Overview

The process of preparing and characterising a CRM typically consists of a number of different steps including;

• assessment of priority needs and confirmation of demand

• literature search and project plan

• raw material selection and processing

• homogeneity testing

• stability testing

• characterisation

• preparation of the certification report and certificate

The sequence of main steps in CRM production is illustrated in Figure 2.1.

Figure 2.1: Key to main steps in CRM production

Each step in the production process will be discussed briefly in the following sections in order that the user can evaluate information on the suitability and quality of a given reference material more readily.

2.1 Assessment of Priority Needs and Confirmation of Demand

This is an essential first step in the production of a new CRM. Clearly, it is important to produce CRMs that meet the priority needs of the analytical community. Assessing this need is usually carried out by the use of surveys, questionnaires, customer liaison, and discussion at technical committees and conferences. For commercial production, the demand for a new CRM needs to be sufficient to ensure that the full production and marketing costs are recovered within the life span of the material. When government funding is available, such as that under the UK's Valid Analytical Measurement (VAM) Programme, the emphasis is usually placed on producing materials which are priority needs, but for which it would not be financially viable to produce commercially.

2.2 Literature Search and Project Plan

It is important to confirm that it is technically...