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71.
The behaviour of ng- and μg-amounts of amines of biochemical interest is compared. ng-amounts are co-precipitated from aqueous solutions with the tetraphenyloborates of potassium, ammonium and creatinine. A separation from potassium chloride, ammonium chloride and creatinine is achieved by extraction of the amines with methanol. The elution volumes of about 50 amines during ion-exchange chromatography using a weakly acidic resin are compared. A procedure has been elaborated by which the amines can be collected from urine. 相似文献
72.
Klaus Sommer 《无机化学与普通化学杂志》1971,383(2):136-143
Hydrolysis of 1-chloro-arsolane, C4H8AsCl, and 1-chloro-arsenane, C5H10AsCl, leads to oxides C8H10As2O and C10H20As2O, respectively. On direct alkylation of arsenic trioxide with 1.4-butane- and 1.5-pentane-bis-magnesium bromide these oxides are formed only in trifling amounts. Better results are gained by alkylation of N,N-dimethylaminodichloroarsane into amino-arsolane and amino-arsenane, which are also transformed into these oxides by hydrolysis. By hydrolysis of 1.4-dichloro-diarsenane only a small amount of 1.4-epoxo-arsenane is formed, whereas mainly a dimer of this oxide results. Solvolysis of 2.6-dichloro-diarsa-[3.3.0]-bicyclooctane with water, hydrogen sulphide or methylamine leads to 7-oxa-, 7-thia- and 7-methylaza-2.5-diarsa-noradamantane, respectively. 相似文献
73.
A graphite rod electrothermal atomizer has been used for the AAS determination of traces of gold in hydrochloric and in hydrobromic acid solutions, and also after extraction into HBr-saturated methyl isobutyl ketone. Photographic film samples were decomposed first by enzyme action then by nitric acid/peroxide oxidation, and the gold was extracted into MIBK. For 10-μl aliquots of solution the 3s limits of detection were 3 × 10?10g for aqueous solutions, 7 × 10?10g for MIBK, and 7 × 10?9 g/cm2 for film. 相似文献
74.
L. Grosse und W. Klaus 《Fresenius' Journal of Analytical Chemistry》1972,259(3):195-203
Zusammenfassung Es werden allgemeine und qualitative Merkmale von Natrium-Carboxymethylcellulose, Methylcellulose und Hydroxyäthylcellulose sowie gravimetrische und titrimetrische Bestimmungsmöglichkeiten der wasserlöslichen Celluloseäther insbesondere im Zusammenhang mit dem Substitutionsgrad beschrieben.Verfahren zur Ermittlung der Viscosität von Lösungen, des Polymerisationsgrades und des Gelteilchengehaltes werden besprochen. Abschließend werden charakteristische Beispiele für das analytische Vorgehen bei Substanzgemischen gegeben, die nur einen geringen Anteil Celluloseäther enthalten.
Erweiterte und umgearbeitete Fassung eines Vortrages, gehalten am 28. 6. 1971 in Baden-Baden.
Frau Dr. G. Bartelmus, Analyt. Laboratorium der Fa. Kalle AG, sprechen wir an dieser Stelle unseren herzlichen Dank für wertvolle Beratung aus. 相似文献
Analysis of water-soluble cellulose ethers
General and qualitative characteristics of sodium carboxymethylcellulose, methylcellulose and hydroxyethylcellulose are presented and gravimetric and titrimetric methods for the determination of water-soluble cellulose ethers are described, especially with regard to the degree of substitution. Procedures for the measurement of the viscosity of solutions, of the degree of polymerisation and of the content of gel particles are discussed. Characteristic examples are presented for the treatment of mixtures containing only a small percentage of cellulose ethers.
Erweiterte und umgearbeitete Fassung eines Vortrages, gehalten am 28. 6. 1971 in Baden-Baden.
Frau Dr. G. Bartelmus, Analyt. Laboratorium der Fa. Kalle AG, sprechen wir an dieser Stelle unseren herzlichen Dank für wertvolle Beratung aus. 相似文献
75.
The electron-impact fragmentation of S-p-tolylester of nitrothiobenzoic acid leads to a previously unknown rearrangement in the case of the ortho compound. This consists of an intra molecular redoxreaction with oxygen transfer from the o-nitro group onto the sulphur of the thiol ester group. The position of the nitro group is not only an essential influence on the fragmentation pattern, but also of dramatic importance in determining the lifetime of the molecular ion. 相似文献
76.
77.
Zusammenfassung Herstellung und Anwendung gepackter Capillarsäulen (innerer Durchmesser: 0,3 mm) zur analytischen Trennung von Kationen durch Komplexelution im Mikromaßstab werden beschrieben. Als Säulenpackung dienen Kugeln eines stark sauren Kationenaustauschers mit einem mittleren Durchmesser von 25 . Die Detektion der getrennten Kationen erfolgt kontinuierlich im Effluent mit Hilfe einer amperometrischen Mikromeßzelle. Die Trennleistung einer 125 mm langen Capillarsäule wird am System Ni2+/Co2+/Iminodiessigsäure gezeigt. Die dosierten Probemengen liegen in der Größenordnung von 5–12 g je Kation.
Herrn Dr. habil. K. Wetzel danken wir für Anregungen und Diskussionen, den Herren W. Rose und K. Rupprecht für praktische Unterstützung bei der vorliegenden Arbeit. 相似文献
Summary Preparation and application of packed capillary columns (interior diameter: 0.3 mm) for analytical separations of cations in micro-scale by means of complex elution are described. The capillary columns are filled with spherical grains in the range of 25 .The detection of separated cations in the effluent is performed by means of an amperometric micro-cell.The separation efficiency of a capillary column (length: 125 mm) is shown for the system Ni2+/Co2+/iminodiacetic acid. The injected quantities of samples are in the range of 5–12 g per cation.
Herrn Dr. habil. K. Wetzel danken wir für Anregungen und Diskussionen, den Herren W. Rose und K. Rupprecht für praktische Unterstützung bei der vorliegenden Arbeit. 相似文献
78.
1-Aminopyrroles (4) are obtained by reaction of 1,2-diazabuta-1,3-dienes (1) and ynamines (2). This reaction represents one of the very rare examples of 1,3-cycloaddition processes of alkynes and hetero-1,3-dienes. 相似文献
79.
A study was made on the inhibition by some 3,3′- and 4,4′-disubstituted azobenzenes of the polymerization of vinylacetate initiated by azoisobutyronitrile at 50°. The inhibitory effects of these substances can be attributed to their ability to engage in radical addition giving a less reactive hydrazyl type radical. The mechanism of the inhibition has been established by ESR and kinetic (stoichiometric) measurements. The value of k5/k2 (characteristic of the reactivity of an inhibitor) was determined for 9 substituents. The radical reactivity of the aromatic azo group was decreased by electron donor substituents and increased by electron acceptors. The substituent effect can be well interpreted by the Hammett equation; the value of the reaction constant was ? = +0.53. 相似文献
80.
A solid-phase reagent based on 1-(4-adamantyl-2-thiasolylazo)-2-naphthol adsorbed onto silica gel was prepared for Co(II) recovery and preconcentration prior to its sorption-spectroscopic detection. The immobilized reagent was applied to the determination of free cobalt ions in natural water. The solid-phase reagent and chemiluminescent method coupled with membrane filtration, gel-permeation and ion-exchange chromatography were applied to the study of the speciation of iron and cobalt in water from the Dnieper reservoirs and lakes of Kyiv City; their predominant forms were complexes of Fe(III) and Co(II) with dissolved organic matter and fulvic acids play a main role in their complexation. 相似文献