Jutta Begerow

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 human blood at environmental concentrations based on double focusing magnetic sector field ICP-MS. It is shown that the practical detection limits in such complex matrices are not essentially limited by instrumental capabilities, but are mainly a result of blank values and spectral interferences. Feasible ways are shown to reduce these blanks and interferences. Ultraviolet photolysis was found to be advantageous over mineral acid digestion techniques, because minimal reagent addition is required. Additional sub-boiling distillation of the commercially available ultrapure nitric acid, working in a clean-air laboratory and a skillful cleaning of all materials resulted in a further reduction of blanks. With the exception of Au, detection limits in blood samples were found to be well below 1 ng l -1 . Taking into account a dilution factor of 22.4 the detection limits related to the final solution were between 0.01 and 0.02 ng l -1 . The Pd, Ir, Pt and Au were detectable in the blood samples of all seven unexposed volunteers.

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.

Determination of benzene, toluene, ethylbenzene and xylenes in indoor air at environmental levels using diffusive samplers in combination with headspace solid-phase microextraction and high-resolution gas chromatography–flame ionization detection

An improved analytical method for passive air sampling is presented based on a combination of commercially available diffusive samplers with headspace solid-phase microextraction and high-resolution gas chromatography with flame ionization detection (HRGC-FID). This procedure is targeted for short-term BTEX (benzene, toluene, ethylbenzene and o-, m- and p-xylenes) determinations at environmental concentrations and can be applied for sampling intervals between 30 min and 24 h. The analytes are adsorbed onto the charcoal pad of a passive sampler and then extracted with carbon disulphide-methanol. After removal of the carbon disulphide by xanthation, the BTEXs are enriched on a Carboxen SPME fiber, thermally desorbed and analysed by HRGC-FID. Detection limits for a sampling interval of 2 h are between 0.4 and 2 micrograms/m3, within-series precision ranges between 6.6 and 12.8%, day-to-day precision is between 11.1 and 15.2%. The results obtained with this procedure are validated by comparison with active sampling. Detection limits and a further reduction of the sampling time are limited by blanks of the chemicals and the diffusive samplers. Procedures to eliminate these blanks are described in detail. Applications such as the determination of BTEXs in indoor air inside buildings, inside a train and a car are presented, indicating the usefulness of the described procedure for short-term measurements of environmental BTEX concentrations. An advantage of passive samplers is the storage stability for at least six months, which is essential for its use in large epidemiological studies.

Determination of physiological noble metals in human urine using liquid-liquid extraction and Zeeman electrothermal atomic absorption spectrometry

An extremely sensitive, reliable and simple procedure is described for the determination of physiological palladium, platinum and gold in human urine. The urine samples were adjusted to pH 4 (Pd, Au) or pH 5 (Pt), followed by conversion of the analytes to their pyrrolidinedithiocarbamate complexes. These complexes were separated from the matrix by liquid-liquid extraction into 4-methyl-2-pentanone resulting in a 25-fold enrichment. Determination was by electrothermal atomic absorption spectrometry (ET-AAS) using longitudinal inverse alternating current Zeeman-effect background correction. The limits of detection calculated from three standard deviations of the blank values were 20 ng l−1 for Pd and Au and 70 ng l−1 Pt. Within-day precision (n = 10, 5 μg l−1) ranged 5.2%–7.7%. The procedure is successfully applied to determine urinary palladium, platinum and gold in nine unexposed persons. Palladium levels in urine ranged < 20–80 ng l−1 (arithmetical mean=38.7 ng l−1), while gold levels ranged < 20–130 ng l−1 (36.0 ng l−1). Physiological platinum levels in urine were all < 70 ng l−1. The accuracy of the procedure was checked by analyzing a series of urine samples by a second independent method (magnetic sector field inductively-coupled plasma-mass spectrometry) in combination with UV photolysis.

