Novel Spectrophotometric Method For Determination Research Articles

A Novel Spectrophotometric Method for Determination of Percarbonate by Using N, N-Diethyl-P-Phenylenediamine as an Indicator and Its Application in Activated Percarbonate Degradation of Ibuprofen

A Novel Spectrophotometric Method for Determination of Percarbonate by Using N, N-Diethyl-P-Phenylenediamine as an Indicator and Its Application in Activated Percarbonate Degradation of Ibuprofen

A Novel Spectrophotometric Method for Determination of Chloramphenicol Based On Diazotization Reaction at Room Temperature

An analytical method for determination of chloramphenicol (CAP) based on the diazotization reaction at room temperature has been developed. The CAP was reduced using zinc powder (Zn) and diazotization reaction was carried out at room temperature in the presence of NaNO2, bismuth nitrate pentahydrate (Bi(NO3)3.5H2O) as catalyst. 2-napthol was used as coupling agent to form a red-violet solution and the absorbance was measured by UV-Vis spectrophotometer at 554 nm. The optimization of analytical parameters including reducing agent, catalyst, coupling agent and time response were 0.15 g, 0.15 g, 230.67 µg/mL and 8-9 min respectively.

Novel Spectrophotometric Method for Determination of Non-Nucleoside Reverse Transcriptase Inhibitor in Bulk and Pharmaceutical Dosage Form

Novel Spectrophotometric Method for Determination of Non-Nucleoside Reverse Transcriptase Inhibitor in Bulk and Pharmaceutical Dosage Form

A Novel Spectrophotometric Method for Determination of Histamine Based on Its Complex Reaction with Ni(II) and Alizarin Red S

The development of analytical methods of histamine using Ni (II) and alizarin red S reagents by UV-Vis spectrophotometry has been done. The objective of this research is to determine the ability of Ni(II) and alizarin red S to form color complex compound with histamine and it will be used to detect the presence of histamine qualitatively and quantitatively as well. Absorbance was measured at a maximum wavelength of 604 nm. In this method, it has been carried out optimization of analytical parameters such as the concentration of Ni(II), the concentration of alizarin red S, pH, and respond time. Analytical parameter optimization showed concentration of Ni(II) is 20 ppm, alizarin red S 75 ppm, pH 8, and a respond time of 15 minutes. Method validation indicated that the coefficient of variation, detection limit, and the limit of quantitation are 0.245%; 9.49 ppm; and 31.62 ppm respectively with a sensitivity of 0.0063/ppm and linearity of 0.99. Accuracy to histamine with a concentration of 50, 75, and 125 ppm are 105.87%, 101.06%, 97.21%, respectively.

Novel Spectrophotometric Method for Determination of the 1,4-Dioxane in Cosmetics Available in the Iraqi Market

Novel Spectrophotometric Method for Determination of the 1,4-Dioxane in Cosmetics Available in the Iraqi Market

A Novel Spectrophotometric Method for Determination of Gabapentin in Pharmaceutical Formulations Using 2,5-Dihydroxybenzaldehyde

A highly simple, rapid, sensitive and selective method is developed for spectrophotometric determination of gabapentin in pure form as well as in pharmaceutical formulations. The method is based on the formation of a yellow Schiff base derived from the condensation of gabapentin drug (1-amino methyl) cyclo hexane acetic acid and 2,5-dihydroxybenzaldehyde (DHBA) exhibiting a maximum absorbance at 445 nm. The composition, molar absorptivity and effect of different excipient have been determined spectrophotometrically. Under optimized experimental conditions, Beer’s law is obeyed in the concentration range 2.57 - 37.25 μg/ml. The method is validated with respect to accuracy, precision, limit of detection and limit of quantification. The Sandell sensitivity, correlation coefficient and regression equation are calculated. The equilibrium constant and free energy change using Benesi-Hildebrand plot are also determined. The Schiff base derived from condensation of gabapentin with DHBA is also synthesized and characterized. The condensation reaction mechanism has been proposed.

A Novel Spectrophotometric Method for Determination of Five 1,4-Dihydropyridine Drugs in Their Tablets and Capsules Using Vanillin Reagent

A selective and new spectrophotometric method is described for determination of five 1,4 dihydropyridine drugs (1,4- DHP); namely nifedipine (NIF), nicardipine (NIC), nimodipine (NIM), felodipine (FEL) and amlodipine (AML). The method is based on a coupling reaction between the cited drugs and vanillin reagent in acidic condition. Under optimized conditions, the red coloured products were measured at 500 nm for NIF, NIC, NIM and FEL or at 479 nm for AML. Molar absorptivities were ranged from 0.575 × 104 － 1.065 × 104 l·mol-1·cm-1, Beer’s law was obeyed at 5 - 70 μg/mL concentration range and the limit of detection was ranged from 0.150 - 1.500 μg/mL. The proposed method was successfully extended to pharmaceutical preparations tablets and capsules and comparison by Student’s t-test and variance ratio F-test showed no significant difference.

