scholarly journals A Rapid and Direct Sensitive Spectrophotometric Method for the Determination of Molybdenum(VI) using Gallacetophenone Phenylhydrazone with Application to Alloy Steel Samples

2011 ◽  
Vol 8 (3) ◽  
pp. 1362-1370 ◽  
Author(s):  
D. Venkataramana Reddy ◽  
P. V. Chalapathi ◽  
A. Varada Reddy

A rapid, sensitive and fairly selective spectrophotometric method has been developed for the determination of molybdenum(VI) using gallacetophenone phenylhydrazone (GPPH) as an analytical reagent. The GPPH forms an orange red species of molybdenum(VI) at a pH range of 3.0-4.0 and the complex is soluble in 20% ethanol. The Mo(VI)-GPPH complex shows maximum absorbance at 375 nm with molar absorptivity and Sandellʼs sensitivity being 1.539x104L/mol cm and 1.5x10-3μg cm-2respectively. The system obeys Beerʼs law in the range of 1.0-6.0 μg/mL. The repeatability of the method was checked by finding the relative standard deviation. The composition of the Mo(VI)-GPPH complex is established as 1:2 by slope analysis method. The instability constant of the complex calculated from Edmond and Birnbaumʼs method is 6.785x10-8at room temperature. The interfering effect of various cations and anions has also been studied. The method has been applied for the determination of Mo(VI) in alloy steel samples.

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Rameshwar Dass ◽  
Jitander K. Kapoor ◽  
Sunita Gambhir

An extractive spectrophotometric method has been developed for microdetermination of molybdenum. At room temperature Mo(VI) was reduced to Mo(V) in 2 M H2SO4using ascorbic acid as a reductant. The Mo(V) formed a yellow-coloured (1 : 2) complex with 6-chloro-3-hydroxy-2-(3′-hydroxyphenyl)-4-oxo-4H-1-benzopyran (CHHB). The complex was quantitatively extracted into toluene and absorbed maximum atλmax404 nm. Beer’s law was obeyed over the concentration range of 2.31 μg Mo ml−1with a molar absorptivity and Sandell's sensitivity of5.62×104 L mol−1 cm−1and 0.0016 μg Mo cm−2, respectively. The relative standard deviation was 0.0025 (in absorbance units) for 10 replicate determinations of 1 μg Mo ml−1. The method was free from the interference of large number of analytically important elements. Molybdenum has been determined satisfactorily in different technical, synthetic, and environmental samples with improved accuracy and precision.


Author(s):  
Mrs. Ritika Makhijani

Rh (III) was determined by simple, sensitive & feasible spectrophotometric method by using analytical reagent N - (o - methoxy benzaldehyde) 2-aminophenol (NOMBAP) . Elemental analysis was used to characterize synthesized Schiff’s base NOMBAP. Rh (III) is extracted quantitatively (99.66%) by NOMBAP into carbon tetra chloride from an aqueous solution having pH range 5.1 – 5.9. An intense peak at 480 nm (λ max) was observed in the extract of n-amyl alcohol. Beer’s law is obeyed over the concentration range 1.0 – 10.0 µg/ml for Rh (III). The molar absorptivity and Sandel’s sensitivity for Rh - NOMBAP system is 8248.23 dm3 mole-1cm-1and 0.08332 μgcm-2 respectively. Mole Ratio & Job’s Continuous Variation and Method show that the extracted species has composition 1:3 (Rh-NOMBAP). Study has been done for interference by various ions. For determination of Rh (III) in alloy the proposed method has been used.


2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
Ibrahim A. Darwish ◽  
Heba H. Abdine ◽  
Sawsan M. Amer ◽  
Lama I. Al-Rayes

Simple and rapid spectrophotometric method has been developed and validated for the determination of paroxetine (PRX) in tablets. The proposed method was based on nucleophilic substitution reaction of PRX with 1,2-naphthoquinone-4-sulphonate (NQS) in an alkaline medium to form an orange-colored product of maximum absorption peak () at 488 nm. The stoichiometry and kinetics of the reaction were studied, and the reaction mechanism was postulated. Under the optimized reaction conditions, Beer's law correlating the absorbance (A) with PRX concentration (C) was obeyed in the range of 1–8 g . The regression equation for the calibration data was: A = 0.0031 + 0.1609 C, with good correlation coefficients (0.9992). The molar absorptivity () was L  1 . The limits of detection and quantitation were 0.3 and 0.8 g , respectively. The precision of the method was satisfactory; the values of relative standard deviations did not exceed 2%. The proposed method was successfully applied to the determination of PRX in its pharmaceutical tablets with good accuracy and precisions; the label claim percentage was %. The results obtained by the proposed method were comparable with those obtained by the official method.


