The on-line coupling of capillary electrophoresis (CE) and electrospray ionization mass spectrome... more The on-line coupling of capillary electrophoresis (CE) and electrospray ionization mass spectrometry (ESI-MS) for speciation analysis is entailed with a number of difficulties due to technical and methodical reasons. The optimization of several parameters in order to provide stable operating conditions are illustrated in detail: the positioning of the CE capillary, the CE buffer system, the concentration sensitivity and the detection mode. Additionally, off-line ESI-MS investigations of metal species with different stabilities were carried out in order to assess the influence of the ESI-process on the analyzed samples. It turned out, that metal ions and weak metal complexes may undergo gas-phase ligand replacement and intramolecular charge transfer reactions. Therefore, the structure of species will be altered. Covalent organometallic compounds and strong metal complexes, on the other hand, will not be altered and will be detected as charged molecular ions and/or as charged ion-solv...
The high resolution potential of capillary electrophoresis (CE) makes CE techniques valuable for ... more The high resolution potential of capillary electrophoresis (CE) makes CE techniques valuable for separations of selenium species, both, organic and inorganic. Such effective separations of charged species are possible using the CZE mode (Z = zone). Very powerful separations can be achieved by capillary isoelectric focusing, when analysing molecules showing different isoelectric points (pI) values, such as organic Se species. Inductively coupled plasma (ICP) MS is an element-specific multi-element detector, providing extremely low detection limits. The combination of CE with ICP-MS promises a powerful tool for metal speciation. Therefore, an online hyphenation of CE [using capillary zone electrophoresis (CZE) or capillary isoelectric focusing (cITP) model] with ICP-MS, which was developed earlier, was modified and applied to selenium speciation. Separation was differentiated from the detection step during hyphenation. This resulted in short separation times (10 min) and a subsequent ...
Arsenic and inorganic arsenic compounds (with the exception of arsenic hydride): BAT value docume... more Arsenic and inorganic arsenic compounds (with the exception of arsenic hydride): BAT value documentation (2016) The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re-evaluated the “Biologischer Arbeitsstoff-Referenzwert” (BAR) as well as the exposure equivalents for carcinogenic substances (EKA) for arsenic and inorganic arsenic compounds (with the exception of arsenic hydride). Available publications are described in detail. The quantification of the various arsenic species is essential to understand the hazardous potential of the arsenic compounds which differ highly in their toxicity. Therefore the BAR for the sum of different arsenic species is no longer valid. Considering published data from occupational not exposed persons, new BAR for the arsenic species of 0.5 μg/l urine for arsenic (+III), 0.5 μg/l urine for arsenic (+V), 2 μg/l urine for monomethylarsonic acid (MMA) and 10 μg/l urine for dimethylarsinic acid (DMA) were ...
AIM Extracorporeal shockwave application (ESWA) is in clinical use to promote disintegration of s... more AIM Extracorporeal shockwave application (ESWA) is in clinical use to promote disintegration of symptomatic calcifications of the rotator cuff of the shoulder. However, disintegration of roentgenologically comparable calcifications of the rotator cuff is not always successfull. It is known from urologic stone lithotripsy that the susceptibility for disintegration of stone-like concrements depends on their mineral content. Therefore, in the present investigation the relative contents of calcium and phosphorus in rotator cuff calcifications were determined. METHOD 39 surgically removed rotator cuff calcifications were analyzed by means of atomic emission spectrometry. RESULTS The relative content of calcium of the rotator cuff calcifications was found to be 22.3 % +/- 5.7 % (mean +/- SD; 6.8 % - 32.4 %), that of phosphorus as 10.5 % +/- 2.4 % (2.7 % - 14.4 %). The data neither depend on the gender of the patients nor on their age at the time point of surgical removal of the rotator cuff calcifications. CONCLUSION Roentgenologically comparable calcifications of the rotator cuff demonstrated distinct individual differences concerning the relative contents of calcium and phosphorus. The present results may serve as the first indication that the susceptibility of rotator cuff calcifications for disintegration may depend on their relative contents of calcium and phosphorus.
