The stable isotope question was not so much if it the “tablets” contained any Viagra or if there was a given or unique stable isotopic signature of Viagra as made by Pfizer. The initial question was if tablets that look like the real thing made by Pfizer and were packaged like Pfizer package the real thing could be easily and quickly distinguished from the real thing made by Pfizer. Yes, they can.
As it so happened, PCA of HNCO isotopic signature tightly clustered all the Pfizer samples (5 different batches purchased from 5 different suppliers). Pfizer must have the entire production process pretty much tightly sewn up. The counterfeit stuff did not even make it inside the 95% confidence ellipse based on Hotelling’s T^2.
Never one to trust anything or anybody unchallenged including myself, we asked a colleague to run all samples in a blinded fashion on his shiny expensive Orbitrap for API and impurities. He also could clearly distinguish between the genuine Pfizer product and the counterfeit but it took him much longer sample-prep- and analysis-time-wise.
I have a methodological question... Would measuring the isotopic composition of Viagra be the best way to test if it’s the real stuff?
Seth D. Newsome
Associate Professor, Biology
Associate Director, CSI
University of New Mexico
Department of Biology
Albuquerque, NM 87131
On Mar 31, 2020, at 11:40 AM, Wolfram Meier-Augenstein (pals) <[log in to unmask]> wrote:
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Not really weird but certainly challenging:
Urine of neonates and preterm babies for energy expenditure determination using the doubly-labelled water method.
Breath of neonates and preterm babies.
Other “oddities” included:
Lacustrine detritus from Antarctic dry valleys.
Soft tissue, axial skeleton, and spicules of gorgonians.
Viagra; purely for scientific reasons (to detect counterfeits); honestly.
Hair and nails of Peruvian mummies.
Chaboutier Chateauneuf-du-Pape wine.
Prof. Dr W Meier-Augenstein, CChem, FRSC
Stable Isotope Forensics & Analytical Sciences
School of Pharmacy & Life Sciences
Robert Gordon University
The Sir Ian Wood Building
Stable Isotope Forensics book, 2nd edition:
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Good afternoon to the isolated isotope geochemists of the world,
In addition to working on “regular” papers, I’d like to assemble an essay/blog this week about “weird, wacky, and funny” isotope samples. In my time, I’ve had several candidates.
Please send me yours! A paragraph on the context or a few sentences would help. Let me know if you’d like to be identified—or not.
This could be fun in itself.
“Always do right. This will gratify some people and astonish the rest.” Mark Twain
Follow my new blog at https://isotopequeen.blogspot.com/
Dr. Marilyn L. Fogel,
Distinguished Professor and Wilbur W. Mayhew Professor of Geo-Ecology
Director of the Environmental Dynamics and Geo-Ecology Institute (http://edge.ucr.edu/)
Dept. of Earth and Planetary Sciences
University of California Riverside
900 University Ave.
Riverside, CA 92521
Robert Gordon University has been awarded a TEF Gold award for the quality of its undergraduate teaching and learning, placing it in the top 20% of Universities in the UK
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