Analysis of gases and vapours by spectroscop1c techniques—I Emission spectroscopy

Theoretical and experimental aspects of the analysis of gases and vapours by emission spectroscopy are discussed and the current literature on molecular emission spectroscopy is reviewed.     

Infrared spectra for the identification of some inorganic anions using nitron as precipitant

Summary Using infrared absorption spectroscopy a method has been developed which permits the identification, either singly or in admixture, of the following anions: ferrocyanide, ferricyanide, cobalticyanide, chlorate, bromate, perchlorate, periodate, nitrate, nitrite, tungstate, molybdate and chromate. The anions are precipitated by nitron, and using the KBr-disc technique characteristic bands are obtained in the near infrared.

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Zusammenfassung Durch Infrarotabsorptionsspektroskopie lassen sich entweder allein oder in Gemischen folgende Anionen identifizieren: Cyanoferrat(II), Cyanoferrat(III), Cyanokobaltat, Chlorat, Bromat, Perchlorat, Perjodat, Nitrat, Nitrit, Wolframat, Molybdat und Chromat. Die Anionen werden mit Nitron gefällt und geben bei Verwendung einer Kaliumbromid-Linse charakteristische Banden im nahen Infrarot.

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Résumé On a développé une méthode permettant l'identification par spectrographie d'absorption infrarouge des anions suivants, séparément ou en mélanges: ferrocyanure, ferricyanure, cobalticyanure, chlorate, bromate, perchlorate, periodate, nitrate, nitrite, tungstate, molybdate et chromate. On précipite les anions par le nitron et l'on met en évidence les bandes caractéristiques dans l'infrarouge proche, par la technique à la pastille de KBr.

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Dedicated to ProfessorA. A. Benedetti-Pichler on the occasion of his 70th birthday.

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One of us (S. A. E. S.) acknowledges gratefully the award of a scholarship from the U. A. R. Government, which has enabled him to take part in this work.     

The post-hydrogenation of low-pressure chemical vapor deposited amorphous silicon

Amorphous silicon films prepared by low pressure chemical vapor deposition were exposed to atomic hydrogen in an rf plasma. Concentrated hydrogen and 20% hydrogen in argon was used for the plasma. The hydrogen concentration as a function of depth was measured for various process parameters with secondary ion mass spectrometry (SIMS). Hydrogenation temperatures of 250 to 400°C and exposure times from 30–120 min were used. The hydrogen surface concentration varied between 4 and 10 at%, whereby the higher values were obtained with plasma treatments in concentrated hydrogen.The fit of an error function diffusion profile to the experimentally measured SIMS concentration results in a diffusion coefficient at 400°C of D = 6 × 10^?14 cm² s^?1.     

Electrochemical reduction of copper(II) galacturonate

The complexes formed in the interaction between copper(II) anda-andβ-galacturonic acid, in the pH range 2.5–11.0, have been investigated by means of d.c. polarography and cyclic voltammetry. Witha-galacturonic acid, no complex is formed with copper up to pH 6. Between pH 6 and about 9.5, a complex is formed in solution. Above pH 9.5, the complex appears to break up releasing the ligand. In the case of β-galacturanic acid, no complex is formed until pH 3.5, and persists in solution up to a pH of about 9.5. A second complex forms above pH 6.9 and co-exists with the first complex up to pH 9.5. The complexes formed with both forms of galacturonic acid were studied and the stability constant of the coppera-galacturonate determined.     

A DTA study of phenols

A comprehensive DTA study is reported of 17 halophenols and of the corresponding p-nitrobenzoylchloride 3,5-dinitrobenzoylchloride and p-phenylazobenzoylchloride derivatives, prepared “in-situ”by heating intimate mixtures of phenol and acid chloride in the DTA system. The thermal analysis data, in particular, the derivative formation temperatures, are interpreted in terms of the inductive, mesomeric and steric effects associated with the ring substituents of the phenol and acid chloride and the extent of inter- and intramolecular hydrogen-bonding existing in these systems. The DTA data collectively provide a reference base for the identification and characterization of halophenols via thermal analysis.     

Organotin (IV) derivatives of L-cysteine and DL-penicillamine

The preparations of chlorodimethyl- and chlorodi-η-butyl tin(IV) derivative of L-cysteine, L-cysteine ethyl ester and DL-pencillamine are described. Infrared, n.m.r. and mass spectral data are presented. The compounds contain SnS bonds and suggestions for structures are made.     

Simultaneous determination of decachlorobiphenyl, octachloronaphthalene and decachloro-1,4-dihydronaphthalene in mixtures, by HPLC

Gas-liquid chromatography cannot distinguish between octachloronaphthalene and decachloro-1,4-dihydronaphthalene, because of the dechlorination of the latter during the chromatographic separation. High-pressure liquid chromatography on S50DS in the reverse-phase mode, with methanol as the solvent, has been successfully used in analytical (both qualitative and quantitative) and semi-preparative applications, involving the major products of the perchlorination of PCBs and PCNs: decachlorobiphenyl, octachloronaphthalene and decachloro-1,4-dihydronaphthalene.