Total (free plus conjugated) concentrations of eight phenols (BPA, triclosan, 2,4-dichlorophenol, 2,5-dichlorophenol, benzophenone-3 as well as butyl paraben (B-paraben), methyl paraben (M-paraben), and propyl paraben (P-paraben)) and 11 phthalate metabolites were quantified at CDC by online solid phase extraction coupled with high performance liquid chromatography-isotope dilution-tandem mass spectrometry14 (link)-17 (link). The CDC laboratory methods have excellent sensitivity and reproducibility for these urine analyses with coefficients of variation (CVs) ranging from 2.7-15%16 -18 .
For this analysis, we examined the total concentrations of the eight phenols and the metabolites of two commonly used phthalates that accounted for the majority of phthalate urine biomarkers in our population: (1) monoethyl phthalate (MEP), the metabolite of diethyl phthalate (DEP); and (2) the micromolar sum (μmol/L) of four metabolites of di(2-ethylhexyl) phthalate (DEHP): mono (2-ethylhexyl) phthalate (MEHP), mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono (2-ethyl-5-oxohexyl) phthalate (MEOHP), and mono (2-ethyl-5-carboxypentyl)phthalate (MECPP). We calculated the molar sum of the four DEHP metabolites (ΣDEHP) by dividing the concentration of each metabolite by its molar mass and summing the resulting measures. In the 149 women participating in the full formative center study, MEP accounted for approximately 38% and ΣDEHP metabolites accounted for 18% of the phthalate metabolites detected in urine.
For this analysis, we examined the total concentrations of the eight phenols and the metabolites of two commonly used phthalates that accounted for the majority of phthalate urine biomarkers in our population: (1) monoethyl phthalate (MEP), the metabolite of diethyl phthalate (DEP); and (2) the micromolar sum (μmol/L) of four metabolites of di(2-ethylhexyl) phthalate (DEHP): mono (2-ethylhexyl) phthalate (MEHP), mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono (2-ethyl-5-oxohexyl) phthalate (MEOHP), and mono (2-ethyl-5-carboxypentyl)phthalate (MECPP). We calculated the molar sum of the four DEHP metabolites (ΣDEHP) by dividing the concentration of each metabolite by its molar mass and summing the resulting measures. In the 149 women participating in the full formative center study, MEP accounted for approximately 38% and ΣDEHP metabolites accounted for 18% of the phthalate metabolites detected in urine.
