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Bericht zur Durchführung des Ringversuchs zur Validierung der Benzolanalytik im Spurenbereich
(2006)
Im Auftrag des Altlastenausschusses (ALA) der Bund/Länder Arbeitsgemeinschaft Boden (LABO) wurde ein Validierungsringversuch für die Bestimmung von leichtflüchtigen monoaromatischen Verbindungen mit Hinweisen auf existierende Prüfwerte, wie BTEX in Boden, im Spurenbereich durchgeführt. 3 Bodenproben mit unterschiedlichen Kontaminationsniveaus der BTEX-Verbindungen, überschichtet mit Methanol, eine Bodenprobe dotiert mit Ottokraftstoff, Super bleifrei, eine BTEX-Standardlösung unbekannter Konzentration, sowie eine BTEX-Standardlösung mit zertifizierten Gehaltsangaben wurden an 21 ausgewählte Teilnehmer verschickt, die überwiegend mit GC-MS analysiert haben. Die Ergebnisse und die Verfahrenskenndaten zeigen, dass die Mehrzahl der Laboratorien mit den angewandten Analysentechniken in der Lage ist, in dem vorgegebenen Kontaminationsbereich empfindlich genug, vergleichbar und richtig messen zu können. GC- FID erweist sich nicht empfindlich und spezifisch genug in dem unteren Spurenbereich, deshalb war schon in dem Aufruf zum Ringversuch auf die Anwendung der GC-MS- Messtechnik verwiesen worden.
ISBN: Im Zuge der Harmonisierung der Rechtsvorschriften der Mitgliedsstaaten der Europäischen Gemeinschaft wurde im September 1996 die Richtlinie 96/59/EG des Rates über die Beseitigung polychlorierter Biphenyle und polychlorierter Terphenyle (PCB/PCT) verabschiedet. Ziel dieser Richtlinie ist die Angleichung der Rechtsvorschriften der Mitgliedstaaten über die kontrollierte Beseitigung der PCB, die Dekontaminierung oder Beseitigung PCB-haltiger Geräte und die Beseitigung von PCB-Abfall. In der Bundesrepublik Deutschland wurde mit der Verabschiedung der PCB/PCT- Abfallverordnung vom 26. Juni 2000 die EU-Richtlinie umgesetzt. Entsprechend der PCB/PCT-Abfallverordnung wird für PCB-haltigen Abfall ein Grenzwert von 50 mg/kg festgelegt. Beim Haupteinsatzgebiet der PCB - als Isolierflüssigkeiten in Transformatoren - ist die Bestimmung des PCB-Gehaltes durch DIN-Normen geregelt. Polychlorierte Biphenyle wurden auch als Weichmacher in Dichtungsmassen und Kunststoffen, z.B. in Kabelummantelungen, und als Flammschutzmittelanstrich für Holz eingesetzt. Für feste Abfallmatrices gibt es keine verbindliche Prüfvorschrift. Ziel des Projektes war die Erarbeitung und Validierung eines Prüfverfahrens zur Bestimmung von PCB und PCT in organischen Abfallmatrices wie Kabelshredder und Altholz.
Ziel des Vorhabens war die Erarbeitung und Validierung eines standardisierbaren Analysenverfahrens für die Bestimmung von leichtflüchtigen Halogenkohlenwasserstoffen (LHKW) und monoaromatischen Verbindungen wie Benzol, Toluol, Ethylbenzol und Xylolen (BTEX) in Boden, die Bereitstellung eines geeigneten Boden-Referenzmaterials dafür und die Durchführung eines Validierungsringversuches. Da die leichtflüchtigen Verbindungen in dem von den kontaminierten Standorten angeschafften Boden schon während des Verarbeitungsprozesses weitgehend verloren gegangen waren, wurde das LHKW- und BTEX-haltige Referenzmaterial durch Einzelflaschendotierung hergestellt. Eine bestimmte Menge eines im Rahmen eines vorhergehenden BMBF-Vorhabens (Förderkennzeichen 07 OTX 20/3) erhaltenen unbelasteten Ackerboden-Referenzmaterials wurde in Glasflaschen eingewogen und unter optimierten Bedingungen mit einer methanolischen Lösung, die ausgewählte leichtflüchtige Substanzen enthält, dotiert. Die anschließende Stabilitätsuntersuchung mit den so hergestellten Proben zeigte, dass es notwendig ist, die Bodenproben mit einem organischen Lösungsmittel (z. B. Methanol) zu überschichten, um Verluste der leichtflüchtigen organischen Substanzen so gering wie möglich zu halten. Die Voruntersuchungen haben gezeigt, dass die Wiederfindungsraten von LHKW und BTEX in Boden ohne Überschichtung sehr schlecht sind. Das erarbeitete Analysenverfahren liegt als Normvorschlag dem Normausschuss ISO/TC 190 - Soil quality vor und wurde im Rahmen eines Ringversuches mit den hergestellten Referenzmaterialien erfolgreich validiert. Das validierte Verfahren mit den Verfahrenskenndaten wurde als ISO DIS 22155 im September 2003 aktualisiert.
