Determination of trace impurities in cobalt by spark source mass spectrometry

An analytical method, SSMS, for the determination of trace impurities in cobalt is described. This element is used as raw material for the production of⁶⁰Co in Embalse Nuclear Power Station. Tin, aluminum, lead, silicon, molybdenum, calcium, vanadium, boron, chromium, zirconium, tungsten, nickel, magnesium, iron, zinc and copper were determined. Manganese, analyzed by AAS, was used as an internal standard. The measurements were semiquantitative. The accuracy of the results was compared with that of emission spectrography and atomic absorption spectrometry, the agreement was found to be satisfactory.     

Determination of Copper,Cadmium and Lead in Zinc Metal by Preconcentration onto Activated Carbon Combined with Direct Current Arc Atomic Emission Spectrography

Abstract

A preconcentration method is described for traces of copper, cadmium and lead from pure zinc metal by use of activated carbon. Ammonium salt of dithiophosphoric acid-o, o-diethylester is used to complex Cu, Cd and Pb. These chelates are sorbed on activated carbon. The traces sorbed on the carbon are determined by direct current arc atomic emission spectrography. The analytical error in the concentration range of 10^?3–10^?4% is less than 6% and relative standard deviation is below 10%.     

Elemental trace determinations in aluminium by enrichment onto activated carbon combined with direct current arc optical emission spectrography

Summary A combined procedure including enrichment by adsorption onto activated carbon and direct current (dc) arc emission spectrography has been investigated for elemental determination. In order to obtain reproducible volatilization of the analyte in the dc arc, the activated carbon was mixed with graphite powder and the arc operated in an argon atmosphere. The procedure has been used to determine some trace impurities in high-purity aluminium metal. The analytical error in the concentration range of 10^–3–10^–5% was less than 10% and the relative standard deviation was below 12%.

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Emissionspektroskopische Bestimmung von Spurenelementen in Aluminium mit Gleichstrom-Lichtbogen nach ihrer vorherigen Anreicherung an Aktivkohle

     

Determination of vanadium in petroleum crudes and fuel oils by gas chromatography

A method is described for determining levels of vanadium as low as 0.1 μg g^-1 in petroleum oils by gas chromatography with flame-ionization detection. The method involves decomposition of the oils, derivatization and solvent extraction of vanadium as the chelate, [2,2,2',2'-tetramethyl-5,5'-(ethane-1,2-diyldiimino)bis(hex-4-en-3-onato)-(2-)] oxovanadium(IV), followed by gas chromatography on a non-polar (SE-30) column. The procedure is applied to a variety of samples, including standard reference and fuel oils used in an interlaboratory study. The results are compared with those of emission spectrography and two standard methods. The new procedure can be extended to the selective, simultaneous detection of copper, nickel and vanadium in such samples.     

The determination of boron in sedimentary rocks by neutron irradiation and prompt γ-ray spectrometry

Prompt γ-rays following the (n_th, α) reaction on¹⁰B have been measured to determine the boron content of sedimentary rocks. Employing an external reactor neutron beam with only modest flux, it is possible to assay boron at concentrations typically encountered in this material (>5 μg/g). The technique relies on the use of chemical standards and the values obtained for 9 North American shales are compared with measurements performed by emission spectrography. Detection limits and statistical errors as a function of beam time are also discussed. Department of Geology, Mcmaster University, Hamilton, Ontario (Canada)     

Investigation of the origin of archaeological glass artefacts by means of pattern recognition

The origin of medieval glass artefacts is studied by using a supervised learning technique, which is shown to be helpful when samples cannot be identified by typical design and appearance. A set of seventy pieces of glass was analyzed for ten trace elements by optical emission spectrography. The data matrix of 33 known objects from five origins was evaluated by multivariate variance and discriminant analysis in a training step. The extracted non-elementary discriminant functions were used to classify the 37 unidentified samples. The classification result is discussed in terms of its cultural/historical information content.     

Dosage,par spectrographie d'émission dans l'air,des halogènes à l'aide d'une source à impulsion. Influence de la polarité

A high power pulsed source has been employed which allows the determination of halogenes to be performed under the usual conditions of emission spectrography. A limit of sensitivity of 5 to 10 ppm has been obtained, except for fluorine where it is of the order of 400 ppm. The conditions for better sensitivity are discussed: influence of the kind of matrix and polarity.     

