 and 9.0. The pH-dependent second-order rate constants were determined and rate constants decreased with an increase in pH. The products of the reaction were identified by high-resolution mass spectrometry. A probable mechanism is proposed which involves the formation of an intermediate complex between permanganate and ZDV, which further undergoes degradation in subsequent fast steps to form various oxidized products. The different parameters like effect of initially added products, solvent polarity, ionic strength, temperature, and pH on the rate of the oxidative degradation of ZDV by permanganate were systematically studied. The various activation parameters were determined from the effect of variation in temperature on the oxidative degradation of ZDV by permanganate in acidic medium and discussed in detail.

Conclusive evidence for autocatalytic behaviour of manganese(II) ions in the oxidative degradation of ondansetron by permanganate in aqueous sulfuric acid medium – a kinetic and mechanistic approach

The oxidation of ondansetron by permanganate in aqueous sulfuric acid medium has been investigated spectrophotometrically under the pseudo-first order condition at 25°C and at constant ionic strength, I=0.60moldm−3. The reaction between ondansetron and permanganate in acid medium exhibits 2:1 stoichiometry. The products are identified and characterised by IR and GC–MS spectral studies. The identified oxidation products are 1-methyl-2-((E)-4-(2-methyl-1H-imidazol-1-yl)but-3-enyl)-1H-indole-3-carboxylic acid and Mn(II), which are different from those obtained by hepatic metabolism. The reaction is autocatalysed due to one of the product, Mn(II). The reaction is first order with respect to MnO4− and less than unit order with respect to ondansetron, acid and Mn(II) concentrations. The oxidation reaction in acid medium proceeds through a permanganate–ondansetron complex that decomposes slowly in a rate-determining step followed by other fast steps to give the products. The reaction constants involved in different steps of the mechanism are calculated at different temperatures. The activation parameters with respect to the slow step of the mechanism are computed, and thermodynamic quantities are also determined.

Spectrophotometric and spectrofluorimetric determinations of veterinary drug enrofloxacin in pharmaceutical formulation

Four simple, sensitive spectrophotometric and spectroflourimetric methods (A-D) for the determination of veterinary drug enrofloxacin (ENFX) in pharmaceutical formulation have been developed. Method (A) is based on formation of ternary complex of ENFX with Pd(II) in presence of methyl cellulose as surfactant and acetate-HCl buffer pH 4.0. Method (B) is based on the oxidation of ENFX with alkaline potassium permanganate to give a green colored reaction product. The reaction was monitored spectrophotometrically by measuring the absorbance of the reaction product at 604 nm. Method (C) is based on the oxidation of the ENFX by a known excess of potassium permanganate in acid medium and subsequent determination of unreacted oxidant by reacting it with safronine O (SFO). Method (D) is based on the chelation of ENFX with Zr(IV), to produce fluorescent chelate. At the optimum reaction conditions, the drug/metal chelate showed excitation maxima at 280 nm and emission maxima at 440 nm. The optimum experimental parameters for the reaction have been studied. The validity of the described procedures was assessed. Statistical analysis of the results has been carried out revealing high accuracy and good precision. The proposed methods were successfully applied for the determination of the selected drug in pharmaceutical preparations with good recoveries. The procedures were accurate, simple and suitable for quality control application.

Determination of tramadol, morphine, nalbuphine and naltrexone analgesic drugs using potassium permanganate by visible spectrophotometry

A simple, rapid, accurate, precise and sensitive spectrophotometric method for the determination of four analgesic drugs namely, tramadol (TRAM), morphine (MORF), nalbuphine (NALB) and naltrexone (NALT) in bulk sample and in dosage forms is described. The method is based on oxidation of the studied drugs by potassium permanganate in acidic medium and determination of the unreacted oxidant by measuring the decrease in the absorbance of indigo carmine (IC) dye at 610 nm. Under the optimum conditions, Beer's law limit, molar absorptivity and Sandell's sensitivity were calculated. The limits of detection and quantification were also reported. Statistical evaluation of the method was examined by determining an intra-day and inter-day precisions. The method was successfully applied to the assay of drugs in their pharmaceutical formulations. No interference was observed from common additives and the validity of the method was tested.

