Previous VAM surveys and studies, along with some of the main regulation and guidelines relating to environmental measurements have been reviewed to identify reference material requirements. Updated information on requirements has been gained through consultation with interested parties and, in particular, the suppliers and users of test kits and portable monitoring instruments. The most popular matrices and analytes, along with more detailed information on specific requirements have been identified.

It is clear that analytical measurements made using portable measuring equipment are not carried out exclusively in the field with samples often being submitted for laboratory analysis using traditional techniques and instrumentation. Although calibration standards appear to be used fairly widely, the current uptake and use of matrix reference materials is low, even though many out-of-laboratory measurements are undertaken in support of legislation, regulation and national guidelines. The impact of regulation on the need for reference materials has been reinforced during discussions with users who themselves have specified a requirement for materials which are representative of analyses undertaken in support of compliance.

Views on the benefits and requirements for reference materials are varied and range from those who do not consider reference materials to be of value to others who believe they are of benefit and have firm views on specific requirements. It is clear that there is a need to increase awareness of the role and application of reference materials in achieving valid analytical measurements.