Tsuyoshi Murahashi

Determination of 1,3-, 1,6-, and 1,8-dinitropyrenes and 1-nitropyrene in urban air by high-performance liquid chromatography using chemiluminescence detection.

A sensitive determination method of 1 3-dinitropyrene (1,3-DNP), 1,6-DNP, 1,8-DNP, and 1-nitropyrene (1-NP) in airborne particulates has been developed. After adding 2-fluoro-7-nitrofluorene as an internal standard, these compounds were extracted with benzene-ethanol, cleaned, and reduced chemically to their corresponding amino derivatives. They were separated on a reversed-phase column with an acetonitrile-imidazole buffer and chemilumigenically detected using bis(2,4,6-trichlorophenyl)oxalate and hydrogen peroxide as postcolumn reagents. Their concentrations in urban air showed two peaks, in the morning and evening, and were higher in autumn and winter than in spring and summer. Mean concentrations were as follows : 1,3-DNP, 2.19 ± 0.81 fmol/m 3 ; 1,6-DNP, 4.03 ± 1.52 fmol/m 3 ; 1,8-DNP, 3.63 ± 1.40 fmol/m 3 ; 1-NP, 0.70 ± 0.28 pmol/m 3 . The mutagenic contribution of each DNP at the above level in air might be comparable to that of 1-NP or more.

Comparison of polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbons in airborne particulates collected in downtown and suburban Kanazawa, Japan

In this study, airborne particulates were collected at three sites, two in a downtown area and the other in a suburban area of Kanazawa, Japan in each season for 7 years. Two polycyclic aromatic hydrocarbons (PAHs), pyrene (Py) and benzo[a]pyrene (BaP) and four nitropolycyclic aromatic hydrocarbons (NPAHs), 1-nitropyrene (NP) and 1,3-, 1,6-, and 1,8-dinitropyrenes (DNP) were determined by high-performance liquid chromatography with fluorescence and chemiluminescence detection. At the downtown sites, the mean concentration of each DNP was about two orders of magnitude lower than that of 1-NP and more than three orders of magnitude lower than those of Py and BaP. This tendency reflected the composition of PAHs and NPAHs in diesel-engine exhaust particulates. Concentrations of these PAHs and NPAHs were higher at the downtown sites than at the suburban site, suggesting the dilution of these compounds during the transportation from the downtown to the suburban area. The concentration ratios of NPAHs to PAHs were larger at the downtown sites than at the suburban site. Studies using UV light and sunlight showed that degradation of NPAHs was faster than that of PAHs. Thus, the lower concentrations of NPAHs in the suburban sites may be due to their being photodegraded faster than PAHs during the atmospheric transportation from the downtown area to the suburban area.

Distribution of nitropyrenes and mutagenicity in airborne particulates collected with an Andersen sampler

Distributions of 1,3-dinitropyrene (1,3-DNP), 1,6-DNP, 1,8-DNP, 1-nitropyrene (1-NP) and mutagenicity in airborne particulates collected in downtown Kanazawa, Japan with an Andersen high-volume air sampler were examined. Mutagenicities of benzene-ethanol extract from particulates were determined by the Ames test using S. typhimurium strains without S9 mix, while concentrations of DNPs and 1-NP were determined by high-performance liquid chromatography (HPLC) using chemiluminescence detection. In the finest particulate fraction (smaller than 1.1 microns), 68% and 75% of the total mutagenicities were observed in TA98 and YG1024 strains, respectively. In the same fraction, 65-82% of three DNPs as well as 84% of 1-NP were observed. Mutagenic contributions of 1,3-DNP, 1,6-DNP, 1,8-DNP and 1-NP in the extract were respectively 0.6, 1.2, 1.8 and 1.6% in the TA98 strain, and 2.5, 5, 9 and 2.1% in the YG1024 strain.

Comprehensive two-dimensional high-performance liquid chromatography for the separation of polycyclic aromatic hydrocarbons

A comprehensive two-dimensional HPLC system for the separation of polycyclic aromatic hydrocarbons was developed using a pentabromobenzyl column as the first dimension and two short monolithic C18 columns as the second dimension. The primary column and two secondary columns were coupled by a 10-port 2-position valve. The effluent from the first dimension was repetitively injected into the second dimension every 12 s. Due to its resolution, this technique is a powerful tool for the separation of polycyclic aromatic hydrocarbons in a complex matrix such as environmental samples.

