Presence Of Potassium Ferricyanide Research Articles

Development of Visible Spectrophotometric Method and its Validation for Dolutegravir in Tablet Dosage Form

Objective: There are several methods for analyzing the same, however, they are time-consuming and costly. We created a new spectrophotometric method for determining Dolutegravir (DLT) in tablet dosage forms that is simple, accurate, and precise. We developed and validated a simple, accurate, and precise colorimetric method for the quantitative analysis of Dolutegravir in bulk and dosage form by ICH recommendations in this study. Methodology: There are several methods for analyzing the same, however, they are time-consuming and costly. We created a new spectrophotometric method for determining Dolutegravir (DLT) in tablet dosage forms that is simple, accurate, and precise. In methanol, the initial stock solution of Dolutegravir was prepared. The method is based on the formation of a blue color chromogen complex from Dolutegravir oxidation-reduction with Ferric chloride in the presence of potassium ferricyanide. Result: The color complex was measured at 710nm. Beers law was observedin the concentration range of 3.5-6.5μg/ml witha coefficient of correlation (R2) was 0.998. The system suitability criteria were found to be within the limits. The LOD and LOQ were found to be 0.91 and 2.47, indicating that the method is sensitive. Conclusion: The relative standard deviation (RSD) and percent recovery values were found to be satisfactory, indicating that the proposed method is suitable, accurate, and precise and that it can be used in routine analysis of Dolutegravir in tablet dosage forms, with relatively low-cost solvents.

Impact of different electrodes, mediators, and microbial cultures on wastewater treatment and power generation in the microbial desalination cell (MDC).

Microbial desalination cell (MDC) can treat wastewater and saline water simultaneously and generate power. The aim of the present research work was to identify the critical factors influencing COD reduction and power generation from the MDC reactor and to optimize the control parameters. The experimental study was conducted by using medium to high-strength wastewater from distillery and brewery industry in batch-wise operation. The maximum voltage of 702 mV and current of 2.16 mA were observed for the carbon brush electrode. The mediated aeration process with the presence of potassium ferricyanide was reported in 87% COD reduction and 992 mV voltage generation. The presence of the microbial culture provided 82% COD reduction and 51% TDS reduction. The maximum current density (CD) of 0.04 mA/cm2 was observed for carbon brush, and a maximum power density (PD) of 15.56 mW/cm2 was found with aeration and potassium ferricyanide mediator. This study provided insight towards the impact of the electrode materials and the effects of mediator, aeration, and microbial culture on MDC performance.

Fermentation redox potential control on the 1,3-propanediol production by Lactobacillus panis PM1

The fermentation redox potential was controlled during the production of 1,3-propanediol (PDO) by Lactobacillus panis PM1. Results show that the best redox potential level was at −200 mV at which had the highest PDO production (23.38 g/L) when compared to that controlled at -250 mV, −150 mV, and without control. For the redox potential level under investigation, the mass PDO yield with respect to glycerol was between 0.66 and 0.82. Potassium ferricyanide was chosen as an oxidant to control the redox potential level. With the addition of oxidant, the batch fermentation time was noticeably reduced compared to the one without the addition of oxidant. Furthermore, co-substrate utilization of glucose and glycerol was observed when potassium ferricyanide was present. It was postulated that such a co-substrate utilization pattern resulted from the redox imbalance where the activities of acetaldehyde dehydrogenase and alcohol dehydrogenase were retarded by the presence of potassium ferricyanide. To overcome the redox imbalance, the glycerol-reductive pathway was triggered to serve as the electron source to fuel the glycolysis pathway and PDO formation. The developed redox potential control strategy may benefit other specifically isolated PDO-producing strains and industrial PDO green processing to further enhance their productivity.