Extracorporeal shockwave application (ESWA) is in clinical use to promote disintegration of sympt... more Extracorporeal shockwave application (ESWA) is in clinical use to promote disintegration of symptomatic calcifications of the rotator cuff of the shoulder. However, disintegration of roentgenologically comparable calcifications of the rotator cuff is not always successfull. It is known from urologic stone lithotripsy that the susceptibility for disintegration of stone-like concrements depends on their mineral content. Therefore, in the present investigation the relative contents of calcium and phosphorus in rotator cuff calcifications were determined. 39 surgically removed rotator cuff calcifications were analyzed by means of atomic emission spectrometry. The relative content of calcium of the rotator cuff calcifications was found to be 22.3 % +/- 5.7 % (mean +/- SD; 6.8 % - 32.4 %), that of phosphorus as 10.5 % +/- 2.4 % (2.7 % - 14.4 %). The data neither depend on the gender of the patients nor on their age at the time point of surgical removal of the rotator cuff calcifications. ...
This chapter describes strategies and methods for speciation investigations using mainly hyphenat... more This chapter describes strategies and methods for speciation investigations using mainly hyphenated techniques of liquid chromatography with element-specific detection. Complete speciation schemes are discussed, starting with the sources of error and problem solutions for sampling and ending with more dimensional, orthogonally chosen coupled-speciation techniques for quality controlled results. The focus in each section is directed to the specific problems being faced with respect to speciation analysis: species stability during sample storage and processing, the choice of the most suitable speciation approaches (direct methods or hyphenated techniques), species separation techniques ranging from ultrafiltration to various forms of liquid chromatography, and capillary electrophoresis, discussing their advantageous as well as their (undesired) potential of changing species. Further, problems in interfacing to element-specific detectors, mainly plasma-based detectors like ICP OES and ICP MS are reported. The chapter concludes with aspects of quality control, including sources of errors and strategies to overcome such problems, such as orthogonal speciation concepts.
Following the end of the Kosovo conflict, in June 1999, a study was instigated to evaluate whethe... more Following the end of the Kosovo conflict, in June 1999, a study was instigated to evaluate whether there was a cause for concern of health risk from depleted uranium (DU) to German peacekeeping personnel serving in the Balkans. In addition, the investigations were extended to residents of Kosovo and southern Serbia, who lived in areas where DU ammunitions were deployed. In order to assess a possible DU intake, both the urinary uranium excretion of volunteer residents and water samples were collected and analysed using inductively coupled plasma-mass spectrometry (ICP-MS). More than 1300 urine samples from peacekeeping personnel and unexposed controls of different genders and age were analysed to determine uranium excretion parameters. The urine measurements for 113 unexposed subjects revealed a daily uranium excretion rate with a geometric mean of 13.9 ng/d (geometric standard deviation (GSD)=2.17). The analysis of 1228 urine samples from the peacekeeping personnel resulted in a geometric mean of 12.8 ng/d (GSD=2.60). It follows that both unexposed controls and peacekeeping personnel excreted similar amounts of uranium. Inter-subject variation in uranium excretion was high and no significant age-specific differences were found. The second part of the study monitored 24 h urine samples provided by selected residents of Kosovo and adjacent regions of Serbia compared to controls from Munich, Germany. Total uranium and isotope ratios were measured in order to determine DU content. (235)U/(238)U ratios were within +/-0.3% of the natural value, and (236)U/(238)U was less than 2 x 10(-7), indicating no significant DU in any of the urine samples provided, despite total uranium excretion being relatively high in some cases. Measurements of ground and tap water samples from regions where DU munitions were deployed did not show any contamination with DU, except in one sample. It is concluded that both peacekeeping personnel and residents serving or living in the Balkans, respectively, were not exposed to significant amounts of DU.