Novel spectrophotometric method for determination of some macrolide antibiotics in pharmaceutical formulations using 1,2-naphthoquinone-4-sulphonate

New, simple and rapid spectrophotometric method has been developed and validated for the assay of two macrolide drugs, azithromycin (AZT) and erythromycin (ERY) in pure and pharmaceutical formulations. The proposed method was based on the reaction of AZT and ERY with sodium 1,2-naphthoquinone-4-sulphonate (NQS) in alkaline medium at 25°C to form an orange-colored product of maximum absorption peak at 452nm. All variables were studied to optimize the reaction conditions and the reaction mechanism was postulated. Beer’s law was obeyed in the concentration range 1.5–33.0 and 0.92–8.0μgmL−1 with limit of detection values of 0.026 and 0.063μgmL−1 for AZT and ERY, respectively. The calculated molar absorptivity values are 4.3×104 and 12.3×104Lmol−1cm−1 for AZT and ERY, respectively. The proposed methods were successfully applied to the determination of AZT and ERY in formulations and the results tallied well with the label claim. The results were statistically compared with those of an official method by applying the Student’s t-test and F-test. No interference was observed from the concomitant substances normally added to preparations.

Novel spectrophotometric methods for determination of desloratidine in pharmaceutical formulations based on charge transfer reaction

A facile, rapid, sensitive and validated spectrophotometric methods for the determination of desloratidine (DES) in pure and in dosage forms is described. The methods are based on the formation of charge transfer complexes between DES and the chromogenic reagents alizarin (I), alizarin red S (II) and quinalizarin (III) producing charge transfer complexes in alcoholic medium which showed an absorption maximum at 528, 505 and 560nm for I, II and III, respectively. The optimization of the reaction conditions such as the type of solvent, reagent concentration and reaction time was investigated. Beer's law is obeyed in the concentration ranges 1.0–16, 0.5–12 and 2.0–20μgmL−1 for I, II and III, respectively. The molar absorptivity, Sandell sensitivity, detection and quantification limits are also calculated. The correlation coefficient was ⩾0.9993 (n=6) with a relative standard deviation (R.S.D.) of ⩽1.13. The methods are successfully applied to the determination of DES in pharmaceutical formulations and the validity assesses by applying the standard addition technique, which compared with those obtained using the reported method.

Novel spectrophotometric method for determination of cinacalcet hydrochloride in its tablets via derivatization with 1,2-naphthoquinone-4-sulphonate

This study represents the first report on the development of a novel spectrophotometric method for determination of cinacalcet hydrochloride (CIN) in its tablet dosage forms. Studies were carried out to investigate the reaction between CIN and 1,2-naphthoquinone-4-sulphonate (NQS) reagent. In alkaline medium (pH 8.5), an orange red-colored product exhibiting maximum absorption peak (λmax) at 490 nm was produced. The stoichiometry and kinetic of the reaction were investigated and the reaction mechanism was postulated. This color-developing reaction was employed in the development of a simple and rapid visible-spectrophotometric method for determination of CIN in its tablets. Under the optimized reaction conditions, Beer's law correlating the absorbance with CIN concentration was obeyed in the range of 3 - 100 μg/ml with good correlation coefficient (0.9993). The molar absorptivity (ε) was 4.2 × 105 l/mol/cm. The limits of detection and quantification were 1.9 and 5.7 μg/ml, respectively. The precision of the method was satisfactory; the values of relative standard deviations (RSD) did not exceed 2%. No interference was observed from the excipients that are present in the tablets. The proposed method was applied successfully for the determination of CIN in its pharmaceutical tablets with good accuracy and precisions; the label claim percentage was 100.80 - 102.23 ± 1.27 - 1.62%. The results were compared favorably with those of a reference pre-validated method. The method is practical and valuable in terms of its routine application in quality control laboratories.

