title: Quantitative determination of 8-isoprostaglandin F(2α) in human urine using microfluidic chip-based nano-liquid chromatography with on-chip sample enrichment and tandem mass spectrometry.
abstract: Urinary 8-isoprostaglandin F(2α) (8-isoPGF(2α)) has been reported as an important biomarker to indicate the oxidative stress status in vivo. In order to quantitatively determine the low contents of 8-isoPGF(2α) (in sub- to low ng mL(-1) range) in physiological fluids, a sensitive detection method has become an important issue. In this study, we employed a microfluidic chip-based nano liquid chromatography (chip-nanoLC) with on-chip sample enrichment coupled to triple quadrupole mass spectrometer (QqQ-MS) for the quantitative determination of 8-isoPGF(2α) in human urine. This chip-nanoLC unit integrates a microfluidic switch, a chip column design having a pre-column (enrichment column) for sample enrichment prior to an analytical column for separation, as well as a nanospray emitter on a single polyimide chip. The introduction of enrichment column offers the advantages of online sample pre-concentration and reducing matrix influence on MS detection to improve sensitivity. In this study, the chip-nanoLC consisting of Zorbax 300A SB-C18 columns and Agilent QqQ Mass spectrometer were used for determining 8-isoPGF(2α) in human urine. Gradient elution was employed for effective LC separation and multiple reaction monitoring (MRM) was utilized for the quantitative determination of 8-isoPGF(2α) (m/z 353→193). We employed liquid-liquid extraction (LLE)/solid-phase extraction (SPE) for extracting analyte and reducing matrix effect from urine sample prior to chip-nanoLC/QqQ-MS analysis for determining urinary 8-isoPGF(2α). Good recoveries were found to be in the range of 83.0-85.3%. The linear range was 0.01-2 ng mL(-1) for urinary 8-isoPGF(2α). In addition, the proposed method showed good precision and accuracy for 8-isoPGF(2α) spiked synthetic urine samples. Intra-day and inter-day precisions were 1.8-5.0% and 4.3-5.8%, respectively. The method accuracy for intra-day and inter-day assays ranged from 99.3 to 99.9% and 99.4 to 99.7%, respectively. Due to its rapidity, enhanced sensitivity, and high recovery, this chip-nanoLC/QqQ-MS system was successfully utilized to determine the physiological biomarkers such as 8-isoPGF(2α) in human urine for clinical diagnosis.
authors.affiliation: Department of Chemistry, Soochow University, Taipei, Taiwan.
authors.forename: Hsin-Yu
authors.initials: HY
authors.lastname: Bai
authors.forename: Shu-Ling
authors.initials: SL
authors.lastname: Lin
authors.forename: Yu-Ting
authors.initials: YT
authors.lastname: Chung
authors.forename: Tsung-Yun
authors.initials: TY
authors.lastname: Liu
authors.forename: Shan-An
authors.initials: SA
authors.lastname: Chan
authors.forename: Ming-Ren
authors.initials: MR
authors.lastname: Fuh
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000652:urine; D002853:Chromatography, Liquid / Q000379:methods*; D015237:Dinoprost / Q000031:analogs & derivatives* / Q000737:chemistry / Q000652:urine; D006801:Humans; D046210:Microfluidic Analytical Techniques / Q000379:methods*; D036103:Nanotechnology; D018384:Oxidative Stress; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D052616:Solid Phase Extraction; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D015415:Biomarkers; C075750:8-epi-prostaglandin F2alpha; D015237:Dinoprost