A Sensitive Indirect Method for the Determination of Titanium by Atomic Absorption Spectrophotometry Using an Air-Acetylene Flame

Abstract

The enhancement of the atomic absorption signal of iron in a fuel-rich air-acetylene flame by small amounts of titanium makes possible the determination of titanium at concentrations of 0.01 to l0ppm. The optimisation of working conditions for the determination of titanium by this indirect method are reported.     

Sequential Separation and Indirect Voltammetric Determination of Silicate and Phosphate

Abstract

An indirect voltammetric method for the determination of silicate at the ppm level was developed. The method is based or. the D.C. polarographic current measurement of molybdate ion formed by the decomposition of 12-molybdophosphoric and 12-molybdosilicic acids. After separation of the heteropoly acids by the liquid-liquid extraction technique, the heteropoly acids are decomposed with a basic buffer. After adjusting the solution to the proper conditions, the current measurement is made at the dropping mercury electrode.     

Indirect Determination of the Pesticide Malathion by Atomic Absorption Spectrophotometry

Abstract

A method for the indirect determination of the pesticide malathion by atomic absorption spectrophotometry (AAS) is proposed and compared with the standard spectrophotometric method.

A study of the influence of the different variables on the hydrolysis and extraction is carried out in order to obtain the best experimental conditions.

The proposed method offers clear advantages over the standard procedure because of the instability of the Cu (II) complex formed. Both methods are applied to the determination of malathion in two commercial formulations.     

Electrochemical Oxidation of Benzylic Amines into the Corresponding Imines in the Presence of Catalytic Amounts of KI

Abstract

Oxidation of various benzylic amines using an indirect electrochemical method was successfully carried out under very mild conditions to afford the corresponding imines in good yields. Our results show that, for this electrolytic system, the iodide ions play an important role as electron carriers.     

Indirect Determination of Phosphate by X-ray Fluorescence Spectrometry Using Polyurethane Foam

Abstract

An indirect X-ray fluorescence method for phosphate has been established based on the extraction of phosphomolybdate by polyurethane foam. The molybdenum, which is associated in a fixed ratio with phosphorus, is determined directly on foam, by X-ray fluorescence spectrometry.     

Spectrophotometric and Indirect Determination of Lincomycin by Atomic Absorption Spectroscopy (AAS)

Abstract

The reaction of lincomycin with cupric ions in alkaline medium was taken as a basis for the colorimetric and indirect atomic absorption spectrometric (AAS) determination of lincomycin hydrochloride.

The AAS procedure was based on the extraction of copper-lincomycin complex at pH 11, into n-butanol. The copper content in this extract was determined by AAS. The response was linear for up to 30 μg ml^?1 of lincomycin. The method is accurate, sensitive and simple.

The proposed methods were applied to pharmaceutical preparations with fine accuracy.     

An Indirect Polarograpric Method for the Determination of Periodate Oxidizable Organic Compounds

Abstract

An indirect polarographic method is described based on the alprade reaction. The formaldehyde produced is determined by its decrease of the hydroxylamine a-c polarographic wave. Sorbitol, ethanediol, mannitol, ethanolamine, serine and threonine are determined in the range 5 – 30 × 10^?6 M while 2.5 – 10 × 10^?6 M triethanolamine are determinable.     

Disopyramide-Selective Membrane Electrode∗

Abstract

A liquid membrane electrode based on disopyramide - dipicrylamine ion - pair complex, dissolved in nitrobenzene as solvent was proposed for the determination of disopyramide - an antiarrhythmic drug. The linear response covers the range from 10^?2 - 5 × 10^?6 M disopyramide solution, with a slope of 51.0 mV/decade (pH range 3.0 to 7.0). The detection limit is 4.7 × 10^?8 M. The electrode shows a good stability, reproducibility and fast response. The selectivity of the electrode is good. The strong interfering ion is thiamine (Vitamin B₁). These characteristics of the electrode made it to be used for the determination of disopyramide through direct and indirect potentiometric methods. Through indirect potentiometric method, disopyramide - as active substance can be determined with an average recovery of 99.98% and a relative standard deviation of 0.24%, and also this method can be used for its determination in pharmaceutical formulations such as capsules and ampoules with a relative standard deviation less than 1%. The electrode can be used at the dissolution tests of disopyramide capsules. The physical processes are numerically simulated by typical equations. The apparent first - order rate constants for disintegration and dissolution processes were calculated.

     

Selective Spectrophotometric Determination of Oxyphenbutazone Using a Chelate Forming Reaction

Abstract

A selective spectrophotometric method for the determination of oxyphenbutazone is described. The method is based on nitrosation reaction and simultaneous formation of copper(II) or cobalt (II) chelate of the nitrosoderivative. The formed chelates are extractable with organic solvents giving yellow solutions whose absorbance are proportional to the concentration of oxyphenbutazone. In addition, the chelate extracts, upon treatment with diethyldithiocarbomate develop an additional indirect method of high selectivity for determining oxyphenbutazone. The developed methods are highly accurate and comparable with an official method.     

INDIRECT ATOMIC ABSORPTION SPECTROMETRIC METHOD FOR THE DETERMINATION OF ARSENIC

Abstract

An indirect atomic absorption spectrometric method for arsenic has been developed on the basis of heteropoly chemistry. Molybdoarsenic acid is formed, extracted and stripped by a basic buffer solution. The resulting molybdate, which is equivalent to a specific amount of arsenic, is determined by atomic absorption spectrometry.     

