Compound RT [min] Monoisotopic mass [Da] Mass error [ppm] Fragments Abundance [counts] CV [%] Metabolic pathway or relation to eye diseases Spermidine 0.8 145.1579 4 P: 129.14, 112.111, 84.035, 75.091, 72.081, 58.064 1 Alanine metabolism Hydroxyglutaric acid 1.2 148.0372 4 N: 129.021, 103.04, 101.024, 85.031, 57.035 6 Butanoate metabolism Aconitic acid 1.2 174.0164 0 N: 129.021, 111.01, 85.03, 41.04 14 Glyoxylate and dicarboxylate metabolism Citric acid 1.2 192.027 1 N: 129.02, 111.01, 87.01, 85.031 5 Glyoxylate and dicarboxylate metabolism, TCA Ascorbic acid 1.2 176.0321 1 N: 127.004, 115.004, 87.009, 71.014, 59.014 5 Glutathione, ascorbate and aldarate metabolism Pyroglutamic acid 1.2 129.0426 3 N: 82.028 1 Glutathione metabolism Indoleacrylic acid 3.6 187.0633 6 P: 170.06, 146.06, 142.065, 15.054 7 Microbial metabolism [25 , 26 ] Hydroxyphenyllactic acid 3.7 182.0579 3 N: 163.04, 135.045, 119.05, 107.049, 92.99, 72.99, 44.996 2 Tyrosine metabolism Phenylacetylglutamine 4.1 264.111 0 N: 145.062, 127.052 0 Phenylalanine metabolism Trimethylamine N-oxide 1.0 75.0684 6 P: 58.065, 42.033, 30.032 1 Methane metabolism p-Cresol 4.6 108.0575 4 N: 106.042, 105.033, 92.028, 77.038 2 Degradation of aromatic compounds p-Cresol sulfate 4.65 188.0143 1 N: 107.05, 79.957 2 Degradation of aromatic compounds Uric acid 1.2 168.0283 3 P: 151.094, 141.04 6 Purine metabolism 1.2 168.0283 5 N: 124.016, 96.021, 69.01, 41.999 0 Aminosalicylic acid or hydroxyanthranilic acid 5.2 153.0426 6 P: 136.039, 108.044, 80.05 0 Tryptophan metabolism Quinic acid 1.1 192.0634 0 N: 173.046, 127.041, 93.035, 85.03, 59.014, 44.997 1 Phenylalanine, tyrosine, and tryptophan biosynthesis Choline 1.0 103.0997 2 P: 60.081, 45.033 2 Phospholipid biosynthesis, DEDs [24 ] Creatine 1.1 131.0695 7 P: 90.055 0 Arginine and proline metabolism Betaine 1.0 117.079 6 P: 59.073, 58.065 2 Methionine metabolism Indole 3.6 117.0578 5 P: 117.057, 100.112, 91.054 0 Tryptophan metabolism; phenylalanine, tyrosine, and tryptophan biosynthesis Pantothenic acid 3.2 219.1107 2 N: 146.081, 99.045, 88.04, 71.05, 44.014 19 Alanine metabolism; pantothenate and CoA biosynthesis Hydroxybenzaldehyde 4.5 122.0368 3 N: 120.022, 92.027 1 Degradation of aromatic compounds Glycolic acid 1.0 76.016 3 N: 72.994, 47.013 7 Glycine, serine, threonine, glyoxylate, and dicarboxylate metabolism; pentose phosphate pathway Threonic acid 1.0 136.0372 0 N: 117.02, 89.025, 75.009, 59.014 1 Ascorbate and aldarate metabolism Hydroxypyruvic acid 1.0 104.011 3 N: 59.014, 41.002, 31.019 0 Glycine, serine, threonine, glyoxylate, and dicarboxylate metabolism Glyceric acid 1.1 106.0266 2 N: 75.009, 59.013, 56.998 3 Glycerolipid, glyoxylate, and dicarboxylate metabolism; pentose and glucuronate interconversion Carnitine 1.0 161.1052 5 P: 103.039, 102.091, 85.028, 60.081, 43.017 1 Glycine, serine, and threonine metabolism Trigonellinamide 1.0 136.0637 4 P: 94.064, 92.049 1 Nicotinate and nicotinamide metabolism Pyrrolidonecarboxylic acid 1.0 129.0426 1 P: 84.044, 56.049, 41.038 3 Glutathione metabolism Taurine 1.0 125.0147 0 N: 79.958 3 Nitrogen, taurine, and hypotaurine metabolism; primary bile acid biosynthesis Acetylcholine 1.1 145.1103 7 P: 87.0437, 60.08, 43.017 1 Phospholipid biosynthesis, DEDs [24 ] Dimethylarginine 1.1 202.1430 5 P: 158.129, 116.07, 88.086, 70.065, 46.064 0 Protein methylation process Acetyl-histidine 1.1 197.0800 4 P: 180.081, 156.076, 152.081, 110.071, 1 Nitrogen metabolism Hypoxanthine 1.2 136.0385 2 P: 119.035, 110.034, 94.039, 92.057, 82.039, 55.028 3 Purine metabolism Lactic acid 1.2 90.0317 1 N: 43.019 13 Pyruvate metabolism, uveitis [27 ], ocular hypertension [28 ] Glutamylleucine 3.6 260.1372 2 N: 130.089 3 Nitrogen metabolism Indoxylsulfuric acid 4.2 213.0096 3 N: 132.046, 80.964, 79.957 6 Tryptophan metabolism
