Table 1.

Unique compounds detected for each method, and those detected in only the organic acid extraction methods.

Method name and number of unique compounds	List of unique compounds
Method 1 (n = 0)	None
Method 2 (n = 13)	Analyte 003 Analyte 013 Analyte 121 Analyte 128	Analyte 135 Analyte 148 Analyte 150	Analyte 156 Analyte 157 Analyte 167	Analyte 171 Analyte 192 Analyte 308
Method 3 (n = 1)	Analyte 322
Method 4 (n = 7)	2,3,4-Trihydroxy-butyraldehyde O-methyl-oxime	Analyte 036 Analyte 071	Analyte 209 Analyte 216	Analyte 325 Malonic acid
Method 5 (n = 91)	2-Amino-benzoic acid 3,4,5-Trihydroxy-pentanoic acid 3,4-Dihydroxy-butyric acid 3R,4S-Tetrahydrofuran-2,3,4-triol 4-Hydroxy-pyrrolidine-2-carboxylic acid 5-Hydroxymethyl-tetrahydro-furan-2,3,4-triol [1] 5-Hydroxymethyl-tetrahydro-furan-2,3,4-triol [2] 5-Oxo-pyrrolidine-2-carboxylic acid Analyte 004 Analyte 005 Analyte 023 Analyte 025 Analyte 029 Analyte 035 Analyte 038 Analyte 043 Analyte 046	Analyte 050 Analyte 057 Analyte 058 Analyte 061 Analyte 063 Analyte 064 Analyte 070 Analyte 072 Analyte 085 Analyte 086 Analyte 087 Analyte 090 Analyte 096 Analyte 099 Analyte 118 Analyte 125 Analyte 126 Analyte 131 Analyte 137 Analyte 145 Analyte 151 Analyte 177 Analyte 183 Analyte 186 Analyte 199	Analyte 210 Analyte 212 Analyte 218 Analyte 220 Analyte 225 Analyte 251 Analyte 253 Analyte 266 Analyte 276 Analyte 278 Analyte 280 Analyte 285 Analyte 287 Analyte 302 Analyte 305 Analyte 306 Analyte 311 Analyte 321 Analyte 323 Arabinofuranose Arabinose Ascorbic acid Aucubin Butane-2,3-diol Creatinine	Dehydroabietic acid Erythronic acid ç-lactone Galactose [1] Galactose [2] Glucose Glucuronic acid Glucuronic acid ç-lactone Glycerol Isocitric lactone meso-Erythritol Methyl galactoside Methylmalonic acid Myo-Inositol [1] Myo-Inositol [2] N-Acetyltyrosine N-benzoyl-glycine Oxalic acid Oxalic acid [1] Oxalic acid [2] Rhamnose Ribofuranose Tagatofuranose Threo-3-deoxy-pentonic acid Xylose
Compounds unique to the organic acid methods (Methods 1–4)* (n = 58)	2,3,4-Trihydroxy-butyraldehyde O-methyl-oxime 2,4-Dihydroxybutyric acid 2-Hydroxy-pentanedioic acid 5-Hydroxymethyl-tetrahydro-furan-2,3,4-triol [1] 5-Hydroxymethyl-tetrahydro-furan-2,3,4-triol [2] Analyte 003 Analyte 013 Analyte 014 Analyte 020 Analyte 022 Analyte 024	Analyte 027 Analyte 031 Analyte 036 Analyte 049 Analyte 052 Analyte 055 Analyte 059 Analyte 071 Analyte 121 Analyte 123 Analyte 128 Analyte 135 Analyte 143 Analyte 144 Analyte 148 Analyte 150	Analyte 156 Analyte 157 Analyte 167 Analyte 168 Analyte 170 Analyte 171 Analyte 173 Analyte 174 Analyte 175 Analyte 176 Analyte 192 Analyte 195 Analyte 205 Analyte 209 Analyte 216 Analyte 226	Analyte 239 Analyte 240 Analyte 255 Analyte 297 Analyte 301 Analyte 308 Analyte 314 Analyte 322 Analyte 325 Benzene-1,2,3-triol Citric acid [miss ID] Malonic acid diethyl ester Octadecanoic acid Propane-1,2,3-triol [1] Tetrahydro-pyran-2,3,4,5-tetraol (isomer 2)

*Some of these compounds were detected across multiple organic acid extraction methods, hence they are not unique to a specific organic acid method (Methods 1–4), however, they were not detected using the direct analysis method (Method 5).