Table 4.

The abundances (ppb) of purines [66] and a pyrimidine [62] in formic acid extracts of carbonaceous meteorites. Numbers in parentheses represent concentrations for tentative structural assignments (i.e., they were usually due to low S/N coupled with a complex multiple reaction monitoring (MRM) chromatogram, not allowing for unambiguous assignment). The + sign indicates the positive identification for the compound (but no quantitation).

	Orgueil	SCO 06043	MET 01070	GRO 95577	ALH 83100	Murchison	LEW 90500	LON 94102	GRA 95229	EET 92042	QUE 99177
Guanine	20	(2)	29	<2 †	21	56	167	244	4	<2 †	<2 †
Hypoxanthine	(5)	(4)	<3 †	<3 †	4	26	23	94	(4)	<3	<3 †
Xanthine	<10 †	<10 †	<10 †	<10 †	(4)	60	22	77	<10 †	<10 †	<10 †
Adenine	7	4	5	<0.5	1	5	10	30	21	5	11
Purine	5	<1 †	<1 †	<1 †	<0.1 †	3	1	6	9	(4)	7
2,6-Diamonopurine	<2 †	<2 †	<2 †	<2	<0.2 †	+	<0.2 †	5	<2 †	<2 †	<2 †
Uracil	27	n.d.	n.d.	n.d.	n.d	33	n.d.	n.d.	n.d.	n.d.	n.d.

^†—Not detected and reported as upper limit. n.d.—not determined.