Synthesis of nickel hexacyanoferrate nanostructure on carbon cloth with predeposited nickel nanoparticles as precursor for binder-free high-performance supercapacitor electrodes

Transition metal (TM) hexacyanoferrates (TM-HCF) have been proven efficient electrode materials for supercapacitors, especially in neutral electrolyte. In this work, nickel hexacyanoferrate (Ni-HCF) with ultra-high mass-loading was synthesized on carbon cloth (CC) with nickel nanoparticles (NiNPs) as the precursor, which were in-situ converted to Ni-HCF with graphene oxide (GO) as the oxidant and NiNPs as the reductant in the presence of potassium ferricyanide. First, NiNPs were potentiostatically electrodeposited on CC. Then, the electrodeposited NiNPs was oxidized to Ni2+ by GO. The produced Ni2+ reacted immediately with potassium ferricyanide to form nanostructured nickel hexacyanoferrate. By tuning the electrodeposition time of NiNPs, the mass of the finally produced Ni-HCF can be easily adjusted. In this work, the mass-loading of Ni-HCF supported on CC reaches up to 26.4 mg cm−2. As the positive electrode, Ni-HCF/CC possesses a high areal capacity of 6.9 C cm−2 at a discharge current density of 10 mA cm−2, excellent cycling stability with 81% of its initial capacitance after 2000 continuous charge/discharge cycles, ultrahigh energy density of 36 W h kg−1 at the power density of 200 W kg−1 and nearly 100% columbic efficiency. The superior energy storage capability of Ni-HCF indicates its promising prospect as the positive electrode material of high performance supercapacitors.

Synthesis, Isolation and Biological Evaluation of a New Active Quinone Methide Derived Curcuminoid

A new curcuminoid, quinone methide cyclopentadione (QMC), was synthesized by oxidation of curcumin (CUR) in the presence of potassium ferricyanide, and further isolated and analyzed. QMC was found to be a relatively water-soluble curcuminoid, and more stable than CUR in citric-phosphate buffer solutions. Unlike CUR, QMC possesses a pH-independent stability. In plasma, QMC was degraded by 50% after 8 hours and reached 30% of its initial concentration after 48h, while CUR was thoroughly decomposed. It has been demonstrated that QMC has a similar anti-proliferative activity as CUR in three different cancer cell lines- MCF-7, PC3 and HT29. Molecular examination of QMC in cancer cells exhibited similar effect to CUR on two transcription factors, Nrf-2 and NF-κB. An anti-inflammatory activity of QMC was demonstrated by measuring MCP-1 secretion levels in TNFα-induced human keratinocytes cell culture, which had been pre-treated with either CUR or QMC. This report presents the advantages of the new quinone methide derived curcuminoid and its pharmaceutical potential as an alternative to the poorly soluble curcumin.

Electrochemical synthesis of Prussian blue from iron impurities in 3D-printed graphene electrodes: Amperometric sensing platform for hydrogen peroxide

This communication shows the electrochemical synthesis of Prussian blue (PB) films on additive manufactured (3D-printed) electrodes from iron impurities found at the graphene-polylactic acid (G/PLA) substrate and its application as a highly selective sensor for H2O2. The 3D-printed G/PLA electrode was immersed in dimethylformamide for 30 min to exposure the iron impurities within the PLA matrix. Next, cyclic voltammograms (200 cycles) in the presence of potassium ferricyanide in 0.1 mol L−1 KCl + 0.01 mol L−1 HCl were performed to grow the PB films. The sensing properties of this novel PB/G/PLA platform were evaluated for the amperometric detection of H2O2 using batch-injection analysis, with a limit of detection of 0.56 μmol L−1 under the application of 0.0 V (vs Ag/AgCl/KClsat.). The applicability of the sensor was demonstrated for the analysis of milk samples (10-fold diluted in the supporting electrolyte), resulting in proper recovery values (94–101%).