The international research project HYCREF, funded by the European Commission in the 5 th Framework programme, aimed to develop methods to prepare homogenous and stable water-, soiland waste reference materials contaminated with mineral oil hydrocarbons and to test certify the mineral oil content by gas chromatographic methods. As mineral oil products are important sources for environmental contaminations a high need exists for certified reference materials for their determination using the new gas chromatographic methods (soil: ISO/FDIS 16703, waste: ENpr 14039, water: ISO 9377-2). The experimental conditions and results for preparation and characterisation of a total of nine reference materials (3 water-, 3 soil- and 3 waste materials) are described and discussed. Target values for the reference materials were defined at the beginning of the project in order to have clear quality criteria, which could be compared with the achieved results at the end of the project. These target specifications were related to the maximum uncertainty from test certification exercises (< 5 % for soil/waste and < 10 % for water), the maximum inhomogeneity between bottles (< 3 %) and minimum requirements for stability (> 5 years for soil/waste and > 2 years for water). The feasibility studies showed that solid materials (soil, waste) could be prepared sufficiently homogenous and stable. The test certified values of the 6 solid materials comprise a wide range of mineral oil content from about 200-9000 mg/kg with expanded uncertainties between 5.7-13.1 % using a coverage factor k (k = 2). The development of new water reference materials –the so-called “spiking pills” for an offshore- and a land-based discharge water represents one of the most innovative aspects of the project. The spiking pill technology facilitates the application and storage and improves the material stability compared with aqueous materials. Additional to the preparation and test certification of the reference materials investigations on the analytical method for the determination of mineral oil hydrocarbons were performed. The results obtained in relation to the optimisation of analytical method (extraction procedure, sample pretreatment, clean-up and measurement) were provided to the respective working group of ISO/TC 190, ISO/TC 147 and CEN/TC 292 and were incorporated into the ongoing standardisation procedures. The new version of ISO/FDIS 16703 (July 2004) includes the improvements based on HYCREF results, for example the increase of the solvent/sample ratio, the removal of acetone from the organic extracts and the use of column technique instead of batch technique for clean-up.
Im Rahmen eines vom Bundesministerium für Wirtschaft und Arbeit (BMWA) geförderten Projektes wird in Kooperation mit dem Verband deutscher Metallhändler (VDM) ein Verfahren zur Quantifizierung der PCB-Kongenere 28, 52, 101, 138, 153, 180 im Gehaltsbereich von 0,1 bis 20 mg in Kunststoffabfällen aus dem Altkabelrecycling entwickelt und validiert. Dazu werden repräsentative Referenzmaterialien für die Laboranalytik aus Granulaten verschiedener Kabelzerlegeprozesse hergestellt und charakterisiert. Die Methodenentwicklung umfasst mahl-, sieb- und schüttguttechnologische Aspekte sowie den Vergleich unterschiedlicher Extraktionsverfahren und chromatographischer Bedingungen. Das validierte Verfahren sieht die Mahlung der technischen Probe auf eine Kornobergrenze von 0,50 mm gefolgt von Extraktion mit einem unpolaren Lösungsmittel bei einer Einwaage von 4 g und gaschromatographischer Bestimmung vor. Die Bestimmungsgrenzen liegen zwischen 0,01 und 0,08 mg/kg. Bei sorgfältiger Wahl der chromatographischen Bedingungen sind Elektroneneinfang- und massenselektive Detektion (MS) gleichwertig. In Gegenwart größerer Mengen bestimmter Komponenten, die in einigen Kabeln enthalten sind, kann der Einsatz eines MS von Vorteil sein. Drei Referenzmaterialien mit Gehalten der genannten Kongenere zwischen 0,1 bis 5 mg/kg werden in einem abschließenden Ringversuch zur Validierung dieser Methode mit 23 ausgewählten Laboratorien eingesetzt. Dabei ergeben sich für die Quantifizierung dieser Kongenere relative Vergleichsstandardabweichungen zwischen 15 und 33 %. Das Verfahren wird in die europäische Normung (CEN 292 „Characterisation of Waste“) eingebracht.
