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A continuous monitoring system for cyanide with a galvanic hydrogen cyanide sensor and an aeration pump for purging was developed. Hydrogen cyanide evolved from cyanide solution using a purging pump was measured with the hydrogen cyanide sensor. The system showed good performance in terms of stability and selectivity. A linear calibration curve was obtained in the concentrating range from 0 to 15...
An ion-chromatography procedure for the simultaneous determination of paracetamol and salicylic acid without suppression using UV detection is proposed. The method is applied to the determination of paracetamol in pharmaceuticals and also permits the quantitation of the total acetylsalicylic acid as salicylic acid.
This paper suggests a non-conventional approach towards the correct determination of stability constants K ijk of mixed complexes from the results of potentiometric titrations. The method is based on inaccurate (in principle) results of titrations made in isomolar titrand–titrant systems. The data thus obtained are validated on the basis of relationships between logK ijk and relative...
The cadmium (II) or lead (II) complex formation with two poly(acrylic acids) of high molecular weight (Mw=2.5×10 5 and 3×10 6 ) was investigated in dilute aqueous solution (NaNO 3 0.1 mol l −1 ; 25°C). Potentiometric titrations were carried out to determine the stability constants of the MA and MA 2 complex species formed. Bjerrum’s method, modified by Gregor...
The slurry technique was applied to the determination of Ni, Cr and Co in wheat flour by electrothermal atomic absorption spectrometry (ETAAS). The influence of the graphite furnace temperature programme was optimized. Optimum sensitivity was obtained by using a mixture of 15% HNO 3 –10% H 2 O 2 as suspended medium for a 3% w/v slurry in the determination of Ni; lower concentrations...
In the present paper, a solid phase extraction system for separation and preconcentration of nickel (ng g −1 ) in saline matrices is proposed. It is based on the adsorption of nickel(II) ions onto an Amberlite XAD-2 resin loaded with 1-(2-pyridylazo)-2-naphthol (PAN) reagent. Parameters such as the pH effect on the nickel extraction, the effect of flow rate and sample volume on the extraction,...
A new resin incorporating benzimidazolylazo group into a matrix of polystyrene divinylbenzene has been prepared. The exchange capacity of the resin for the ions mercury(II), silver(I) and palladium(II) as a function of pH has been determined. The resin exhibits no affinity for alkali or alkaline earth metals. It is highly selective for Hg(II), Ag(I) and Pd(II). In column operation, it has been observed...
An aqueous two-phase system of dodecyl triethylammonium bromide (C 12 NE, cationic surfactant) and sodium dodecyl sulfate (SDS, anionic surfactant) mixture is proposed for the extraction of some dyes and porphyrin compounds. Transparent two phase-systems are formed when the surfactant concentrations and C 12 NE/SDS ratios are in certain regions. In this study, the aqueous two phase-systems...
Spectrophotometric determinations of palladium(II) and tartaric acid were respectively investigated by using the color reactions between 2(5-nitro-2-pyridylazo)-5-(N-propyl-N-3-sulfopropylamino)phenol(5-NO 2 .PAPS) and palladium(II) in strong acidic media, and between 5-NO 2 .PAPS, niobium(V) tartaric acid in weak acidic media. The calibration graphs were linear in the range of 0–25...
A kind of strong anion exchanger (SAX) was prepared with chloromethylstyrene encapsulated silica. This strong anion silica column has superior ability for the separation of anions, organic acids and also the mixture of them. Using this strong anion exchanger, the sulfonic acids can be separated. With gradient elution, the separation of petroleum mono- and di- sulfonates in Yumen sample can be also...
Microwave-assisted extraction (MAE) was examined as an alternative to the traditional Soxhlet method of extracting C 60 and C 70 from fullerene soot. MAE of 0.20 g of fullerene soot with 95:5 toluene–acetonitrile yielded greater than 7.8 mg of C 60 and greater than 0.54 mg of C 70 in 4 min with no further increase in yield after 30 min of irradiation. By comparison,...
The double divisor–ratio spectra derivative and ratio spectra–zero crossing methods were applied to the analysis of an effervescent tablet containing the title compounds without using a chemical separation procedure. In the use of both methods, the calibration graphs were linear in the range of 8–28 μg ml −1 for three compounds. Comparison of the results obtained by the two methods indicates...
A novel potentiometric, enantioselective membrane electrode based on graphite paste (graphite powder and paraffin oil) has been constructed. The graphite paste is impregnated with 2-hydroxy-3-trimethylammoniopropyl-β-cyclodextrin (as chloride salt) solution, 10 −3 mol l −1 . The potentiometric, enantioselective membrane electrode can be used reliable for S-captopril assay as raw material...
Transport of Ag + as Ag(CN) 2− ions through a bulk liquid membrane is reported. The bulk liquid membrane used is a solution of Victoria blue (VB) in chloroform. The effects of pH of the source phase, cyanide concentration in the source phase, sodium hydroxide in the receiving phase, and VB concentration in the organic phase on the efficiency of the transport system were studied...
A supported liquid membrane (SLM) method for the speciation of chromium has been developed. The method is based on selective extraction and enrichment of anionic Cr(VI) and cationic Cr(III) species in two serially connected SLM units. Methyltricaprylammonium chloride (Aliquat) and di-(2-ethylhexyl) phosphoric acid (DEHPA), respectively were used as the selective extractants in the membrane liquid...
Heparin has a variety of biological activities, most of them due to heparin’s high sulfate groups. To gain insight into the mechanism of activation of the spectroscopic probe with sulfate groups of heparin in vitro, we have used a cationic dye by a spectrophotometric method. It is considered that the combination of heparin with methylene blue is due to noncovalent binding forces. Dye binding requires...
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