Electrochemical study of 1,2-Naphthoquinone-4-sulphonate and 1,2-Naphthoquinone semicarbazone

Summary A study of the electrochemical characteristics of 1,2-naphthoquinone-4-sulphonate, sodium salt, and of the semicarbazone of 1,2-naphthoquinone (Naftazone) was carried out using d.c., a.c. and d.p. polarography and cyclic voltammetry. Changes in the waves as a function of concentration and pH indicate evidence of adsorption phenomena at the potential of the reduction wave. These techniques also indicate the formation of a mercury derivative in the case of Naftazone. The quantitative determination of these two compounds is possible by polarography. Limits of detection are 5×10^–6 and 5×10^–8 M, respectively.

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Elektrochemische Untersuchung von 1,2-Naphthochinon-4-sulfonat und 1,2-Naphthochinon-semicarbazon

Zusammenfassung Die elektrochemischen Eigenschaften von 1,2-Naphthochinon-4-sulfonat und -semicarbazon (Naftazon) wurden mit Hilfe der Gleichstrom-, Wechselstrom und Differentialpuls-Polarographie sowie der cyclischen Voltammetrie untersucht. Veränderungen an den Stufen in Abhängigkeit von Konzentration und pH-Wert deuten auf Adsorptionsvorgänge beim Potential der Reduktionsstufe hin. Im Falle von Naftazon wurde die Bildung eines Quecksilberderivats nachgewiesen. Beide Substanzen können polarographisch mit Nachweisgrenzen von 5×10^–6 bzw. 5 × 10^–8 M bestimmt werden.

     

Determination of the isoelectric point of a purified milk clotting enzyme preparation by analytical and preparative isoelectric focusing

Ohne Zusammenfassung

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Determination of the isoelectric point of a purified milk clotting enzyme preparation by analytical and preparative isoelectric focusing

     

Papier-chromatographische Trennung und Bestimmung von 1-Aminoanthrachinon- und 1-Amino-4-bromanthrachinon-2-sulfons?ure

Ohne Zusammenfassung

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Separation and determination of 1-aminoanthraquinone- and 1-amino-4-bromoanthraquinonesulphonic acid by paper chromatography

     

Peroxydisulphate oxidations VII. Identification of aromatic amines and phenols by thin-layer chromatography

Ohne Zusammenfassung

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On a specific detection of morphine by thin-layer chromatography

     

Studies on 1, 2, 4-Benzothiadiazine 1, 1-Dioxide IX.1 Synthesis and Pharmacological Evaluation of 1, 2, 4-Benzothiadiazine 1, 1-Dioxide Biphenyl Tetrazoles as Angiotensin II Antagonists

In the course of our investigations on the development of cardiovascular agents, 3-butyl-2-[2′-(2H-tetrazol-5-yl)bipheny]-4-yl]methyl-2H-1, 2, 4-benzothiadiazine 1, 1-dioxide ( 2 ) was considered as a potential angiotensin II antagonist on the basis of bioisosteric replacement of the quinazoline ring of compound 1 with a 1, 2, 4-benzothiadiazine 1, 1-dioxide ring system. Alkylation of 6 with 4 afforded 7 and 8 in 24% and 28% yields, respectively. An attempt to remove the trityl group of compounds 7 and 8 under acidic condition gave the ring opened products 9 and 11 in 28% and 36% yields, respectively. However, compounds 2 and 10 were obtained in 46% and 85% yields when compounds 7 and 8 were refluxed in methanol. Preliminary assays of compounds 9 and 11 against angiotensin II receptors revealed weak activity with IC₅₀ values of 3.6 μM and 5.4 μM, respectively. Compound 10 (IC₅₀ = 87 nM) exhibited stronger binding affinity than compound 2 (IC₅₀ = 750 nM).     

Photochemical and thermal transformations of diazo derivatives of 1-aryloxy- and 1-arylthio-2-aminoanthraquinones

In the photochemical and thermal decomposition of diazonium derivatives of 1-aryloxy- and 1-arylthio-2-aminoanthraquinones in CH ₃ COOH and dioxane, high yields of intramolecular arylation products — anthra-[2, 1-d]-4-tert-butylbenzo-[b]-furan-and anthra-[2, 1-d]-4-tert-butylbenzo-[b]-thiophene-8,13-diones — are formed. It was established that 2-azo derivatives of 1-aryloxy- and 1-acyloxyanthraquinones synthesized on the basis of the diazonium salts are stable under photolysis conditions.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 3, pp. 582–585, March, 1992.     

Analysis of air particulate matter and fly ash by spark source mass spectrometry

Summary A procedure is described for the spark source mass spectrometric analysis of a large number of trace constituents in airborne particulate matter and fly-ash. A simple sample preparation procedure and a fully automatic photoplate analysis allows determination of ca. 50 elements with a precision of 20% within 4–5 h.

