Auflistung nach Autor:in "Leng, Gabriele"

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DPHP metabolites in urine samples of the German Environmental Specimen Bank from 1999 to 2012
(2014) Schütze, Andre; Gries, Wolfgang; Kolossa-Gehring, Marike; Apel, Petra; Schröter-Kermani, Christa; Brühning, Thomas; Leng, Gabriele; Koch, Holger Martin
The aim of this study was to investigate a possible time trend and status quo of
dipropylheptylphthalate (DPHP) exposure. DPHP is used as a substitute of other high molecular weightphthalates in high temperature applications (e.g cable wires, roofing membranes, etc.). DPHP was selected inthe cooperation project between the German Federal Ministry for Environment (BMU) and the German ChemicalIndustry Association (VCI) due to its listing as High Production Volume (HPV) chemical in the European Union.The BMU-VCI project establishes new human biomonitoring methods and biomarkers for fifty emergingsubstances. 300 urine samples (24-hour voids) from the German Environmental Specimen Bank were analyzedfor three specific, secondary oxidized DPHP metabolites (with hydroxyl, oxo and carboxy modifications of thealkyl side chain). Urine samples were collected in the years 1999, 2003, 2006, 2009 and 2012, 60 samples peryear, from 30 male and 30 female volunteers (age: 21-29 years). The samples were analyzed by liquid/liquidextraction followed by GC-HRMS, which enabled us to distinguish between DPHP and Di-iso-decyl phthalate(DiDP) metabolites. The limit of quantification was between 0.15 ìg/l and 0.3 ìg/l, depending on the metabolite.All samples were blinded before analysis. DPHP metabolites were not detected in the years 1999-2006.Thereafter, detection rates increased from 3.3% in 2009 to 21.7% in 2012. As expected, mono-oxo-propylheptylphthalate (oxo-MPHP) was the most abundant metabolite, with concentrations between Quelle: 24th Annual Meeting ofThe International Society of Exposure Science: Exposure Science Integration to Protect Ecological Systems,Human Well-Being, and Occupational Health; Abstrct Book ISES 2014 / International Society of Exposure Science, Cincinnati: 2014, S.128
New biomarkers for DPHP, 2-MBT and MDI
(2015) Gries, Wolfgang; Leng, Gabriele; Kolossa-Gehring, Marike; Fiddicke, Ulrike
1. Analytical determination of specific 4,4- Methylenediphenyl-diisocyanate (MDI) hemoglobin adducts: MDI is one of the most important isocyanates in the industrial production of polyurethane and other MDI based synthetics. Because of its reactivity it builds adducts with proteins. Analysis of MDI is routinely done by determination of 4,4-methylene dianiline as marker for MDI exposure in urine and blood. This procedure does not allow distinguishing between the source of exposure; MDA or MDI. This method was developed to detect the MDI specific hemoglobin adduct 5-isopropyl-3[4-(4-aminobenzyl)phenyl] hydantoin in human blood.
2. Analytical method for the selective determination of major Di-(2-propylheptyl)-phthalate (DPHP) metabolites in human urine: DPHP is a specific phthalic acid ester of isomeric C10 alcohols and is marketed as plasticizer for polyvinyl chloride . The object of this method development is the sensitive and selective determination of the three major DPHP metabolites mono-2-(propyl-6-hydroxy-heptyl)-phthalate, mono-2-(propyl-6-oxoheptyl)-phthalate and mono-2-(propyl-6-carboxy-hexyl)-phthalate in human urine among those originating from DIDP or DINP. Values up to 3.8 ìg/L OH-MPHP were detected in 51 urines of children during the "Pilot Phase of the 5th German Environmental Survey-Part 1Ł.
3. Rapid and sensitive LC-MS/MS determination of 2-Mercaptobenzothiazole (MBT) in human urine: MBT is one of the most important vulcanization accelerators in the industrial production of rubber. Incorporated MBT is excreted in urine mainly as conjugates. A method was developed to determine the internal MBT dose in human urine. Total MBT is measured after enzymatic hydrolysis followed by application of high pressure liquid chromatography tandem mass spectrometry in positive electrospray ionization mode. In the "Pilot Phase of the 5th German Environmental Survey-Part 1Ł MBT vThe International Societyof Exposure Science: 25th Annual Meeting: Exposures in an Evolving Environment; October 18 - 22, 2015 - Henderson, Nevada, S. alues up to 5.95 ìg/L were analyzed in 51 urines of children.
In: The International Societyof Exposure Science: 25th Annual Meeting: Exposures in an Evolving Environment; October 18 - 22, 2015 - Henderson, Nevada, S.137
New human biomonitoring methods for chemicals of concern̶the German approach to enhance relevance
(2017) Fiddicke, Ulrike; Leng, Gabriele; Kolossa-Gehring, Marike; Angerer, Jürgen; Wolz, Birgit
New human biomonitoring methods for chemicals of interest
(2014) Fiddicke,Ulrike; Kolossa-Gehring, Marike; Apel, Petra; Schröter-Kermani, Christa; Bader, Michael; Leng, Gabriele; Koch, Holger M.