Purification of Biliary Protein and Its Effect on Calcium Carbonate Mineralization

The biliary protein (BP) was isolated from pig bile by gel filtration. The interaction between Ca²⁺ and protein was measured by fluorescence spectra. The result showed that there was a strong coordination between biliary protein and Ca²⁺. The CaCO₃ crystals obtained in systems with and without BP were characterized by scanning electron microscopy, Fourier transform infrared spectrography and powder X‐ray diffractometry. The possible formation mechanism of CaCO₃ in biliary protein solution was discussed.     

Spectrographic investigation of neodymium malates in aqueous solutions

Conclusions Using high-resolution spectrography the authors have investigated the neodymium chloride-malic acid system in aqueous solution at pH 2.0–8.0.They have determined the composition and calculated the stability constants of the complexes NdMal⁺ and NdMal₂ ^–.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1474–1477, July, 1980.     

Problems and optimization of sampling,storage, and sample preparation in the determination of the trace element composition of human saliva

Experimental results are reported on the effect of the procedure of sampling, storage conditions, and sample preparation of saliva on the concentrations of trace elements determined by atomic emission digital spectrography of liquid samples with spectrum excitation from their dry residues in an AC arc at a tip of a carbon electrode. Recommendations on the optimization of the stages of sampling, storage, and preparation of saliva samples are given.     

Fluorescence emission and absorption spectra of single Anabaena sp. strain PCC7120 cells

The fluorescence emission and absorption spectra of single Anabaena sp. strain PCC7120 cells including vegetative cells and heterocysts have been studied in intact filaments in vivo with confocal microscopy and grating spectrography. The diameters of the excitation and detection areas in the cells are less than 1.0 microm. Heterogeneities within the same cell and among different cells are observed. The evident spectral heterogeneities in heterocysts, not reported previously, are attributed to the different stages of the evolution of phycobilisomes in heterocysts. The photosystem II in heterocysts were found to be not metabolized completely.     

Resonance scattering method for the ultrasensitive determination of peptides using semiconductor nanocrystals

Resonance light scattering (RLS) of the functionalized ZnS nanocrystals-peptides system and its analytical application have been studied. The RLS intensity can be efficiently enhanced when various peptides were added. The mechanism of the RLS enhancement of ZnS nanocrystals was discussed. The change of RLS intensity was in proportion to the concentration of peptides. The limits of detection were in range of 2.8-5.7 ng mL⁻¹. Application results to synthetic samples showed simplicity, rapidity, high sensitivity and satisfactory reproducibility of the presented method. Measurements of real samples also give satisfactory results which were in good agreement with those obtained using high performance liquid chromatography (HPLC) and liquid chromatography-mass spectrography (LC-MS) methods.     

Determination of sodium in high purity silica by activation analysis

High purity fused silica samples and NBS standards were irradiated in the Sandia Reactor Facility for 2 hr at a thermal flux of 10(10) neutrons/cm(2)/sec. (24)Na was produced by the reaction (23)Na(n, gamma)(24)Na (14.9 hr half-life, alpha = 0.5 barn), and decayed with emission of 1.37 and 2.75 MeV gamma-rays. With the stated flux and irradiation time, sodium at the 3 ppm level has been determined with a standard deviation of 0.2 ppm. Values obtained by thermal neutron-activation analysis agree well with results obtained by emission spectrography and flame spectrophotometric methods.     

Facile Synthesis of 4-Oxo-4H-quinolizine-2-carboxamide Derivatives

A facile synthetic method for the construction of 2-substituted-4-oxo-4H-quinolizine-based core structure has been successfully developed. The synthesis made use of a one-pot Stobbe condensation followed by cyclization starting from the commercially available 2-pyridinecarbaldehyde. The structure of the formed 4-oxo-4H-quinolizine-2-carboxylate was fully confirmed by mass spectra, ¹H NMR and ¹³C NMR, correlation spectrography, heteronuclear multiple bond correlation, and heteronuclear single quantum coherence (HSQC) spectra. The ethyl carboxylate moiety was then further functionalized via direct aminolysis by a range of amines to afford the corresponding 4-oxo-4H-quinolizine-2-carboxamides 4a–i in moderate to good yields.     