The speciation of trace element species in solid matrices like liver samples is still problematic... more The speciation of trace element species in solid matrices like liver samples is still problematic due to two reasons. On the one hand direct methods with sufficient selectivity and sensitivity are currently not available. Therefore extraction procedures have to be applied which are often problematic in respect to species stability. On the other hand there are no reference materials with known amounts of metal proteins like metallothionein-isoforms (MT) and superoxide dismutase (SOD) for quality control. So the aim of this study was to develop and optimise procedures for the species-preserving extraction of the model compounds MT and SOD from liver samples. Spiking experiments were performed to overcome the lack of appropriate reference materials. In a first step the stability of the model species without liver matrix was investigated by the variation of several extraction parameters. The extractant and exposure to ultrasonic energy especially had a great influence on the recovery of the species while temperature, buffer concentration and atmospheric conditions were less critical. In a second step spiked liver samples were extracted with a selection of procedures taken from the literature. Most of these methods provided recoveries between 70% and 100%. Additionally the buffer concentration and the extractant-to-liver ratio were varied for optimisation. The metal balance of an extraction showed recoveries of 81% for Cd, 94% for Cu and 87% for Zn.
Background/Objectives:The apparent widespread extent of zinc (Zn) deficiency in developing countr... more Background/Objectives:The apparent widespread extent of zinc (Zn) deficiency in developing countries and the efficacy of oral Zn supplements as an adjunct to oral rehydration therapy make oral Zn supplementation an increasingly important modality in clinical medicine and public health. In this study we aimed to compare the relative bioavailability of oral doses of 30 mg of Zn in two dosing formsSubjects/Methods:In total, 10 healthy male volunteers ingested oral Zn doses with 200 ml plain water at about 0830 hours in the fasting state on two occasions, once as 30 mg of Zn in an aqueous solution of reagent grade zinc sulfate (ZnSO4) and another time as 1.5 NutriSet Zn tablets (Nutriset, Malaunay, France); on a third occasion, only plain water was consumed. Venous blood specimens were collected at baseline, 60, 120, 180 and 240 min after ingestion and the plasma Zn was measured for each sample.Results:The relative bioavailability of oral Zn from a commonly used, tableted (NutriSet) for...
The on-line coupling of capillary electrophoresis (CE) and electrospray ionization mass spectrome... more The on-line coupling of capillary electrophoresis (CE) and electrospray ionization mass spectrometry (ESI-MS) for speciation analysis is entailed with a number of difficulties due to technical and methodical reasons. The optimization of several parameters in order to provide stable operating conditions are illustrated in detail: the positioning of the CE capillary, the CE buffer system, the concentration sensitivity and the detection mode. Additionally, off-line ESI-MS investigations of metal species with different stabilities were carried out in order to assess the influence of the ESI-process on the analyzed samples. It turned out, that metal ions and weak metal complexes may undergo gas-phase ligand replacement and intramolecular charge transfer reactions. Therefore, the structure of species will be altered. Covalent organometallic compounds and strong metal complexes, on the other hand, will not be altered and will be detected as charged molecular ions and/or as charged ion-solv...
The high resolution potential of capillary electrophoresis (CE) makes CE techniques valuable for ... more The high resolution potential of capillary electrophoresis (CE) makes CE techniques valuable for separations of selenium species, both, organic and inorganic. Such effective separations of charged species are possible using the CZE mode (Z = zone). Very powerful separations can be achieved by capillary isoelectric focusing, when analysing molecules showing different isoelectric points (pI) values, such as organic Se species. Inductively coupled plasma (ICP) MS is an element-specific multi-element detector, providing extremely low detection limits. The combination of CE with ICP-MS promises a powerful tool for metal speciation. Therefore, an online hyphenation of CE [using capillary zone electrophoresis (CZE) or capillary isoelectric focusing (cITP) model] with ICP-MS, which was developed earlier, was modified and applied to selenium speciation. Separation was differentiated from the detection step during hyphenation. This resulted in short separation times (10 min) and a subsequent ...