2008 ◽  
Vol 27 (2) ◽  
pp. 149 ◽  
Author(s):  
Ivana Savić ◽  
Goran Nikolić ◽  
Vladimir Banković

Simple, accurate and reproducible UV-spectrophotometric method was developed and validated for the estimation of phenylephrine hydrochloride in pharmaceutical nasal drops formulations. Phenylephrine hydrochloride was estimated at 291 nm in 1 mol⋅dm-3 sodium hydroxide (pH 13.5). Beer’s law was obeyed in the concentration range of 10–100 μg⋅cm−3 (r2 = 0.9990) in the sodium hydroxide medium. The apparent molar absorptivity was found to be 1.63×103 dm3⋅mol−1⋅cm−1. The method was tested and validated for various parameters according to the ICH (International Conference on Harmonization) guidelines. The detection and quantitation limits were found to be 0.892 and 2.969 μg⋅cm−3, respectively. The proposed method was successfully applied for the determination of phenylephrine hydrochloride in pharmaceutical nasal drops formulations. The results demonstrated that the procedure is accurate, precise and reproducible (relative standard deviation < 1 %), while being simple, cheap and less time consuming, and hence can be suitably applied for the estimation of phenylephrine hydrochloride in different dosage forms.


1997 ◽  
Vol 80 (2) ◽  
pp. 388-391 ◽  
Author(s):  
Ritu Kesari ◽  
Manish Rai ◽  
Vinay Kumar Gupta

Abstract A sensitive spectrophotometric method was developed for determination of paraquat, a widely used herbicide. Paraquat was reduced with glucose in an alkaline medium, and the blue radical ion obtained was measured at 600 nm. Beer’s law was obeyed at 0.1–1.2 ppm paraquat. The molar absorptivity was 1.26 × 105 L mol-1 cm-1. The standard deviation and relative standard deviation were ± 0.007 and 2.0%, respectively, for 5 μg paraquat/10 mL analyzed over 7 days. The method was free from interference by other commonly used pesticides and metal ions. The method may be used to the determine paraquat in plants, fruits, grains, water, blood, and urine.


2011 ◽  
Vol 8 (4) ◽  
pp. 1528-1535 ◽  
Author(s):  
F. Nekouei ◽  
Sh. Nekouei

A simple, fast, reproducible and sensitive method for the flotation- spectrophotometric determination of Al3+is reported. The apparent molar absorptivity (ε) of the ion associate was determined to be 8.35×104L mol-1cm-1. The calibration curve was linear in the concentration range of 1.0-50 ng mL-1of Al3+with a correlation coefficient of 0.9997. The limit of detection (LOD) was 0.621 ng mL. The relative standard deviation (RSD) at 10 and 30 ng mL-1of aluminium were 1.580 and 2.410% (n=7) respectively. The method was applied for measuring the amount of aluminium in water samples.