Bilanzierung der Schwefelbelastung im Grundwasser an einem ausgewählten Industriestandort, Berlin
(2004)
Die Bundesanstalt für Materialforschung und -prüfung (BAM) ist vom Senat für Stadtentwicklung, Berlin, und von der Bundesanstalt für vereinigungsbedingte Sonderaufgaben (BvS) beauftragt worden, die Bilanzierung der Schwefelkomponenten für ein bis drei ausgewählte Grundwasserproben an einem Berliner Industriestandort vorzunehmen. Es handelt sich bei den Boden- und Grundwasserkontaminationen ausnahmslos um industrielle Altlasten. Da der Gehalt an organisch gebundenen Schwefelverbindungen, kolloidalem Schwefel und gelösten Sulfiden für die Dimensionierung von Grundwasseraufbereitungsanlagen (Aktivkohle, Katalysator) von großer Bedeutung ist und am Standort teilweise sehr hohe Schwefelkontaminationen auftreten, sollen vor einem erneuten Ausschreibungsverfahren zur Grundwassersanierung an drei sehr unterschiedlichen, aber für den Standort typischen Grundwassermessstellen entsprechende Bilanzen für die Schwefelbelastung erstellt werden. Dabei sind sowohl die summarischen Kenngrößen wie Summe Gesamtschwefel, ausblasbare (POS) und extrahierbare leicht- und schwerflüchtige organische Schwefelverbindungen und an Aktivkohle adsorbierbare Schwefelverbindungen (AOS) von Interesse, als auch eine Zuordnung der Hauptkontaminationen über ein halbquantitatives GC-MS-Screening. Im Artikel werden die angewendeten Verfahren vorgestellt. Die Ergebnisse werden diskutiert, gegenübergestellt und ihre Belastbarkeit eingeschätzt.
Ziel der vorliegenden Untersuchungen, die im Rahmen einer Diplomarbeit der Fachhochschule Lausitz/Senftenberg an der BAM durchgeführt wurden, war ein Vergleich unterschiedlicher Extraktionsverfahren für die Bestimmung von extrahierbarem organischem Halogen (EOX) in Bodenproben. EOX ist ein für die rasche Bewertung der Organochlor- Belastung kontaminationsverdächtiger Flächen wertvoller Summenparameter, der sämtliche mit organischen Lösungsmittel extrahierbare Organohalogenverbindungen erfasst. Gegenwärtig existiert jedoch kein für die Bodenanalytik genormtes Verfahren für die Durchführung von EOX-Bestimmungen. Daher wird in der Praxis auf das für Schlämme und Sedimente entwickelte Verfahren nach DIN 38414 S17 (1990) zurückgegriffen, so auch in der Bundesbodenschutz- und Altlasten-Verordung (BBodSchV). Literaturangaben und Erfahrungen mit der Wiederfindungsrate polarer Extraktionsmittel und moderner Extraktionsverfahren bei Organochlorpestiziden, die eine bedeutende Quelle für EOX in Schlämmen und Böden darstellen, lassen vermuten, dass das genannte Normverfahren systematisch zu Unterbefunden neigen könnte. Für die Untersuchungen wurden an der BAM entwickelte Boden-Referenzmaterialien mit "natürlicher", über jahrzehntelangen Eintrag entstandener DDT- und Lindan-Belastung verwendet. Neben den klassischen Extraktionsverfahren nach Soxhlet kamen die ultraschallunterstützte Extraktion, die Mikrowellen- und die beschleunigte Lösungsmittelextraktion (ASE) jeweils mit Lösungsmitteln unterschiedlicher Polarität zum Einsatz. Extraktionsausbeuten und Wiederholpräzision der einzelnen Varianten wurden verglichen und vor dem Hintergrund der Ergebnisse unabhängiger Verfahren wie der gaschromatographischen Bestimmung der einzelnen Organochlorverbindungen bewertet. Die Polarität des Extraktionsmittels weist auch bei trockenen Böden den größten Einfluss auf die Extraktionsausbeuten der in den untersuchten Proben enthaltenen Organochlorverbindungen auf. Die Mischung Hexan/Aceton (1:1), die sich für die Extraktion verschiedener organischer Parameter bewährt hat, ist hinsichtlich der EOX-Analytik der existierenden Norm überlegen.
