Zur Bestimmung N-substituierter Aniline mit Natriumchlorit

Zusammenfassung Es wird eine photometrische Bestimmungsmethode beschrieben für Anilin (40–720 g/ml), Monoäthylanilin (90–1650 g/ml) und Diäthylanilin (100–1600 g/ml) mit Natriumchlorit in äthanolisch-wäßrigen Lösungen, sowie für Diäthylanilin (85–1140 g/ml) und Dimethylanilin (30–330 g/ml) neben den primären und sekundären Aminen in essigsaurer Lösung mit demselben Reagens. Das Verfahren liefert gute Ergebnisse.

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Summary A photometric procedure is described for the determination of aniline (40–720 g/ml), monoethylaniline (90–1650 g/ml), and diethylaniline (100–1600 g/ml) with sodium chlorite in aqueous ethanolic solutions and of diethylaniline (85–1140 g/ml) and dimethylamline (30 to 330 g/ml) in presence of the primary and secondary amines in acetic acid solution using the same reagent. Good results have been obtained,

     

Simultaneous determination of copper,mercury and lead by first-order derivative spectrophotometry using dithizone as reagent

A first-order derivative spectrophotometric method has been developed for the simultaneous determination of copper, mercury and lead at g/L levels using dithizone as reagent. The procedure involves the simultaneous extraction of these elements by dithizone in chloroform from weakly alkaline solutions. Linear calibration curves were obtained in the ranges 0.5–10 (Cu), 1–10 (Hg) and 1–10 (Pb) g present in 40 ml of aqueous phase with detection limits of 5 g/L (Cu) and 20 g/L (Hg and Pb). The R.S.D.s for 100 g/L of copper, mercury and lead were 2.5, 2.6 and 3.1% respectively, for 5 determinations. The method is applicable for the determination of copper and lead in marine sediment samples with good precision and accuracy.     

Fällungsanalyse im Mikrogrammbereich: Eine neue Methode

Zusammenfassung Eine neue Methode zur Durchführung gravimetrischer Bestimmungen im Mikrogrammbereich wurde beschrieben; diese beruht im wesentlichen darauf, daß der Niederschlag nicht mehr zusammen mit dem Filter, sondern nach Überführen mit einem geeigneten Lösungsmittel in einem separaten Wägegefäß gewogen wird.Die dazu nötigen Geräte und deren Herstellung wurden beschrieben. Nach dieser Methode wurden folgende Bestimmungen mit zufriedenstellender Richtigkeit durchgeführt: 2,5–25g Al, 5–50g Cu und 5–50g Zn mit Oxin, 2,5–25g Fe(III) und 2,5–25g Ti(IV) mit N-Benzoyl-phenylhydroxylamin, 5–50g Ni und 5–50g Cu mit Salicylaldoxim, 2,5–50g Co(II) und 2,5–50g Fe(III) mit -Nitroso--naphthol sowie 5–50g Chlorid als Silberchlorid.

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Precipitation analysis in the microgram-scale: A new method

Summary A new method for gravimetric determinations in the microgram-scale is described. This method is based on the fact that the precipitate is not weighed together with the filter but is transferred to a separate weighingvessel using a suitable solvent. The necessary simple devices and their use are described. The following determinations were carried out with satisfying accuracy: 2,5–25g Al, 5–50g Cu and 5–50g Zn with Oxine, 2,5–25g Fe and 2,5–25g Ti withN-benzoylphenylhydroxylamine, 5–50g Ni and 5–50g Cu with salicylaldoxime, 2,52–50g Co and 2,5–50g Fe with -nitroso--naphthol and 5–50g chloride as silver chloride.

     

Simultaneous determination of cobalt,nickel and iron by multi-wavelength spectrophotometry

A method for the simultaneous spectrophotometric determination of cobalt, nickel and iron based on the formation of their complexes with 1,5-bis(di-2-pyridylmethylene) thiocarbonohydrazide is proposed. The absorption curves of these complexes overlap severely in the scanning range 390–510 nm. The analyte concentrations are calculated by a least squares fit of the pure spectra to the mixture spectra, which therefore makes the simultaneous determination of these metallic ions possible without tedious pretreatment. The detection limits afforded by the proposed method range from 0.05 g/ml for Fe and Ni to 0.1 g/ml for Co. Root-mean-squared errors of prediction of 0.085 g/ml for Co, 0.048 g/ml for Ni and 0.1172 g/ml for Fe were obtained using the wavelength range 400–510 nm and 0.147 g/ml for Co, 0.107 g/ml for Ni and 0.127 g/ml for Fe using the wavelength range 420–434 nm. The effect of interferences is studied and the proposed method is applied to analysis for the above elements in synthetic samples and real samples, such as biological materials and alloys.     

