Selective determination of tantalum in ores by extraction with N-phenylbenzohydroxamic acid in toluene

1990 ◽  
Vol 55 (7) ◽  
pp. 1686-1690 ◽  
Author(s):  
José Aznarez ◽  
Juan Carlos Vidal ◽  
Cecilia Vaquero
Keyword(s):  
Hydrochloric Acid ◽  
Acid Solution ◽  
Aqueous Phase ◽  
Spectrophotometric Determination ◽  
Absorption Maximum ◽  
Good Accuracy ◽  
Molar Absorptivity ◽  
Selective Determination ◽  
Accuracy And Precision

A method for tantalum(V) spectrophotometric determination in a non-aqueous phase is proposed. Tantalum(V) is extracted with N-phenylbenzohydroxamic acid into toluene from a 5M hydrochloric acid solution. The colour is then developed by addition of 4-(2-pyridylazo)-resorcinol (PAR) solution in N,N-dimethylformamide and pyridine to an aliquot of the extracted phase. The Ta(V)-PAR complex gives an absorption maximum at 547 nm with a molar absorptivity of 3.88 ± 0.04 . 104 l mol-1 cm-1. The method has been applied to the selective determination of tantalum in ores with good accuracy and precision.

VALIDATED RP-HPLC AND UV-SPECTROSCOPY METHODS FOR THE ESTIMATION OF DAPAGLIFLOZIN IN BULK AND IN TABLETS

INDIAN DRUGS ◽  
2017 ◽  
Vol 54 (03) ◽  
pp. 44-51
Author(s):  
B. Sabbagh ◽  
B. V. S. Lokesh ◽  
G. A. Akouwah ◽  
Keyword(s):  
Good Accuracy ◽  
Uv Spectroscopy ◽  
Linear Regression Analysis ◽  
Molar Absorptivity ◽  
Hplc Method ◽  
Rp Hplc ◽  
Accuracy And Precision ◽  
Significant Difference ◽  
Uv Visible

Two methods were developed for the determination of dapagliflozin (DAPA) in pure form and in tablets. The procedure utilized was UV-Visible Spectroscopy and RP-HPLC with PDA detector to quantify DAPA in bulk and tablets. The sensitive linear range was identified for both methods within 0.5-5.0μg/mL. The linear regression analysis was identified for both methods with correlation coefficient(r)>0.99. The LOD and LOQ values were found to be 0.05 μg/mL and 0.5 μg/mL for the method by UV-Spectroscopy. The molar absorptivity (ε) was calculated as 1.27 X 105 L.mol-1cm-1. The RP-HPLC method produced LOD and LOQ values of 1.0 ng/mL and 0.5 μg/mL. Both methods were simple, precise, reproducible to quantify the amount of unknown in bulk as well as in tablets and estimated accurately within the range of 100.0±0.5%. Statistical analysis was performed on the data obtained. There was no significant difference between the developed and reported methods with p>0.05. Both methods can be applied for routine analysis of DAPA in bulk and tablets with good accuracy and precision.

scholarly journals Utility of Certain π-Acceptors for the Spectrophotometric Determination of Hydralazine Hydrochloride

2003 ◽  
Vol 71 (3) ◽  
pp. 179-194
Author(s):  
W. El-Hawary ◽  
A. Shoukry ◽  
A. Talat
Keyword(s):  
Spectrophotometric Determination ◽  
Good Accuracy ◽  
Picric Acid ◽  
Pharmaceutical Preparations ◽  
Detection Limits ◽  
Several Variables ◽  
Accuracy And Precision ◽  
Hydralazine Hydrochloride ◽  
Ml Detection

