2020. Determination of Phosphodiesterase Type 5 Enzyme (PDE-5) Inhibitors and Analogues as Adulterants in Selected Herbal Products using Gas Chromatography–Electron Impact-Mass Spectrometer (GC-EI-MS). Baghdad Science Journal. 17, 4 (Dec. 2020), 1190. DOI:https://doi.org/10.21123/bsj.2020.17.4.1190.