The presence of fullerenes up to C 116 was observed in condensable material from a benzene/oxygen flame. The flame material was Soxhlet-extracted with toluene for 363 h, fractionationed by means of a silica-based semipreparative HPLC column, and analyzed by HPLC coupled to a mass spectrometer via a heated nebulizer interface using a 2-(1-pyrenyl)ethylsilica stationary phase. UV-vis spectra were measured for C 60 , C 60 O, C 60 ‚CH 4 , C 70 , C 70 O, C 76 , C 78 , C 80 , C 84 , a C 84 adduct, C 86 , C 88 , C 90 , C 92 , C 94 , C 96 , C 98 , C 100 , C 102 , and C 108 . Isomers could be discerned for C 78 , C 90 , and C 94 . A calibration using external standards was performed for C 60 , C 70 , C 76 , C 78 , and C 84 . For all other species the relative abundances were estimated based on HPLC peak integration results. Electric arc soot was extracted under similar conditions and the quantification of fullerenes compared to the data obtained with flame-generated condensable material. Except for C 60 and C 76 , the abundances were significantly higher in the case of flame-generated condensable material. Also, striking differences between the two fullerene production methods are seen in the relative abundances of C 78 isomers. Considering the present results and the ease with which the experimental setup could be scaled up, flame-generated condensable material represents an excellent starting material for the preparative isolation of higher fullerenes.

Few studies have characterized the regional scale (300-500 km) variability of the mutagenicity of respirable airborne particles (PM2.5). We previously collected 24-h PM2.5 samples for 1 year from background, suburban, and urban sites in Massachusetts (MA) and rural and urban sites in upstate New York (NY) (n = 53-60 samples per site). Bimonthly composites of these samples were mutagenic to human cells. The present report describes our effort to identify chemical classes responsible for the mutagenicity of the samples, to quantify spatial differences in mutagenicity, and to compare the mutagenicity of samples composited in different ways. Organic extracts and HPLC fractions (two nonpolar, one semipolar, and one polar) of annual composites were tested for mutagenicity in the h1A1v2 cells, a line of human B-lymphoblastoid cells that express cytochrome P450 CYP1A1 cDNA. The mutagenic potency (induced mutant fraction per microg organic carbon) of the semipolarfractions was the highest at all five sites, accounting for 35-82% of total mutagenic potency of the samples, vs the nonpolar (4-38%) and polar (14-32%) fractions. These results are consistent with previous studies. While unfractionated extracts exhibited no spatial variations, the mutagenicity of semipolar fractions at the NY sites was approximately 2-fold higher than at the MA sites. This suggests there may be significant regional differences in the sources and/ or transport and transformation of mutagenic compounds in PM2.5. In addition, mutagenic potency was sensitive to whether samples were fractionated and how they were composited: unfractionated annual composite samples at the NY sites were significantly less mutagenic than their semipolar fractions and the annual average of bimonthly composites; spatial differences in the mutagenic potency of bimonthly composites and the semipolar fractions were not apparent in the annual composites.