Estimation of immobilized horseradish peroxidase in a low salt concentration for an irreversible electrochemical system

We examined the direct electron transfer of horseradish peroxidase (HRP) at HRP/carbon paste (CP)-modified electrodes under irreversible electrochemical conditions. The amount of electroactive HRP (Γ) was estimated as 2.0 × 10−9 to 3.9 × 10−9 mol, indicating that the effectiveness factor, defined as the ratio of the amount of electroactive HRP to the amount of HRP incorporated into CP, was 0.14–0.24. In the presence of potassium ferricyanide(III) (K3Fe(CN)6) and potassium hexacyanoferrate(II) (K4Fe(CN)6) as mediators, the electroactive surface area of only HRP on the HRP/CP-modified electrode was 0.0164 cm2. The theoretically calculated coverage area of electroactive HRP on the HRP/CP-modified electrode was much greater than the electroactive surface area of the CP electrode. In addition, the rate constant (k°) of the electrochemical reaction of HRP at the HRP/CP-modified electrode was 0.006 s−1 for the oxidation process.

Immunosensing of S100β biomarker for diagnosis of spinal cord injuries (SCI)

S100 calcium-binding protein β (S100β), a member of the S100 protein family, is one of the spinal cord injury (SCI) biomarkers extensively studied for its diagnostic and prognostic potential. The concentration of S100β is found to increase in the blood and cerebrospinal fluid (CSF) after SCI. Here, we developed an electrochemical immunosensor that offers label-free and direct detection of S100β to aid the diagnosis and prognosis of SCI. A screen-printed graphene electrode was modified by electrochemically reducing nitrate from 4-nitrobenenediazonium tetrafluoroborate to an amine group. The covalent conjugation of S100β monoclonal antibody was then achieved on the electrode surface by activating the amine group using glutaraldehyde. Characterization of the electrode was implemented using differential pulse voltammetry (DPV) in presence of potassium ferricyanide (K3[Fe(CN)6]) redox probe. Upon testing the samples on the modified electrode with different concentrations of S100β, the DPV current peak decreased with the increase in concentration of S100β biomarker. We achieved sensitive and selective label-free detection of S100β in the dynamic range of 1pg/ml–104pg/ml for samples prepared in phosphate buffer saline (PBS), artificial CSF (aCSF), and human blood serum. The performance of the immunosensor was validated by correlating the results for samples tested with commercially available enzyme-linked immunosorbent assay (ELISA) method.

Oxidative Transformation of Demethoxy- and Bisdemethoxycurcumin: Products, Mechanism of Formation, and Poisoning of Human Topoisomerase IIα.

Extracts from the rhizome of the turmeric plant are widely consumed as anti-inflammatory dietary supplements. Turmeric extract contains the three curcuminoids, curcumin (≈80% relative abundance), demethoxycurcumin (DMC; ≈15%), and bisdemethoxycurcumin (BDMC; ≈5%). A distinct feature of pure curcumin is its instability at physiological pH, resulting in rapid autoxidation to a bicyclopentadione within 10-15 min. Here, we describe oxidative transformation of turmeric extract, DMC, and BDMC and the identification of their oxidation products using LC-MS and NMR analyses. DMC autoxidized over the course of 24 h to the expected bicyclopentadione diastereomers. BDMC was resistant to autoxidation, and oxidative transformation required catalysis by horseradish peroxidase and H2O2 or potassium ferricyanide. The product of BDMC oxidation was a stable spiroepoxide that was equivalent to a reaction intermediate in the autoxidation of curcumin. The ability of DMC and BDMC to poison recombinant human topoisomerase IIα was significantly increased in the presence of potassium ferricyanide, indicating that oxidative transformation was required to achieve full DNA cleavage activity. DMC and BDMC are less prone to autoxidation than curcumin and contribute to the enhanced stability of turmeric extract at physiological pH. Their oxidative metabolites may contribute to the biological effects of turmeric extract.