Indirect Determination of Vanadium by Atomic Absorption Spectrometry

Abstract

An indirect atomic absorption spectrometric method for vanadium has been developed on the basis of heteropoly chemistry. Molybdovanadophosphoric acid is formed, extracted and stripped by a basic buffer solution. The resulting molybdate, which is equivalent to a specific amount of vanadium, is determined by atomic absorption spectrometry.     

The Determination of Low Levels of Cyanide Ion Using a Silver Responsive Ion Selective Electrode

Abstract

An analysis of the potentiometric titration curves for the silver-cyanide system indicates two possible approaches to the determination of cyanide ion at low levels. Both involve an indirect measurement of the silver ion in equilibrium with argentocyanide complex. These procedures are considerably more sensitive than the conventional method using a “silver iodide” cyanide responsive electrode.     

A New Kinetic-Fluorimetric Method for the Determination of Silver Based on Its Inhibitory Effect on the Oxidation of 2-Hydroxybenzaldehyde Thiosemicarbazone with Hydrogen Peroxide Catalyzed by Iron (III)

Abstract

An indirect kinetic determination of silver based on its inhibitory effect on the oxidation of 2-hydroxybenzaldehyde thiosemicarbazone with hydrogen peroxide catalyzed by iron (III) is described. The reaction is followed spectrofluorimetrically by measurement of the initial rate at the wavelengths of the oxidation product (λ_exc=365nm, λ_em=440nm.). The calibration curves are linear between 50-400 ng.ml^?1 of silver with a precision of ± 2.3%. The proposed method has few interferences.     

Continuous Determination of Free Cyanide by Means of Membrane Diffusion of Gaseous HCN and An Electrode Indicator Technique

Abstract

A continuous measurement system for free cyanide has been developed based on the principle of diffusion across a gas-permeable membrane to affect the separation of hydrogen cyanide from the acidified sample solution. The cyanide absorbed in the alkaline indicator solution is subsequently analyzed by an indirect technique using a silver ion-selective electrode. In the concentration range of 30 to 400 μg CN^?/L, the accuracy and precision of this method is approximately two percent. The detection limit of this system is approximately 0.5 μg CN^?/L.     

INDIRECT DETERMINATION OF MERCURY BY ATOMIC ABSORPTION SPECTROPHOTOMETRY USING ZINC HOLLOW CATHODE LAMP

Abstract

An indirect atomic absorption spectrophotometric method for mercury has been developed on the basis of solvent extraction chemistry. Mercury(II) was converted into a bromo-complex anion and extracted into 1,2-dichloroethane with the 2,2′-bipyridyl-zinc chelate cation. The resulting zinc in the extract, which was equivalent to a specific amount of mercury, was determined by atomic absorption spectrophotometry. The sensitivity for the determination of mercury could be enhanced to the level of zinc by the proposed method.     

Chemiluminescent Detection of Gatifloxacin Residue in Milk

Abstract

An indirect competitive chemiluminescent enzyme-linked immunosorbent assay (CL-ELISA) for detection of gatifloxacin residue in milk was developed in this study. Compared with conventional colorimetric ELISA using the same antibody, the developed CL immunoassay shows a significant improvement in sensitivity and detectability with an IC₅₀ of 0.4 ng mL^?1 and a detection limit of 0.001 ng mL^?1 and thus is suitable to be used as a highly sensitive screening method to detect and regulate illegal use of gatifloxacin in food and food products. The test kit was applied to detect milk samples spiked by gatifloxacin, and satisfactory results were obtained.     

Indirect Determination of Ranitidine Hydrochloride Using a Chloride Ion Selective Electrode

Abstract

A simple, rapid, and reliable potentiometric method is described for determination of ranitidine hydrochloride in pharmaceutical formulations. Experiments were performed to determine the suitability of using a chloride-ion selective electrode for the indirect estimation of ranitidine hydrochloride. The precision and accuracy of the potentiometric method were determined. We found that they not differ significantly. The advantage of the proposed method is the fact that it can be applied without filtration of the drug sample before analysis.     

Indirect Atomic Absorption Spectrometric (AAS) Determination of Atenolol

Abstract

The Cu(II)-atenolol complex was prepared, and characterized by elemental analysis and spectroscopic techniques (via. IR, electronic and EPR spectra). The spectral results obtained indicate tetrahedral geometry around the Cu(II) ion. An indirect atomic absorption spectrometric method was undertaken to estimate atenolol in pharmaceutical preparations, based on its reaction with Cu²⁺ in alkaline medium. The method is simple, rapid, accurate and sensitive.     

Indirect Microdetermination of Hydroxide Ions by Atomic Absorption Spectrophotometry

Abstract

A simple indirect atomic absorption spectrophotometric method is described for the determination of hydroxide ions. The method is based on the reduction of silver ions which takes place when hydroxide sample is treated with silver (I) solution in presence of manganese(II) ions. The unconsumed silver is determined by atomic absorption spectrophotometry. The effects of a number of factors have been studied and the method was employed for the determination of free alkali in paper samples.     

Determination of Phosphorus in Chlorosilanes) And High Purity Silica By Atomic Absorption Spectrophotometer

Abstract

Determination of traces of impurities in chloro-silanes and high purity silica are important in the preparation of semiconductor grade silicon. The author have developed an indirect method for the determination of phosphorus in these materials. Phosphorus is extracted as phosphoantimonyl molybdate complex in methyl isobutyl ketone. The concentration of phorphorus is calculated by determining the concentration of antimony by atomic absorption spectrophotometer as antimony and phosphorus are present in 1:1 molar ratio in the complex. The method is selective and enables the determination of 0.1 ppm of phosphorus.