Ziel des Forschungsprojektes war es, systematische Untersuchungen der Verfahrensschritte für die gas-chromatographische Bestimmung von Mineralölkohlenwasserstoffen (MKW) in Feststoffen aus dem Altlastenbereich entsprechend der Methode des Fachgremiums Altlastenanalytik (FGAA) sowie des Verfahrens ISO/DIS 16703 durchzuführen, Wege zur Optimierung einzelner Verfahrensschritte aufzuzeigen und beide Verfahren miteinander zu vergleichen. Es wurden Untersuchungen zu den Verfahrensschritten Extraktion, Extraktreinigung, Messung und Integration durchgeführt. Im Ergebnis der Untersuchungen wurde festgestellt, dass die Extraktion von Feststoffproben (20 g) mit einem Extraktionsvolumen von mind. 40 mL Aceton und 20 mL n-Heptan erfolgen muss, um eine zufriedenstellende Extraktionsausbeute zu gewährleisten. Im Rahmen dieses Projektes wurde ein Rechenprogramm für die Bestimmung der Rest- Aceton-Konzentration in Heptan-Extrakten erstellt. Mit diesem Programm können auch die Wasservolumina ermittelt werden, die für eine gewünschte Rest-Aceton-Konzentration notwendig sind. Anhand von Bodenextrakten, PAK-, Stearylstearat- und Triglycerid-Standardlösungen wurde nachgewiesen, dass die Säulen-Technik eine wesentlich effektivere Extraktreinigung bewirkt als das sogenannte Batch-(Schüttel-) Verfahren. In einem Modellversuch an drei verschiedenen Bodenextrakten wurde gezeigt, dass die zwischen FGAA- und ISO-Verfahren unterschiedliche Art der Peak-Integration eines GC-FID Chromatogramms zwischen n-Dekan (C10) und n-Tetracontan (C40) keinen Einfluss auf das Endergebnis hat. Eine Basislinienkorrektur des Proben-Chromatogramms ist daher nicht erforderlich. Das FGAA-Verfahren enthält in seiner Vorschrift für die Berechnung des MKW-Gehalts im Probenmaterial einen systematischen Fehler von etwa 8 %. Dieser Fehler entsteht durch den Unterschied zwischen dem theoretischen Extraktvolumen von 150 mL und dem realen Extraktvolumen von etwa 139 mL. Dieser systematische Fehler sollte in einer nachfolgenden Fassung des FGAA-Verfahrens vermieden werden.
Entwicklung, Herstellung und Einsatz von Referenzmaterialien für die organische Umweltanalytik
(2000)
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.
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
Entwicklung, Herstellung und Einsatz von Referenzmaterialien für die organische Umweltanalytik
(2000)
Referenzmaterialien
(1998)
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.
Feasibility and limits in preparation of reference materials for the organic emvironmental analysis
(1995)
The validation of a robust quantification procedure for EtG in hair using GC–NCI–MS is presented. Aqueous extraction is followed by complete lyophylization of the extract and derivatization with pentafluoropropionic anhydride (PFPA) under controlled temperature and duration. Clean-up of extracts was dispensable and standard single quadrupole MS displayed sufficient selectivity and sensitivity. The method displayed a wide linearity range and enabled LOD of 0.68 pg/mg, LOQ of 2.4 pg/mg, and precision below 8.12%. Since EtG was seen to display prolonged stability in the aqueous extracts and after derivatization with PFPA this straightforward procedure allows a routine throughput of large quantities of samples with little proneness to procedural scatter of results. The method was applied to demonstrate the homogeneity of two hair reference materials with mean EtG contents of 8.48 pg/mg and 22.0 pg/mg. Aside from the application in homogeneity studies of hair reference materials predominantly in the concentration range of 10–50 pg/mg the method was also designed for daily routine quantification of real-world sample with regard to drinking behavior assessment.
