title: Quantitative detection of nine phthalate metabolites in human serum using reversed-phase high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry.
abstract: We developed a highly sensitive method for the quantitative detection of nine phthalate ester metabolites in human serum. This method requires denaturation of the serum enzymes immediately after blood collection to avoid the hydrolysis of the contaminant diester parent compounds introduced during blood collection and storage. Before analysis, the samples were subjected to an enzymatic deconjugation to hydrolyze the glucuronidated phthalate monoesters and a solid-phase extraction to isolate the monoesters from other serum components. The extracts were analyzed using reversed-phase high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry. The limits of detection of all nine phthalate monoesters in serum were in the low nanogram-per-milliliter range (0.6-1.3 ng/mL). Stable isotope-labeled internal standards for all analytes were used to improve precision and for recovery corrections. This highly selective method permits the analysis of phthalate monoesters without interferences resulting from the hydrolysis of the ubiquitous contaminant phthalate diesters by serum enzymes. In addition, it allows the direct measurement of the active phthalate monoester metabolites reportedly responsible for the reproductive and developmental toxicity of certain phthalates.
authors.affiliation: Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA.
authors.forename: Kayoko
authors.initials: K
authors.lastname: Kato
authors.forename: Manori J
authors.initials: MJ
authors.lastname: Silva
authors.forename: John W
authors.initials: JW
authors.lastname: Brock
authors.forename: John A
authors.initials: JA
authors.lastname: Reidy
authors.forename: Nicole A
authors.initials: NA
authors.lastname: Malek
authors.forename: Carolyn C
authors.initials: CC
authors.lastname: Hodge
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nakazawa
authors.forename: Larry L
authors.initials: LL
authors.lastname: Needham
authors.forename: Dana B
authors.initials: DB
authors.lastname: Barr
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D006801:Humans; D010795:Phthalic Acids / Q000097:blood* / Q000378:metabolism*; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D013997:Time Factors
chemical_list: D010795:Phthalic Acids