Reference materials play a vital role for the verification of the quality control of environmental analysis. In particular, Certified Reference Materials (CRMs) certified for a range of chemical para-meters are highly demanded by routine control laboratories. This report briefly summarizes the preparation and certification of a white cabbage reference material (BCR 679) certified for a range of trace elements.
1. INTRODUCTION
The Bowen's kale [1] has been the first multi-element reference material ever produced for the quality control of trace element determinations in plants. Owing to its success, this material has rapidly been exhausted, which encouraged the European Commission (through the BCR/SM&T activity) to fund a collaborative project aiming to produce a new multi-element cabbage reference material.
Cabbage is frequently used in environmental monitoring and food control, and reference materials are hence required for ensuring quality assurance purposes. Indeed, only accurate analytical results allow valid conclusions to be drawn about a situation and its evaluation and development. The use of certified reference materials permit verification of the accuracy of the measurements and therefore reduces the loss of European wealth caused by incorrect analytical results.
A feasibility study has been conducted in the frame of a first EC-funded contract (1990-1992) to find out the optimal conditions for producing cabbage containing low to medium trace element contents. A first cabbage material was produced, which was considered not suitable for use as a candidate reference material owing to its too low trace element contents. A second material was hence proposed in the frame of the project CARMEN (Preparation of a cabbage reference material for environmental monitoring and food analyses) funded under the 4th Framework Pro-gramme (Standards, Measurements and Testing Programme) [2,3].
To meet these objectives, the following eight tasks have to be performed: Task 1: Production of the plant material. Task 2: Cutting and freeze-drying. Task 3: Preparation of the high-level reference material. Task 4: Homogeneity testing. Task 5: Stability testing. Task 6: Certification measurements. Task 7: Data evaluation, statistical protocols and preparation of the intermediate and certification reports. Task 8: Overall coordination.
2. RESULTS
In the meantime all tasks could successfully completed and the the technical meeting on the certification of RM679 was held in september 1999. The Darft Certification Report as written from Dr R. Herzig could be submitted to SM&T in spring 2000 for evaluation and ratification by the co-authors and the Certification Committee, as well. After an intensive evaluation procedure, the final version of the 'CRM679 Certification Report' have been accepted from Dr P. Quevauviller (SM&T-representative) for printing of the EUR-Report on 18.12.2000, after the formal ratification by the Certification Committee.
The EUR-Report and the new CRM679 will be available in autumn 2001 at the Joint Research Centre - Institute for Reference Materials and Measurements (IRMM) - Retieseweg, B-2440 Geel; Telephone 14.571722 - Fax 14.590406 - Email:
bcr.sales@irmm.jrc.be.This new material (BCR 679) was certified for its contents of Cd, Cu, Fe, Hg, Mn, Mo, Ni, Sb, Sr, Tl and Zn, as listed below [4,5]. Indicative values were also given for As, B, Ba, Ca, Cr, Mg, and P.
This new plant Reference Material BCR 679 gives for the very first time real certified values for trace elements of high toxicological interest, such as thallium and specific considerations of the 'combined uncertanity' are also given in the EUR-Report.
