Spectrophotometer Determination of Nitrite Using Salbutamol sulphate as a Reagent

Abstract

A simple spectrophotometric method for the trace determination of nitrite (NO^? ₂) is described. Nitrite is reacted with Salbutamal sulphate in acidic medium which gives a yellow colour in alkaline medium (?pH 7) and can be determined in the presence of several cations and anions. Beer's law is obeyed in the range of 1.8 to 27.6 ppm of nitrite with the molar absorptivity 1.8 × 10³ 1 × mole^?1 × cm^?1 at 4l0 nm. The proposed method can also be utilized for the determination of nitrate (NO^? ₃) after its reduction to nitrite. The method has been applied for the determination of various samples containing traces of nitrite.     

Sensitive Spectrophotometric Determination of Copper(II) in the Presence of Manganese

Abstract

This paper recommends a simple and convenient procedure for the determination of copper(II) in the presence of large amounts of manganese. An aqueous solution of hydroxylamine hydrochloride and diluted sulphuric acid was used for dissolution and reduction of MnO₂. The copper(II) was complexed with an ethanolic 0.05% PAN solution in the pH range of 2 - 3 in aqueous medium. The absorbances of copper-PAN complexes are measured at 550 nm where molar absorptivity is 2.10 L.mol^?1.cm^?1.

The complex obeys Beer's Law from 0.1 to 4 ppm. of copper. Manganese(II) up to 1000 ppm. doesn't interfere. The method is sensitive and reproducible.

It has been applied to the analysis of samples containing 0.01 to 5% of copper on manganese dioxide catalysts.     

Spectrofluorimetric Determination of Antimony

Abstract

A spectrofluorimetric procedure for the determination of micromolar concentrations of antimony(III) was devised based on its reduction of cerium(IV) to produce fluorescent cerium(III). The method was optimized and the reaction was fast enough in hydrochloric acid media without the need for iodide or osmium(VIII) as catalysts. Linear calibration graphs were obtained in the range 1-10 10^?6M. The standard deviation for determining 5 × 10^?6M antimony(III)(10 times) was 1.43 × 10^?7M and the relative error was -3.4 %. The method was applied to the determination of antimony(III) in its mixture with antimony(V), total antimony was later determined after reduction with mercury metal in deoxygenated solutions. The affect several reducing agents on the determination of antimony-was also examined.     

The Determination of Manganese by Means of Tetrazolium Violet

Abstract

The optimum conditions for extraction of manganese (VII) as an ion-association complex with Tetrazolium Violet (TV) has been determined. The ratio MnO₄ ^?: TV⁺ is 1:1. Beer's law is obeyed in the range of 0.05 - 0.6 μg ml^?1 manganese (VII). The molar absorptivity of the ion-pair is (6.67 ± 0.05) × 10⁴ L mol^?1cm^?1, extraction constant K_ex = 3.1 × 10⁴, distribution constant K_D = 56.5 and association constant β = 5.59 × 10². A sensitive and selective method for determination of microquantities of manganese (VII) in soils has been developed.     

Simultaneous Determination of Valsartan and Hydrochlorothiazide in Tablets by High-Performance Liquid Chromatography

ABSTRACT

A method for the simultaneous determination of valsartan and hydrochlorothiazide in tablets is described. The procedure, based on the use of reversed-phase high-performance liquid chromatography, is linear in the concentration range 5.0-10.0 μg ml^?1 for valsartan and 0.5-2.0 μg ml^?1 for hydrochlorothiazide, is simple and rapid and allows accurate and precise results. The limit of detection was 1.0 μg ml^?1 for valsartan and 0.05 μg ml^?1 for hydrochlorothiazide.     

Indirect Spectrophotometric Determination of Vanadium(IV) by Flow Injection Analysis Based on the Redox Reaction with Copper(II) in the Presence of Neocuproine

Abstract

An indirect photometric method with a continuous-flow analysis is presented for the determination of trace amounts of vanadium(IV). It is based on the redox reaction of copper(II) with vanadium(1V) in the presence of neocuproine. In the presence of neocuproine, copper(I1) is reduced easily by vanadium(I V) to a copper(1)-neocuproine complex, which shows a n absorption maximum at 454 nm. By measuring t h e absorbance of the complex at this wavelength, vanadium(1V) in t h e range 2×10^?6 - 8 × mol dm^?5 mol dm^?3 can be determined at a rate of 120 samples h^?1. The fractional determination of vanadium(1V) and iron(I1) is also studied.     

