This post was co-authored by Thu Truong, J.D., Senior Associate, Science and Technology Group, and Ron George, Ph.D, Director, Science and Technology Group

Prior to USP 42 – NF 37 (effective April 30, 2019), USP Chapter <197>, Spectroscopy Identification Tests, stated, “The IR absorption spectrum of a substance, compared with that obtained concomitantly for the corresponding USP Reference Standard, provides perhaps the most conclusive evidence of the identity of the substance that can be realized from any single test.”  The chapter implies that both the sample and standard be analyzed concomitantly, and identification made by comparing the spectrum of the sample against that of the standard.

However, the current version of Chapter <197> allows, “if the USP Reference Standard spectrum was obtained previously using equivalent instruments and conditions, it is appropriate to compare the same spectrum with the stored USP Reference Standard spectrum.”  With this flexibility, the accuracy and validity of the reference standard spectra maintained on hardcopy printouts or within the system library are crucial in determining the identification of the analyzed material.  There surely will be significant advantages and interest in using stored/archived reference standard spectra for conforming sample identities.

For hardcopy spectral documentation, the required controls and management of archived reference standard spectra are straightforward and well understood.  This is not quite as simple for electronically stored reference standard spectra.  The security and accessibility of the electronic spectral library are important to ensure the accuracy and validity of the reference standard spectra.  For an electronic library of the reference standard spectra, the spectral software, including the spectra library, must be properly configured and verified for the intended use.  The system configuration and validation must be supported with adequate, properly documented IQ/OQ/PQ reports.  In particular, when qualifying systems intended to facilitate use of stored reference standard spectra, answers to the following questions should be considered:  (1) Should reference standard spectra be obtained and used to build the spectrum library or commercially purchased with in-house verification?  (2) What will be the procedure to control and update the library?  (3) How will user types and user access privileges to the spectral library be established?  (4) Can unauthorized personnel delete, modify, overwrite, or rename the spectra maintained in the library?  (5) Will the system audit trail capture any changes made to the library and/or the spectra?  (6) What data and metadata must the reviewer evaluate during the routine electronic data review to ensure the proper identification and detection of any discrepancies between the spectra of the analyzed sample and that of the reference standard?

Please contact Thu Truong at or Ron George, Ph.D. at R.George@staging.lachmanconsultants.flywheelsites.comfor additional information and/or services related to ensuring the integrity of laboratory data.