title: Comparison of liquid chromatography-microchip/mass spectrometry to conventional liquid chromatography-mass spectrometry for the analysis of steroids.
abstract: The feasibility of a microfluidic-based liquid chromatography-electrospray ionization/mass spectrometric system (HPLC-Chip/ESI/MS) was studied and compared to a conventional narrow-bore liquid chromatography-electrospray ionization/mass spectrometric (LC-ESI/MS) system for the analysis of steroids. The limits of detection (LODs) for oxime derivatized steroids, expressed as concentrations, were slightly higher with the HPLC-Chip/MS system (50-300 pM) using an injection volume of 0.5 μL than with the conventional LC-ESI/MS (10-150 pM) using an injection volume of 40 μL. However, when the LODs are expressed as injected amounts, the sensitivity of the HPLC-Chip/MS system was about 50 times higher than with the conventional LC-ESI/MS system. The results indicate that the use of HPLC-Chip/MS system is clearly advantageous only in the analysis of low-volume samples. Both methods showed good linearity and good quantitative and chromatographic repeatability. In addition to the instrument comparisons with oxime derivatized steroids, the feasibility of the HPLC-Chip/MS system in the analysis of non-derivatized and oxime derivatized steroids was compared. The HPLC-Chip/MS method developed for non-derivatized steroids was also applied to the quantitative analysis of 15 mouse plasma samples.
authors.affiliation: Division of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Helsinki, Finland. linda.ahonen@helsinki.fi
authors.forename: Linda
authors.initials: L
authors.lastname: Ahonen
authors.forename: Pekka
authors.initials: P
authors.lastname: Keski-Rahkonen
authors.forename: Taija
authors.initials: T
authors.lastname: Saarelainen
authors.forename: Jenni
authors.initials: J
authors.lastname: Paviala
authors.forename: Raimo A
authors.initials: RA
authors.lastname: Ketola
authors.forename: Seppo
authors.initials: S
authors.lastname: Auriola
authors.forename: Matti
authors.initials: M
authors.lastname: Poutanen
authors.forename: Risto
authors.initials: R
authors.lastname: Kostianen
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D005260:Female; D057230:Limit of Detection; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D046210:Microfluidic Analytical Techniques; D010091:Oximes / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D013256:Steroids / Q000097:blood*
chemical_list: D010091:Oximes; D013256:Steroids