7 ethoxyresorufin o deethylase 7 er

PCB-126 and PCB-11 were from Ultra Scientific (North Kingstown, RI), beta-naphthoflavone (BNF) from Fisher Scientific (Pittsburg, PA), and 7-ethoxyresorufin-O-deethylase (7-ER) from MP Biomedicals (Solon, OH). All chemicals were dissolved in 100% dimethyl sulfoxide (DMSO) from Fisher Scientific (Fair Lawn, NJ). Stock solutions were stored at −20°C in glass amber vials, and were fully thawed and vortexed before use. For zebrafish concentration analyses, PCB-13 was used as a surrogate standard (SS) from AccuStandard (New Haven, CT), d5-PCB-30 was used as an internal standard (IS) from Cambridge Isotope Laboratories (Andover, MA), and pesticide-grade hexane was used from Fisher Chemical (Beerse, Belgium).

3,3’,4,4’,5-pentachlorobiphenyl (PCB-126) was purchased from Ultra Scientific (North Kingstown, RI), benzo[a]pyrene (B[a]P) from Sigma-Aldrich (St. Louis, MO), and 7-ethoxyresorufin-O-deethylase (7-ER) from MP Biomedicals (Solon, OH). 3,3’-dichlorobiphenyl (PCB-11), 3,3’-dichlorobiphenyl-4-ol (4-OH-PCB-11) and 3,3′-dichloro-4-sulfooxy-biphenyl (4-OH-PCB-11-Sulfate) were synthesized at the Iowa Superfund Research Program (Iowa City, IA) via the Suzuki coupling reaction as described (32 (link), 33 (link)). The authentication of these compounds follow guidelines established previously (34 (link)) and is documented elsewhere (6 (link)). The solubility of PCB-11 in water is 354 μg/L (35 ) and its octanol-water partition coefficient is log 5.28 (36 ). All chemicals were dissolved in 100% dimethyl sulfoxide (DMSO) from Fisher Scientific (Fair Lawn, NJ), stored as stock solutions in glass amber vials at −20°C, and were fully thawed and vortexed before use.