Lothar Dunemann

Aromatic hydrocarbons in the atmospheric environment: Part I. Indoor versus outdoor sources, the influence of traffic

Abstract Six aromatic hydrocarbons (benzene, toluene, ethylbenzene and the three isomeric xylenes) were monitored in the indoor and outdoor air of 115 private non-smoker homes (∼380 rooms), about half of which were located in two city streets in Hannover (Northern Germany) with high traffic density, the other half in rural areas with hardly any traffic at all. This environmental monitoring was complemented by human biomonitoring (i.e. the determination of aromatic hydrocarbons in blood and exhaled air). Particular attention was paid to benzene as a result of its carcinogenicity. In the city streets with high traffic density, an average benzene concentration of 3.1xa0μgxa0m −3 and in the rural areas of 1.8xa0μgxa0m −3 was found in these non-smoker homes (all data=geometric means), which reflects the influence of the traffic (automobile exhaust) on the benzene level found indoors. Source identification is also possible by determining the indoor/outdoor ( I / O ) concentration ratio. For the rooms facing the city street, this I / O ratio is close to 1 for all aromatic hydrocarbons studied with the exception of toluene ( I / O =3.5), while in the rural areas I / O ratios for the individual compounds ranging in 6–9 were determined, with the exception of benzene where the I / O ratio is only 1.5. These I / O ratios in the city street with high traffic density indicate that an equilibrium between indoor and outdoor air is almost reached. Indoor sources prevail only in the case of toluene. In contrast, in the rural area, indoor sources dominate for all aromatic hydrocarbons except benzene, the indoor level of which is mainly influenced by the outdoor air even in areas of very low traffic density. However, weak indoor sources must exist also for this compound even in non-smoker homes. The internal exposure of the non-smoking inhabitants of these homes to benzene is very low. Depending on the living area, mean values of 61–67xa0ngxa0l −1 benzene in blood and 0.9–1.2xa0μgxa0m −3 in the exhaled air were found.

Determination of physiological palladium, platinum, iridium and gold levels in human blood using double focusing magnetic-sector field inductively coupled plasma mass spectrometry

A procedure is described for the determination of Pd, Ir, Pt and Au in nhuman blood at environmental concentrations based on double focusing nmagnetic sector field ICP-MS. It is shown that the practical detection nlimits in such complex matrices are not essentially limited by ninstrumental capabilities, but are mainly a result of blank values and nspectral interferences. Feasible ways are shown to reduce these blanks and ninterferences. Ultraviolet photolysis was found to be advantageous over nmineral acid digestion techniques, because minimal reagent addition is nrequired. Additional sub-boiling distillation of the commercially navailable ultrapure nitric acid, working in a clean-air laboratory and a nskillful cleaning of all materials resulted in a further reduction of nblanks. With the exception of Au, detection limits in blood samples were nfound to be well below 1 ng l n -1 n. Taking into account a ndilution factor of 22.4 the detection limits related to the final solution nwere between 0.01 and 0.02 ng l n -1 n. The Pd, Ir, Pt and Au nwere detectable in the blood samples of all seven unexposed nvolunteers.

Determination of selected microbial volatile organic compounds by diffusive sampling and dual-column capillary GC-FID-a new feasible approach for the detection of an exposure to indoor mould fungi?

A new, analytically valid procedure is described to assess the exposure of human beings to the so-called microbial volatile organic compounds (MVOCs) in air. The method can be used routinely for large sample numbers and is especially valuable as a basis for further research on the correlation between single MVOCs and indoor mould growth. The procedure is based on the fact that fungi produce a variety of volatile organic compounds, such as 3-methylbutan-1-ol, 3-methylbutan-2-ol, fenchone, heptan-2-one, hexan-2-one, octan-3-one, octan-3-ol, pentan-2-ol, alpha-terpineol, and thujopsene, which they emit into the indoor environment. Using diffusive samplers, these MVOCs are adsorbed onto charcoal during a sampling interval of four weeks. The described method is thus superior to existing methods which use short-term active sampling. After desorption with carbon disulfide, the MVOCs were determined by dual-column gas chromatography with flame ionization detection using the large-volume injection technique for sample introduction. The detection limits ranged between 0.15 and 0.53 microgram m-3, within-series precision was found to range between 6.5 and 19.0%, and recovery was between 77 and 118%. The procedure has been successfully applied in the context of a large field study to measure the indoor MVOC exposure in childrens rooms of 132 dwellings. The objective of the study was to examine the relation between indoor mould growth, the indoor MVOC exposure and the prevalence of adverse health effects. Information about mould formation has been obtained by a questionnaire and by the determination of colony forming units of mould fungi in mattress dust. With the exception of 3-methylbutan-2-ol, fenchone, nonan-2-one, octan-2-one, and thujopsene, indoor air concentrations of all MVOCs under investigation were significantly higher inside damp and mouldy dwellings. From the primary MVOCs under investigation, 3-methylbutan-1-ol, hexan-2-one, heptan-2-one, and octan-3-ol were found to be most reliable indicators for mould formation. A correlation was also found between selected MVOCs and the occurrence of mould species in mattress dust. Aspergillus sp. correlated with heptan-2-one, hexan-2-one, octan-3-ol, octan-3-one, and alpha-terpineol, while the occurrence of Eurotium sp. was correlated with higher indoor air concentrations of 3-methylbutan-1-ol, 3-methylbutan-2-ol, heptan-2-one, hexan-2-one, octan-3-ol, and thujopsene. Children living in dwellings with elevated MVOC levels had a higher prevalence of asthma, hay fever, wheezing, and irritations of the eyes. These positive associations persisted after controlling for confounding factors such as age, sex, body-mass index, number of siblings, social status, passive smoking, type of heating, and ventilation habits. However, they were not statistically significant. This lack of significance may be a result of the small number of investigated samples.

