PNA has been conducting a number of studies into the adulteration of male enhancement herbal suplements with PDE5 inhibitors such as viagra, cialis and a wide number of analogs (Mw approximately 475 amu). Standard materials for the analogs are quite expensive so in th eprocess of developing ID and purity methods on our NMR systems we ran the 1H NMR on our 300, 60, and 43 MHz NMR systems at a concentration of 5mg/ml which equates to 0.01 Molar. This PDF of the NMR data demonstrates the sensitivity and resolution obtainable on these bench-top 5mm NMR systems. They can readily look at samples at these concentrations. They can readily be utilized as screening tools or as quantitation and identification analyzers.
The PDF file containing the Varian 300, Aspect-60, and Magritek 43 MHz data can be found here: NMR Data-0.01 Molar_PDE5 Analogs 300_60_43_MHz