Ternary Complex Nickel(II)/3-(4′,5′-Dimethyl-2′-Thiazolylazo)-2,6-Dihydroxybenzoic Acid/Cyanide. Spectrophotometric Determination of Nickel

Abstract

A spectrophotometric method for nickel has been developed based on the formation of a ternary complex in the system Ni(II)/3-(4′,5′-dimethyl-2′-thiazolylazo)-2,6-dihydroxybenzoic acid/cyanide at pH 9.2 (borate buffer), which allows the determination of 0.05–0.47ppm of nickel (ε = 3.53×10⁴ 1.mol^?1. cm^?1) at 538nm. Interferences have been studied and the method applied to the determination of nickel in low alloy steels.     

Resolution and Trace Determination of Selected Oxyanions in Binary and Ternary Mixtures by Differential Pulse Polarography

Abstract

Resolution and trace determination of selected oxyanions in binary and ternary mixtures were studied by differential pulse polarography (DPP) at the dropping mercury electrode. The applicability of DPP for the simultaneous determination of the investigated oxyanions (TeO^{2- 4}, VO^? ₃, IO^? ₃, IO^? ₄, and BrO^? ₃) in the binary and ternary mixtures was also examined with regard to the dependence of the DP current on various parameters such as pH, pulse amplitude, scan rate and drop time. Statistical analysis is included on t h e observed concentrations for each of the oxyanions in the mixture and compared with that obtained by the calibration curves. Limits of detection and quantitat - ion have been calculated for the DPP determination of binary and ternary mixtures of these lected oxyanions.     

Spectrophotometric Determination of Copper(II) as the Azide Complexes,in the Presence of Iron(III) Cations

Abstract

A method for the spectrophotometrio determination of copper(II), in the presence of iron(III) cations (excess), was stablished. The masking of iron is made with sodium fluoride salt in 50 % (v/v) water/acetone medium. In the recommended conditions, absorbances for cupric complexes are measured at 435 nm where molar absorptivity is 6.00 × 10³ 1 mol^?1 cm^?1.

The stable ayetern obeys Beer's law and is suitable for the copper determination in concentration range from 2.0 to 9.0 mg 1^?l. The iron(III) ion interference (until ca. 600 mg 1^?l) can be completely suppressed. The influence of diverse ions and several others factore were studied.

The results show that copper(II) can be accurately determined by azide apectrophotometric method, if the samples were suitablely treated by the recommended procedure.     

A Rapid,Simple, and Sensitive Spectrophotometric Determination of Traces of Vanadium (V) in Foodstuffs,Alloy Steels,and Pharmaceutical,Water, Soil,and Urine Samples

Abstract

A rapid, simple, sensitive, and selective spectrophotometric method is investigated for the determination of traces of vanadium (V) in foodstuffs, alloy steels, and pharmaceutical, water, soil, and urine samples in aqueous DMF medium. The metal ion forms a green colored complex with 2-hydroxy-3-methoxy benzaldehyde thiosemicarbazone (HMBATSC) in an acidic buffer of pH 6.0. The green colored solution, having an absorbance maximum at 380 nm, is stable for more than 72 hours. Beer's law is obeyed in the range of 0.051–2.037 µg ml^?1. The molar absorptivity and Sandell's sensitivity of the method are found as 2.75 × 10⁴ l mol^?1 cm^?1 and 0.0018 µg cm^?2, respectively. The green colored complex has 1:2 [V(V)-HMBATSC] stoichiometry. The stability constant of the complex is determined as 3.267 × 10¹¹ by Job's method. The optimum reaction conditions and other analytical parameters are studied. A sensitive and selective second-order derivative spectrophotometry has also been proposed for the determination of V(V). The interference of various cations and anions are studied. The present method is successfully applied to the determination of vanadium (V) in foodstuffs, alloy steels, and pharmaceutical, water, soil, and urine samples.     

Extraction,Separation and Spectrophotometric Determination of Bismuth(III) Using 1(4′-Bromophenyl) 4,4,6-Trimethyl (1H,4H)-Pyrimidine-2-Thiol

Abstract

The operating conditions for the spectrophotometric determination of bismuth(III) with 1-(4′-bromophenyl)-4,4,6-trimethyl-(1H,4H)-pyrimidine-2-thiol (4′bromo PTPT) as a ligand by a liquid-liquid extraction technique are presented. In acidic conditions bismuth(III) forms a yellow complex with the ligand which can be extracted in chloroform with an absorption maxima at 410 nm. The molar absorptivity is 1.5×10⁴ l mole^?1 cm^?1 and Sandell's sensitivity is 14.3 ng cm^?2. The difference in the absorbance between the chloroform blank and bismuth(III) sample increases linearly in the concentration range 2-14 ppm at 0.3 M hydrochloric acid. The proposed method is extremely sensitive, rapid, reproducible and has been satisfactorily applied to the determination of trace amounts of bismuth(III) in synthetic mixtures, alloys and pharmaceutical formulations and also provides binary separation of bismuth(III) from selenium, tellurium, lead, antimony, copper and gold. The overall process of extraction and determination takes about 15 to 20 min.     