2018 ◽  
pp. 49-55
Author(s):  
Y. M. Zhuk ◽  
S. O. Vasyuk

In this investigation a visible spectrophotometric method for the determination of sotalol based on the absorbance of colored product of the reaction between sotalol hydrochloride and bromcresol purple in acetone medium at 399 nm measurement was developed. The optimal conditions for the quantitative determination of sotalol hydrochloride in the content of pharmaceutical drugs were established. The stoichiometric relationship coefficients between sotalol hydrochloride and bromcresol purple were determined. The validation of the worked out procedure on such validated characteristics as linearity, precision, accuracy and robustness was carried out. The aim. To develop a highly sensitive, easy to use, cost-effective and valid method for quantitative determination of sotalol hydrochloride in dosage forms. The analysis method. Visible spectrophotometry. The analytical parameters such as molar absorptivity, Beer’s law limits and Sandell’s sensitivity values were calculated. The developed methods give the result with repeatability sufficient for dependable determination the investigated substance in pharmaceutical formulations. Accuracy established by analyte addition technique. Determined factors that influence on the absorbance value: reagent quantity and timing stability. Sample solutions stable during 30 min. Addition to sample solution ± 10% bromcresol purple solution is not change the absorbance value. Established that reaction between sotalol hydrochloride and bromcresol purple proceeds in acetone medium at room temperature. Molar absorption coefficient is 2,62∙103.


2019 ◽  
Vol 53 (4) ◽  
Author(s):  
Padmarajaiah Nagaraja ◽  
Naef Ghllab Saeed Al-Tayar ◽  
Anantharaman Shivakumar ◽  
Ashwinee Kumar Shresta ◽  
Avinash K. Gowda

A very simple, sensitive and fairly selective direct spectrophotometric method is presented for the rapid determination of thallium(III) at trace level. The method is based on the oxidation of 2-hydrazono-3-methyl-2,3-dihydrobenzo[d]thiazole hydrochloride (MBTH) by thallium(III) in phosphoric acid medium to form a diazoniumcation, which couples immediately with 10,11-dihydro-5Hdibenzo[b,f]azepine (IDB) at room temperature giving a blue colored species having a maximum absorption at 660 nm. The reaction conditions and other important analytical parameters were optimized.The calibration curve was found to be linear over the range of 0.1-4 μg/mL with molar absorptivity of 4.5 × 104 L mol- cm-1 and Sandell’s sensitivity of 0.00454 μg cm-2. The relative standard deviation and limit of detection have been found to be 0.58% and 0.0147 μg/mL respectively. Almost all common anions and cations are found notto interfering in matrix level of the analytical process. The method has been successfully applied for the determination of thallium(III) in synthetic standard mixtures, water and human urine samples. The performance of proposed method was evaluated in terms of student’s t-test and variance ratio F-test, to find out the significance of proposed method over the reported methods.    


1993 ◽  
Vol 76 (3) ◽  
pp. 601-603 ◽  
Author(s):  
A A Al-Warthan ◽  
S S Al-Showiman ◽  
S A Al-Tamrah ◽  
A A BaOsman

Abstract The formation of a red complex between boron and the quinalizarin reagent was investigated and used as the basis for a simple and sensitive spectrophotometric method for boron in date cultivars. At 620 nm, the absorbance was linear (r= 0.999) over the 0.25-2.5 μg/mL concentration range. The molar absorptivity was found to be 2.23 x 103mol-1cm-1 and the relative standard deviation for 10 replicates (1.0 μg/mL) was 0.97%.


2008 ◽  
Vol 59 (1) ◽  
pp. 3-7
Author(s):  
Aurora Reiss ◽  
Mihaela Mureseanu ◽  
Nicolae Muresan

5-Hydroxy-6-mercapto-benzo [a] phenazine (HMBP) is proposed as a sensitive and selective analytical reagent for the extractive spectrophotometric determination of copper (II). Copper reacts with HMBP to give a dark red complex which is soluble in chloroform. The composition of the CuII � HMBP complex is established as 1:2 by Job�s continuous variation method and molar ratio method. The instability constant of the complex calculated by Job�s relation for nonisomolar series is 4.65 . 10-9, at room temperature. The CuII-HMBP complex in chlorophorm shows a maximum absorbance at 495 nm, with molar absorptivity and Sandell�s sensitivity values of 7.39 . 103dm3 mol-1 cm-1 and 0.012 mg cm-2, respectively. Beer�s law is obeyed in the concentration range 0.67 - 26.90 mg mL-1 and the detection limit is 0.59 mg mL-1. A repetition of the method is checked by finding the relative standard deviation (RSD) at 1.00 mg mL-1 CuII of 0.6%. The method is successfully employed for the determination of copper (II) in environmental samples. The reliability of the method is assured by analysing the standard alloys and by inter-comparison of experimental values, using an atomic absorption spectrometer.


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