An electrochemiluminescent biosensor based on polypyrrole immobilized uricase for ultrasensitive uric acid detection

An electrochemiluminescent (ECL) biosensor based on immobilized uricase has been developed for uric acid detection with luminol as signaler. The uricase has been embedded in polypyrrole (PPy) matrix on platinum electrode during the electropolymerization of pyrrole monomer at potential of 0.80V versus Ag/AgCl. This ECL-based biosensor responds to uric acid due to yielded hydrogen peroxide during its catalytic oxidization by uricase with potassium ferricyanide acted as an electron receptor to promote the enzymatic reaction. The so-generated hydrogen peroxide enhanced the ECL intensity of luminol. The kinetic parameters of enzymatic reaction as maximum reaction rates (Vmax) and Michaelis–Menten constants (Km) are also evaluated for 1.42×10−3As−1 and 3.4×10−7M in the presence of potassium ferricyanide, which were all greatly improved. The resulting biosensor showed excellent analytical performance for determination of uric acid as more than 50 times sensitivity than a bare electrode. It gives a 75pM of detection limit and a relative standard deviation of 4.4% for 6.25×10−9M uric acid (n=6). This ECL-based biosensor has been successfully applied for determination of uric acid in porphyra and kelp samples.

Spectrophotometric Determination of Cefotaxime Sodium with Potassium Ferricyanide

A spectrophotometric method has been set up to determine cefotaxime sodium using potassium ferricyanide as the spectroscopic probe reagent.With the presence of potassium ferricyanide,the degradation product of cefotaxime sodium can reduce Fe3 + to Fe2 + at pH 3.0,which facilitate the formation of soluble Prussian Blue(KFeⅢ[FeⅡ(CN) 6]).The absorbance of soluble Prussian Blue is measured at its absorption maximum of 730 nm and the amount of cefotaxime sodium can be indirectly calculated.Under optimized conditions,a good linear relationship is obtained in the range of 0.040 ～ 24 mg/L of cefotaxime sodium.The linear regression equation is A = 0.05088 + 0.2166ρ(mg/L) with linear correlation coefficient of 0.9986.The detection limit and relative standard deviation are 0.01 mg/L and 1.36%,respectively.Tthe apparent molar absorption coefficient of indirect determination of cefotaxime sodium is 2.3 × 105 L/(mol·cm).This method has been successfully applied to the determination of cefotaxime sodium in pharmaceutical and serum samples.

A facile method for the synthesis of thiocoumestan derivatives

Abstract magnified imageAn efficient synthesis of thiocoumestan derivatives, starting from catechols and 4‐mercaptocoumarin in the presence of potassium ferricyanide as an oxidizing agent (Decker oxidation) was developed. The results indicate that the 4‐mercaptocoumarin participates in Michael addition reactions with in situ generated o‐benzoquinones. The present work has led to the development of a one‐pot oxidative method for the synthesis of the 6H‐benzothieno[3,2‐c][1]benzopyron‐6‐one derivatives. J. Heterocyclic Chem., (2009).

Spectrophotometric determination of perphenazine with the detection system of potassium ferricyanide–Fe(III) in pharmaceutical and serum samples

In this paper, a novel spectrophotometric method has been established to determine perphenazine using the detection system of potassium ferricyanide–Fe(III). In the presence of potassium ferricyanide, it has been demonstrated that Fe(III) is reduced to Fe(II) by perphenazine at pH 4.0. In addition, soluble prussian blue (KFe III[Fe II(CN) 6]) is produced by the reaction between the in situ formed Fe(II) and potassium ferricyanide. The absorbance of soluble prussian blue is measured at the absorption maximum of 735 nm, and the amount of perphenazine can be calculated based on this absorbance. The absorbance is linear to perphenazine concentration in the ranges of 0.05–25.00 μg/mL with correlation coefficients of 0.9997, and the linear regression equation is A = 0.0069 + 0.1285 C (μg/mL). The detection limit (3 σ/ k) is 0.049 μg/mL, and the relative standard deviation (R.S.D.) is 0.86% ( n = 11). Moreover, the apparent molar absorption coefficient of indirect determination of perphenazine is 5.2 × 10 4 L/mol cm. The parameters with regard to determination are optimized, and the reaction mechanism is discussed. This method has been successfully applied to the determination of perphenazine in pharmaceutical and serum samples. Analytical results obtained with this novel assay are satisfactory.