Electrochemical Reduction of Metronidazole and Its Determination in Pharmaceutical Dosage Forms by D.C. Polarography

Abstract

A simple d.c. polarographic method has been developed for the determination of metronidazole in dosages forms. In Robinson - Britton buffer (pH 4.38) and in presence of 1.60 × 10^?3 % Triton X-100, the drug produced a well defined 4-electron polarographic wave followed by another wave of about half the height of the first wave. The current is proportional to the concentration and permits the drug to be determined by d.c. polarography in the concentration range 5.0 × 10^?5 -7.0 × 10^?4 M. Results obtained by the proposed method are in excellent agreement with that provided by the USP-XX method. A rapid, sensitive and accurate polarographic method for the determination of metronidazole in the tablets which are produced locally is proposed.     

Some Arylidene-2-Pyridylhydrazone Derivatives as Reagents for Spectrophotometric Determination of Palladium (II)

Abstract

A method for spectrophotometric determination of palladium by complexation with Arylidene-2-pyridylhydrazone derivatives in 50% (V/V) ethanolic solution are described-Pd(II) forms a 1:1 complex with the reagents. Beer's law is obeyed over the range 0.2-6.5 μg ml^?1. The effect of pH, effect of excess reagent, stability of complexes as well as the tolerance amount of many metal ions have been reported. The method is applied, with fair accuracy, to the determination of pd(II) in synthetic solutions.     

Determination of Trace Amounts of Copper by Adsorptive Stripping Voltammetry

ABSTRACT

A technique is presented for the determination of trace amounts of copper(II) by adsorptive cathodic stripping voltammetry. The procedure is based on adsorptive accumulation of copper(II)-Alizarin Red S (ARS) complex on a hanging mercury drop electrode, followed by a stripping voltammetric measurement of the reduction current of the adsorbed complex at -0.16 V (vs. Ag/AgCl). The height of the copper -ARS reduction peak is linearly dependent upon the copper(II) concentration between 0.2-15 and 15-500 ng.ml^?1. The detection limit of the technique is 0.05 ng.ml^?1 copper(II) for a collection time of 1 minute. The method is free from most interferences. The procedure has been successfully applied to the determination of trace amounts of copper(II) in some analytical grade salts.     

A Polarographic Study on Dipyridamole and its Determination in Commercial Tablets

Abstract

The direct current polarographic behaviour of dipyridamole, a coronary vasodilator, in the supporting electrolyte consisting of 0.2 M KCl, 20 % (v/v) ethanol and buffer solutions is described in this study. Morphologically well-defined DC polarographic curves have appeared within the pH range of 7–8 and the optimum polarographic conditions found were, a potential rate of 4 m V.s^?1, drop time of 1 s and a pressure of 1000 dyne.cm^?2. The factor effecting the polarographic current was diffusion-controlled and the reduction reaction was highly reversible. The effect of concentration on the limiting current was examined using DC, SCAP, SIAP and DP polarographic modes at pH 7.8 and optimum conditions. Linear calibration equations with good correlations were obtained for all techniques. DP polarography was used among the modes for the determination of dipyridamole in the tablets. The results obtained were compared with the results of the UV-spectrophotometric method. Using the Mann-Whitney U-test, it was concluded that there is an insignificant variance between the two methods. The relative standard deviations are 75±1% and 75.3±0.7% for DP polarographic and UV-spectrophotometric methods, respectively. The determination method proposed in this study seems to be accurate, rapid and practical. Therefore, it may be suitable for the content uniformity test (USP XXI).     

Indirect Determination of Bromhexine by Atomic Absorption Spectrophotometry

Abstract

A new procedure for determination of Bromohexine is described. The method consists of extracting an ion pair between the Bromhexine and the inorganic complex Co(SCN)² ₄ and measuring Co in the organic phase by AAS at 240. 7 nm. The optimal experimental conditions: pH, concentration of Co(SCN)² ₄, shaking time, phase ratio, number of extractions and the linear range of calibration are studied.

The organic phase used is 1,2-dichloroethane. The standard deviation of the method is 10^?3. The interference of foreign substances which accompany the Bromhexine in pharmaceutical preparations is studied, and the method is applied to their quantitative determination in medicines.     

