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General Spectroscopy - How is IV dealing with delayed supply of NIST SRM 3144

 

We have been attempting to purchase NIST SRM 3144 to support Rh analysis for the past few months. Finally, NIST have provided a response to say that this will be out of stock, most likely until Feb 2020. How is IV managing with the lack of SRM availability?

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Brian Alexander, PhD Total posts: 18

NIST provides a great service, and we're grateful for the relationship we have developed with them over the years. Occasionally, NIST will not have a particular SRM immdeiately available, and in those instances we rely either upon a different SRM if the method permits, or the acceptable ISO approach of an unbroken chain of comparisons. As a different NIST SRM may not meet your needs, the second option may be more appropriate, whereby you purcahse a commercial Rh certified reference material (CRM) that has traceability to SRM 3144. The "unbroken chain of comparisons" aspect can have consequences, as it may not be clear how those comparisons were obtained, and the fact that the associated uncertainty tends to increase with an increasing number of comparisons. For those infrequent occasions when we cannot immdiately obtain the desired NIST SRM, we rely upon existing in-house CRMs that were certified by direct comparison to a previous lot of the specific NIST SRM. 

Posted: 08/19/19 14:59:40

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