Germination induces the glucosylation of the Fusarium mycotoxin deoxynivalenol in various grains
(2012)
In food, the mycotoxin deoxynivalenol (DON) often occurs in conjunction with its 3-β-D-glucopyranoside (D3G). The transformation of DON to D3G through glucosylation is catalysed by plant enzymes, however, the exact circumstances are not well understood. In order to investigate the role of enzymatic glucosylation in germinating grains, DON treated kernels were steeped and germinated under laboratory conditions. Furthermore, the effect of malting on the DON content of the contaminated barley was investigated. In all cases, DON and its derivatives were quantified by HPLC-MS/MS before, during and after the experiments. Amongst the six tested cereals; wheat, rye, barley, spelt, and millet transformed DON to D3G during germination whilst the oats were inactive. For wheat, barley, and spelt the initial DON content was reduced by 50%, with the loss being almost entirely accounted for by D3G formation. As D3G might be cleaved during digestion, the elevated D3G concentration may obscure the toxicologically relevant DON content in processed food and beer. The germination process has a major influence on the 'masking' of DON, leading to high quantities of D3G that may be missed in common mycotoxin analyses.
Aim: The objective of the study was to provide conclusive evidence for the effect of particle size reduction as by milling on the extractable content of ethyl glucuronide (EtG) of hair samples. Methods: A number of real case hair samples and two pooled hair materials with EtG contents in the range of 1030 pg/mg were systematically compared with regard to the extraction yield of EtG after cutting to 23 mm length and pulverization with a ball mill. After the respective treatment the samples were submitted to aqueous extraction followed by quantification of EtG using HPLC-MS/MS. Results: It was unequivocally demonstrated that milling of hair samples prior to aqueous extraction significantly increases the extractable EtG content compared with cut hair. The effect ranged between 137 and 230% and was seen to occur regardless of the extent of pulverization. Cooling of samples was not necessary to prevent partial degradation of EtG during the grinding procedure. Conclusion: The options currently employed at choice in analytical practice (cutting or milling) were seen to significantly affect the extractable amount of EtG in hair. This is suspected to influence the degree of equivalence of quantification results obtained in different laboratories as well as their respective classification of a test subject's drinking behaviour on the basis of currently recommended cut-off values.
A procedure has been developed for the determination of arsenobetaine in fish matrix by HPLC–ESI-MS/MS. Hereby (trimethylarsonium)-1,2-13C-acetate (arsenobetaine) is used as internal calibration standard. Arsenobetaine was determined in a fish material (Sea Bass) with an expanded uncertainty of 3.8%.
Die zuverlässige Überwachung geltender Mykotoxin-Grenzwerte ist elementarer Bestandteil von Lebensmittelsicherheit und Verbraucherschutz. Durch die zunehmende Bedeutung der Qualitätssicherung ist auch die Nachfrage an zertifizierten Referenzmaterialien (ZRM) in den letzten Jahren deutlich gestiegen. Dem steht derzeit jedoch nur eine sehr begrenzte Auswahl geeigneter ZRM gegenüber.
The reliability in measurement results obtained during environmental monitoring is crucial for the assessment and further planning of remediation efforts on the respective contaminated sites by the responsible authorities. A case study concerned with groundwater contaminated with perchloroethylene, trichloroethylene and 1,1,2-trichlorotrifluoroethane including their degradation products which involves private contract laboratories and an independent provider of quality assurance (QA) is presented. The experience gained with biannual monitoring campaigns over 14 years indicates that the selection of contractors on basis of accreditation status and successful performance in interlaboratory comparisons are not sufficient. Rather the auditing of the contractors by the QA provider prior to each campaign and the crosschecking of selected monitoring samples by the QA provider led to a lasting improvement of reliability in the contractors' measurement results. A mean deviation of 20% from the reference value determined by the QA provider for the crosschecked samples was reached.
