title: Fast and sensitive determination of urinary 1-hydroxypyrene by packed capillary column switching liquid chromatography coupled to micro-electrospray time-of-flight mass spectrometry.
abstract: The present work reports capillary liquid chromatographic column switching methodology tailored for fast, sensitive and selective determination of 1-hydroxypyrene (1-OHP) in human urine using micro-electrospray ionization time-of-flight mass spectrometric detection. Samples (100 microl) of deconjugated, water diluted and filtered urine samples were loaded onto a 150 microm I.D.x 30 mm 10 microm Kromasil C(18) pre-column, providing on-line sample clean-up and analyte enrichment, prior to back flushed elution onto a 150 microm I.D.x 100 mm 3.5 microm Kromasil C(18) analytical column. Loading flow rates up to 100 microl/min in addition to the use of isocratic elution by a mobile phase composition of acetonitrile/water (70/30, v/v) containing 5 mM ammonium acetate provided elution of 1-OHP within 5.5 min and a total analysis time of less than 15 min with manual operation. Ionization was performed in the negative mode and 1-OHP was observed as [M-H](-) at m/z 217.08. The method was validated over the concentration range 0.2-40 ng/ml 1-OHP in pre-treated urine, yielding a coefficient of correlation of 0.997. The within-assay (n=6) and between-assay (n=6) precisions were in the range 6.4-7.3 and 7.0-8.1%, respectively, and the recoveries were in the range 96.2-97.5 within the investigated concentration range. The method mass limit of detection was 2 pg, corresponding to a 1-OHP concentration limit of detection of 20 pg/ml (0.09 nmol/l) diluted urine or 0.3 ng/ml (1.35 nmol/l) urine.
authors.affiliation: Department of Chemistry, University of Oslo, PO Box 1033, Blindern, N-0315, Oslo, Norway. anders.holm@kjemi.uio.no
authors.forename: Anders
authors.initials: A
authors.lastname: Holm
authors.forename: Paal
authors.initials: P
authors.lastname: Molander
authors.forename: Elsa
authors.initials: E
authors.lastname: Lundanes
authors.forename: Steinar
authors.initials: S
authors.lastname: Øvrebø
authors.forename: Tyge
authors.initials: T
authors.lastname: Greibrokk
mesh_terms: D011721:Pyrenes / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D014556:Urine
chemical_list: D011721:Pyrenes; C033146:1-hydroxypyrene