New horizons in human biomonitoring of environmentally and occupationally relevant metals—sector-field ICP-MS versus electrothermal AAS

Sector-field ICP-MS (SF-ICP-MS) was used for the quasi-simultaneous determination of selected trace and ultra-trace elements of occupational and environmental interest, such as Al, Co, Cr, Cu, Fe, Mn, Ni, Pt, V and Zn, in human urine and serum. In the case of urine, Pb, Cd and Tl were additionally determined. Sample pretreatment was restricted to UV photolysis and to a subsequent moderate dilution with 0.5% HNO3 solution without using any chemical separation and enrichment. Contamination was carefully controlled at each step of the analytical procedure. Calibration was carried out by the standard addition procedure. Owing to spectral interferences, the determination of Al, Co, Cr, Cu, Fe, Ni, V and Zn was performed in the medium resolution (MR) mode (m/Δm ≅ 3000), while the determination of non-interfered elements, such as Cd, Mn, Pb, Pt and Tl, was carried out at low resolution (LR) to gain a maximum of sensitivity. The accuracy of the procedure was checked by the analysis of commercially available quality control serum and urine samples, by comparison with electrothermal (ET-)AAS as a second independent method and by successful participation in an inter-laboratory comparison programme. The results obtained with both methods were in excellent agreement. Regarding the quality control materials, good agreement was also achieved between the found and assigned values. The described SF-ICP-MS multi-element method is thus suitable for the quasi-simultaneous determination of trace and ultra-trace elements in urine and serum covering a wide range of concentrations. It is especially valuable for rapid multi-element screening purposes in cases of unknown exposures (non-target screening) and for determinations at very low concentrations, which are not accessible to AAS techniques.

Determination of physiological platinum levels in human urine using magnetic sector field inductively coupled plasma mass spectrometry in combination with ultraviolet photolysis

An extremely sensitive and reliable procedure for the determination of physiological (normal) Pt levels in human urine is described based on UV photolysis of the sample followed by the determination of Pt with magnetic sector field ICP-MS. Owing to the low blank values, which are a consequence of the minimal reagent addition required, UV photolysis was used to decompose the organic matrix components. Magnetic sector field ICP-MS operated in the low resolution mode afforded detection limits that were 100 times lower than those obtained in the high resolution mode or with conventional quadrupole ICP-MS and was found to be advantageous for the ultratrace determination of non-interfered isotopes. The detection limit in urine samples was 0.24 ng l–1 using standard nickel cones. The use of a high performance nickel skimmer cone did not result in an improvement in the detection limit, because the analyte and background signals were enhanced to a similar extent. The urinary Pt levels in 16 non-exposed persons ranged between 0.48 and 7.65 ng l–1(arithmetic mean: 1.72 ng l–1).

Mass spectral interferences in the determination of trace levels of precious metals in human blood using quadrupole magnetic sector field and inductively coupled plasma mass spectrometry

The results of the determination of physiological levels of precious metals in blood with a new type of magnetic sector field high resolution (HR)-ICP-MS instrument are presented. Palladium levels, for example, ranged between 32 and 102.5 ng l–1. HR-ICP-MS operating in the low resolution mode is advantageous for such ultratrace analyses as it is about 100 times more sensitive than in the HR mode or conventional quadrupole (Q)-ICP-MS. It is also shown that the determination of Rh and Pd in the ng l–1 range is impaired by spectral interferences originating from Cd+, Pb2+, SrO+, RbO+, CuAr+ and ZnAr+. Using standard instrumental operating conditions on a Q-ICP-MS instrument, Pb2+:Pb+ and SrO+ :Sr+ ratios were found to be about 0.1%, which results in a severe impairment of the determination of physiological Rh and Pd concentrations in body fluids. The resolution of the HR instrument used (m/Δm= 7500) was not sufficient to separate Rh and Pd from all spectral overlaps. These remaining spectral interferences can only be overcome by an appropriate sample preparation step.