The interaction of hydralazine hydrochloride with picric acid (I), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) (II), 2,4-dinitrobenzoic acid (III), bromanil (IV) and chloranil (V) was found to be useful for its spectrophotometric determination. The determination was carried out at 520, 510, 550, 540 and 535 nm for the reaction with (I), (II), (III), (IV) and (V), respectively. The effect of several variables on the colouring process was studied. The proposed methods have been applied successfully for the determination of hydralazine hydrochloride in pure samples and in pharmaceutical preparations with good accuracy and precision. The results were compared to those obtained by the official and pharmacopoeia1 methods. The linear ranges for obedience of Beer's law are up to 118, 54,639, 27.5 and 78.6 mg/l, Ringbom ranges are 13-100, 7.6-44.7, 77.4-445.0, 5.8-25.8 and 22.5-63.1 μg/ml, Detection limits are 4.8, 2.2, 18.4, 1.2 and 5.9 mg/l, and RSD 0.042, 0.037, 0.043, 0.013 and 0.073 for reactions of hydralazine hydrochloride with I, II, III, IV and V, respectively.

scholarly journals New Application of Chromotropic Acid for the Determination of Some Sulphonamides in their Pharmaceutical Preparations

2002 ◽  
Vol 70 (1) ◽  
pp. 49-55
Author(s):  
Abou-Attia Fekria M. ◽  
Issa Y.M. ◽  
El Reis M.A. ◽  
Aly F.A. ◽  
Abd El- MoetY M.
Keyword(s):  
Azo Dye ◽  
Good Accuracy ◽  
Pharmaceutical Preparations ◽  
Pharmaceutical Formulations ◽  
Extraction Process ◽  
Molar Absorptivity ◽  
Chromotropic Acid ◽  
Time Consumption ◽  
Accuracy And Precision

The formation of the azo-dye using chromotropic acid as a coupling agent was applied to the determination of five sulphonamides. The spectrophotometric studies as well as microanalysis of the studied sulphonamides- chromotropic acid azo dyes revealed the existence of the 1:1 coupling product. The absorbance of the formed azo dye is measured at 510 nrn, and has a large molar absorptivity (ε = 2.87 - 3.29 × 104 1 mol−1cm−1). Beer's law was obeyed over the concentration range 0.5-9.0 µg ml−1. The assay results of pharmaceutical formulations showed good accuracy and precision over the concentration range used. The proposed method avoids time-consumption, extraction process and temperature control.

scholarly journals Spectrophotometric Determination of Some Antihistaminic Drugs Using 7,7,8,8-Tetracyanoquinodimethane (TCNQ)

2006 ◽  
Vol 89 (1) ◽  
pp. 46-52 ◽  
Author(s):  
Amr M Badawey ◽  
Samah S Abbas ◽  
Hayam M Loutfy
Keyword(s):  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Good Accuracy ◽  
Pharmaceutical Formulations ◽  
European Pharmacopoeia ◽  
Accuracy And Precision ◽  
Antihistaminic Drugs ◽  
Assay Conditions ◽  
Sensitive Spectrophotometric Method

Abstract A simple and sensitive spectrophotometric method is suggested for analysis of 3 antihistaminic drugs, acrivastine (I), mequitazine (II), and dimethindene maleate (III). The method is based on reaction of the drugs with 7,7,8,8-tetracyanoquinodimethane (TCNQ) in acetonitrile to form highly stable colored products that are measured at 750, 766, and 844 nm for I and II, and 480 and 618 nm for III. Beer's law is obeyed in the ranges of 560 g/mL for I, 550 g/mL for II, and 1070 g/mL for III. The optimum assay conditions and their applicability to the determination of the cited drugs in pharmaceutical formulations are described. The method is statistically analyzed as compared with the European Pharmacopoeia (2001) method for the analysis of dimethindene maleate and reference methods for acrivastine and mequitazine drugs revealing good accuracy and precision.

scholarly journals Use of Π-Acceptors for Spectrophotometric Determination of Dicyclomine Hydrochloride

2003 ◽  
Vol 86 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Lories I Bebawy ◽  
Yosry M Issa ◽  
Kamal M Abdel Moneim
Keyword(s):  
Spectrophotometric Determination ◽  
Good Accuracy ◽  
Experimental Conditions ◽  
Chloranilic Acid ◽  
Colored Complex ◽  
Complex Species ◽  
Spectrophotometric Methods ◽  
Accuracy And Precision ◽  
Colored Complexes