Corollary of Additives on Gamma and Pulse Radiolytic Degradation of Aqueous Potassium permanganate Solution

The effect of additives on the reduction of potassium permanganate solutions, induced by 60Co γ-rays and highly accelerated electrons, has been investigated in acidic medium. In gamma radiolytic degradation of potassium permanganate in acidic medium in the presence of additives such as manganese dioxide (MnO2), potassium sulphate (K2SO4), sodium persulphate (Na2S2O8), ammonium chloride (NH4Cl) and mixture of potassium sulphate and ammonium chloride (K2SO4+NH4 Cl), the value of G(-MnO4−) is found to be higher at lower dosages and gradually decreases as the dose is increased. G(-MnO42-) is also observed to increase with an increase in the amount of the additives. In pulse radiolysis of acidic potassium permanganate solutions there is formation of MnO42- when K2SO4 and Na2S2O8 are used as additives. MnO43- peak is observed with additive mixture of K2SO4+NH4Cl. The kinetics of the reaction was also studied for various concentrations of potassium permanganate solutions with additives and first order spectra were obtained.

Study of the kinetics and mechanism of oxidation of some esters by potassium permanganate in acid medium

Study of the kinetics and mechanism of oxidation of some esters by potassium permanganate in acid medium

Kinetics and mechanisms of oxidation of d-fructose and d-lactose by permanganate ion in acidic medium

The oxidations of D-fructose and D-lactose were monitored spectrophotometrically by potassium permanganate in acidic medium at λmax 545 nm. Reaction demonstrated that the two oxidative species of permanganate were involved in an acidic oxidation of the sugars. It was established that respective acids of sugars as well as arabinonic and formic acid were the oxidation products. Respective acids of sugars were the results of reactive oxygen species of permanganate ions in acidic conditions while arabinonic and formic acids due to the cleavage of C__C bond through MnO-4 species. It was first order kinetics with respect to [MnO-4 ], [fructose], [lactose] and [H+]. Hg was used to accelerate the slow oxidation of lactose. Effect of varying salt electrolyte concentration was insignificant showing that the molecular species was involved in the rate determining step. Formic and arabinonic acids and respective acids were analyzed through spot and spectroscopic studies respectively. Reaction was monitored at different temperatures and thermodynamics activation parameters were determined. A mechanism consistent with kinetic studies, spectral evidences, stoichiometry of the reactions and product analysis has been proposed for the oxidation of fructose and lactose in absence and presence of catalyst respectively.

SPECTROPHOTOMETRY MICRODETERMINATION OF SOME ANTIHYPERTENSIVE DRUGS IN PURE FORM AND IN PHARMACEUTICAL FORMULATIONS

Simple, rapid, accurate, precise and sensitive spectrophotometric method for the microdetermination of enalapril maleate (ENM) and lisinopril dihydrate (LIS) has been developed. The method is based on oxidation of the drug by potassium permanganate in acidic medium and determine the unreacted oxidant by measuring the decrease in absorbance for three different acidic dyes; acid red 73 (AR), amaranth dye [acid red 27] (AM) and acid orange 7 (AO) at a suitable λ max (510, 521 and 484 nm for ENM and 509, 521 and 485 nm for LIS), respectively. Regression analysis of Beer’s law plots showed good correlation in the concentration ranges 0.7–12, 0.5–7.6 and 0.6–9.5 µg mL–1 and 0.5–9.0, 0.4–6.1 and 0.4–7.2 µg mL–1 for ENM and LIS using AR, AM and AO, respectively. The apparent molar absorptivity, Sandell sensitivity, detection and quantitation limits are calculated. Statistical treatment of the results reflects that the proposed procedures are precise, accurate and easily applicable for the determination of ENM and LIS in pure and in pharmaceutical preparations.

Utility of oxidation–reduction reaction for the spectrophotometric determination of amlodipine besylate

A simple, rapid, accurate, precise and sensitive spectrophotometric method for the determination of amlodipine besylate (ADB) in bulk sample and in dosage forms is described. The method is based on oxidation of the drug by potassium permanganate in acidic medium and determine the unreacted oxidant by measuring the decrease in absorbance for five different dyes; methylene blue (MB), acid blue 74 (AB), acid red 73 (AR), amaranth dye (AM) and acid orange 7 (AO) at a suitable λmax 663, 609, 511, 520, and 484nm, respectively. Regression analysis of Beer's law plots showed good correlation in the concentration ranges 1.0–24, 0.9–22, 1.2–26, 0.9–12.8 and 1.0–14μgml−1, respectively. The apparent molar absorptivity, Sandell sensitivity, detection and quantitation limits were calculated. For more accurate results, Ringbom optimum concentration ranges were 1.2–22.4, 1.1–20, 1.4–24.5, 1.0–12.3 and 1.3–13.2μgml−1, respectively. Statistical treatment of the results reflects that the proposed procedures are precise, accurate and easily applicable for the determination of amlodipine besylate in pure form and in pharmaceutical preparations.

