Chromatographic, spectroscopic, and electrochemical studies of benzo(a)pyrene derivatives: 9,10 dihydrobenzo(a)pyren-7(8H)-one and 7,8,9,10-tetrahydrobenzo(a)pyrene

Polycyclic aromatic hydrocarbons (PAHs) are a large diverse class of toxic, carcinogenic, and mutagenic hydrophobic organic molecules consisting of two or more fused aromatic rings. Their global distributions have made PAHs ubiquitous environmental pollutants. For these reasons PAHs often serve as strong indicators for pollutant persistence and environmental damage. In this research the synthesis, spectroscopic, chromatographic, and electrochemical studies of two benzo(a)pyrene derivatives 7,8,9,10-tetrahydrobenzo(a)pyrene (7,8,9,10-H4BaP) and 9,10- dihydrobenzo(a)pyrene-7(8H)-one (9,10-H 2BaP) were studied. Of the 16 USEPA priority environmental pollutants benzo(a)pyrene is known to be the most toxic. HPLC and GC studies show 9,10-H 2BaP to be more polar than 7,8,9,10-H4BaP. UV-Vis, FT-IR, fluorescence and NMR were used to characterize 7,8,9,10-H4BaP and 9,10-H2BaP. Spectroscopic and chromatographic data is important for detection of these pollutants in the environment. The fluorescence quantum yields of 9,10-H2BaP in cycicohexane and methanol were 2X greater than that of 7,8,9,10-H4BaP; indicative of a more reactive compound. Cyclic voltammetric studies in acetonitrile showed the redox differences between 7, 8,9,10-H4BaP and 9,10-H2BaP at concentrations > 2 mM. Three to four reductive peaks were observed for 7,8,9,10-H4BaP and 9,10-H2BaP, respectively. These studies serve as benchmarks for future studies in environmental samples.