Polarographic reduction of D-glucurono-γ-lactone in nonaqueous media

Summary The nonaqueous polarographic reduction of D-glucurono--lactone in dimethylformamide using tetrabutylammonium iodide as the supporting electrolyte (apparent E_1/2=– 1.94 V versus mercury pool) is analytically applicable over the concentration range of 50–300g/ml.

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Zusammenfassung Die polarographische Reduktion von D-Glucuronsäure--lacton in Dimethylformamid mit Tetrabutylammoniumjodid als Trägerelektrolyt (E_1/2=–1,94 V gegen Quecksilber) ist im Konzentrationsbereich 50 bis 300g/ml analytisch anwendbar.

     

Simultaneous determination of neodymium and erbium in rare earth mixture with 5,7-dibromo-8-hydroxyquinoline and TX-100 by third-derivative spectrophotometry

The absorption spectra of 4f electron transitions of the complexes of neodymium and erbium with 5,7-dibromo-8-hydroxyquinoline in the presence of octylphenol poly(ethyleneglycol)ether have been studied by normal and third-derivative spectrophotometry. The proposed method is free of interference of other rare earths. The calibration graphs were linear up to 18 g/ml of neodymium and 21 g/ml of erbium (in the final solution). The derivative molar absorptivities are 395 l.mol^–1.cm^–1 for neodymium and 3421.mol^–1.cm^–1 for erbium. The corresponding values of Sandell's sensitivity were 0.36 and 0.49 g.cm^–1, respectively. The relative standard deviations evaluated from ten independent determinations of 2.5 g/ml of neodymium and erbium are 1.5 and 3.8% for neodymium and 1.8 and 4.1% for erbium in absence and presence of 70 g of lanthanum, respectively. The detection limits (signal to noise ratio=2) are 0.23 g/ml for neodymium and 0.30 g/ml for erbium. The method has been used for the determination of neodymium and erbium in mixed rare earths with satisfactory results.     

Determination of some trace elements in high-purity aluminium, zinc and commercial steel by AAS after preconcentration on amberlite XAD-1180 resin

The determination of trace metals, e.g. Bi, Cd, Pb, in high-purity aluminium, zinc and commercial steel by flame or graphite furnace atomic absorption spectrometry following their preconcentrations as iodo complexes on XAD-1180 resin by means of a short column system is described. The recoveries are quantitative (95%). The relative standard deviations varies between 6% and 10%. The relative errors are less than 8% in a concentration range of 1 × 10^–3 –4 × 10^–5%. Detection limits for flame AAS and GFAAS were in the ranges of 0.002–0.110 g/ml and 0.0003–0.004 g/ml or in the ranges of 0.08–4.40 g/g and 0.012–0.16 g/g with respect to the solid samples, respectively.     

Application of l-cysteine-capped nano-ZnS as a fluorescence probe for the determination of proteins

Nanometer-sized l-cysteine-capped ZnS particles have been synthesized and used as a fluorescence probe to investigate the effect of proteins on fluorescent intensity. With =190 nm, maximum and constant synchronous fluorescence enhancement was produced at 267 nm and pH 5.12 in the presence of proteins. A highly sensitive synchronous fluorescence method for the rapid determination of proteins has been developed. Under optimum conditions, calibration graphs are linear over the range 0.03–8.0 g mL^–1 for bovine serum albumin (BSA), 0.01–6.0 g mL^–1 for human serum albumin (HSA), 0.05–8.0 g mL^–1 for -globulin (-G), and 0.04–4.0 g mL^–1 for ovalbumin, respectively. The relative standard deviations of seven replicate measurements were 1.75% for 1.0 g mL^–1 BSA, 1.90% for 1.0 g mL^–1 HSA, 1.65% for 1.0 g mL^–1 -G, and 2.32% for 1.0 g mL^–1 ovalbumin.     

