【讨论】标准物质的定义

标准物质是由国家计量所颁布实施检测校正用的物质，权威计量单位购买标准溶液是标准物质，有浓度、使用年限的。而参考物与标准物是区别的，计量论证评审时都要核对国家标准物质是否合理标准的。

茶叶标准物质是否有证，标准物质要有相关标准物质证明。

NIST的定义是参考物质（RM）和有证参考物质（CRM），国内不同部门之间说法也不一致，环境方面的称呼是标准样品（简称标样），其它领域为标准物质（简称标物），标准样品和标准物质在学术领域都是有证标准参考物质，也就是常说的国家一级或二级类的物质，学术领域内的标准品是不具有级别证书的，只用来做量值的粗略参考和性质的测定，对照品就只用来做定性参考。
目前学术领域以外的比较混乱，对标准物质、标准品、对照品没有明显的概念区分。

附NIST英文定义：
Reference Material (RM) - Material, sufficiently homogeneous and stable with respect to one or more specified properties, which has been established to be fit for its intended use in a measurement process
1.    RM is a generic term.
2.    Properties can be quantitative or qualitative, e.g. identity of substances or species.
3.    Uses may include the calibration of a measurement system, assessment of a measurement procedure, assigning values to other materials, and quality control.
4.    A single RM cannot be used for both calibration and validation of results in the same measurement procedure.
5.    International Vocabulary of Metrology – Basic and General Concepts and Associated Terms has an analogous definition (VIM - ISO/IEC Guide 99:2007, 5.13), but restricts the term "measurement" to apply to quantitative values and not to qualitative properties. However, Note 3 of ISO/IEC Guide 99:2007, 5.13, specifically includes the concept of qualitative attributes, called "nominal properties".
(ISO Guide 30:1992/Amd 1:2008)
Certified Reference Material (CRM) - Reference material characterized by a metrologically valid procedure for one or more specified properties, accompanied by a certificate that provides the value of the specified property, its associated uncertainty, and a statement of metrological traceability
1.    The concept of value includes qualitative attributes such as identity or sequence. Uncertainties for such attributes may be expressed as probabilities.
2.    Metrologically valid procedures for the production and certification of reference materials are given in, among others, ISO Guides 34 and 35.
3.    ISO Guide 31 gives guidance on the contents of certificates.
4.    VIM has an analogous definition (ISO/IEC Guide 99:2007, 5.14).
(ISO Guide 30:1992/Amd 1:2008)