A novel method for spectrophotometric determination of pregabalin in pure form and in capsules

BackgroundPregabalin, a γ-amino-n-butyric acid derivative, is an antiepileptic drug not yet official in any pharmacopeia and development of analytical procedures for this drug in bulk/formulation forms is a necessity. We herein, report a new, simple, extraction free, cost effective, sensitive and reproducible spectrophotometric method for the determination of the pregabalin.ResultsPregabalin, as a primary amine was reacted with ninhydrin in phosphate buffer pH 7.4 to form blue violet colored chromogen which could be measured spectrophotometrically at λmax 402.6 nm. The method was validated with respect to linearity, accuracy, precision and robustness. The method showed linearity in a wide concentration range of 50-1000 μg mL-1 with good correlation coefficient (0.992). The limits of assays detection was found to be 6.0 μg mL-1 and quantitation limit was 20.0 μg mL-1. The suggested method was applied to the determination of the drug in capsules. No interference could be observed from the additives in the capsules. The percentage recovery was found to be 100.43 ± 1.24.ConclusionThe developed method was successfully validated and applied to the determination of pregabalin in bulk and pharmaceutical formulations without any interference from common excipients. Hence, this method can be potentially useful for routine laboratory analysis of pregabalin.

A novel spectrophotometric method for determination of cyanide using cobalt (II) phthalocyanine tetracarboxylate as a chromogen

Cobalt (II) phthalocyanine tetracarboxylate [Co (II)Pc-COOH] has been prepared and used in aqueous solutions as a novel chromogenic reagent for the spectrophotometric determination of cyanide ion. The method is based on measuring the increase in the intensity of the monomer peak in the reagent absorbance at 682 nm due to the formation of a 1 : 2 [Co (II)Pc-COOH] : [CN] complex. The complex exhibits a molar absorptivity (ε) of 7.7 × 104 L mol−1 cm−1 and a formation constant (Kf ) of 5.4 ± 0.01 × 106 at 25 ± 0.1°C. Beer's law is obeyed over the concentration range 0.15–15 µg mL−1 (5.8 × 10−6–5.8 × 10−4 M) of cyanide ion, the detection limit is 20 ng mL−1 (7.7 × 10−7 M) the relative standard deviation is ±0.7% (n = 6) and the method accuracy is 98.6 ± 0.9%. Interference by most common ions is negligible, except that by sulphite. The proposed method is used for determining cyanide concentration in gold, silver and chromium electroplating wastewater bath solutions after a prior distillation with 1 : 1 H2SO4 and collection of the volatile cyanide in 1 M NaOH solution containing lead carbonate as recommended by ASTM, USEPA, ISO and APAHE separation procedures. The results agree fairly well with potentiometric data obtained using the solid state cyanide ion selective electrode.

Conjugated autoxidizable triene (CAT) assay: A novel spectrophotometric method for determination of antioxidant capacity using triacylglycerol as ultraviolet probe

Described here is a novel spectrophotometric method for estimating antioxidant capacity in a 96-well microplate using as UV probes the conjugated triene triacylglycerols (TAGs) naturally present in tung oil. The TAGs of this commercially available oil contain around 86% eleostearic acid, an octadecatrienoic acid with conjugated trienes exhibiting strong UV absorption at 273 nm. In an oil-in-water emulsion at 37 °C, the azo initiator 2,2′-azobis(2-amidinopropane) dihydrochloride generated a constant flux of peroxy radicals, which destroyed the conjugated trienes. The absorbance decay at 273 nm, related to oxidative degradation of conjugated triene TAGs, was monitored in the absence and presence of various concentrations of antioxidants. To validate this new method, the antioxidant capacity of four phenolic compounds (gallic acid, (–)-epicatechin, chlorogenic acid, and rosmarinic acid) was measured using an area-under-the-curve calculation and expressed as Trolox equivalents, the value for Trolox being taken as reference. The order of efficacy was found to be rosmarinic acid > chlorogenic acid ∼ epicatechin > Trolox > gallic acid, which can be partially explained by the number of catecholic moieties and the polarity of these antioxidants. Moreover, the conjugated autoxidizable triene (CAT) assay provided good insight into antioxidant behavior (i.e., retarder or chain breaker). The same molecules were then analyzed in 2,2-diphenyl-1-picrylhydrazyl and fluorescein-based oxygen radical absorbance capacity assays, and the results are discussed critically with respect to those obtained with the CAT assay. This new method may constitute an easy-to-use, sensitive, and high-throughput in vitro protocol for evaluation of the antioxidant capacity of pure molecules and natural extracts in lipid oxidation.

