TY - JOUR A1 - Schiel, D. A1 - Rienitz, O. A1 - Jährling, R. A1 - Güttler, B. A1 - Matschat, Ralf A1 - Scharf, Holger A1 - Birkhahn, Jürgen A1 - Labarraque, G. A1 - Fisicaro, P. A1 - Borchers, U. A1 - Schwesig, D. T1 - Metrological concept for comparable measurement results under the European water framework directive: demonstration of its applicability in elemental analysis JF - Accreditation and quality assurance N2 - Within the scope of a project of the 'European Association of National Metrology Institutes' (EURAMET), a European metrological dissemination System (network) providing traceable reference values assigned to matrix materials for validation purposes is described and put to the test. It enables testing laboratories (TL) to obtain comparable results for measurements under the 'EU Water Framework Directive 2000/60/EC' (WFD) and thus, to comply with a core requirement of this very directive. The dissemination system is characterized by the fact that it is available to all laboratories throughout Europe which intend to perform measurements in the context of the WFD and that it can ensure sustainable metrological traceability to the International System of Units (SI) as a reference point for the measurement results. This Dissemination system is set up in a hierarchical manner and links up the level of the national metrology institutes (NMI) with that of the TLs via an intermediate level of calibration laboratories (CL) by comparison measurements. The CLs are expert laboratories with respect to the measurement of the analytes considered here (within the project, the CLs are called potential calibration laboratories (PCL)) and are additionally involved in the organization of comparison measurements within the scope of regional quality assurance (QA) systems. Three comparison measurements have been performed to support the approach. A total of about 130 laboratories participated in this exercise with the focus on the measurement of the priority substances Pb, Cd, Hg, and Ni defined in the WFD. The elemental concentrations in the water samples roughly corresponded to one of the established environmental quality standards (EQS), the annual average concentration (AA-EQS), which is defined in the daughter Directive 2008/105/EC of the WFD. It turned out that a significant number of TLs still need to improve their measurement methods in order to be able to fulfill the Minimum requirements of the WFD, in particular, with regard to the elements Cd and Hg probably due to their low EQS values. Furthermore, it became obvious that the hierarchical Dissemination system suggested here actually corresponds to the measuring capabilities of the three participating Groups (NMIs, PCLs, and TLs). KW - Metrology KW - Metrological traceability KW - Comparability KW - Elemental analysis KW - Water framework directive PY - 2011 DO - https://doi.org/10.1007/s00769-011-0792-z SN - 0949-1775 SN - 1432-0517 VL - 16 IS - 10 SP - 489 EP - 498 PB - Springer CY - Berlin AN - OPUS4-24485 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Alasonati, E. A1 - Fabbri, B. A1 - Fettig, Ina A1 - Yardin, C. A1 - Del Castillo Busto, M.E. A1 - Richter, Janine A1 - Philipp, Rosemarie A1 - Fisicaro, P. T1 - Experimental design for TBT quantification by isotope dilution SPE-GC-ICP-MS under the European water framework directive JF - Talanta N2 - In Europe the maximum allowable concentration for tributyltin (TBT) compounds in surface water has been regulated by the water framework directive (WFD) and daughter directive that impose a limit of 0.2 ng L-1 in whole water (as tributyltin cation). Despite the large number of different methodologies for the quantification of organotin species developed in the last two decades, standardised analytical methods at required concentration level do not exist. TBT quantification at picogram level requires efficient and accurate sample preparation and preconcentration, and maximum care to avoid blank contamination. To meet the WFD requirement, a method for the quantification of TBT in mineral water at environmental quality standard (EQS) level, based on solid phase extraction (SPE), was developed and optimised. The quantification was done using species-specific isotope dilution (SSID) followed by gas chromatography (GC) coupled to inductively coupled plasma mass spectrometry (ICP–MS). The analytical process was optimised using a design of experiment (DOE) based on a factorial fractionary plan. The DOE allowed to evaluate 3 qualitative factors (type of stationary phase and eluent, phase mass and eluent volume, pH and analyte ethylation procedure) for a total of 13 levels studied, and a sample volume in the range of 250–1000 mL. Four different models fitting the results were defined and evaluated with statistic tools: one of them was selected and optimised to find the best procedural conditions. C18 phase was found to be the best stationary phase for SPE experiments. The 4 solvents tested with C18, the pH and ethylation conditions, the mass of the phases, the volume of the eluents and the sample volume can all be optimal, but depending on their respective combination. For that reason, the equation of the model conceived in this work is a useful decisional tool for the planning of experiments, because it can be applied to predict the TBT mass fraction recovery when the experimental conditions are drawn. This work shows that SPE is a convenient technique for TBT pre-concentration at pico-trace levels and a robust approach: in fact (i) number of different experimental conditions led to satisfactory results and (ii) the participation of two institutes to the experimental work did not impact the developed model. KW - Tributyltin KW - Organotin compounds KW - Solid-phase extraction KW - Experimental design KW - Water framework directive KW - Isotope dilution PY - 2015 DO - https://doi.org/10.1016/j.talanta.2014.11.064 SN - 0039-9140 VL - 134 SP - 576 EP - 586 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-32696 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -