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A series of generic nitrite assay systems based on the single step nitrosation of phenol derivatives are presented. The chemical reactivity offered by the C-nitroso compounds provides an opportunity to pursue a number of analytical strategies of which three spectroscopic (UV/Vis) and two electrochemical options (linear sweep voltammetry/differential pulse voltammetry) were evaluated. The capacity...
A highly sensitive and selective second derivative spectrophotometric method has been developed for the determination of ruthenium and iron in mixtures. The method is based on the formation of the binary complexes of iron and ruthenium with 4,7-diphenyl-1,10-phenanthroline (bathophenanthroline) in the presence of ethyleneglycol. These complexes are formed at pH 4.0–6.0 upon heating at 90°C for 60...
An interlaboratory study describing the assignment of reference values to the extractable concentrations of metals in industrial sludge using NJDEP and USEPA methods is presented. Industrial waste containing high concentrations of alkali, alkaline earth, ferrous and transition metals was dried, size-reduced and homogenized. Multiple aliquots of this material were analyzed in two different government...
Synergistic extraction of trivalent rare earths from nitrate solutions using mixtures of bis(2,4,4-trimethylpentyl)dithiophosphinic acid (Cyanex 301=HX) and trialkyl phosphine oxide (Cyanex 923=TRPO) in xylene has been investigated. The results demonstrate that these trivalent metal ions are extracted into xylene as MX 3 .3HX with Cyanex 301 alone. In the presence of Cyanex 923, La(III) and...
A new and simple method of solventless extraction of volatile organic compounds (VOCs) from air is presented. The sampling device has an adsorbing carbon coating on the interior surface of a hollow needle, and is called the inside needle capillary adsorption trap (INCAT). This paper describes a study of the reproducibility in the preparation and sampling of the INCAT device. In addition, this paper...
The cooling effluents in power stations are chlorinated to avoid excessive biofouling. However, this disinfecting treatment leads to the formation of halogenated by-products, mainly trihalomethanes, haloacetonitriles and halophenols. There is therefore a need for precise and accurate methods that allow trace level determinations of these compounds. Experimental procedures combining liquid–liquid extraction...
Ozone was tested as an alternative digestion/oxidation system to the permanganate/peroxidisulfate currently used in the cold vapor mercury method. The results indicate that the digestion of comparable size samples to the ‘Standard Method’ was complete in less than 2 min. A 0.5 ml (10 ppb) sample size was completely oxidized in less than 30 s. The batch system used produced a limit of detection (LOD)...
The use of high temperature molecular absorption spectrometry for the determination of chloride in drinking and ground water samples is described. The chloride is measured by monitoring the absorbance of vaporised aluminium chloride molecule. The effect of various components commonly present in natural waters were studied and any serious interference was found. The accuracy was assessed by comparing...
A redox reaction of cysteine with iron(III) proceeds slowly in the presence of 1,10-phenanthroline (phen). However, this reaction is accelerated in the presence of copper(II) as a catalyst, producing an iron(II)–phen complex (λ max =510 nm). A sensitive spectrophotometric flow-injection method is proposed for the determination of copper(II) based on its catalytic action on this redox reaction...
A method developed to determine organic and inorganic selenium species in human urine samples is presented in detail. After a simple sample treatment based on elimination of non-charged organic compounds, selenium species were separated by high performance liquid chromatography (HPLC) on a Spherisorb 5 ODS/AMINO column using two different chromatographic conditions: phosphate buffers at pH 2.8 and...
A detailed comparison of the performance of inductively coupled plasma mass spectrometry (ICP-MS), with quadrupole and double-focusing instruments for the speciation of selenium in urine has been carried out. Selenium sensitivity about 23–59 times higher with double-focusing ICP-MS detection was observed, but limits of detection were only 1–8.7 times better because of background noise. Selenium species...
With fluorometry this paper has proved that α-cyclodextrin (CD) and γ-CD do not form inclusion complexes with procaine, while β-CD and HP-β-CD do. Their molar ratios are demonstrated both 1:1 with the equimolar variation method. The constant current coulometric titration method (CCCT) is first proposed and applied in the determination of the CD inclusion constant. To compare with this method, the...
A biosensor for the specific determination of l-ascorbic acid in fruit juices and vitamin C tablets was developed using ascorbate oxidase (EC 1.10.3.3) from cucumber (Cucumis sativus L.) in combination with a dissolved oxygen probe. Ascorbate oxidase immobilized with gelatin using glutaraldehyde and fixed on pretreated teflon membrane served as an enzyme electrode. The phosphate buffer (50 mM, pH...
A urea biosensor prepared by covalent binding of urease directly to the surface of an ammonium-sensitive field effect transistor (FET) is described. Nonactin incorporated in carboxylated polyvinyl chloride was used to obtain the sensitive membrane of the ammonium-sensitive FET. The grafting of urease on the polyvinylchloride–COOH membrane surface was performed through carbodiimide coupling. The activity...
A spectrophotometric method for the determination of lactic acid in milk samples based on the use of a photochemical reaction carried out in a Flow Injection System is proposed. Determination is based on the reaction between lactic acid and Fe(III), which is reduced to Fe(II) in the presence of UV light, being the latter made to react with o-phenanthroline. The complex formed between Fe(II) and o-phenanthroline,...
This review deals with liquid phase separation of major arsenic and selenium species followed by element specific detection. It concerns papers published since 1980 and describing only currently used methods that were or could be applied to As and Se speciation in environmental matrices. Methods performances are compared on the basis of efficiency, rapidity, absolute and concentration detection limits...
A hydride generation gas phase molecular absorption spectrometry (HG-GPMAS) method for the determination of butyltin compound is optimized by experimental design. This method is based on the conversion of the butyltin chloride into gaseous monobutyltin hydride by adding a sodium tetrahydroborate (III) solution. The hydride generated is collected in a liquid nitrogen cryogenic trap. This is revolatilized,...
9,10-Bis[bis(β-hydroxyethyl)aminomethyl]anthracene (1) showed weak emission, suggesting that photoinduced electron transfer (PET) from amine group to excited anthracene occur. The PET fluoroionophore (1) was found to display unique photophysical properties in the presence of the guest metal cations in H 2 OCH 3 OH (1:1, v/v). Complexation of 1 with guest metal cations increased the...
A sensitive method for the measurement of phenazopyridine hydrochloride (PAP) by differential pulse polarography (DPP) based on adsorptive stripping technique, using a hanging mercury drop electrode (HMDE) is described. The voltammetric peak is obtained at −0.760 V, which corresponds to the reduction of the azo group in Britton–Robinson buffer. The redox behaviour is reversible. Optimum conditions...
The new method of preconcentration by extraction for flow injection analysis (FIA) with luminescence and photometric detection is proposed. Preconcentration is carried out on extraction-chromatographic column, extract is eluted by extragent with the following separation of extract from aqueous phase in chromatomembrane cell. Possibilities of the proposed method are illustrated in the examples of FIA...
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