Estimation of inorganic phosphate in aqueous solutions of DNA: A modification of the Berenblum-Chain method

Some modifications of the stannous chloride reduction method for the estimation of inorganic phosphate reported by Berenblum-Chain are suggested. By this method, it is possible to measure 25 g l^–1 of phosphorus /P/ as inorganic phosphate in the presence of macromolecules like deoxyribonucleic acid /100 g ml^–1/, as compared to 200 g l^–1 of P by the original method. If a larger sample volume /30 ml/ is used, even 5 g l^–1 of P can be measured.     

Nuclear interferences of uranium and thorium in a reactor neutron activation analysis determination of cerium using the radionuclides141Ce and143Ce

The interference contributions of uranium and thorium to the determination of cerium based on radionuclides¹⁴¹Ce and¹⁴³Ce produced by irradiation in a reactor core was determined. The values of the interference contributions for¹⁴¹Ce were 0.28±0.01 g Ce/g U and /2.01±0.05/x10^–3 g Ce/g Th, and for¹⁴³Ce 1.33±0.03 g Ce/g U and /9.0±0.2/x10^–3 g Ce/g Th.     

Determination of traces of sodium alkylbenzenesulphonate by high-performance liquid chromatography. Application to water

Summary For the trace determination of sodium alkylbenzenesulphonate (ABS) by HPLC the following conditions were employed: Shimadzu ZORBAX SIL Column (5 m, 4.6 mm i.d. x 150 mm) as stationary phase, 0.2% ammoniaethanol (v/v) as mobile phase, UV detector at 225 nm, injection volume 12 l. The chromatograms of ABS were simple and sharp (detection limit of ABS 0.02 g in 12 l of ethanol). The calibration curves of ABS were linear in a concentration range of 0.03 0.3 g in 12 l of ethanol. In the case of linear sodium dodecylbenzenesulphonate positive errors of 1 4% were caused by non-ionic surfactants or laurylsulphate (6 times excess), 10 50% positive errors were caused by 2 6 times excess of household detergents.Standard water samples containing ABS were treated with a weak base anion-exchange resin, the adsorbed ABS were eluted, and then determined either by HPLC or by the methylene blue spectrophotometric method. Recoveries of ABS in water were about 92 107% by HPLC.

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Bestimmung von Spuren Natriumalkylbenzolsulfonat mit Hilfe der HPLC. Anwendung auf Wasser

Zusammenfassung Für die Spurenbestimmung von Natriumalkylbenzolsulfonat (ABS) durch HPLC werden die folgenden Bedingungen empfohlen:Shimadzu ZORBAX SIL (5 m, 4,6 mm x 150 mm) als stationäre Phase, 0,2% Ammoniak/Ethanol als mobile Phase, UV-Detektor bei 225 nm, Injektionsvolumen 12 l. Die erhaltenen Chromatogramme sind einfach und scharf (Nachweisgrenze 0,02 g in 12 ml Ethanol). Die Eichkurven sind im Konzentrationsbereich von 0,03–0,3 g in 12 l Ethanol linear. Im Falle des linearen Natriumdodecylbenzolsulfonats werden bei Anwesenheit von nicht-ionischen oberflächenaktiven Substanzen oder von Laurylsulfat in 6fachem Überschuß positiver Fehler von 1–4% erhalten; bei 2–6fachem Überschuß von Haushaltswaschmitteln ergeben sich positive Fehler von 10–50%.Standard-Wasserproben werden zunächst einer Behandlung mit einem Anionenaustauscher unterzogen, die adsorbierten ABS eluiert und durch HPLC oder nach der Methylenblaumethode analysiert. Wiederfindungsraten liegen bei 92–107%.

     

Selective determination of neodymium and erbium in mixtures with other lanthanides by second-derivative spectrophotometry of complexes with benzoyl-indan-1,3-dione and cetylpyridinium chloride

The absorption spectra of 4f electron transitions of the neodymium and erbium complexes with benzoyl-indan-1,3-dione and cetylpyridinium chloride have been studied by conventional and derivative spectrophotometry. The second-derivative spectrum has been used to eliminate the interference of the other lanthanides, and to increase the sensitivity by a further factor of 4–6. Beer's Law is obeyed for 6–29 g/ml Nd and 7–33 g/ml Er. The relative standard deviations evaluated from 10 independent determinations of 5.0 g/ml Nd and Er were 1.1% (Nd) and 1.6% (Er). The detection limits obtained from the sensitivity of the calibration graphs and 3s _b, (standard deviation of the blank,n = 11) were 0.63 g/ml Nd and 0.61 g/ml Er. The quantification limits (10s _b) were 2.1 g/ml Nd and 2.0 g/ml Er. A method for the direct determination of neodymium and erbium in rare earth mixtures with good accuracy and selectivity is proposed.     

