title: Microchip for combining gas chromatography or capillary liquid chromatography with atmospheric pressure photoionization-mass spectrometry.
abstract: We present a microfabricated nebulizer chip for combining atmospheric pressure photoionization-mass spectrometry (APPI-MS) with gas chromatography (GC) or capillary liquid chromatography (capLC). The chip consists of a silicon plate and a glass plate or two glass plates. The chip includes a sample inlet channel, auxiliary gas and dopant inlet, vaporizer channel, nozzle, and platinum heater. The sample eluted from the capLC or GC is mixed with auxiliary gas and dopant (toluene) in the heated vaporizer. The chip forms a confined jet of the sample vapor, which is photoionized as it exits the chip. The analytical performance of GC- and capLC-microchip APPI-MS was evaluated with some polycyclic aromatic hydrocarbons, amphetamines, and steroids. The GC-muAPPI-MS method provides high sensitivity down to 0.8 fmol, repeatability (RSD = 7.5-14%), and linearity (r = 0.9952-0.9987). The capLC-muAPPI-MS method shows high sensitivity down to 1 fmol, good repeatability (RSD = 3.6-8.1%), and linearity (r = 0.9989-0.9992).
authors.affiliation: Division of Pharmaceutical Chemistry, Faculty of Pharmacy, P.O. Box 56, FI-00014 University of Helsinki, Finland.
authors.forename: Markus
authors.initials: M
authors.lastname: Haapala
authors.forename: Laura
authors.initials: L
authors.lastname: Luosujärvi
authors.forename: Ville
authors.initials: V
authors.lastname: Saarela
authors.forename: Tapio
authors.initials: T
authors.lastname: Kotiaho
authors.forename: Raimo A
authors.initials: RA
authors.lastname: Ketola
authors.forename: Sami
authors.initials: S
authors.lastname: Franssila
authors.forename: Risto
authors.initials: R
authors.lastname: Kostiainen
mesh_terms: D000662:Amphetamines / Q000032:analysis; D001274:Atmospheric Pressure; D002849:Chromatography, Gas / Q000295:instrumentation / Q000379:methods*; D002853:Chromatography, Liquid / Q000295:instrumentation / Q000379:methods*; D005740:Gases; D005898:Glass / Q000737:chemistry; D006358:Hot Temperature; D056656:Lab-On-A-Chip Devices; D013058:Mass Spectrometry / Q000295:instrumentation / Q000379:methods*; D046208:Microchip Analytical Procedures / Q000379:methods*; D010777:Photochemistry / Q000295:instrumentation / Q000379:methods*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012825:Silicon / Q000737:chemistry; D013256:Steroids / Q000032:analysis; D014050:Toluene / Q000737:chemistry; D014835:Volatilization
chemical_list: D000662:Amphetamines; D005740:Gases; D011084:Polycyclic Aromatic Hydrocarbons; D013256:Steroids; D014050:Toluene; D012825:Silicon