TABLE OF CONTENTS When selecting a CRM for use as an instrument calibration standard a number of factors will need to be considered.
As all analytical data are ultimately traceable to the calibration standard on which the data are based, it is important that the CRM used as the calibration standard is as fully documented as possible. The producer of the CRM will issue a certificate to accompany it which should be retained as an important part of the analytical records of the laboratory using the CRM. A certificate for a CRM will usually include the information listed below. In the absence of a certificate, the user should endeavour to establish as much information as possible about the material, using the list as a guide.
Name and address of the producer of the material
Description/name of the material
Physical/chemical form of the material
Sample number/batch number/certificate number
Date of production/issue
Shelf life/expiry date
Property values
Uncertainty of property values
Procedures used to characterise the material (determine the property value)
Information on the traceability of property values to the SI (kg, metre, mole etc.)
Further aspects of some of these features of are discussed in Sections 4.4.2 to 4.4.5 below.
The magnitude of the property value ( e.g. concentration) of the CRM used as the calibration standard must be appropriate to the sample being analysed. For example, if...
