Table 2.

Experimental Uncertainties of CCS Values for the Studied Metabolites (Ų)^a

no.	compound name	experimental CCS (Literature)	experimental CCS (this work)	error (%)b	consensus
1	camosine	152.2	147.9	2.89	150.1
2	L-anserine	156.0	151.7	2.81	153.9
3	abscisic acid	160.6	165.0	2.69	162.8
4	O-succinyl-l-homoserine	147.5	142.3	3.63	144.9
5	L-tyrosine	145.8	139.0	4.86	142.4
6	L-citrulline	139.5	131.2	6.33	135.4
7	quinolinic acid	139.0	131.1	6.01	135.1
8	nicotinic acid	128.4	126.6	1.38	127.5
9	guanidinoacetic acid	126.9	127.2	0.25	127.1
10	citramalic acid	124.9	117.7	6.09	121.3
11	N-methyl-l-glutam.ate	133.7	130.0	2.85	131.9
12	serotonin	151.9	144.2	5.34	148.1
13	L-mimosine	143.5	143.1	0.26	143.3
14	L-tryptophan	143.5	145.8	1.60	144.7
15	L-ornithine	129.8	127.4	1.88	128.6
16	N,N-dimethylglycine	123.9	127.2	2.59	125.6
17	kynurenine	151.1	144.2	4.76	147.7
18	L-asparagine	131.5	125.8	4.56	128.7
19	L-2-aminoadipic Acid	131.5	131.6	0.05	131.6
20	glutamine	133.5	127.9	4.34	130.7

^aNitrogen gas was used as the drift gas for CCS measurement. The average of two experimental data, i.e., consensus CCS values, is also reported.

^bAverage % of error is 3.3 ± 2