Mycotoxins are important non-anthropogenic food and feed contaminants, which can be present on almost every agricultural commodity. Effective consumer protection therefore essentially depends on food surveillance by reliable quantitative analysis enabled by appropriate quality control. Certified (matrix) reference materials (CRMs) are versatile tools to support Quality assurance. However, in the case of ochratoxin A (OTA), a hepato- and nephrotoxic mycotoxin, which is regulated in various foods, there is a lack of suitable CRMs. This lack has now been overcome by the development of two European Reference Materials (ERM®) for the Determination of OTA in roasted coffee (ERM®-BD475) and red wine (ERM®-BD476). This article discusses the material preparation process as well as the results of homogeneity and stability testing. Furthermore, the results of the inhouse certification studies carried out at BAM Federal Institute for Materials Research and Testing are presented and discussed. Interlaboratory comparison studies involving selected expert laboratories with documented Expertise in the field of mycotoxin analysis were conducted to confirm the certified values determined by BAM. The certified ochratoxin A values and their corresponding expanded uncertainties (k = 2) were assigned in full compliance with the requirements of ISO Guide 35 and are as follows:
(6.0 ± 0.6) µg kg-1 for roasted coffee, ERM®-BD475, and (0.52 ± 0.11) µg L-1 for red wine, ERM®-BD476.
The title compound, {2-[(2-carbamoylethyl)amino]-3-methylpentanoic acid}, C9H18N2O3, is of interest with respect to its biological activity. It was formed during an addition reaction between acrylamide and the amino acid isoleucine. The crystal structure is a three-dimensional network built up by intermolecular N–H···O and O–H···N hydrogen bonds.
The title compound [systematic name: (2R,3R,4S,5R,6R) 2-(acetoxymethyl)-6-propoxytetrahydro-2H-pyran-3,4,5-triyl triacetate], C17H26O10, was formed by a Koenigs-Knorr reaction of 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide and n-propanol. The central ring adopts a chair conformation. The crystal does not contain any significant interactions such as hydrogen bonds.
The nature and concentrations of volatile organic compounds (VOCs) in chars generated by hydrothermal carbonization (HTC) is of concern considering their application as soil amendment. Therefore, the presence of VOCs in solid HTC products obtained from wheat straw, biogas digestate and four woody materials was investigated using headspace gas chromatography. A variety of potentially harmful benzenic, phenolic and furanic volatiles along with various aldehydes and ketones were identified in feedstock- and temperature-specific patterns. The total amount of VOCs observed after equilibration between headspace and char samples produced at 270 °C ranged between 2000 and 16,000 µg/g (0.2–1.6 wt.%). Depending on feedstock 50–9000 µg/g of benzenes and 300–1800 µg/g of phenols were observed. Substances potentially harmful to soil ecology such as benzofurans (200–800 µg/g) and p-cymene (up to 6000 µg/g in pine wood char) exhibited concentrations that suggest restrained application of fresh hydrochar as soil amendment or for water purification.
Ergotaminine
(2012)
The title compound {systematic name: (6aR,9S)-N-[(2R,5S,10aS,10bS)-5-benzyl-10b-hydroxy-2-methyl-3,6-dioxooctahydro-8H-oxazolo[3,2-a]pyrrolo[2,1-c]pyrazin-2-yl]-7-methyl-4,6,6a,7,8,9-hexahydroindolo[4,3-fg]quinoline-9-carboxamide}, C33H35N5O5, was formed by an epimerization reaction of ergotamine. The non-aromatic ring (ring C of the ergoline skeleton) directly fused to the aromatic rings is nearly planar [maximum deviation = 0.317 (4) Å] and shows an envelope conformation, whereas ring D, involved in an intramolecular N–H···N hydrogen bond exhibits a slightly distorted chair conformation. The structure displays chains running approximately parallel to the diagonal of bc plane that are formed through N–H···O hydrogen bonds.