Simultaneous determination of zinc and mercury with 5,10,15,20-tetrakis(3-chloro-4-sulfophenyl)porphine by differential rate kinetics and flow injection analysis

A rapid and sensitive differential rate kinetic method for the simultaneous and sequential determination of zinc and mercury with 5,10,15,20-tetrakis-(3-chloro-4-sulfophenyl)porphine (m-Cl-TPPS₄) has been based on flow injection spectrophotometry. By proper stopped-flow of the merging zone, the metalloporphyrin complexes of zinc and mercury were simultaneously determined at the maximum absorbance wavelength of 425.7 nm with the proportional equation. The relative standard deviations for 1.0 g/ml zinc and 5.0 g/ml mercury with 100 l sampling volume were 0.43% and 0.62%, respectively, for 8 parallel determinations. The calibration graphs were linear over the concentration range 0–3.0 g Zn/ml and 0–12.0 g Hg/ml. The method has been applied to the analysis of synthetic water samples with satisfactory recovery.     

ET-AAS in the Analysis of high-purity mercury

ET-AAS is investigated for the analysis of high purity mercury. Two possibilities are proposed: ET-AAS determination of trace analytes in the presence of high mercury concentrations or after matrix separation by reduction. The ET-AAS analysis of high-purity mercury under optimal instrumental parameters permits fast and reproducible determination of 0.03 gg^–1 Al, Cd and Mn; 0.05 gg^–1 Cu, Co, Cr, Fe, Ni and Pb and 0.2 gg^–1 V. Preliminary mercury matrix reductive separation with ascorbic acid allows determination of 0.005 gg^–1 Cd, 0.02 gg^–1 Cu, Cr and Mn, 0.03 g g^–1 Co, Ni and Pb, 0.05 g g^–1 Al and Fe and 0.1 gg^–1 V, but the reproducibility is lower. The main advantage of the second procedure is that it avoids laboratory and instrument pollution with toxic mercury.     

Spektrophotometrische Bestimmung von Dimethylamin in Dimethylformamid

Zusammenfassung Dimethylaminspuren in Dimethylformamid werden spektrophotometrisch durch Reaktion mit Schwefelkohlenstoff und zweiwertigem Kupfer in nichtwäßrigem Milieu ermittelt. Als Reaktionsmedium bewährt sich eine 40% ige äthanolische Pyridinlösung, in welcher Dimethylformamid im Gegensatz zu wäßrigen Lösungen nicht hydrolysiert wird. Die Bildung von Kupferdimethyldithiocarbamidat verläuft in dieser Lösung stöchiometrisch, das Absorptionsmaximum der gelben Lösung liegt bei 445 nm. Die Bestimmung wird durch Anwesenheit von Ameisensäure gestört, die mit Hilfe eines stark basischen trockenen Anionenaustauschers beseitigt werden kann. Der Bestimmungsfehler beträgt im Bereich von 5–65 g Dimethylamin etwa 0,9 g.

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Summary Traces of dimethylamine in dimethylformamide are determined spectrophotometrically by the reaction with carbon disulphide and bivalent copper in non-aqueous medium. A 40% ethanolic solution of pyridine is useful as reaction medium. In this solution—contrary to aqueous solutions—dimethylformamide is not hydrolyzed and copper dimethyldithiocarbamidate is formed stoichiometrically, the absorption maximum of the yellow solution being at 445 nm. The determination of dimethylamine is interfered with by formic acid which can be removed by a strongly basic anion exchanger. The error of the determination in the range of 5–65 g of dimethylamine is about 0.9 g.