A sensitive method for the determination of 6-nitrochrysene, 2-nitro-fluoranthene and 1-, 2- and 4-nitropyrenes in airborne particulates using high-performance liquid chromatography with chemiluminescence detection

Abstract A sensitive method for the determination of 6-nitrochrysene (NC), 2-nitrofluoranthene (NF) and 1-, 2- and 4-nitropyrenes (NP) in airborne particulates is described. After ultrasonic extraction of airborne particulates with benzene/ethanol, the extract was injected into a high-performance liquid chromatographic (HPLC) system. The system consisted of four pumps, an auto injector, two separation columns (ODS), a reduction column (zinc/glass beads), a concentration column (ODS), a switching valve, a column oven, a chemiluminescence detector and an integrator. Nitroarenes were separated on the first separation column and reduced to their corresponding aminoarenes through the reduction column. The elution bands containing the analytes were concentrated selectively onto the concentration column by increasing the water concentration of the mobile phase. By rotating the switching valve, the analytes were introduced into the second separation column, separated and then detected chemilumigenically. Detection limits were in the 0.3–5 fmol range. Utilizing the above method, atmospheric concentrations of the above five nitroarenes in Kanazawa were determined.

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.

Determination of nitroarenes in precipitation collected in kanazawa, Japan

Eight nitroarenes, 1,3-, 1,6- and 1,8-dinitropyrenes, 1-, 2- and 4-nitropyrenes, 6-nitrochrysene and 2-nitrofluoranthene, in precipitation collected in Kanazawa were determined. The nitroarenes in the precipitation were concentrated onto solid phase extraction cartridges, and identified with high-performance liquid chromatography with chemiluminescence detection. The nitroarene concentrations in the precipitation were in the range 0.016-15 pmol/L, and the nitroarene composition tended to be the same as that in airborne particulates. 1-Nitropyrene in river water and seawater were also determined. 1-nitropyrene concentrations on the days after rain (19-110 fmol/L) were higher than those on the days before rain (4,11 fmol/L). Moreover, 1-nitropyrene concentrations in the river water were much lower than those in the precipitation, but were higher than those in the seawater. These results suggested that the nitroarenes in the precipitation and the river water came from airborne particulates.

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.

Comparison of Polycyclic Aromatic Hydrocarbons and Nitropolycyclic Aromatic Hydrocarbons in Airborne and Automobile Exhaust Particulates

Abstract Polycyclic aromatic hydrocarbons (PAH) and nitropolycyclic aromatic hydrocarbons (NPAH) in airborne particulates collected simultaneously at downtown and suburban sites and in exhaust particulates from diesel and gasoline engine vehicles were determined. The mean concentrations of all compounds in the atmosphere were lower at the suburban site. The differences between the two sites were smaller in airborne particulates than in the atmosphere. However, the difference in NPAH concentrations in particulates between the two sites was greater than the difference in PAH concentrations, suggesting that the NPAH were less stable than the PAH. The concentrations of 1-nitropyrene and 1,3-, 1,6- and 1,8-dinitropyrenes were generally much higher in automobile exhaust particulates than in airborne particulates because the former were collected directly. However, 2-nitrofluoranthene and 2-nitropyrene were observed in airborne particulates but not in automobile exhaust particulates. The diurnal concentrations showed that 2-nitrofluoranthene and 2-nitropyrene might be formed by a hydroxyl radical-initiated reaction followed by nitration.

Determination of mutagenic 3-nitrobenzanthrone in diesel exhaust particulate matter by three-dimensional high-performance liquid chromatography

Mutagenic 3-nitrobenzanthrone was determined in diesel exhaust particulate matter by three-dimensional high-performance liquid chromatography. Nitrophenylethyl, C18 and pyrenylethyl stationary phases were used as the first, second and third dimensions, respectively. Methanol was used as a mobile phase for the first and second dimensions, and dichloromethane was used for the third. Each column was coupled by a 6-port valve with a concentrator column. Effluent from the third dimensional column was detected by a photodiode array detector. The calibration graph showed good linearity in the range of 1-1000 ng ml(-1), and the detection limit (S/N = 3) was 1 ng ml(-1) 3-Nitrobenzanthrone could be detected within 45 min without the requirement of a clean-up procedure. 3-Nitrobenzanthrone in diesel exhaust particulate matter was detected in the range of 27-56 pg mg(-1) extract (n = 3).