Stephen retired in 2016 from the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland where he is a Scientist Emeritus. He is currently a part-time Scientific Consultant in the Office of Dietary Supplements at the National Institutes of Health (NIH-ODS) where he provides support for the Analytical Methods and Reference Materials Program. He received a B.A. in Chemistry from Weber State University and a Ph.D. in Analytical Chemistry from Arizona State University. During his 40-year career at NIST, he was involved primarily in the development of Standard Reference Materials (SRMs) for trace organic constituents in environmental, clinical, food, and dietary supplement matrices.
At NIST, Stephen was Chief of the Analytical Chemistry Division (2005 – 2012) and Leader of the Organic Analytical Methods Group (1995 – 2004), Separation Science Group (1990 – 1995), and Liquid Chromatography Group (1984 – 1990), all within the Analytical Chemistry Division. Throughout his career at NIST, he interacted extensively with other Federal government agencies through interagency agreements to develop SRMs to support the regulatory needs of these government agencies, including the Environmental Protection Agency (EPA), National Oceanic and Atmospheric Administration (NOAA), Centers for Disease Control and Prevention (CDC), and the National Institutes of Health (NIH).
Stephen is currently an editor of the journal Analytical and Bioanalytical Chemistry and Topical Editor for Analytical Separation Techniques for Polycyclic Aromatic Compounds. He served as Chair of the Division of Analytical Chemistry of the American Chemical Society (1996) and as President of the International Society of Polycyclic Aromatic Compounds (2003-2005). He received the 2001 Polycyclic Aromatic Hydrocarbon Research Award of the International Society of Polycyclic Aromatic Compounds (ISPAC), the 2006 Harvey W. Wiley Award from AOAC INTERNATIONAL, the 2014 Reference Material Achievement Award from the Technical Division on Reference Materials of AOAC INTERNATIONAL, and the 2015 Hillebrand Prize from the Chemical Society of Washington. He was selected as a Fellow of the American Chemical Society in 2013. In 2016, he served as a director-at-large and since 2017 as a director on the AOAC Board of Directors.