Kinetics of oxidation of nicotinic and isonicotinic acids by permanganate in acidic medium

The most important feature of this study of the oxidation of nicotinic acid (Nic) and isonicotinic acid (lnic) by permanganate in acidic medium is the complete solution of the rate laws (A) for Nic and (B) for Inic by varying [H + ] over an extended concentration range. - d[MnO 4 - ]/dt = {k 0 K 1 [H + ] + k K 1 K 2 [H + ] 2 + k 3 K 1 K 2 K 3 [H + ] 3 }[MnO 4 - ][Nic] 0 / {1 + K 1 [H + ] + K 1 K 2 [H + ] 2 ] (A) - d[MnO 4 - ]/dt = {k K 2 [H + ] + k 3 K 2 K 3 [H + ] 2 } [MnO 4 - ] t [lnic]/{1 + K 2 [H + ]} (B) The relationships of the rate parameters and their values are as follows: K 1 (NC 5 H 4 COO - + H + = HN + C 5 H 4 COO - [B]), 1.78 × 10 4 (30) (Nic); K 2 (HN + C 5 H 4 COO - [B] + H + = HN + C 5 H 4 COOH [C]), 46.2 (30) (Nic), 33.6 (40) (Inic); k s ([B] + MnO 4 - → products), 1.56 x 10 -3 L mol -1 s -1 (30) (Nic); k ([C] + MnO 4 - → products), 1.64 x 10 -2 (30) (Nic), 1.68 x 10 -3 L mol -1 s -1 (40) (lnic) and k 3 K 3 ([C] + HMnO 4 → products), 2.02 x 10 -2 (30) (Nic), 3.2 x 10 -3 L 2 mol -2 s -1 (40°) (inic). The reactivity of Nic was greater than that of Inic.

Spectrophotometric Determination of Pipazethate HCl and Dextromethorphan HBr using Potassium Permanganate

Rapid, simple and sensitive validated spectrophotometric methods have been described for the assay of pipazethate HCl (PiCl) and dextromethorphan HBr (DEX) either in pure form or in pharmaceutical formulations. The proposed methods were based on the oxidation of the studied drugs by a known excess of potassium permanganate in acidic medium and estimating the unreacted permanganate with amaranth dye (method A), acid orange II (method B), indigocarmine (method C) and methylene blue (method D), in the same acid medium at a suitable λmax=521, 485, 610 and 664 nm, respectively. Beer's law is obeyed in the concentration range of 2.0-16 and 2.0-15 μg mL-1 for PiCl and DEX, respectively with correlation coefficient (n=6) ≥ 0.9993. The apparent molar absorptivity and sandell sensitivity values are in the range 1.062-1.484 × 104, 3.35-4.51 × 104 L mol-1 cm-1 and 29.36-41.03, 8.21-11.06 ng cm-2 for PiCl and DEX, respectively. Different variables affecting the reaction were studied and optimized. The proposed methods were applied successfully to the determination of the examined drugs either in a pure or pharmaceutical dosage forms with good accuracy and precision. No interferences were observed from excipients and the results were in good agreement with those obtained using the official methods.

Comparative rate study on the oxidation of nicotinamide and isonicotinamide by permanganate in acidic medium

A comparative rate study on the oxidation of nicotinamide and isonicotinamide by potassium permanganate has been carried out in acidic solutions over an extended [H + ]-range (1x 10 -5 -1.0 mol L -1 ). Under the similar reaction conditions, the oxidation of pyridine is imperceptible. Further, in the absence of acid none of the two amides Is oxidized and in both cases, the N-protonated amide species appears to be reactive. For nicotinamide, the results are in agreement with the two-term rate law (A). The oxidation product was corresponding N-oxide. On the other hand, the oxidation of isonicotinamide follows a simpler rate law (B). The values of k 0 , K and k,K, for nicotinamide were found to be 5.5 x 10 -3 L mol -1 s -1 , 1.8 x 10 4 and 1.0 x 10 -2 L mol -1 s -1 , respectively at 35 °C. And for isonicotinamide, the k 0 and K values were 4.4 x 10 -3 L mol -1 s -1 and 5.6 x 103 respectively at 35 °C. The oxidation of nicotinamide is faster than the oxidation of isonicotinamide. It appears that the presence of -CONH 2 group at position 3 activates the ring nitrogen more for oxidation than the presence of this group at position 4.