Introduction The German initiative to develop new human biomonitoring (HBM) methods forsubstances of interest is a cooperation of the Federal Ministry for the Environment, Nature Conservation,Building and Nuclear Safety (BMUB) and the German Chemical Industry Association (VCI) which started in2010. Emphasis is placed on substances either with potential health relevance or for which an exposure of the
general population can be assumed. Methods After identification of relevant chemicals by an expert panel HBMmethods are developed and first applied to about 40 non occupationally exposed persons. The analyticalmethods are cross-validated by the working group ´Analyses in biological Materials of the German ResearchFoundation (DFG) and published together with pilot-test results in international, peer-reviewed journals. ResultsNew HBM methods for methylenediphenyl diisocyanate (MDI ), used in polyurethane and adhesives, thevulcanization accelerator 2-mercaptobenzothiazole (2-MBT), the plasticizer alternatives Hexamoll® DINCH anddi-2-propylheptyl phthalate (DPHP), the alkylphenols 4-tert-octylphenol and 4-nonylphenol and the technicalsolvents N-methyl- and N-ethyl-2-pyrrolidone (NMP/NEP) have already been developed and applied. For someof these chemicals a considerable background exposure seems to be unlikely (e.g. MDI), for other substances(e.g. NMP/NEP) a ubiquitous background was detected. For DINCH and DPHP, trends of increasing exposurewere observed in urine samples from the German Environmental Specimen Bank, mirroring the marketintroduction of the substances. The relevance of the findings needs to be assessed by toxicologically derivedHuman Biomonitoring Values (Biomonitoring Equivalents) and by population representative studies.Consequently, we plan to include these substances in the 5th German Environmental Survey. The results willcontribute to a realistic exposure and risk assessment for these "newŁ chemicals in German children.
Quelle: 24th Annual Meeting ofThe International Society of Exposure Science: Exposure Science Integration to Protect Ecological Systems,Human Well-Being, and Occupational Health; Abstract Book ISES 2014 / International Society of Exposure Science, Cincinnati: 2014, S.159
New human biomonitoring methods for chemicals of interest
(2013) Fiddicke,Ulrike; Kolossa-Gehring, Marike; Apel, Petra; Leng, Gabriele; Koch, Holger M.
New specific and sensitive biomonitoring methods for chemicals of emerging health relevance
(2017) Leng, Gabriele; Fiddicke, Ulrike; Gries, Wolfgang; Kolossa-Gehring, Marike
In this publication the challenges to cope for the aim to obtain innovative biomonitoring methods in our laboratory are visualized for di(2-propylheptyl)phthalate, 2-mercaptobenzothiazole, 3,5-di-tert-butyl-4-hydroxytoluene, 4-nonylphenol, 4-tert-octylphenol, 3-(4-methylbenzylidene)camphor, 4,4'-methylene diphenyl diisocyanate, and Hexabromocyclododecane. For these substances new specific markers were explored based on animal or human kinetic data with urine being the preferred matrix compared to blood. The determination of these markers was complex in all cases, because the sample preparation as well as the detection by high performance liquid chromatography, capillary gas chromatography coupled to tandem mass spectrometers or high resolution mass spectrometry should enable the lowest possible detection limit by use of minimal biological sample volumes. To get a first hint of a possible background level, the analytical methods were applied to urine samples of about 40 persons for each chemical. For Di(2-propylheptyl)phthalate and 2-Mercaptobenzothiazole first results are presented from population biomonitoring. Quelle: http://www.sciencedirect.com
The German Human Biomonitoring Programme
(2016) Kolossa-Gehring, Marike; Apel, Petra; Leng, Gabriele; Fiddicke, Ulrike
The German initiative to enhance human biomonitoring
(2015) Kolossa-Gehring, Marike; Apel, Petra; Leng, Gabriele; Koch, Holger; Fiddicke, Ulrike
The German Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety (BMUB) and the German Chemical Industry Association e. V. (VCI) cooperate since 2010 to increase the knowledge on the internal exposure to chemicals of the general population. Scientific coordination and HBM studies are in the responsibility of the Federal Environment Agency. Emphasis is placed on substances with either a potential health relevance or on substances to which the general population might potentially be exposed to a considerable extent. After identification of relevant chemicals by an expert panel human biomonitoring (HBM) methods are developed and first applied to about 40 non-occupationally exposed individuals. The analytical methods are cross-validated by the working group ´Analyses in biological Materials of the German Research Foundation (DFG) and published together with pilot-test results in international, peer-reviewed journals. In parallel the Human Biomonitoring Commission of the Federal Environment Agency derives toxicologically based Human Biomonitoring-values to interpret the relevance of the exposure levels observed. Up to now 29 chemicals have been chosen for method development, 10 analytical methods are finished and HBM-values for 6 substances have most recently been derived. Application of the new methods in samples from the German Environmental Specimen Bank revealed decreasing, stable or increasing time trends for the technical solvents N-ethyl-2-pyrrolidone and N-methyl-pyrrolidone and the plasticizer alternatives Hexamoll® DINCH and di-2-propylheptyl phthalate (DPHP). Exposure levels in none of the samples analyzed up to now exceeded the respective HBM-I-value. As a next step the new methods will be applied to samples from children and adolescents from the population representative 5th German Environmental Survey. Our HBM studies contribute to a realistic exposure and risk assessment for these chemicals in Germany.
Quelle: http://www.ises2015.org/