title: Analysis of small molecules by ultra thin-layer chromatography-atmospheric pressure matrix-assisted laser desorption/ionization mass spectrometry.
abstract: The feasibility of ultra thin-layer chromatography atmospheric pressure matrix-assisted laser desorption ionization mass spectrometry (UTLC-AP-MALDI-MS) has been studied in the analysis of small molecules. Because of a thinner adsorbent layer, the monolithic UTLC plates provide 10-100 times better sensitivity in MALDI analysis than conventional high performance thin-layer chromatography (HPTLC) plates. The limits of detection down to a low picomole range are demonstrated by UTLC-AP-MALDI-MS. Other advantages of UTLC over HPTLC include faster separations and lower solvent consumption. The performances of AP-MALDI-MS and vacuum MALDI-MS have been compared in the analysis of small drug molecules directly from the UTLC plates. The desorption from the irregular surface of UTLC plates with an external AP-MALDI ion source combined with an ion trap instrument provides clearly less variation in measurements of m/z values when compared with a vacuum MALDI-time-of-flight (TOF) instrument. The performance of the UTLC-AP-MALDI-MS method has been applied successfully to the purity analysis of synthesis products produced by solid-phase parallel synthesis method.
authors.affiliation: Faculty of Pharmacy, Division of Pharmaceutical Chemistry, University of Helsinki, FIN-00014 Helsinki, Finland.
authors.forename: Piia K
authors.initials: PK
authors.lastname: Salo
authors.forename: Hannele
authors.initials: H
authors.lastname: Salomies
authors.forename: Kirsi
authors.initials: K
authors.lastname: Harju
authors.forename: Raimo A
authors.initials: RA
authors.lastname: Ketola
authors.forename: Tapio
authors.initials: T
authors.lastname: Kotiaho
authors.forename: Jari
authors.initials: J
authors.lastname: Yli-Kauhaluoma
authors.forename: Risto
authors.initials: R
authors.lastname: Kostiainen
mesh_terms: D001274:Atmospheric Pressure; D002855:Chromatography, Thin Layer / Q000379:methods*; D008790:Metoprolol / Q000032:analysis / Q000737:chemistry; D008874:Midazolam / Q000032:analysis / Q000737:chemistry; D008958:Models, Molecular; D008970:Molecular Weight; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D014700:Verapamil / Q000032:analysis / Q000737:chemistry
chemical_list: D014700:Verapamil; D008790:Metoprolol; D008874:Midazolam