title: Application of Orbitrap-mass spectrometry to differentiate isomeric sildenafil- and thiosildenafil-like analogues used for the adulteration of dietary supplements.
abstract: Two groups of isomeric phosphodiestrase-type 5 inhibitors (PDE-5), consisting of four sildenafil- and three thiosildenafil-like analogues, have been successfully differentiated using high-resolution MS/MS. The optimised MS/MS data obtained from each compound were used to build a database with the aid of mass processing software. Isomeric compounds with very close chromatographic separation like dimethylsildenafil and homosildenafil could be distinguished by their unique fingerprint fragment ions in the MS/MS database. All fragment ions were within the mass tolerance of 5 ppm. One case study using an adulterated dietary supplement is included to provide more insights into this application.
authors.affiliation: a Pharmaceutical Laboratory, Applied Sciences Group , Health Sciences Authority , Singapore , Singapore.
authors.forename: Chee-Leong
authors.initials: CL
authors.lastname: Kee
authors.affiliation: a Pharmaceutical Laboratory, Applied Sciences Group , Health Sciences Authority , Singapore , Singapore.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Ge
authors.affiliation: a Pharmaceutical Laboratory, Applied Sciences Group , Health Sciences Authority , Singapore , Singapore.
authors.forename: Min-Yong
authors.initials: MY
authors.lastname: Low
mesh_terms: D019587:Dietary Supplements / Q000032:analysis*; D004340:Drug Contamination; D059022:Food Safety; D006801:Humans; D007536:Isomerism; D058986:Phosphodiesterase 5 Inhibitors / Q000737:chemistry / Q000302:isolation & purification*; D011743:Pyrimidines / Q000737:chemistry / Q000302:isolation & purification*; D000068677:Sildenafil Citrate / Q000031:analogs & derivatives / Q000302:isolation & purification*; D013450:Sulfones / Q000737:chemistry / Q000302:isolation & purification*; D053719:Tandem Mass Spectrometry / Q000295:instrumentation / Q000379:methods*; D064804:Urological Agents / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D058986:Phosphodiesterase 5 Inhibitors; D011743:Pyrimidines; D013450:Sulfones; D064804:Urological Agents; D000068677:Sildenafil Citrate; C539492:thiosildenafil
keywords: Orbitrap mass spectrometry; dietary supplements; high-resolution MS/MS; isomeric PDE-5 analogues