Internal lead and cadmium exposure in 6-year-old children from western and eastern Germany

Lead and cadmium levels in blood and deciduous teeth (shed incisors only) of 6-year-old German children were determined in 1991 in a large epidemiological study carried out in rural and urban areas of western Germany (Duisburg, Essen, Gelsenkirchen, Dortmund, Borken) and eastern Germany (Leipzig, Halle, Magdeburg, Osterburg, Gardelegen, Salzwedel). In total, blood lead and cadmium levels of 2311 German children and tooth lead and cadmium levels of 790 German children were analyzed. Blood lead levels were generally low in all study areas with geometric means between 39.3 μg/1 and 50.8 μg/l in the western German and between 42.3 μg/1 and 68.1 μg/l in the eastern German study areas. The mean blood lead level of Turkish children (n = 213) living in the western German study areas was 50.1 μg/l and thus 5.6 μg/1 higher than the overall geometric mean of the western German children. The higher exposure may be explained by a higher oral uptake from food and different living conditions. These children were excluded from multiple regression analysis because they were all living in the western study areas. The mean tooth lead levels ranged between 1.50 and 1.74 μg/g in the western and between 1.51 μg/g and 2.72 μg/g in the eastern study areas. Thus, they show a distribution pattern similar to blood. Blood and tooth lead levels were higher in urban than in rural areas and higher in the eastern German than in the western German study areas. With regard to the blood and tooth cadmium concentrations, no significant differences between the study areas could be found. The mean cadmium levels in blood ranged between 0.12 μg/1 and 0.14 μg/l and the mean tooth cadmium concentrations between 20.8 ng/g and 27.8 ng/g. Blood and tooth lead and cadmium levels of the eastern and western German children were thus mainly at a relatively low level in all rural and urban study areas. The study demonstrates and confirms that blood and tooth lead levels are influenced by several demographic, social, and environmental variables. The results indicate that there has been a further significant decrease of lead and cadmium exposure in western German children since our last epidemiological study carried out in the same study areas in 1985/1986.

Screening method for the determination of 28 volatile organic compounds in indoor and outdoor air at environmental concentrations using dual-column capillary gas chromatography with tandem electron-capture-flame ionization detection

Abstract A gas chromatographic method is presented for the simultaneous determination of 28 volatile organic compounds (VOCs) in indoor and outdoor air at environmental concentrations. Using diffusive (passive) samplers, the VOCs were adsorbed onto charcoal during a four-week sampling period and subsequently desorbed with carbon disulphide. After injection, using a cold split-splitness injector, the mobile phase was split via a Y-connector and led onto two capillary columns of different polarity switched in parallel. This dual-column configuration provides additional information about the VOC components and can be obtained for verification purposes. Detection was in both cases performed by connecting each column with a non-destructive electron-capture detector and a flame ionization detector switched in series. By this procedure sensitivity is increased because no effluent splitting is required. At the same time, sample throughput is enhanced drastically since several items of information are obtained simultaneously. The procedure has been successfully applied in the context of a large field study to measure outdoor air concentrations in three areas with different traffic density. It is applicable to indoor air measurements in like manner.

Long-term mercury excretion in urine after removal of amalgam fillings.

The long-term urinary mercury excretion was determined in 17 28- to 55-year-old persons before and at varying times (up to 14 months) after removal of all (4–24) dental amalgam fillings. Before removal the urinary mercury excretion correlated with the number of amalgam fillings. In the immediate post-removal phase (up to 6 days after removal) a mean increase of 30% was observed. Within 12 months the geometric mean of the mercury excretion was reduced by a factor of 5 from 1.44 μg/g (range: 0.57–4.38 μg/g) to 0.36 μg/g (range: 0.13–0.88 μg/g). After cessation of exposure to dental amalgam the mean half-life was 95 days. These results show that the release of mercury from dental amalgam contributes predominantly to the mercury exposure of non-occupationally exposed persons. The exposure from amalgam fillings thus exceeds the exposure from food, air and beverages. Within 12 months after removal of all amalgam fillings the participants showed substantially lower urinary mercury levels which were comparable to those found in subjects who have never had dental amalgam fillings. A relationship between the urinary mercury excretion and adverse effects was not found. Differences in the frequency of effects between the pre- and the post-removal phase were not observed.