Arsenic and inorganic arsenic compounds (with the exception of arsenic hydride): BAT value docume... more Arsenic and inorganic arsenic compounds (with the exception of arsenic hydride): BAT value documentation (2016) The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re-evaluated the “Biologischer Arbeitsstoff-Referenzwert” (BAR) as well as the exposure equivalents for carcinogenic substances (EKA) for arsenic and inorganic arsenic compounds (with the exception of arsenic hydride). Available publications are described in detail. The quantification of the various arsenic species is essential to understand the hazardous potential of the arsenic compounds which differ highly in their toxicity. Therefore the BAR for the sum of different arsenic species is no longer valid. Considering published data from occupational not exposed persons, new BAR for the arsenic species of 0.5 μg/l urine for arsenic (+III), 0.5 μg/l urine for arsenic (+V), 2 μg/l urine for monomethylarsonic acid (MMA) and 10 μg/l urine for dimethylarsinic acid (DMA) were ...
AIM Extracorporeal shockwave application (ESWA) is in clinical use to promote disintegration of s... more AIM Extracorporeal shockwave application (ESWA) is in clinical use to promote disintegration of symptomatic calcifications of the rotator cuff of the shoulder. However, disintegration of roentgenologically comparable calcifications of the rotator cuff is not always successfull. It is known from urologic stone lithotripsy that the susceptibility for disintegration of stone-like concrements depends on their mineral content. Therefore, in the present investigation the relative contents of calcium and phosphorus in rotator cuff calcifications were determined. METHOD 39 surgically removed rotator cuff calcifications were analyzed by means of atomic emission spectrometry. RESULTS The relative content of calcium of the rotator cuff calcifications was found to be 22.3 % +/- 5.7 % (mean +/- SD; 6.8 % - 32.4 %), that of phosphorus as 10.5 % +/- 2.4 % (2.7 % - 14.4 %). The data neither depend on the gender of the patients nor on their age at the time point of surgical removal of the rotator cuff calcifications. CONCLUSION Roentgenologically comparable calcifications of the rotator cuff demonstrated distinct individual differences concerning the relative contents of calcium and phosphorus. The present results may serve as the first indication that the susceptibility of rotator cuff calcifications for disintegration may depend on their relative contents of calcium and phosphorus.
Extracorporeal shockwave application (ESWA) is in clinical use to promote disintegration of sympt... more Extracorporeal shockwave application (ESWA) is in clinical use to promote disintegration of symptomatic calcifications of the rotator cuff of the shoulder. However, disintegration of roentgenologically comparable calcifications of the rotator cuff is not always successfull. It is known from urologic stone lithotripsy that the susceptibility for disintegration of stone-like concrements depends on their mineral content. Therefore, in the present investigation the relative contents of calcium and phosphorus in rotator cuff calcifications were determined. 39 surgically removed rotator cuff calcifications were analyzed by means of atomic emission spectrometry. The relative content of calcium of the rotator cuff calcifications was found to be 22.3 % +/- 5.7 % (mean +/- SD; 6.8 % - 32.4 %), that of phosphorus as 10.5 % +/- 2.4 % (2.7 % - 14.4 %). The data neither depend on the gender of the patients nor on their age at the time point of surgical removal of the rotator cuff calcifications. ...
This chapter describes strategies and methods for speciation investigations using mainly hyphenat... more This chapter describes strategies and methods for speciation investigations using mainly hyphenated techniques of liquid chromatography with element-specific detection. Complete speciation schemes are discussed, starting with the sources of error and problem solutions for sampling and ending with more dimensional, orthogonally chosen coupled-speciation techniques for quality controlled results. The focus in each section is directed to the specific problems being faced with respect to speciation analysis: species stability during sample storage and processing, the choice of the most suitable speciation approaches (direct methods or hyphenated techniques), species separation techniques ranging from ultrafiltration to various forms of liquid chromatography, and capillary electrophoresis, discussing their advantageous as well as their (undesired) potential of changing species. Further, problems in interfacing to element-specific detectors, mainly plasma-based detectors like ICP OES and ICP MS are reported. The chapter concludes with aspects of quality control, including sources of errors and strategies to overcome such problems, such as orthogonal speciation concepts.
