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A certified reference material is a particular form of measurement standard. Reference materials are particularly important for analytical chemistry and clinical analysis. [2] Since most analytical instrumentation is comparative, it requires a sample of known composition (reference material) for accurate calibration.
The δ values and absolute isotope ratios of common reference materials are summarized in Table 1 and described in more detail below. Alternative values for the absolute isotopic ratios of reference materials, differing only modestly from those in Table 1, are presented in Table 2.5 of Sharp (2007) [1] (a text freely available online), as well as Table 1 of the 1993 IAEA report on isotopic ...
Chemicals that meet this standard may be sold as "ACS Reagent Grade" materials. Reagent standards relieve chemists of concern over chemical purity. "ACS Reagent Grade", is regarded as a gold standard measure and is in some cases required for use in chemical manufacturing, usually where stringent quality specifications and a purity of equal to ...
A primary standard in metrology is a standard that is sufficiently accurate such that it is not calibrated by or subordinate to other standards. Primary standards are defined via other quantities like length, mass and time. Primary standards are used to calibrate other standards referred to as working standards. [1] [2] See Hierarchy of Standards.
Pharmacopoeial reference standards are a subset of pharmaceutical reference standards. They are established for the intended use described in pharmacopeial texts (monographs and general chapters). Pharmacopeial reference standards are available from various pharmacopoeias such as United States Pharmacopeia and the European Pharmacopoeia. Where ...
Elemental analysis is a process where a sample of some material (e.g., soil, waste or drinking water, bodily fluids, minerals, chemical compounds) is analyzed for its elemental and sometimes isotopic composition.
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The pKa of KHP is 5.4, so its pH buffering range would be 4.4 to 6.4; however, due to the presence of the second acidic group that bears the potassium ion, the first pKa also contributes to the buffering range well below pH 4.0, which is why KHP is a good choice for use as a reference standard for pH 4.00. [8] [9]