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Analyse von Luftstaub und Flugasche mit der Funken-Massenspektrometrie

Zusammenfassung Es wird ein Verfahren zur Bestimmung einer großen Zahl von Spurenbestandteilen in Luftstaub und Flugasche mit Hilfe der Funken-Massenspektrometrie beschrieben. Eine einfache Probenvorbereitung und eine vollautomatische Photoplattenauswertung erlaubt die Bestimmung von etwa 50 Elementen mit einer Genauigkeit von 20% innerhalb von 4–5h.

     

High performance electrophoresis: A new method of continuous elution of electrophoretically separated high and low molecular weight compounds

Conclusions The purification of serum proteins is a precise and suitable test for the performance of an electrophoresis apparatus. The molecular weights and the isoelectric points of the various serum proteins cover a wide range. Consequently, the protein pattern observed after gel electrophoresis is very complex. Moreover, elution of the electrophoretically purified serum proteins is particularly complicated because some proteins such as albumin and transferrin appear as highly concentrated overloaded bands. If the elution method employed does not work extremely efficiently, residual quantities of albumin and transferrin, respectively, remain in the elution chamber and contaminate the following, slower protein zones. As Fig. 2 shows, no tailing of proteins can be observed in the pure fractions of this electrophoretic run, despite their high concentrations. Even in the case of proteins of low electrophoretic mobility in the late fractions, such as haptoglobins and immunoglobins, no dilution occurred.From these results it appears that the electrophoretic methods described provide a practical and highly efficient way of separating and analyzing high and low molecular weight ampholytes. Thus, technical aspects should no longer be the factor limiting realization of High Performance Electrophoresis.

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HPE: Eine neue Methode der kontinuierlichen Elution elektrophoretisch getrennter hoch- und niedrigmolekularer Verbindungen

     

Application of an automated sample processor to the analysis of benzodiazepine drugs and their metabolites in blood serum by HPLC

Conclusions An automated sample processor (PREP^TM I) can be applied to the extraction of benzodiazepine drugs and metabolites from blood serum. The absolute extraction recoveries are greater than 90%. The dried extracts can be used for analysis by techniques such as liquid chromatography. Comparison of the LC results to a GC method with manual liquid-liquid extraction was excellent for concentrations up to 30 mole · 1^–1.

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Anwendung eines automatischen Extraktionsgerätes bei der Analyse von Benzodiazepinen und ihren Metaboliten in Blutserum durch HPLC

     

Trace element analysis and microanalysis of silicate and carbonate rocks by flameless atomic absorption spectrophotometry

Summary Flameless atomic absorption spectrophotometric methods for the microanalysis and trace element analysis of rocks are described. The microanalysis of the elements Al, Fe, Mn and Ti so far determined can be carried out in the diluted solution of the digested samples (2.5 mg substance/250 ml to 5 mg/100 ml) without additional separation. In the case of trace element analysis the elements may be determined either directly in the solution (Sr, Pb) or after separation. Separation can be carried out by extraction from the solution (Tl) or by the volatilization technique with the solid substance heated to 1000–1200°C (Tl, Pb, Cd, Bi). For Hg the method of electrolytical separation together with the volatilization technique is suitable. The methods were tested with rock standards for precision and accuracy.

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Spuren- und Mikroanalyse von Silicat- und Carbonatgesteinen durch flammenlose Atomabsorptions-Spektralphotometrie

Zusammenfassung Verfahren zur Mikro- und Spurenanalyse von Gesteinen mit Hilfe der flammenlosen Atomabsorptions-Spektralphotometrie werden beschrieben. Bei der Mikroanalyse können ohne zusätzliche Trennverfahren die bisher untersuchten Elemente Al, Fe, Mn und Ti direkt aus den verdünnten Aufschlußlösungen (2,5mg Probe/ 250 ml bis 5 mg/100 ml) bestimmt werden. Bei der Spurenanalyse erfolgt die Bestimmung entweder direkt aus der Aufschlußlösung (Sr, Pb) oder nach Abtrennung des Elementes. Die Abtrennung kann mittels Extraktion aus der Aufschlußlösung (Tl) oder auch durch Verdampfung aus der Festsubstanz bei 1000–1200°C (Tl, Pb, Cd, Bi) erfolgen. Für Hg eignet sich ein elektrolytisches Trennverfahren in Verbindung mit der Verdampfungsanalyse. Die Verfahren wurden mit Gesteinsreferenzproben auf ihre Reproduzierbarkeit und Genauigkeit geprüft.

We thank Prof. Dr. K. H. Wedepohl for his continued interest in our work and we are grateful to him for his generous support. We are much obliged to Prof. Dr. A. G. Herrmann for his valuable advice and encouragement in technical matters. Financial assistance from the DFG is gratefully acknowledged.