Quantitative determination of ultra-traces of chlorinated compounds in high-volume air samples from the Arctic using polyurethane foam as collection medium

Summary A method has been developed for the determination of very low concentrations (pg/m³) of organic chlorinated compounds in air. Chlorinated benzenes, hexachlorocyclohexanes, polychlorinated biphenyls and the DDT group. Since most of the atmospheric burden of such compounds occurs in the gas phase, a high volume sampling method has been developed using carefully precleaned polyurethane foam as collection medium. Samples of 2000–4000 m³ were taken at different sites in the Arctic. The foam quality as well as the precleaning procedure of the foam and the clean-up of the sample are described in detail. The recovery of both the extraction and sample pretreatment was in the range of 80–115% for nanogram amounts. Sampling efficiency for the first foam plug was 80–100%.The sampling efficiency is influenced by different factors (temperature, air humidity, sampling volume). For quantification and identification, the highly selective methods of negative ion chemical ionization mass spectrometry and electron capture detection were combined with high resolution gas chromatography. The detection limit of the method was for most compounds less than a few pg/m³. Some preliminary data from the Arctic measurements are presented and are briefly discussed.

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Quantitative Bestimmung von Ultraspuren chlorierter Verbindungen in großvolumigen Luftproben aus der Arktis mit Hilfe von Polyurethanschaum als Sammelmedium

Zusammenfassung Das beschriebene Verfahren dient zur Bestimmung von chlorierten Verbindungen (chlorierte Benzole, Hexachlorcyclohexane, polychlorierte Biphenyle, DDT-Gruppe) in niedrigen Konzentrationen (pg/m³) in Luft. Da die meisten dieser Verbindungen gasförmig vorkommen, wurde eine Probenahmemethode für große Volumina unter Verwendung von sorgfältig vorgereinigtem Polyurethanschaum als Adsorptionsmedium entwickelt. Proben von 2000–4000 m³ wurden an verschiedenen Stellen der Arktis genommen. Die Vorbehandlung des Schaums und der Probe wird ausführlich beschrieben. Bei ng-Mengen lag die Wiederfindung bei 80–115%. Die Leistungsfähigkeit der ersten Schaumschicht lag bei 80–100%. Durch Temperatur, Luftfeuchtigkeit und Probenahmevolumen wird die Leistungsfähigkeit beeinflußt. Zur Identifizierung und quantitativen Bestimmung wurde die Negativionen-Massenspektrometrie mit chemischer Ionisation und die EC-Detektion mit der Hochleistungs-Gas-Chromatographie kombiniert. Die Nachweisgrenze lag für die meisten Verbindungen bei weniger als einigen pg/m³. Einige Daten der arktischen Messungen werden vorgestellt und kurz diskutiert.

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Partly presented at the Fourth European Conference on Analytical Chemistry, Helsinki/Espoo, Finland 1981     

Organometallic complex compounds,part 51. Ligand property controlled CO-insertion in nickel complexes: Separation of electronic and steric effects

Summary The influence of twenty phosphorus-containing ligands on the CO insertion with four-coordinated Ni¹¹ complexes as starting reagents is reported. Quantitative separation of the electronic and steric effects by a multilinear regression analysis (55% electronic and 45% steric influence) is presented together with a three dimensional representation. An increase in donor-capacity favours CO insertion and an increase in steric hindrance leads to a decrease in the fraction of the corresponding ketone.     

Second class currents and broken SU(3)-symmetry

In the SU(3) limit, a second class, T-normal axial vector current, which transforms like an octet, can give rise to pseudotensor terms in the matrix elements for leptonic decays of baryons. With first order symmetry breaking, this second class current may generate pseudovector and pseudoscalar form factor contributions. It is an anti-hermitian current, but, even with SU(3) breaking, it does not need to disturb the chiral SU(2) × SU(2) algebra of charges.