Chemicals / pH measurement

Whats the difference between a NIST buffer and a NIST traceable buffer

pH buffers
pH buffers

We often get asked about supplying NIST buffers, however we offer both NIST buffers and Buffers which are traceable to NIST standards. They are different products so here is a simple guide to the differences.

NIST buffers: NIST is the National Institute of Standards and Technology, an agency of the U.S. Department of Commerce, it was founded in 1901 as the United States first federal physical science research laboratory. NIST produces a range of standards and standard methods of analysis and standard reference materials for a range of industries. They also provide methodologies for a range of testing in many fields of science.

NIST have defined a series of Buffers which are made up to an exact formula, and give the maximum buffering capacity for a praticular mixture of weak acid and congugate base (or weak base and congugate acid). However these buffers are not round numbers at 25°C, the standards are for example 4.005(Potassium Hydrogen Phtalate), 6.865 (Potassium Dihydrogen Phosphate/ Disodium Phosphate) and 9.180 (Sodium Teraborate Decahydrate (Borax)). These are NIST buffers

Although these buffers are the ideal values they are not so easy to check against as whole numbers, partucularly on old fashioned meters which had a dial rather than a digital display. Ranges of buffers are available which are whole numbers such as 4, 7 and 10. although they are not made to the exact NIST formula they are made to the same standard and quality, hence are referred to as NIST traceable buffers

 

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