Cyclohexane-1, 3-Dione bis (4-Methylthiosemicarbazone) as a Spectrophotometric Reagent for the Determination of Zn (II)

Abstract

The spectrophotometric study of reddish cyclohexane-1, 3-dione bis (4-methylthiosemicarbazone)-Zn(II) was made in dimethylformamide-water solution (λ_max= 475 nm, ∑ = 3.3×10⁴ 1.mole^?1. cm^?1. Sandell sensitivity = 2×10^?2 μg Zn(II).cm^?2, stoichiometry 1:1, and apparent stability constant 6.1×10⁴). A new method for the spectrophotometric determination of Zn(II) is proposed for concentrations between 0.1 and 2.5 ppm. The relative error (95% confidence level) is 0.7% for 1.0 pprn of Zn(II).

The extraction with ethylacetate of the reddish complex was also studied spectrophotometrically (λ_max = 493 nm, ∑ in organic phase = 4.8×10⁴ 1.mole^?1.cm. Sandell sensitivity = 3.4×10^?4 μg Zn(II).cm^?2, stoichiometry 1:1, apparent extraction constant 1.4×10⁴). A new method for the extraction-spectrophotometric determination of Zn(II) is proposed for concentrations, in aqueous phase, between 0.02 and 0.30 ppm. The relative error (95% confidence level) is 1.0% for 0.15 pprn of Zn(II).     

Determination Of SE(IV) in the Presence of SE(VI) at NG ML− Concentration Levels by a Kinetic Spectrophotometric Method

ABSTRACT

The catalytic effect of Se(IV) on the reduction reaction of thionine(TN) by sulfide ion is used for determination of trace amounts of selenium(IV) ion by a kinetic-spectrophotometric method. This new method is simple and highly sensitive. The reaction was monitored spectrophotometrically by measuring the decrease in absorbance of the reaction mixture at 598 nm. The fixed time method was used for the first 45s from initiation of the reaction. Under the optimum conditions, in the concentration range of 2-90 ng ml^? of selenium(IV), a quite linear regression equation (r = 0.9984, n = 14) was obtained. The experimental detection limit of the method (S/N = 3) was 1.3 ng ml^?. The relative standard deviation of ten replicate measurements is 2.51% for a 40 ng ml^? solution of selenium. The proposed method is used to the study of selenium (IV,VI) speciation in water at ng ml^? levels. This method was extended for the determination of selenium in real samples.     

Spectrophotometic Determination Of Tin In Steels With2-(5-Nltro-2-Pyridylazo)-5-[N-n-Propyl-N-(3-Sulfopropyl)Amino]phenol

ABSTRACT

A highly sensitive azo dye, 2-(5-nitro-2-pyridylazo)-5-[N-n-propyl-N-(3-sulfopropyl)amino]phenol (Nitro-PAPS), is used as a colorimetric reagent for the determination of tin(IV) content. Nitro-PAPS reacts with tin(IV) to form a water-soluble complex in 1.0 M acetic acid. Full color development is attained within 5 minutes, and maintains constant absorbance for at least 24 hours. The apparent molar absorptivity is 7.7 x 10⁴ dm³ mol^?1 cm^?1 at a maximum wavelength of 580 ran. Beer's law is obeyed for tin(IV) in the range of 0-1.2 μg ml^?1. The proposed method is successfully applied to the determination of trace amounts of tin in steels.     

Rapid Extraction Spectrophotometric Determination of Platinum Using Anisaldehyde-4-Phenyl-3-Thiosemicarbazone as a Chromogenic Reagent

Abstract

The synthesis, spectral characteristics and analytical applications of anisaldehyde-4-phenyl-3-thiosemicarbazone (APT) are described. A simple, rapid, selective and sensitive spectrophotometric method for the determination of platinum was developed based on the colour reaction between platinum (IV) and anisaldehyde-4-phenyl-3-thio-semicarbazone (APT) in the pH range 1.7 - 3.0. The yellow coloured species has an absorption maximum at 360 nm. The complexation is complete within 1 min. A five-fold excess of the reagent is required for complete complex formation. Beer's law is obeyed over the concentration range 0.1 -20 ppm of Pt(IV). The mtilar absorptivity and Sandell's sensitivity are 1.58 × 10⁴ l. mol^?1 cm^?1 and 0.0123 ug of Pt(IV) cm^?2, respectively. The effects of pH, time concentration of reagent, order of addition of reagents and the interference from various ions were investigated. The method has been employed for the determination of platinum in synthetic mixtures whose composition correspond to some alloys.