title: Quantifying phthalate metabolites in human meconium and semen using automated off-line solid-phase extraction coupled with on-line SPE and isotope-dilution high-performance liquid chromatography--tandem mass spectrometry.
abstract: We developed an analytical method using off-line solid-phase extraction (SPE) coupled with on-line SPE and isotope-dilution high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) to determine the concentrations of phthalate metabolites in human meconium and in semen. First, we used off-line SPE to remove interfering proteins and other biomolecules from the samples. Then, we preconcentrated the phthalate metabolites in the extract using on-line SPE before measuring them by HPLC-MS/MS. For most of the analytes, the limits of detection ranged between 0.2 and 0.7 ng/g for meconium and between 0.3 and 0.7 ng/mL for semen. The recovery after off-line SPE varied for most analytes between 65 and 99% at concentrations ranging from 3.0 to 30.0 ng/mL in semen and between 67 and 103% at concentrations ranging from 2.0 to 10.0 ng/mL in meconium. Precision measured by the relative standard deviation ranged from 3.2 to 19.1% for intraday and from 3.9 to 18.6% for interday. We validated this novel approach--which is applicable to other biological matrixes, including serum and breast milk--on spiked samples and on five meconium samples and one pooled semen sample from people with no known occupational exposure to phthalates.
authors.affiliation: Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, USA.
authors.forename: Kayoko
authors.initials: K
authors.lastname: Kato
authors.forename: Manori J
authors.initials: MJ
authors.lastname: Silva
authors.forename: Larry L
authors.initials: LL
authors.lastname: Needham
authors.forename: Antonia M
authors.initials: AM
authors.lastname: Calafat
mesh_terms: D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D008297:Male; D008470:Meconium / Q000737:chemistry*; D010795:Phthalic Acids / Q000032:analysis* / Q000378:metabolism; D015203:Reproducibility of Results; D012661:Semen / Q000737:chemistry*; D052616:Solid Phase Extraction / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D010795:Phthalic Acids; C032279:phthalic acid