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- Englisch (41) (entfernen)
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- Brominated flame retardant (4)
- Chiral separation (3)
- Extraction (3)
- Gas chromatography (3)
- HPLC-MS/MS (3)
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- Diastereomers (2)
- Flame retardant (2)
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Organisationseinheit der BAM
Feste Referenzmaterialien für die Spurenanalytik umweltrelevanter organischer Schadstoffe erfordern aufgrund der geringen thermischen Belastbarkeit der Analyten besondere Aufarbeitungsstrategien für die Herstellung repräsentativer Teilproben. Das in der Fachgruppe I.2 seit 1994 für diesen Zweck systematisch aufgebaute technologische Instrumentarium wird vorgestellt, und das im Laufe der Jahre angesammelte Know How wird anhand von Beispielen vermittelt. Das im Laboratorium I.21 entwickelte Qualitätssystem für eine optimale Logistik der Arbeitsabläufe der Probenherstellung und -verwaltung sowie für eine bedarfsgerechte Charakterisierung der Materialien wird ausführlich erläutert.
Bezüglich der Verwendung der Referenzmaterialien wird herausgestellt, daß es zwei gleichberechtigte Anwendungsrichtungen gibt: die interne Qualitätskontrolle mit zertifizierten Referenzmaterialien (ZRM, z.B. für die Methodenvalidierung) und die externe Qualitätskontrolle (Proficiency Testing = Kompetenzbewertung von Prüflaboratorien). Referenzmaterialien für das Proficiency Testing, die im Umweltbereich in viel größeren Stückzahlen umgesetzt werden können als ZRM, weisen bezüglich Homogenität und Charakterisierung die gleichen Qualitätskriterien wie ZRM auf. Diese Materialien haben - auch im internationalen Maßstab - stark an Bedeutung gewonnen.
Ein englisches Abstract gibt es nicht, aber eine Grobgliederung zur Vortragsankündigung:
This lecture includes:
· the technological and logistical aspects of reference material preparation and sub-sampling and subsequent sample management,
· appropriate measurement strategies for homogeneity and stability studies,
· the use of relevant statistical tests to evaluate those measurement data,
· the organisation of interlaboratory studies based on traceable measurements
The role of matrix reference materials in the process of demonstrating the degree of equivalence of measurement results obtained from intercomparisons is outlined, reviewing exemplary selected experience gained at BAM regarding the determination of organic contaminants in environmental matrices.
The specific characteristics of reference materials employed in the process of demonstrating equivalence between laboratories in the course of proficiency testing as well as the development, comparison and validation of methods are elaborated. The demand is for series of appropriately characterised samples which are fit for the purpose and it is seen from representative examples that the utilisation of such tailor-made RM designed to tackle the specific need of an analytical problem dominates over certified matrix reference materials in this context. Concluding, the role of certified matrix reference materials in quality assurance is briefly looked at both from the users and providers points of view.
A method for the determination of the novel brominated flame retardant tetrabromobisphenol A bis(2,3-dibromopropylether), 1,1'-(isopropylidene)bis[3,5-dibromo-4-(2,3-dibromo-propoxy)-benzene] (TBBPA-dbpe), was developed. Technical TBBPA-dbpe was purified and the results of a thorough physical characterisation are reported. The application of APCI-MS is discussed and the fragmentation patterns are described. Quantification of TBBPA-dbpe was done by HPLC-DAD using external calibration. The validation of the method was accomplished using sediment and sewage sludge samples spiked with defined amounts of authentic TBBPA-dbpe. The average recovery rates of TBBPA-dbpe from spiked samples ranged from 35 to 91% (sediment) and from 57 to 98% (sewage sludge) depending on the respective extraction method. Pressurised fluid extraction (PFE) and fluidised bed extraction were superior to classical Soxhlet and sonication procedures and yielded recovery rates between 90 and 98% with relative standard deviations of 2%. The limits of detection (DTC), identification (ID) and determination (DTM) using HPLC-DAD were 10, 21 and 30 ng g-1 in sediment and 22, 44 and 72 ng g-1 in sewage sludge, respectively.
The performance of twelve laboratories with previously established proficiency in the determination of the mineral oil content in a fresh water sediment is described. The summation parameter total petrol hydrocarbon (TPH) is defined according to ISO 16703:2004 with regard to the sample preparation to be applied, the flame ionisation detection (FID) and the boiling range of C10C40 to be integrated. Comprehensive tests of homogeneity and stability have been carried out on the candidate material using appropriate models. The outcome of the study served as the basis for the certification of the candidate reference material as ERM-CC015a. The certified mass fraction is 1,820±130mgkg-1 and traceability was established by using an appropriate calibration standard certified for the mass fraction of C10C40. The interlaboratory scatter of measurement results in this exercise can largely be explained by the variability of the individual calibrations based on this common calibration standard.
A procedure for the quantification of the PCB marker congeners 28, 52, 101, 138, 153, 180 in plastic waste form the recycling of cables in the range of content between 0.1 mg kg-1 and 20 mg kg-1 was validated. Representative reference materials for laboratory analyses were produced using granulates from different recycling processes. The method development included aspects of grinding, sieving, homogenising as well as the comparison of extraction methods and chromatographic conditions. The validated procedure foresees grinding of the technical sample to an upper particle size limit of 0.50 mm followed by extraction with an unpolar solvent such as n-hexane and gas chromatographic determination. LOD and LOQ for individual congeners ranged between 0.01 mg kg-1 and 0.08 mg kg-1. Electron capture detection (ECD) and mass selective detection (MS) were equivalent if chromatographic conditions were appropriately selected. The application of MS was advantageous in presence of significant amounts of interfering components which have been found in some cables.
Three reference materials containing the marker congeners in the range of 0.1 mg kg-15 mg kg-1 were submitted to a final validation intercomparison with 23 selected field laboratories using the developed method. Relative reproducibility standard deviations varied between 15% and 33%.
The interlaboratory variability in the quantification of adsorbable organically bound halogens (AOX) in industrially contaminated soil is presented. Three consecutive rounds of a proficiency testing scheme, in which between 88 and 119 routine laboratories participated, yielded relative reproducibility standard deviations between 7 and 20% at AOX contents between 10.9 and 268 mg kg-1. Nineteen laboratories with established proficiency were invited to participate in the certification of the AOX content in three soil reference materials meant for the internal quality control in analytical laboratories. The certified values are (1349 ± 59) mg kg-1, (80 ± 7) mg kg-1 and (102 ± 8) mg kg-1, respectively.
1,2,5,6,9,10-Hexabromocyclododecane (HBCD) is a widely used flame retardant, which tends to persist in the environment and accumulates in biota. The six stereoisomers (three racemates named α-, β-, and γ-HBCD) of the technical mixture were isolated with high-performance liquid chromatography (HPLC). Direct separations were performed on a chiral stationary phase containing permethylated -cyclodextrin (NUCLEODEX -PM column) and the pure enantiomers of α-, β-, and γ-HBCD were physically characterized for the first time. The absolute configurations of all six isomers were determined by anomalous dispersion using single crystal X-ray crystallography. Optical rotations αD in tetrahydrofuran were +4.2/-4.0 (α-HBCD), +26.1/-27.5 (β-HBCD), and +68.0/-66.3 (γ-HBCD). The sense of rotation could be correlated with the absolute configurations of α-, β-, and γ-HBCD enantiomers and their order of elution on a chiral permethylated β-cyclodextrin-bonded stationary phase. The diastereomers α-, β-, and γ-HBCD displayed distinctly different melting points as well as 1H-, 13C NMR, and IR spectra.