Magnetic Circularly Polarized Luminescence in the Photoexcited States of Racemic [n]Helicenes (n=3-5,7) in Tetrahydrofuran and Dimethyl Sulfoxide Solutions.

This paper reports the first magnetic circularly polarized luminescence (MCPL) characteristics of racemic helicenes, including four unsubstituted [n]helicenes (n=3,4,5,7) and two [4]helicene derivatives bearing methoxy substituents, in tetrahydrofuran (THF) and dimethyl sulfoxide (DMSO) solutions. The value of |gMCPL | was calculated to be of the order of 10-3  T-1 within 350-430 nm under the north-up (N-up) and south-up (S-up) Faraday geometries in an external magnetic field of 1.6 T. The [n]-dependent MCPL signs were altered by the N-up and S-up geometries.

Determination of 3-nitrobenzanthrone in surface soil by normal-phase high-performance liquid chromatography with fluorescence detection.

A sensitive method for determining 3-nitrobenzanthrone in surface soil was developed. 3-Nitrobenzanthrone was reduced to 3-aminobenzanthrone by refluxing at 60 degrees C with hydrazine and Raney nickel for 20 min, and 3-aminobenzanthrone was determined by normal-phase high-performance liquid chromatography (HPLC) with fluorescence detection. We used a cyanopropyl stationary phase and an n-hexane-ethyl acetate (3:1, v/v) mobile phase, since 3-aminobenzanthrone exhibits fluorescence in a low-polarity solvent such as n-hexane or ethyl acetate, but not in a polar solvent such as water or methanol. The calibration graph showed good linearity (r2>0.9999) in the range of 0.002-2 ng, and the detection limit was 0.002 ng (S/N=3). 3-Nitrobenzanthrone in extracts from surface soil collected in the Chubu area (central area) of Japan was determined after clean-up using silica gel chromatography and high-performance liquid chromatography on a pyrenylethyl stationary phase. The concentration of 3-nitrobenzanthrone in surface soil was determined in the range of 1.2-1020 pg/g soil.

Mutagenic activity and quantification of nitroarenes in surface soil in the Kinki region of Japan.

To clarify the mutagenic potential of surface soil in the Kinki region of Japan, particularly in Osaka and neighboring cities, 62 surface soil samples were collected and their organic extracts were examined by the Ames/Salmonella assay. All of the samples were mutagenic toward TA98 in both the presence and absence of a mammalian metabolic activation system (S9 mix). While all of the samples showed mutagenicity toward TA100 with S9 mix, only 45/62 (73%) were mutagenic without S9 mix. Fifty (81%) of the samples showed higher activity toward TA98 than TA100. The mean values of the mutagenicities of soil samples collected in Osaka prefecture (n=35) toward TA98 with and without S9 mix were 2315 and 1630 revertants per gram of soil, respectively, and these were 2.9 and 2.6 times as high as the values for samples from other prefectures (n=27), respectively. Three dinitropyrene (DNP) isomers, i.e. 1,3-, 1,6- and 1,8-DNP, and 3-nitrobenzanthrone (NBA) in the surface soil samples were quantified by fluorometric detection of the corresponding amino compounds, i.e. diaminopyrene isomers and 3-aminobenzanthrone, using high-performance liquid chromatography (HPLC). The three DNP isomers were detected in all of the soil samples (n=26) that were mainly collected in Osaka prefecture, and the amounts of 1,3-, 1,6- and 1,8-DNP were 6-1526, 11-1772 and 10-2092pg/g of soil, respectively. The contribution ratios of 1,3-, 1,6- and 1,8-DNP to the mutagenicity of soil extracts toward TA98 without S9 mix were 0.2-12, 0.3-12 and 0.5-27%, respectively. The amount of 3-NBA in soil samples (n=8) was 144-1158pg/g of soil, and the contribution ratio of 3-NBA to the mutagenicity of soil extracts was 2-38%. These results suggest that the surface soils in the Kinki region were highly polluted with mutagens and the pollution levels in Osaka prefecture were higher than those in other areas. DNP isomers and 3-NBA may be major mutagens that contaminate surface soil in this region.