A Novel Spectrophotometric Method for the Determination of Levodopa with the Detection System of Potassium Ferricyanide‐Fe(III)

AbstractIn this paper, a novel method has been established to determine levodopa with the detection system of potassium ferricyanide‐Fe(III). In the presence of potassium ferricyanide, it has been demonstrated that Fe(III) is reduced to Fe(II) by levodopa at pH 4.0. In addition, the in situ formed Fe(II) reacts with potassium ferricyanide to form soluble prussian blue (KFeIII[FeII(CN)6]). Beer's law is obeyed in the range of levodopa concentrations of 0.01–4.00 μg mL−1 at the maximal absorption wavelength of 735 nm. The linear regression equation is A = 0.0082 + 0.61365 C (μg mL−1) with a correlation coefficient of 0.9996. The detection limit (3σ/k) is 9 ng mL−1, and R.S.D. is 0.73% (n = 11). Moreover, the apparent molar absorption coefficient of indirect determination of levodopa is 1.2 × 105 Lmol−1cm−1. The parameters with regard to determination are optimized, and the reaction mechanism is discussed. This method has been successfully applied to determine levodopa in pharmaceutical, serum and urine samples. Analytical results obtained with this novel assay are satisfactory.

Cloud point extraction coupled with derivative of carbofuran as a preconcentration step prior to HPLC

Abstract Carbofuran can be hydrolysed to from 2,3-dihydro-2,2-dimethyl-7-benzofuranol (BF). BF is coupled with 4-aminoantipyrene (AP) in presence of potassium ferricyanide (K3Fe(CN)6) to generate red coloured derivative(BFAP)having λmax 530 nm. Cloud point extraction (CPE) methodology and using surfactant Triton X-100 as extractant was applied as a preconcentration step prior to HPLC, the surfactant-rich phase containing BFAP was then analysed by HPLC in visible region. The high back ground absorbance of Triton X-100 in UV region was completely avoided. A new visible detection method with high-performance liquid chromatography (HPLC) has been developed for the determination of carbofuran. Using this method, we found that carbofuran residues could be determined with recoveries ranging from 80.4% to 84.5%, relative standard deviations in the range of 2.51–3.26% for three fortified rice levels, and the limit of detection as 5.0 × 10−4 cJ/cK.

Determination of isoniazid among pharmaceutical samples and the patients’ saliva samples by using potassium ferricyanide as spectroscopic probe reagent

A novel method to determine isoniazid with high sensitivity and good selectivity has been established by using potassium ferricyanide as spectroscopic probe reagent. In the presence of potassium ferricyanide, it has been demonstrated that iron(III) is reduced to iron(II) by isoniazid at pH 4.0. In addition, the in situ formed iron(II) reacts with potassium ferricyanide to give soluble prussian blue. The absorbance of soluble prussian blue is measured at the absorption maximum of 735 nm, and the amount of isoniazid can be calculated based on this absorbance. A good linear relationship of the concentration of isoniazid versus absorbance is observed with a linear range of 0.040–8.00 μg mL −1. The linear regression equation is A = −0.00286 + 0.28588 C (μg mL −1) with a correlation coefficient of 0.9992. The detection limit (3 σ/ k) is 0.037 μg mL −1, and its relative standard deviation (R.S.D.) is 0.35% ( n = 11). Moreover, the apparent molar absorption coefficient of indirect determination of isoniazid is 3.92 × 10 4 L mol −1 cm −1. The parameters with regard to determination are optimized, and the reaction mechanism is discussed. This method has been successfully applied to the determination of isoniazid in pharmaceutical samples and saliva samples of patients.

