Polarographic determination of some carcinogenic aminoazobenzenes

Summary The polarographic procedure can be used for the quantitative analysis of all the aminoazobenzenes tested in this study as indicated by proportionality between diffusion current and concentration. There is no significant correlation between the half-wave potential and carcinogenic potency for rat liver for three monosubstituted and seven disubstituted derivatives ofp-dimethylaminoazobenzene. These ring-substituted azocarcinogens rank from weak to very strong for carcinogenic potency against rat liver. Also aminoazobenzenes such as the noncarcinogenic 4-amino-4-dimethylaminoazobenzene and the carcinogenic N,N-dimethyl-4-amino-N-formyl-N-methyl-4-aminoazobenzene and N,N-dimethyl-4-amino-N-acetyl-N-methyl-4-aminobenzene have similar have-wave potentials. On the other hand, the noncarcinogenic 4-aminoazobenzene, 4-amino-N-methyl-4-aminoazobenzene and N-methyl-4-amino-N-methyl-4-aminoazobenzene have half-wave potentials that are about 100 mv more negative than that of all other aminoazobenzenes discussed in this report.

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Zusammenfassung Die Proportionalität zwischen Konzentration und Stromdurchfluß bietet die Grundlage zur polarographischen Bestimmung aller in dieser Arbeit geprüften Aminoazobenzole. Zwischen dem Halbwellenpotential und der carcinogenen Wirkung gegenüber Rattenleber besteht bei drei monosubstituierten und sieben disubstituierten Derivaten desp-Dimethylaminoazobenzols keine signifikante Korrelation. Diese ringsubstituierten Azocarcinogene zweigen schwache bis sehr starke carcinogene Wirkung gegenüber Rattenleber. Aminoazobenzole wie das nicht-carcinogene 4-Amino-4-dimethylaminoazobenzol und die carcinogenen Verbindungen N,N-Dimethyl-4-amino-N-formyl-N-methyl-4-aminoazobenzol und N,N-Dimethyl-4-amino-N-acetyl-N-methyl-4-aminoazobenzol haben ähnliche Halbwellenpotentiale. Andrerseits ist das Halbwellenpotential der nicht-carcinogenen Verbindungen 4-Aminoazobenzol, 4-Amino-N-methyl-4-aminoazobenzol und N-Methyl-4-amino-N-methyl-4-aminoazobenzol ungefähr um 100 mV negativer als das aller anderen hier behandelten Aminoazobenzole.

     

Polarographic determination of NTA in the presence of metal ions

Summary The determination of NTA in water containing large amounts of metal ions strongly complexing with NTA, even in acid solution, appears to be possible after removal of the metal ions by electrolysis at a mercury pool electrode. After the electrolysis NTA can be determined in the usual way by a suitable voltammetric method, which in the present work was a.c. polarography.

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Polarographische Bestimmung von Nitrilotriessigsäure in Gegenwart von Metallionen

Zusammenfassung Die quantitative Bestimmung von Nitrilotriessigsäure, NTA, in wäßrigen Lösungen, die große Mengen Metallionen enthalten, die mit NTA auch in saurer Lösung stabile Komplexe bilden, ist nach Entfernung dieser Metallionen durch Elektrolyse an einer Quecksilberelektrode möglich. Nach der Elektrolyse kann NTA nach einer der üblichen voltammetrischen Methoden bestimmt werden. In dieser Arbeit wurde dazu die Wechselstrompolarographie angewendet.

Lecture presented at Euroanalysis I Conference, 28. 8.–1. 9. 1972 in Heidelberg, Germany.     

Polarographic reduction of some potential antidiabetic compounds

The polarographic reduction of 4-arylhydrazone-N′-benzysulphonyl-3-methyl-2-pyrazoline-5-ones gave two, two-electron transfer, well defined, well separated, diffusion controlled, irreversible waves in B.R. buffers of pH range 7.0–11.0. In acidic medium the E_1/2 values of the two waves are so close that only one 4-electron transfer, well defined, diffusion controlled, irreversible waves is obtained. The reduction in these compounds takes place at the-NH-N=C-bond. The effect of substituents and its correlation with the Hammett substituent constant (σ) have also been studied.     

Polarographic determination of phenothiazine and N-substituted compounds

Summary Phenothiazine was nitrated and the structure of the compound formed was elucidated by U.V., I.R., N.M.R. and mass spectroscopy techniques. It has been proved that two nitro-groups were fixed on the ring. The d.c. and a.c. polarographic reductions showed that the two nitro-groups were reduced into aminogroups. The reduction proceeds in two waves, with a total of 12 electrons. N-substituted phenothiazine compounds were also investigated using the same technique.

