Formation of C H Ablation of Graphite, Coal or C Particles Suspended in Selected Solvents - Polyynes: Synthesis, Properties, and Applications - page 129

FIGURE 7.4 (a) HPLC chromatogram. (b) and (c) UV absorption spectra of HPLC
peaks E and A in (a) resulting from unfocused 355 nm laser irradiation on graphite
particles suspended in benzene for 60min. 1:1 mixture of hexane/methanol solution
was used as an HPLC solvent.

In order to further confirm the formation of polyynes, GC/MS spectra
of products were measured. A weak GC peak with a parent ion of m/z

98
was observed at a retention time of about 4.1min in benzene, toluene,
hexane, cyclohexane, and methanol. The mass spectrum of the GC peak
at 4.1min was composed of a strong peak at m/z

¼

¼ 98 and a weak peak at

m/z 97 with a relative intensity of 0.0093. These two peaks could be

assigned to C 8 H 2 þ and C 8 H þ , respectively. In addition, a GC peak with
a parent ion of m/z

¼

122 was detected at a retention time of 12.7min.
The mass spectrum of the GC peak at 12.7min consisted of a strong peak
at m/z

¼

121, 120, 85, and 61, with rela-
tive intensities of 0.090, 0.032, 0.020, and 0.052, respectively. These five
peaks were ascribable to C 10 H 2 þ ,C 10 H þ ,C 10 þ ,C 7 H þ ,C 5 H þ , respectively.

¼ 122 and weak peaks at m/z ¼