Novel Spectrophotometric Method for Determination of Trace Germanium in Soils with Methybenzeneazosalicylfluorone using Ultrasound‐Assisted Leaching

The research describes a very novel method for spectrophotometric determination of trace germanium in soils. The method is based on the color reaction of germanium (IV) with a new reagent, methybenzeneazosalicylfluorone (MBASF), in the presence of 6.0 M phosphoric acid and Triton X‐100. The reaction can complete rapidly and form a 1∶2 red complex with a maximum absorption at 501 nm under room temperature. The absorbance of the complex at 501 nm increases linearly with the concentration up to 18 µg of germanium (IV) in 25 mL of the solution; the apparent molar absorptivity was 2.18 ×10 5 L mol−1 cm−1. The interference study shows the reaction system has an excellent selectivity. All common metal and interference ions reported in other literatures can be tolerated in considerable amounts. The analytical characteristics in sensitivity and selectivity are superior over all reagents reported previously. Moreover, a very simple procedure was also developed for the dissolution of soil samples in the work. The analyte was leached from soil samples by adding 2.0 mL of concentrated hydrofluoric acid to 500–1000 mg of the sample, and the mixture was then submitted to a 10‐min ultrasonic treatment. After adding 0.6 g of boric acid and 10 mL of concentrated phosphoric acid, the filtered solution was applied directly to spectrophotometric determination of trace germanium. The detection limit, calculated using three times the standard error of estimate of the calibration graph, was 2.75 ng l−1. The reliability of the proposed method were verified by analyzing several certified reference materials and using the standard addition method.

A novel spectrophotometric method for determination of kinetic constants of aldehyde oxidase using multivariate calibration method

Although phenanthridine has been frequently used as a specific substrate for the assessment of aldehyde oxidase activity, the use of this method is questionable due to a lower limit of detection and its validity for kinetic studies. In the present study, a novel sensitive multivariate calibration method based on partial least squares (PLS) has been developed for the measurement of aldehyde oxidase activity using phenanthridine as a substrate. Phenanthridine and phenanthridinone binary mixtures were prepared in a dynamic linear range of 0.1–30.0 μM and the absorption spectra of the solutions were recorded in the range of 210–280 nm in Sorenson's phosphate buffer (pH 7.0) containing EDTA (0.1 mM). The optimized PLS calibration model was used to calculate the concentration of each chemical in the prediction set. Hepatic rat aldehyde oxidase was partially purified and the initial oxidation rates of different concentrations of phenanthridine were calculated using the PLS method. The values were used for calculating Michaelis–Menten constants from a Lineweaver–Burk double reciprocal plot of initial velocity against the substrate concentration. The limits of detection for phenanthridine and phenanthridinone were found to be 0.04 ± 0.01 and 0.03 ± 0.01 μM (mean ± SD, n = 5), respectively. Using this method, the K m value for the oxidation of phenanthridine was calculated as 1.72 ± 0.09 μM (mean ± SD, n = 3). Thus, this study describes a novel spectrophotometric method that provides a suitable, sensitive and easily applicable means of measuring the kinetics of phenanthridine oxidation by aldehyde oxidase without the need for expensive instrumentation.

Novel Method for Spectrophotometric Determination of L-Tryptophan in the Enzymatic Resolution of DL-N-Acetyl-Tryptophan

A novel spectrophotometric method for the determination of tryptophan (Trp) has been proposed. The sensitive and simple method was based upon the finding that NaNO2 and Trp formed a diazotized product in nitric acid medium, and that a bright magenta color developed for the product on coupling to N-(1-naphthyl) ethylenediamine dihydrochloride (NEDA) which was stable for at least 40 min. The absorption maximum was observed at 550 nm, and the apparent molar absorptivity was 8.48×103 L·mol−1·cm−1. A linear dependence of absorbance on Trp concentration allowed sensitive quantification of Trp over the range of 1–20 µg mL−1, and the detection limit was 0.5 µg mL−1. The method has been successfully applied to the determination of L-Trp in the DL-N-acetyltryptophan enzymatic resolution system. The relative standard deviations (n=6) and recoveries were found to be 0.97–2.21% and 97.5–101.3%, respectively. The accuracy of the new method was confirmed by the results from capillary electrophoresis. Furthermore, the interference study showed that DL-N-acetyltryptophan (substrate), CoCl2 (activator), and other common amino acids did not exhibit any detectable interference with Trp determination.

A Novel method for spectrophotometric determination of triglycerides

AbstractA new method for the spectrophotometric determination of triglycerides at microgram levels has been developed. The method relies on the quantitative degradation ofO‐acyl lipids with hydrazine and the subsequent conversion of the fatty acid hydrazides to the correspondingN′‐isopropylidenealkanohydrazides by reaction with acetone. Results are presented for triolein and some oils of plant origin.