title: A simplified protein precipitation and filtration procedure for determining serum vitamin B6 by high-performance liquid chromatography.
abstract: Protein precipitation followed by centrifuge filtration was tested as a simplified sample preparation procedure for quantifying pyridoxal 5'-phosphate (PLP) and 4-pyridoxic acid (4PA) in serum by high-performance liquid chromatography. Serum samples (n=160) were prepared by both centrifuge filtration and an established technique using traditional supernatant extraction with manual filtration. Bland-Altman bias analysis (95% confidence levels [CLs]) of the results showed a -1.3 (-2.2, -0.5)% difference in PLP values and a -6.2 (-7.3, -5.2)% difference in 4PA values using the simplified sample preparation. These deviations were found to be well within allowable biases on the basis of biologic variation.
authors.affiliation: Nutritional Biomarkers Branch, Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA. mrybak@cdc.gov
authors.forename: Michael E
authors.initials: ME
authors.lastname: Rybak
authors.forename: Christine M
authors.initials: CM
authors.lastname: Pfeiffer
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D011506:Proteins / Q000737:chemistry*; D011732:Pyridoxal Phosphate / Q000097:blood* / Q000302:isolation & purification; D011735:Pyridoxic Acid / Q000097:blood* / Q000302:isolation & purification
chemical_list: D011506:Proteins; D011735:Pyridoxic Acid; D011732:Pyridoxal Phosphate