Standard reference material: a standard sample with one or more specific characteristic values, which are determined by an effective measurement procedure.
It is accompanied by a statement that the specified eigenvalue, its uncertainty and the traceability of the measurement are provided.
Environmental reference material (ERM): an environmental sample or material with one or more sufficiently unified and completely determined characteristic values, which has passed technical evaluation and attached with a certificate of use, is mainly used for calibrating and verifying environmental monitoring and analysis instruments, evaluating and verifying environmental monitoring and analysis methods or determining the characteristic values of other environmental samples.
CERM: an environmental standard sample that has passed the expert technical evaluation organized by the competent department of environmental protection, approved, issued and authorized by the competent department of national standardization, and attached with a national standard sample certificate. One or more characteristic values determined by the traceability program of the measurement unit that can accurately reproduce its characteristic values have the uncertainty of the specified confidence level. Standard sample: A standard sample is a material or substance with one or more sufficiently uniform and well-defined characteristics, which is used for calibrating instruments, evaluating detection (analysis) methods and assigning values to materials.