2001 Volume 47 Issue 1 Pages 28-35
The formation of nitrated pyrenes was investigated on nine metallic oxides as soil components with pyrene and various nitrogen sources under xenon lamp irradiation. The metallic oxides studied were CaO, Al2O3, MgO, Fe2O3, SiO2 (quartz, silicic anhydride, and silica gel forms), and TiO2 (rutile and anatase forms). Nitrated pyrene as a reaction product was extracted with benzene: ethanol (4 : 1, v/v) and analyzed by GC/MS selected ion monitoring (SIM). In the presence of indoor air, 1-nitropyrene (1-NP) was produced in all nine metallic oxides, and the yield of 1-NP was high on silicon dioxide (SiO2; silicic anhydride and silica gel forms) and titanium dioxide (TiO2; rutile and anatase forms). 2-Nitropyrene (2-NP) and 4-nitropyrene (4-NP) were produced in aluminum oxide (Al2O3), magnesium oxide (MgO), and TiO2 (rutile form). In the presence of nitrogen dioxide gas (NO2 gas), nitrite ion (NO2-) or nitrate ion (NO3-), 1-NP was produced in SiO2 (silicic anhydride and silica gel forms), TiO2 (rutile and anatase forms), Al2O3, and MgO. 2- and 4-NP were produced in most samples of Al2O3 and MgO. Accordingly, NO2 gas, NO2-, and NO3- were shown to be nitrogen sources for the formation of nitrated pyrenes in these metallic oxides. In addition, in the presence of these nitrogen sources, 2- and 4-NP were produced on metallic oxides as soil components. The yields and formation patterns of the three types of mononitrated pyrenes differed in the various metallic oxides, as well as with the type of nitrogen source (NO2 gas, NO2- or NO3-). Hence, the nature of the photochemical reaction in the formation of the nitrated pyrenes differed depending on the type of metallic oxide and source of nitrogen. The yields of nitrated pyrenes depended on the amount of NO2- in Al2O3 and MgO and on the amount of NO3- in Al2O3 and SiO2 (silicic anhydride form). In these experiments, dinitropyrenes were not detected in all cases.
