title: Measuring environmental phenols and chlorinated organic chemicals in breast milk using automated on-line column-switching-high performance liquid chromatography-isotope dilution tandem mass spectrometry.
abstract: Breast milk is one possible route of exposure to environmental chemicals, including phenols and chlorinated organic chemicals for breast-fed infants. We developed a highly sensitive method of analyzing breast milk for triclocarban (3,4,4'-trichlorocarbanilide) and eight phenolic compounds: bisphenol A (BPA), 4-tert-octylphenol (4-tOP), ortho-phenylphenol (OPP), 2,4-dichlorophenol, 2,5-dichlorophenol, 2,4,5-trichlorophenol, 2,4,6-trichlorophenol, and 2-hydroxy-4-metoxybenzophenone (BP-3). The method includes adding a solution containing a stable isotope of each chemical, enzymatic hydrolysis of the conjugated chemicals in the milk, and on-line solid-phase extraction coupled with high performance liquid chromatography-tandem mass spectrometry. It can also be used to measure the free (unconjugated) species by omitting the enzymatic deconjugation step. The method, validated using pooled breast milk samples, has inter-day coefficient of variations ranging from 4.8 to 18.9% for most analytes, and spiked recoveries generally about 100%. Detection limits for most analytes are below 1 ng/mL in 100 microL of breast milk. We tested the usefulness of the method by measuring concentrations of these nine compounds in 20 breast milk samples. BPA, OPP, and BP-3 were detected in more than 60% of the samples tested. The free species of these compounds appear to be most prevalent in milk.
authors.affiliation: Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Highway, Mailstop F17, Atlanta, GA 30341, USA.
authors.forename: Xiaoyun
authors.initials: X
authors.lastname: Ye
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Kuklenyik
authors.forename: Larry L
authors.initials: LL
authors.lastname: Needham
authors.forename: Antonia M
authors.initials: AM
authors.lastname: Calafat
mesh_terms: D002224:Carbanilides / Q000032:analysis*; D005591:Chemical Fractionation / Q000379:methods; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004785:Environmental Pollutants / Q000032:analysis*; D005260:Female; D006801:Humans; D006843:Hydrocarbons, Chlorinated / Q000032:analysis*; D013058:Mass Spectrometry / Q000379:methods; D008895:Milk, Human / Q000737:chemistry*; D009862:Online Systems; D010636:Phenols / Q000032:analysis*; D012680:Sensitivity and Specificity
chemical_list: D002224:Carbanilides; D004785:Environmental Pollutants; D006843:Hydrocarbons, Chlorinated; D010636:Phenols; C009540:triclocarban