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Polarographische Bestimmung von Phenothiazin und seinen N-substituierten Derivaten

Zusammenfassung Phenothiazin wurde nitriert und die Struktur der gebildeten Verbindung mit Hilfe der IR-, UV-, KMR- und Massenspektrometrie untersucht. Es ergab sich, daß zwei Nitrogruppen am Ring gebunden waren. Durch Gleich- und Wechselstrompolarographie wurden die Nitrogruppen zu Aminogruppen reduziert, wobei sich zwei Wellen (insgesamt 12 Elektronen) ergaben. Mit denselben Methoden wurden auch N-substituierte Derivate untersucht.

Lecture presented at Euroanalysis I Conference, 28. 8.–1. 9. 1972 in Heidelberg, Germany.     

Polarographic determination of uranium and lead in the presence of each other

Summary The microanalysis of solutions of dioxouranium- (VI) has been investigated employing differential pulse polarography. These studies show that uranium and lead can be determined accurately and economically in the presence of each other. The lead current peak occurs at –0.325 V, the uranium peak at – 0.200 V. Quantitative determinations are possible in the presence of Bi, Zn, Co and Fe.

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Polarographische Bestimmung von Uran und Blei nebeneinander

     

Polarographic behaviour of some organotin(IV) compounds in dimethyl sulphoxide

The differential pulse polarographic behaviour in dimethyl sulphoxide (DMSO) of 14 organotin(IV) compounds having the general formula R₃SnX (R = Me, Ph; X^? = NCS^?, N₃^?, N₃^?, NO₃^?, OH^?, NCO^? and OAc^?) and ⁿBu₃SnCl and ⁿBu₂SnCl₂ has been studied. The peak potential was found to depend markedly on the organic group and to a lesser extent on the nature of the anion X. The phenyltin compounds were reduced at lower potentials than the corresponding methyltin compounds. The data obtained could be used for trace determination of these compounds. Linear calibration curves were obtained over the concentration range of 2.8 × 10^?4 to 1.9 × 10^?6 mol dm^?3.     

Polarographic reduction of some mesoionic 2,3-diaryl-2 H-tetrazolium-5-thiolate compounds

The polarographic behaviour at the DME of 2,3-diphenyl-, 2,3-di(4-methylphenyl)- 2,3-di(3-chlorophenyl- and 2,3-di(2-chlorophenyl)-2 H-tetrazolium-5-thiolate compounds was investigated in 10% (v/v) aqueous methanol over a wide range of pH. The reduction proceeded through one four-electron irreversible wave to give the corresponding thiocarbazide. A mechanism for this reduction was proposed and subsequently substantiated by a controlled potential electrolysis of a mesoionic compound whereby the identify of the final reduction product has been proved spectrophotometrically to be the thiocarbazide.     

Polarographic waves of tri-n-butyl phosphate and polarographic determination of uranium in the presence of tri-n-butyl phosphate

The results of a study on the polarographic behaviour of TBP and its influence on the determination of uranyl ions is presented. The half-wave potential of the adsorption wave of TBP depends on the concentration of TBP, type of supporting elec trolyte and its concentration. In the presence of TBP the polarographic wave of U(VI) ion is changed. Below 7·10^?5 M TBP the polarographic wave of U(VI) is not affected, between 7·10^?5 and 2·10^?4 M TBP the shape, height and half-wave potential of U(VI) waves are changed and above 2·10^?4 M, up to saturated solution of TBP, the waves of U(VI) do, not change further. The bes supporting electrolytes for the determination of U(VI) are KNO₃ or NaClO₄ in concentrations of 0.1 to 0.5 M, pH 1–2 and TBP concentrations from 3·10^?4 to 1.2·10^?3 M.     

过氧化氢存在下平行催化氢波法测定奥沙普秦

在0.2mol/LKH2PO4-Na2HPO4(pH5.5±0.1)支持电解质中,奥沙普秦产生一催化氢波,峰电位Ep=-1.25V(vs.SCE)。当1×10-2mol/LH2O2存在时,该催化氢波的峰电流增加12倍,峰电位基本不变,产生一较灵敏的平行催化氢波。其二阶导数峰峰电流ip″与奥沙普秦浓度在1.0×10-7~2.6×10-5mol/L范围内呈线性关系(r=0.9995,n=10),检出限为5.0×10-8mol/L。该方法可用于药物制剂中奥沙普秦含量的测定。