Abstract Simple, rapid, accurate, and sensitive spectrophotometric methods are described for the determination of dicyclomine hydrochloride. The methods are based on the reaction of this drug as an n-electron donor with 2,3-dichloro-5,6-dicyano-p-benzoqunione (DDQ), p-chloranilic acid (p-CA), and chloranil (CL) as Π-acceptors to give highly colored complex species. The colored products are measured spectrophotometrically at 456, 530, and 650 nm for DDQ, p-CA, and CL, respectively. Optimization of the different experimental conditions were studied. Beer's law was obeyed in concentration ranges of 20–100, 50–250, and 80–600 μg/mL for DDQ, p-CA, and CL, respectively. Colored complexes are produced in organic solvents and are stable for at least 1 h. The methods were applied to Spasmorest™ antispasmotic tablets and ampoules with good accuracy and precision.

scholarly journals A Sensitive Spectrophotometric Estimation of Nimodipine in Tablets and Injection Using Phloroglucinol

2013 ◽  
Vol 2013 ◽  
pp. 1-7
Author(s):  
Hemavathi N. Deepakumari ◽  
Hosakere D. Revanasiddappa
Keyword(s):  
Azo Dye ◽  
Absorption Maximum ◽  
Reference Method ◽  
Molar Absorptivity ◽  
Ratio Test ◽  
Reaction Sequence ◽  
Accuracy And Precision ◽  
Relative Standard ◽  
Bulk Drug

A rapid, simple, and sensitive spectrophotometric method has been described for the determination of nimodipine in bulk drug, tablets, and injection. The proposed method is based on the diazotization of reduced nimodipine with nitrous acid followed by coupling with phloroglucinol to form colored azo dye and showing absorption maximum () at 410 nm. The formed colored azo dye is stable for about more than 2 h. The method obeyed Beer’s law over the concentration range of 0–25 μg/mL and the corresponding molar absorptivity value is  L/moL/cm. The Sandell sensitivity values limits of detection (LOD) and quantification (LOQ) values have also been reported for the developed method. The accuracy and precision of the method was evaluated on intra- and interday basis; the relative error (%RE) and the relative standard deviation (RSD) were <2.0%. All variables have been optimized and the presented reaction sequence was applied to the analysis of nimodipine in bulk drug, tablets, and injections. The performance of this method was evaluated in terms of Student’s -test and variance ratio -test to find out the significance of proposed method over the reference method.

scholarly journals Spectrophotometric determination of ceftazidime in pharmaceuticals using resorcinol and 2-methylphenol

2021 ◽  
pp. 35-44
Author(s):  
O. Kostiv ◽  
◽  
O. Korkuna
Keyword(s):  
Hydrochloric Acid ◽  
Alkaline Medium ◽  
Spectrophotometric Determination ◽  
Molar Absorptivity ◽  
Azo Compounds ◽  
Azo Coupling ◽  
Spectrophotometric Methods ◽  
Maximum Absorbance ◽  
Stoichiometric Ratios

We developed two fast, simple and sensitive spectrophotometric methods for the determination of ceftazidime in drugs by using phenolic reagents resorcinol and 2-methylphenol. The methods are based on a previous antibiotic diazotization in the medium of hydrochloric acid (CHCl=12 M) and its following azo coupling with reagents in an alkaline medium with the formation of effective analytical forms that allow determining ceftazidime and have maximum absorbance at 519 nm and 516 nm for resorcinol and 2- methylphenol, respectively. The azo coupling products of diazotized ceftazidime exhibit effective molar absorptivity in the range of (6.31–6.84)103 M–1 cm–1. Stoichiometric ratios of the azo compounds components were established using continuous variations methods and they were the same in both cases (1:1). The developed methods allow determining from 2.75 to 185.5 g mL–1 of ceftazidime with resorcinol (LOQ=2.54 g mL–1) and 0.32191.3 g mL–1 of ceftazidime with 2-methylphenol (LOQ=0.28 g mL–1). The developed methods have been successfully tested in the analyses of one-component preparations (powders for injection solutions).

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