Quantitative Spurenanalyse von Thallium in biologischem Material

Determination of rubidium in human serum

Field desorption mass spectrometry (FD-MS) combined with stable isotope dilution has been used to determine rubidium concentrations from human serum. Samples obtained from 110 healthy volunteers (50 males, 60 females) were examined. The rubidium concentrations found varied from 0.96 to 3.56 mumoles/l, the average value being 1.96 mumoles/l. The precision of the measurements within a batch was 0.8%. The time for 1 analysis, including sample preparation is about 30 min, the total sample consumption is 100-200 mul. The corresponding potassium concentrations were also determined from all these serum samples; a weak trend towards higher potassium levels with increasing rubidium concentration is found.

Repeated surveillance of exposure to thallium in a population living in the vicinity of a cement plant emitting dust containing thallium

From 1979 to 1981, several medical surveys were carried out among a population living in the vicinity of a cement plant that emitted dust containing thallium until August, 1979. Air, soil, plants, and domestic animals in the area were contaminated by thallium and this led to an increased intake of thallium in the population, mainly due to the consumption of home-grown vegetables and fruit. In order to assess the degree of the individuals' exposure to thallium, thallium levels in 24-h urine samples (TlU) were determined. Three surveys were carried out from September to December, 1979 to assess the degree of thallium exposure of different parts of the general population. Subjects with relatively high exposure, as indicated by the results of the above mentioned population surveys, or those suffering from health disorders that might be related to an increased intake of thallium, were reexamined several times from 1979-1981. Special attention was also given to children attending a kindergarten situated about 0.5 km from the cement plant. As compared to an "unexposed" reference population (mean TlU: 0.3 microgram/l), the majority of the population living in the cement plant area had significantly elevated urinary thallium levels (range: less than 0.1-76.5 micrograms/l) indicating a substantially increased environmental exposure. A reduction of the intake of thallium was mainly achieved by the fact that the population, as advised by the authorities, largely avoided the consumption of home-grown, potentially contaminated foodstuffs. Reports on the teratogenicity of thallium in certain animal species caused great concern that thallium might have exerted teratogenic effects on the newborn of women exposed to thallium during pregnancy. Therefore, an investigation of children born between January, 1978 and August, 1979 (n = 297) was carried out. Although the number of congenital malformations was greater than expected, we conclude, considering carefully all data available, that there is likely no causal relationship between thallium and the occurrence of congenital malformations in the children investigated.

Time-dependent excretion of lithium, sodium, potassium, rubidium, magnesium and strontium in the urine of a multiple sclerosis patient

Field desorption mass spectrometry and stable isotope dilution have been used for direct trace analysis of metals in urine. Samples were collected over 24 h at 2 h intervals from a hospitalized multiple sclerosis patient. Quantitative determinations of Li+, Rb+, Mg2+ and Sr2+ from individual samples have been made and correlated with the amounts of urine excreted as well as with the time of day. The concentrations of Na+ and K+ were determined by flame photometry. The quantities of metals excreted in urine during the course of 24 h were 0.0129 mg for lithium, 4700 mg for sodium, 2100 mg for potassium, 1.4 mg for rubidium, 78.8 mg for magnesium and 0.2356 mg for strontium. The maximal absolute quantities excreted of all metals determined correspond with the largest volume of urine. The highest amounts of potassium, rubidium and strontium were found in urine during the daytime (8.00-20.00), whilst magnesium was excreted increasingly during the night hours (20.00-8.00). The excretion of lithium and sodium is fairly even over the entire 24 h period. It is noteworthy that similarities in the excretion profile and the concentration course are observed between Li+ and Na+ on one hand and between K+ and Rb+ on the other. Moreover, the lower concentration of Rb+ ions in urine of multiple sclerosis patients, in comparison to healthy individuals and clinical controls as reported previously, was confirmed.

Determination of lithium and rubidium in physiological fluids and tissues of rabbits during the reproductive phase

1. The natural concentrations of lithium and rubidium were determined during the reproductive phase of rabbits by field desorption mass spectrometry. 2. Samples of serum, milk, amniotic fluid and placenta tissue were analysed. 3. The concentration changes in serum during the reproductive phase were between 2.61 and 5.02 micrograms/l for lithium and between 107.78 and 136.28 micrograms/l for rubidium. 4. Correlations between the concentration in maternal serum and bone growth of the fetus as well as the formation of milk were found. 5. Concentrations of 9.30 micrograms/l lithium and 1780.00 micrograms/l rubidium in the milk lead to the assumption that these trace metals are essential for the metabolism of the young rabbit.

Quantitative measurement of time-dependent thallium distribution in organs of mice by field desorption mass spectrometry

The time-dependent distribution of the toxic heavy metal TI in mouse organs was determined after feeding 80, 130, and 160 mg/kg TI. Quantitative measurements were performed by field desorption mass spectrometry with stable isotope dilution. No pretreatment of the tissue samples, other than homogenizing and centrifugation, was necessary. The precision of the data was about +/- 10%. The main results are as follows: Heart, liver, kidney, and stomach showed an organ-specific initial uptake of TI during the first 2-3 h. This was followed by a period of washout to relatively low TI levels. Brain TI uptake was comparatively low and constant during the first 12 h. In the terminal stage (24 h) all organs, including the brain, contained increased TI levels of the same order of magnitude.