Fish biliary polycyclic aromatic hydrocarbon metabolites estimated by fixed-wavelength fluorescence: Comparison with HPLC-fluorescent detection

Fixed wavelength fluorescence (FF) was compared to high-performance liquid chromatography with fluorescence detection (HPLC-F) as an estimation of polycyclic aromatic hydrocarbon (PAH) exposure to fish. Two excitation/emission wavelength pairs were used to measure naphthalene- and benzo[a]pyrene (B[a]P)-type metabolites. Early nonmetabolite fluorescent peaks were negligible in HPLC chromatograms of bile of brown bullhead, white sucker, and common carp. Linear regression analysis of FF and HPLC-F data had r(2) values between 0.89 and 1.00. Although the linear regression was significant, the absolute HPLC-F and FF values were not equivalent. HPLC-F values for B[a]P-type metabolites were always higher than those determined by FF. For naphthalene-type metabolites there was no consistent relationship between the HPLC-F and FF values. These inequivalencies were possibly due to the variable HPLC-elution patterns caused by the composition of metabolites and the unique fluorescent response exhibited in different solvent concentrations. Nevertheless, mean concentration estimates divided by the value obtained at the reference site were similar by both methods. The FF method can be used to estimate biliary PAH concentrations in these three species and allows PAH metabolites to become a routine measurement end point for environmental assessments.