LC-MS-Based Metabolic Fingerprinting of Aqueous Humor

Table 5

The list of lipids and amino acids identified in aqueous humor.

Compound	RT [min]	Monoisotopic mass [Da]	Mass error [ppm]	Fragments	Abundance [counts]	CV [%]	Metabolic pathway or relation to eye diseases
Acetylcarnitine	1.2	203.1158	6	P: 145.049, 85.028, 60.08		7	FAO
Butyrylcarnitine	3.4	231.1471	4	P: 173.08, 85.028, 60.08		4	FAO
Hexanoylcarnitine	4.6	259.1784	2	P: 99.082, 85.027		2	FAO
Octanoylcarnitine	5.6	287.2097	5	P: 229.141, 127.11, 85.029		1	FAO
Decanoylcarnitine	6.4	315.241	1	P: 85.028, 60.081		3	FAO
Palmitic amide	6.7	255.2562	2	P: 102.089, 88.075, 57.069, 43.052		1	Endocannabinoids metabolism
Stearamide	7.6	283.2875	1	P: 88.076		15	Endocannabinoids metabolism
Hexadecasphinganine	6.6	273.2668	4	P: 256.263, 106.086, 88.075, 57.069		4	Sphingolipids metabolism
Hydroxysphinganine	6.7	317.293	1	P: 300.29, 256.264, 88.075, 57.069		15	Sphingolipids metabolism
5 : 1 dicarboxylic fatty acid	1.2	130.0266	2	N: 85.03, 41.039		17	Fatty acid metabolism
Suberic acid	4.6	174.0892	3	N: 111.08, 83.051		6	Fatty acid metabolism
Nonanedioic acid	5.1	188.1049	3	N: 169.091, 125.097, 97.064		5	Fatty acid metabolism
Sebacic acid	5.6	202.1205	3	N: 183.101, 139.112		4	Fatty acid metabolism
Undecanedioic acid	6.1	216.1362	3	N: 197.12, 153.13		3	Fatty acid metabolism
Undecanedicarboxylic acid	7.0	244.1675	2	N: 225.15, 181.16		1	Fatty acid metabolism
Arginine	1.0	174.117	5	P: 158.093, 130.097, 116.071, 70.065, 60.055		1	Arginine and proline metabolism, urea cycle, Canavan disease, DEDs [24]
Glutamine	1.0	146.0691	4	P: 130.049, 101.07, 102.054, 84.044, 56.049, 41.038		19	Nitrogen, arginine, proline, pyrimidine, alanine, aspartate, glutamate, glutamine and purine metabolism, aminoacyl-tRNA biosynthesis
	1.0	146.0691	1	N: 128.036, 127.051, 109.041, 101.071, 99.056, 84.046, 74.025, 58.03, 41.998		5
Histidine	1.0	155.0695	5	P: 110.072, 93.044, 83.06		1	Nitrogen, alanine, and histidine metabolism, aminoacyl-tRNA biosynthesis
Phenylalanine	3.0	165.079	4	P: 149.059, 131.048, 120.08, 103.053		0	Nitrogen and phenylalanine metabolism; aminoacyl-tRNA, phenylalanine, tyrosine, and tryptophan biosynthesis; DEDs [24]
	3.0	165.079	7	N: 147.045, 103.055, 72.009		2
Tryptophan	3.6	204.0899	0	N: 186.057, 159.093, 142.067, 116.05, 74.024		1	Nitrogen, tryptophan, glycine, serine, and threonine metabolism; aminoacyl-tRNA, phenylalanine, tyrosine, and tryptophan biosynthesis

P or N indicates polarity in which metabolite was detected, positive or negative, respectively. Abundance is a value representing metabolite intensity calculated by MFE algorithm. FAO: fatty acid oxidation; DEDs: dry eye disorders.