     

Analysis for fungicides in paint

Summary Simple methods have been developed for the determination of copper and 8-hydroxyquinoline in paint films. Copper is separated from 8-hydroxy-quinoline by precipitation as copper sulphide and is determined photometrically either by means of diphenylcarbazone (0.1–1g Cu/ml) or benzoin oxime (1 to 10 g Cu/ml). 8-Hydroxyquinoline is determined by measuring the optical density in the ultraviolet region.

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Zusammenfassung Einfache Verfahren zur Bestimmung von Kupfer und 8-Hydroxychinolin in Anstrichfilmen werden beschrieben. Kupfer wird als Sulfid abgetrennt und photometrisch mit Diphenylcarbazon (0,1–1g Cu/ml) oder Benzoinoxim (1–10g Cu/ml) bestimmt. 8-Hydroxychinolin wird durch Messung der UV-Absorption bestimmt.

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Part III: Hoffmann, E., A. Saracz, and B. Bursztyn: Z. analyt. Chem. 208, 431 (1965).     

Electrothermal AAS studies of Sm, Eu, Dy, and Er separated from uranium

Summary Studies were conducted on the assay of Sm, Eu, Dy and Er separated from uranium using aqueous standards by electrothermal AAS with Massmann type graphite furnace. The working curves were found to be linear in the ranges Sm (1–10 g/ml), Eu (0.05–0.6 g/ml), Dy (0.1–0.8 g/ml) and Er (0.1–1.0 g/ml). The values obtained for synthetic samples agreed favourably with those obtained by emission spectrographic method. Experiments using pyrolytic carbon coated tubes with and without pretreatment by La, Ta and Y have shown an enhancement with treatment upto a maximum of 15% and improve the memory effect marginally. The effect of Ta treatment was found to be singularly useful in improving the general behaviour of Sm. The interference effects of lanthanides, other than the analyte, were found to be negligible. However, the presence of uranium was found to affect the absorbance. The absorbance of Eu was found to be nearly independent of uranium after an initial increase. On the other hand, the absorbance of other elements studied was found to drastically decrease after an initial enhancement. Detailed investigations of temperature dependence of absorbance were carried out using Eu, Dy and Er. The differences in the behaviour of these elements is attributed to probable differences in the modes of their atomization.

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Untersuchung von aus Uran abgetrenntem Samarium, Europium, Dysprosium und Erbium durch elektrothermische Atomabsorptions-Spektralphotometrie

Zusammenfassung Die Untersuchungen wurden mit Hilfe des Graphitrohrofens nach Maßmann durchgeführt. In folgenden Bereichen ergaben sich lineare Eichkurven: Sm 1–10 g/ml, Eu 0,05–0,6 g/ml, Dy 0,1–0,8 g/ml, Er 0,1-1,0 g/ml. Die aus synthetischen Proben erhaltenen Ergebnisse stimmten gut mit den durch Emissionsspektrographie erhaltenen überein. Versuche wurden mit Röhren mit pyrolytischen Kohlenstoffüberzug mit und ohne Vorbehandlung durch La, Ta und Y durchgeführt und ergaben eine bis 15%ige Steigerung durch die Behandlung sowie eine mäßige Besserung des Memoryeffektes. Eine Behandlung mit Ta war besonders für Sm vorteilhaft. Störungen durch andere Lanthanide waren vernachlässigbar. Uran beeinflußte jedoch die Absorption. Im Falle von Eu zeigte sich nach anfänglicher Zunahme fast eine Unabhängigkeit, während bei den anderen untersuchten Elementen nach anfänglicher Zunahme eine beträchtliche Abnahme auftrat. Mit Eu, Dy und Er wurde ebenfalls die Temperaturabhängigkeit der Absorption untersucht. Festgestellte Unterschiede im Verhalten werden auf unterschiedliche Atomisierung zurückgeführt.

     

Path of “dry” electrons before localization in liquid hydrocarbons

Conclusions On the basis of measurements of values of in liquid hydrocarbons, it has been shown that the path length before localization of a photoliberated electron increases with increasing mobility of the excess electron, from approximately 40 Å (methylcyclohexane) to 200 Å (isooctane). In a liquid with10^–2 cm²/V·sec (methylcyclohexane, hexane), the localization takes place before or immediately after thermalization of the electron. In a liquid with>10^–1 cm²/V·sec, the electron passes through the main part of its path before localization, being in thermal equilibrium with the medium.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2198–2203, October, 1985.