Following the end of the Kosovo conflict, in June 1999, a study was instigated to evaluate whethe... more Following the end of the Kosovo conflict, in June 1999, a study was instigated to evaluate whether there was a cause for concern of health risk from depleted uranium (DU) to German peacekeeping personnel serving in the Balkans. In addition, the investigations were extended to residents of Kosovo and southern Serbia, who lived in areas where DU ammunitions were deployed. In order to assess a possible DU intake, both the urinary uranium excretion of volunteer residents and water samples were collected and analysed using inductively coupled plasma-mass spectrometry (ICP-MS). More than 1300 urine samples from peacekeeping personnel and unexposed controls of different genders and age were analysed to determine uranium excretion parameters. The urine measurements for 113 unexposed subjects revealed a daily uranium excretion rate with a geometric mean of 13.9 ng/d (geometric standard deviation (GSD)=2.17). The analysis of 1228 urine samples from the peacekeeping personnel resulted in a geometric mean of 12.8 ng/d (GSD=2.60). It follows that both unexposed controls and peacekeeping personnel excreted similar amounts of uranium. Inter-subject variation in uranium excretion was high and no significant age-specific differences were found. The second part of the study monitored 24 h urine samples provided by selected residents of Kosovo and adjacent regions of Serbia compared to controls from Munich, Germany. Total uranium and isotope ratios were measured in order to determine DU content. (235)U/(238)U ratios were within +/-0.3% of the natural value, and (236)U/(238)U was less than 2 x 10(-7), indicating no significant DU in any of the urine samples provided, despite total uranium excretion being relatively high in some cases. Measurements of ground and tap water samples from regions where DU munitions were deployed did not show any contamination with DU, except in one sample. It is concluded that both peacekeeping personnel and residents serving or living in the Balkans, respectively, were not exposed to significant amounts of DU.
The speciation of trace element species in solid matrices like liver samples is still problematic... more The speciation of trace element species in solid matrices like liver samples is still problematic due to two reasons. On the one hand direct methods with sufficient selectivity and sensitivity are currently not available. Therefore extraction procedures have to be applied which are often problematic in respect to species stability. On the other hand there are no reference materials with known amounts of metal proteins like metallothionein-isoforms (MT) and superoxide dismutase (SOD) for quality control. So the aim of this study was to develop and optimise procedures for the species-preserving extraction of the model compounds MT and SOD from liver samples. Spiking experiments were performed to overcome the lack of appropriate reference materials. In a first step the stability of the model species without liver matrix was investigated by the variation of several extraction parameters. The extractant and exposure to ultrasonic energy especially had a great influence on the recovery of the species while temperature, buffer concentration and atmospheric conditions were less critical. In a second step spiked liver samples were extracted with a selection of procedures taken from the literature. Most of these methods provided recoveries between 70% and 100%. Additionally the buffer concentration and the extractant-to-liver ratio were varied for optimisation. The metal balance of an extraction showed recoveries of 81% for Cd, 94% for Cu and 87% for Zn.
Background/Objectives:The apparent widespread extent of zinc (Zn) deficiency in developing countr... more Background/Objectives:The apparent widespread extent of zinc (Zn) deficiency in developing countries and the efficacy of oral Zn supplements as an adjunct to oral rehydration therapy make oral Zn supplementation an increasingly important modality in clinical medicine and public health. In this study we aimed to compare the relative bioavailability of oral doses of 30 mg of Zn in two dosing formsSubjects/Methods:In total, 10 healthy male volunteers ingested oral Zn doses with 200 ml plain water at about 0830 hours in the fasting state on two occasions, once as 30 mg of Zn in an aqueous solution of reagent grade zinc sulfate (ZnSO4) and another time as 1.5 NutriSet Zn tablets (Nutriset, Malaunay, France); on a third occasion, only plain water was consumed. Venous blood specimens were collected at baseline, 60, 120, 180 and 240 min after ingestion and the plasma Zn was measured for each sample.Results:The relative bioavailability of oral Zn from a commonly used, tableted (NutriSet) for...
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