Table 5.

Melanoma-originated metabolites ¹ identified via targeted screening in positive ionization, and their corresponding detected parent ions, adducts and MS/MS fragments, theoretical and experimental m/z, ppm error, retention time (t_R), isotopic ratio RSD (%), p value, Fold Change (FC) and reliability score.

Name	Adducts	Theoretical m/z	Experimental m/z	ppm Error	tR (min)	Adducts	MS/MS	Isotopic Ratio RSD (%)	p Value	FC	Trust Level
Inosine	M+H	269.0880	269.0884	1.31	1.20	M+K, M+Na, 2M+H	136	< 30%	8.77E−14	0.50	10
Hypoxanthine	M+H	137.0458	137.0456	−1.53	0.86	M+2K-H, M+K	119, 109	< 30%	2.51E−08	94.26	9.5
Creatinine	M+H	114.0662	114.0659	−2.03	0.78	M+2K-H, M+K	86	< 30%	0.000462	6.89	8
Betaine	M+K	156.0421	156.0420	−0.41	0.69	M+2K-H		ND 2	1.72E−12	3.50	4
Isovaleric acid	2M+ACN+H	246.1700	246.1701	0.41	3.75		85	< 30%	0.000229	0.74	4
Propionic acid	2M+ACN+H	190.1074	190.1074	0	3.68	M+ACN+H		ND	2.07E−05	0.46	4
S-Adenosyl-homocysteine	M+H	385.1289	385.1293	0.98	1.02			< 30%	1.21E−09	3.38	2.5
Allantoic acid	2M+H	353.1169	353.1166	−0.68	4.41			< 30%	0.01502	0.83	2.5
Methylglyoxal	2M+K	183.0054	183.0054	0	0.76			< 30%	2.12E−09	20.70	2.5
Butyric acid	2M+ACN+H	218.1392	218.1388	−1.83	1.48			< 30%	1.22E−12	3.75	2.5
Formic acid	M+2K+H	122.9250	122.9242	−6.22	0.69			< 30%	1.06E−05	1.60	2.5
Dihydroxy acetone	M+2K+H	166.9512	166.9507	−3.17	0.71			ND	1.56E−07	2.90	2
Dimethyl arginine	M+H	203.1508	203.1503	−2.59	0.75			ND	2.23E−06	0.17	2
Pyroglutamic acid	M+2K+H	205.9616	205.9617	0.44	0.72			ND	0.002998	0.60	2
Glycolic acid	2M+NH4	170.0659	170.0655	−1.96	1.02			ND	2.99E−12	5.37	2
Hippuric acid	M+ACN+H	221.0921	221.0922	0.42	1.42			ND	1.47E−08	0.05	2
Urea	M+2Na-H	105.0035	105.0032	−2.31	0.62			ND	0.000128	2.63	2

¹ AUC > 0.8, for metabolites in bold, ²: not detected.