Vergleich verschiedener spektrographischer analysenverfahren zur analytischen homogenitätsprüfung am beispiel der untersuchung von kupferproben

A number of methods using optical emission spectrography have been compared in order to obtain some measure of the analytical error of this technique. They include (1) measurement at several spots at closely adjacent positions on one sample; (2) measurement by repeated sparking at one position on the sample; (3) local averaging of measuued values obtained by the multiple-spot method; (4) the line-pair method of Hemschik and Schufrenhauer; (5) Skogerboe's three-line method. The results are compared amongst themselves and also with some electron microprobe measurements on the same sample.     

Determination of impurities in bismuth by solid-liquid extraction and emission spectrography

Summary A high-purity bismuth metal or bismuth nitrate sample is dissolved in nitric acid and converted to solid basic bismuth nitrate by heating. Impurities such as iron, cobalt, copper, and zinc at the low ppm or ppb level are extracted from the solid with water and determined by DC arc emission spectrography.

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Zusammenfassung Hochgereinigtes Wismutmetall oder Wismutnitrat werden in Salpetersäure gelöst und durch Erhitzen in festes basisches Wismutnitrat übergeführt. Verunreinigungen wie Eisen, Kobalt, Kupfer und Zink in ppm- oder ppb-Mengen werden aus der festen Probe mit Wasser extrahiert und emissionsspektrographisch bestimmt.

     

Analysis of the chemical composition of solid petroleum hydrocarbons by electron attachment (EA) mass spectrography with negative ions

The composition of solid saturated hydrocarbons from slack-wax after reaction with urea has been investigated by electron-attachment (EA) mass spectrography with negative ions. From the spectra of the samples the content of paraffin hydrocarbons, monocyclic, dicyclic and other polycyclic naphthenes was calculated. The presence of n-paraffins up to C₄₆, isoparaffins and cycloalkanes up to C₅₂ has been confirmed. In the paraffin series the concentration of normal paraffin hydrocarbons containing one and two ¹³C atoms was determined. On the basis of the results obtained the constitution of the samples and the possible structures of the hydrocarbons were discussed. The results obtained have shown that the solid hydrocarbons which react with urea not only consist of one- or two-ring systems, but also of systems with up to five and six rings.     

Determination of platinum, palladium and silver in geological materials and their concentrates by fire assay and emission spectrography

A method is described for the determination of platinum down to 10 ng, palladium to 5 ng and silver to 10 pg in 50 or 100 g of sample. Fire-assay techniques are used to preconcentrate these metals into a bead which is first treated with nitric acid to dissolve palladium and silver and then with aqua regia to dissolve platinum. Both solutions are diluted and adjusted to pH 4, then analysed by optical emission spectrography of the residue from a measured volume evaporated on a pair of flat-top graphite electrodes. This method requires much less sample handling than most published methods for these elements.     

On the nature of the anhydride of the lactam of guanidinoglutaric acid

When glutamic acid is amidinated, guanidinoglutaric acid is formed. This is readily converted by boiling in water to its lactam [2-imino-4-oxo-5-(3′-propane acid) imidazolidine; GGAL]. In the present study GGAL is dehydrated to form a second lactam, anhydro-GGAL (AGGAL), with trifluoroacetic anhydride. The molecular weight of this compound was ascertained gravimetrically by precipitation with flavianic acid and by mass spectrography to be 153.14. UV and infrared spectra and hydrogen and ¹³C NMR studies determined its structure as an imidazolidine ring fused to a pyrrol ring, 2-imino-4-oxo-imidazolidine-1,5-pyrrolidone-8. On paper electrophoresis, GGAL traveled to the anode, while AGGAL traveled to the cathode. On TLC plates (butanol 60, H₂O 25, acetic 15), the R_f value of GGAL was 0.42 and that of AGGAL was 0.38, confirming that AGGAL was more basic than GGAL. The preparation of 1,3-di-(phenylcarbamoyl)-GGAL is also described.     

Diverses methodes d'analyse des alliages d'etain et de samarium

Several methods of analysis for tin-samarium alloys are studied: chemical analysis, X-ray fluorescence and arc spectrography. Their characteristics and the results obtained are compared. The chemical methods are most precise but are insensitive and tedious. X-Ray fluorescence is suitable for routine work and for control of alloy homogeneity. Arc spectrography is by far the most sensitive method The methods can be applied to alloys of other rare earths with tin.