Spectroelectrochemical sensing of pyrene metabolites 1-hydroxypyrene and 1-hydroxypyrene-glucuronide

Spectroelectrochemical sensing in an optically transparent thin layer electrode (OTTLE) cell was used for detecting the polycyclic aromatic hydrocarbon (PAH) biomarkers 1-hydroxypyrene (1-pyOH) and 1-hydroxypyrene-glucuronide (1-pyOglu) in phosphate buffer and artificial urine. This approach uses selective electrochemical modulation of a fluorescence signal by sequentially oxidizing the analytes in an OTTLE cell to distinguish between their overlapping fluorescence spectra. This technique allows for complete oxidation and signal modulation in approximately 15 min for each analyte; a mixture of 1-pyOH and its glucuronic acid conjugate can be analyzed in 30 min. Calibration curves consisting of the fluorescence change vs analyte concentration for 1-pyOH and 1-pyOglu yielded linear ranges from 10 nM to 1 μM and from 1 nM to 1 μM, respectively. With the use of these results, the calculated limits of detection were determined to be 1 × 10(-8) M for 1-pyOH and 9 × 10(-11) M for 1-pyOglu.