Certification of chromium in a range of environmental certified reference materials

The element chromium is routinely determined to control the contamination levels in environmental and biological matrices. The increasing awareness of the need for quality assurance in analytical laboratories will enhance the demand for reference materials certified for chromium. This need, combined with the difficulties arising in the determination of this element, has led to the production of additional reference materials of various matrices certified for their chromium content. The Standards, Measurements and Testing programme (formerly BCR) of the European Commission has conducted a certification campaign, the aim of which was to certify the total chromium content in five different types of environmental and biological matrices. Three materials (fly ash, CRM 038; beech leaves, CRM 100; and rye grass, CRM 281) have already been certified for a range of trace elements and were additionally certified for chromium; two new materials (aquatic plant, CRM 596; and sewage sludge, CRM 597) were prepared for the purpose of this certification. The materials were analysed by a group of nine laboratories with proven adequacy of QC and using different analytical methods.