A practical method for the quantification of
total purgeable organic sulfur (POS) in highly contaminated
groundwater is described. Volatile organic sulfur
compounds (VOSC) are purged from the water samples by
a stream of oxygen and combusted. The emerging sulfur
dioxide is absorbed in H2O2 and converted to sulfate which
is quantified by ion chromatography and reported as mass
sulfur equivalent. The overall limit of quantification is
0.03 mg l1. The content of POS is balanced with the total
VOSC determined by GC-AED after liquidliquid extraction.
Separate determination of the non-volatile organic
sulfur compounds by direct combustion of the water sample
and adsorption to charcoal yielded a mass balance of
the total sulfur content. Semi-quantitative GC-MS after
purge & trap accumulation revealed that the VOSC mixture
is composed of C1C4 alkyl sulfides. The implementation
of the developed methodology for the quantification of
VOSC as potential catalyst poison in a cleaning plant
for groundwater contaminated with volatile haloorganics
(VOX) is presented.
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.
The aim of this study was to investigate the distribution of zearalenone in wheat kernels contaminated with this mycotoxin. Kernels from a sample of a wheat harvest affected by Fusarium culmorum were sorted into six groups according to their visual attributes. Milled portions of these groups were analysed by high-performance liquid chromatography with fluorescence and diode array detection. The clean-up was performed with an immunoaffinity column after methanol/water (4:1, v/v) extraction. The zearalenone content of the unsorted kernel fraction was 74 µg/kg. The group of healthy-looking kernels was contaminated with only 6 µg/kg of zearalenone. The groups of kernels that appeared shrunken and chalky white, damage routinely caused by Fusarium, were contaminated with 170 and 117 µg/kg, respectively. A remarkably high level of zearalenone contamination, 2,184 µg/kg, was observed for the group of reddish kernels. An association between the presence of the red pigment aurofusarin and high levels of zearalenone was found. Therefore, this pigment may be used as a marker of high zearalenone content.
The interconversion of the stereoisomers contained in technical 1,2,5,6,9,10-hexabromocyclododecane, a major brominated flame retardant increasingly found in the environment and in biota, was investigated at elevated temperatures. The application of pure enantiomers of the three constituents α-, β-, and γ-HBCD enabled the unambiguous elucidation of the individual isomerisation reactions as well as the quantification of all respective rate constants. At 160 °C the rate constants range over two orders of magnitude from 1.50 × 10-3 to 1.88 × 10-5 mol(%) s-1. A preliminary mechanistic explanation for the differences of the rate constants which govern the composition of HBCD diastereomers at equilibrium is given.
A method has been derived to completely recover mineral oil dispersed in water. The method involves three steps: the emulsification of the mineral oil by adding amphiphiles, the breaking of the emulsion by adding salts and the extraction of the mineral oil by a non-polar aprotic solvent. Various amphiphiles and types and concentrations of salts were tested. By using amphiphiles with HLB numbers in the range 4.7 to 40 a complete recovery of the mineral oil could be obtained for a combination of salts Na2SO4 + NaH2PO4 with total ionic strength of 6 mol/L.
Ochratoxin A (OTA) is a mycotoxin produced by Aspergillus ochraceus and Penicillium verrucosum. It has been found and analysed in several foods and feeds. Owing to its toxicity and occurrence in food and feed, the European Community has issued directives and some countries have their own regulations for OTA contents in food, feed and beverages. This work describes a method for the determination of OTA in mulled and red wine. It is based on combined anion exchange/reversed-phase clean-up and was analysed by liquid chromatography coupled with tandem mass spectrometry (multiple reaction monitoring). The method was validated with natural contaminated and spiked wine samples with OTA contents from 1.34 to 3.48 g kg1. Owing to its accuracy, good reproducibility and repeatability, this easy method is a good alternative to liquid chromatographyfluorescence detection methods.
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%.
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.