Comparison between capillary electrophoresis and ion-chromatography for analysis of inorganic anions

Separation and detection of some selected inorganic anions with capillary electrophoresis are shown. The anions are separated in microbore capillaries (25 μm* 0.2 m) and detected with a UV-detector. Results are compared with the method of ion exchange chromatography. In consideration of the most important physical and chemical parameters an easy kind of computer simulation for such electropherograms was developed.To get optimal results of separation and UV-detection in capillary electrophoresis some parameters of the device HPE 100, i.e. loading time in the electrokinetic sample injection mode and the running voltage are varied. The behaviour of absorption in the UV region of the chosen anions as well as the influence of pH values in retention behaviour are investigated. There is a simple way to calculate the electrophoretic mobilities from known retention times. Approximate limits of detection for all anions and for each technique are given.

Development of a combined ultra- and diafiltration technique for use in speciation analysis of protein-bound cadmium in plants

SummaryA combination of stepwise ultrafiltration with subsequent diafiltration for application in speciation analysis of aqueous biological samples is presented which allows the determination of distribution patterns without changing the native binding forms (species). This is possible without additional buffers and, furthermore, is less time consuming than conventional ultrafiltration. It is shown that preliminary statements about binding forms can be made by an optimization of this technique for the separation of an individual sample by recording and interpreting the filtration profile. The developed filtration technique is used for the evaluation of distribution patterns of proteins and cadmium species of an extract from self-cultivated dwarf runner beans to which cadmium was offered for uptake. According to these investigations, the cadmium species are present overwhelmingly in the molecular weight range >30,000 g/mol (61% of the total cadmium content).

Ionenaustausch- und gel-chromatographische Analysenverfahren zur Charakterisierung von Metall-Bindungsformen — Anwendung auf wäßrige Extrakte aus Soja- und Weizenmehl

SummaryBy coupling gel-chromatography with photometric measurements in chemical reaction detectors, distribution patterns are given for metal species (Fe, Zn) bound to organic compounds in aqueous fiuor extracts. First results about kinds and stability of possible species are received by comparison of the distribution patterns for metal ions, with those of the UV-absorbing substances and of functional groups determined by photometry. For further speciation ion-exchange techniques and complexation reactions with photometric reagents are described. The results for iron, e.g., show that metal complexes from flour extracts can be differentiated into kinetically labile and stable as well as cationic, anionic and neutral species. In comparison with previous works, the combination of these techniques leads to more detailed information about the complexation of metals by the organic compounds involved.ZusammenfassungVerteilungsmuster für organisch-gebundene Metallanteile (Fe, Zn) in wäßrigen Mehlextrakten werden durch die Kopplung von gel-chromatographischer Trennung nach unterschiedlichen Molekülgrößenbereichen und photometrischer Messung der Metallgehalte in einem chemischen Reaktionsdetektor ermittelt. Aus dem Vergleich der Verteilungsmuster für Metallionen, UV-absorbierende Stoffe sowie photometrisch bestimmbare funktionelle Gruppen lassen sich erste Informationen über Stabilität und Aufbau möglicher Bindungsformen erhalten. Zur weiteren Differenzierung der Bindungsformen bzw. Spezies werden Ionenaustauschverfahren und Umkomplexierangsversuche mit photometrischen Reagentien beschrieben. Die Ergebnisse am Beispiel des Eisens zeigen, daß eine Differenzierung der Metallkomplexe aus Mehlextrakten in kinetisch labile und stabile sowohl kationische, anionische als auch ungeladene Spezies möglich ist. Eine Kombination dieser Verfahren ermöglicht im Vergleich zu früheren Arbeiten differenzierte Aussagen über die an der Metallkomplexierung beteiligten organischen Bindungspartner.

Coupling techniques in speciation analysis

SummaryDirect coupling techniques in speciation analysis lead to reproducible results with lower risks of trace contamination or losses of analytes in a shorter period of time. The direct coupling mode seems to be most promising for liquid chromatographic separation methods — especially gel permeation chromatography — and for some electrophoretic methods — as flow-through and capillary techniques. Promising detection methods are Flame-AAS and ICP-OES but also hydride-generation AAS and chemical reaction detectors in continuous-flow technique.