Spectrophotometric method for the estimation of Oxcarbazepine in tablets

The objective of this work was to develop a simple, accurate, rapid and sensitive method for the estimation of oxcarbazepine in tablets. The estimation is based on the reduction of ferric ions in its salt form to ferrous ions by the drug, which in presence of potassium ferricyanide produces green colored chromogen measured at 770 nm against reagent blank. The chromogen obeyed linearity over 4 to 28 mg/ml (r=0.9981) with percent relative standard deviation (% RSD) of 0.4267. Recovery studies gave values ranging between 98.26 and 98.76. The proposed method is simple and suitable for routine determination of oxcarbazepine in tablets.

Photoreduction of Molecular Oxygen in Preparations of Photosystem II under Photoinhibitory Conditions

Preparations of photosystem II (PSII) from pea (Pisum sativum L.) leaves were used to study the evolution and reduction of molecular oxygen under photoinhibitory conditions. Under these conditions, the photoinduced oxygen uptake did not exceed 10% of the total oxygen-evolving activity in PSII preparations. Both the Hill and the Mehler reactions were found to occur simultaneously under long-term illumination of PSII preparations with high-intensity light in the presence of potassium ferricyanide. During this light treatment in the presence of potassium ferricyanide, the rate of oxygen uptake increased gradually reaching 30% of the oxygen-evolving activity. The photogeneration of superoxide anion radical at increasing light intensities followed a typical light-response curve with a light saturation at 800 W/m2. The results provide evidence that the Mehler reaction is the major source for superoxide and hydrogen peroxide in PSII preparations under photoinhibitory conditions and that the Mehler reaction in PSII proceeds more effectively at high light intensities. The relatively low and sustained rate of oxygen photoreduction in PSII preparations under photoinhibitory conditions substantiates the hypothesis on the involvement of Mehler reaction in cell signaling and regulation.

Biochemical background of toxic interaction between tiamulin and monensin

Tiamulin, a diterpene antibiotic, is used for treatment of pulmonary and gastrointestinal infections in swine and poultry. Combined administration of tiamulin and ionophores (e.g. monensin) to farm animals may lead to intoxication manifested in severe clinical symptoms. Tiamulin metabolite complex with cytochrome P450 has been suggested to be the basis of drug-interactions. However, the formation of metabolic intermediate complex is questionable. The effect of tiamulin-treatment on cytochrome P450 activities was investigated in rats. Ethylmorphine and aminopyrine N-demethylation activities as well as monensin metabolism ( O-demethylation) increased in liver microsomes of tiamulin-treated (200 mg/kg) animals. CYP3A1 induction caused by tiamulin was confirmed by the results of Western blot analysis. To test metabolic intermediate complex formation as a result of tiamulin treatment, cytochrome P450 activities were also determined in the presence of potassium ferricyanide. The findings together with those of in vitro complex formation suggested that formation of metabolic intermediate complexes of tiamulin with cytochrome P450 could be excluded. On the other hand, the results of inhibition studies showed significant decrease of ethylmorphine or aminopyrine as well as monensin demethylation in the presence of tiamulin. Our results proved that tiamulin has dual effect on cytochromes P450. It is able to induce and directly inhibit CYP3A enzymes, which are predominantly responsible for monensin O-demethylation. The direct effect of tiamulin as an inhibitor might play a more important role in toxicity than its putative effect as a chemical inducer of CYP3A enzymes.

Sequential injection spectrophotometric determination of phenylephrine hydrochloride in pharmaceutical preparations

A fully automated sequential injection spectrophotometric method for the determination of phenylephrine hydrochloride in pharmaceutical preparations is reported. The method is based on the condensation reaction of the analyte with 4-aminoantipyrine in the presence of potassium ferricyanide. The absorbance of the condensation product was monitored at 503nm. A linear relationship between the relative peak height and concentration was obtained in the range 0.5–17.5mgl−1. The detection limit (as 3σ value) was 0.09mgl−1 and repeatability was 0.8 and 0.6% at 2.5 and 5mgl−1, respectively. Results obtained by this method agreed very well with those obtained by the AOAC official method.