Distribution of Trichothecenes, Zearalenone, and Ergosterol in a Fractionated Wheat Harvest Lot
(2008)
To investigate possible co-occurrences of type B trichothecenes and zearalenone within a Fusarium culmorum-infected wheat harvest lot, kernels were fractionated into six groups by visual criteria. The Fusarium-damaged kernels were subdivided into white, shrunken, and red kernel groups, and the remaining kernels were sorted into healthy, black spotted, and nonspecific groups. The distribution patterns of nivalenol, deoxynivalenol, zearalenone, and ergosterol were determined for possible correlations. Significant correlations between the distribution patterns were found for the mycotoxins and ergosterol for the grouped kernels (r = 0.997-0.999, p < 0.0001). Additionally, remarkably outstanding levels of nivalenol (24-fold more than the mean at 1.16 mg/kg), deoxynivalenol (27-fold more than the mean at 0.16 mg/kg), zearalenone (25-fold more than the mean at 77 µg/kg), and ergosterol (17-fold more than the mean at 13.4 mg/kg) were found in the red kernel group. Further, detailed mycotoxin and ergosterol analyses were carried out on various segments (kernel surface, conidia, bran, and flour) of the red kernels. However, the mycotoxin and ergosterol distribution profiles revealed nonsignificant correlations for these kernel segments, with the exception of deoxynivalenol and nivalenol, which were moderately correlated (r = 0.948, p = 0.035).
High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) can be used for simultaneous quantification of various mycotoxins in contaminated food samples. Therefore, multi-mycotoxin methods have been developed in the last couple of years. To enlarge these methods for further analytes, we have developed a LC-MS/MS method for the quantification of the mycotoxin aurofusarin. Additionally, further LC-MSn experiments were performed to demonstrate the fragmentation pattern of aurofusarin. Applicable multiple reaction monitoring (MRM) transitions of aurofusarin were found and optimized by parameter variation of the tandem mass spectrometer. The applicability of the developed method was tested by analysis of naturally contaminated wheat.
The 2-year international joint project HYCREF (Contract-No. G6RD-CT-2002-00854), funded by the European Commission in the 5th Framework programme, aimed to develop methods to prepare homogenous and stable water-, soil- and waste reference materials contaminated with mineral oil hydrocarbons and to test certify the mineral oil content by gas chromatographic methods. As mineral oil products are important sources for environmental contaminations, appropriate reference materials certified by using the new gas chromatographic methods (soil: ISO/FDIS 16703, waste: prEN 14039 and KW/04, water: ISO 9377-2) are highly needed. Additional to the HYCREF-results presented in part Imineral contaminated soilsthis second paper gives an overview of the feasibility study for the preparation and test certification of three waste reference materials (offshore marine sediment, building material and industrial waste). The following specifications, which had been defined in the project work plan, were reached successfully: uncertainty of the mineral oil content resulting from the certification exercise ≤ 5% and a between-bottle inhomogeneity of ≤ 3%. All three materials have been evaluated for long- and short term stability. They contain different levels and types of mineral oil and cover the full application range of ISO/FDIS 16703 and prEN 14039 (10010,000 mg/kg). The expanded uncertainties U cert of the three materials are about 6%. In this way, they are comparable to ERM®-CC015a (U cert=7.1%, mineral oil in a river sediment) and are suited to close the present gap of commercially available CRM for mineral oil determination in waste.
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.
Liquid chromatography coupled with tandem mass spectrometric detection has gained more importance for mycotoxin determination in recent years. In addition to instrumental improvements, the development of LC-MS-MS has also been a consequence of the availability of stable isotope internal standards, e.g., 13C-labelled mycotoxins. Thus, the LC-ESI-MS-MS method using a 13C15-deoxynivalenol internal standard as a state-of-the-art technique was selected as a reference procedure for an in-house method comparison study of the determination of deoxynivalenol (DON) in wheat materials. Alternative methods include LC-diode array detection, which is a frequently used routine procedure for DON-analysis, and gas chromatography after trimethylsilylation. For GC application, an electron capture detector and a negative chemical ionisation mass spectrometry detector were used, which have both been well described in the literature. The method comparison was conducted using t test statistics. Additionally, this study also calculates important method performance characteristics, including accuracy, linearity, limit of detection, limit of quantification, recovery, and variation coefficient. Furthermore, this is the first report of a GC-MS method for the determination of DON using a fully carbon-labelled 13C15-DON as an IS. The GC-MS using 13C15-DON as an IS has produced comparable results to the 13C-IS-LC-MS-MS reference method with a similar sensitivity. ECD detection was slightly less sensitive, but is also suited for DON analysis in wheat. Due to the high LOQ, the LC-DAD method seems highly applicable to the measurement of highly contaminated samples.