P-7
Reference material artifacts for calibration and quality control of molecular absorption spectrophotometers
Presenter: Jerry Messman, Stranaska LLC

Molecular absorption spectrophotometry plays an important measurement role in the chemical analysis of beer ingredients and products. Spectrophotometric methods require instrument standardization to ensure adequate spectral resolution, minimal stray radiant energy (stray light), and that the spectrophotometer's wavelength and photometric scales are accurate with respect to the measurement objectives of the analytical methods. Analytical metrology is integral to science-based instrument standardization and also to the acceptance and interpretation of the absorbance measurement data, results, and calculations. This presentation will provide a critical overview of the array of reference material artifacts that is available for science-based calibration and quality control of spectrophotometers with operational functionality in the ultraviolet, visible, and near infrared regions of the electromagnetic spectrum. Glass and metal-on-quartz filters, calibration solutions sealed in cuvettes, and consumable calibration solutions issued in ampoules and/or bottles will be reviewed. The overview will include a critique of the advantages and disadvantages of both conventional and newly developed reference material artifacts. This presentation will also provide scientific insight into the metrological aspects of reference material artifacts with respect to their scope of calibration, measurement traceability chain, pathway, timeline, and uncertainty budget.

Jerry D. Messman holds a Ph.D. degree in analytical chemistry from the University of Maryland (College Park, MD) and a B.A. degree in chemistry and mathematics from Chadron State College (Chadron, NE). During his tenure at the National Institute of Standards and Technology (NIST) from 1988 to 1992, Jerry directed all NIST activities involving the production, certification, and recertification of UV/VIS spectrophotometric standard reference materials (SRMs). Currently, as director of Stranaska LLC, Jerry is responsible for strategic research, development, and educational outreach for advancing analytical metrology worldwide. Jerry is in his second year of ASBC membership.