1. Electronic Supplementary Material Journal: Food Analytical Methods Determination of Small Phenolic Compounds in Tequila by Liquid Chromatography – Ion Trap Mass Spectrometry Armando Alcazar Magana, Kazimierz Wrobel, Julio Cesar Torres Elguera, Alma Rosa Corrales Escobosa, Katarzyna Wrobel* Chemistry Department, University of Guanajuato, 36000 Guanajuato, Mexico * Corresponding author. Phone: +52 473 7327555, Fax: +52 472 7326252, E-mail: katarzyn@ugto.mx katarzyn@ugto.mx

2. Fig. 1S. Structures of phenolic compounds analyzed StructureR2R2 R3R3 R4R4 R5R5 R6R6 NameNumber HOH H Gallic acid 1 HOH HH Protocatechuic acid 3 OHHH H 2,5-Dihydroxybenzoic acid 8 HHOHHH 4-Hydroxybenzoic acid 9 OH HHH 2,3-Dihydroxybenzoic acid 11 HOCH 3 OHHH Vanillic acid 14 HOCH 3 OHOCH 3 H Syringic acid 15 OHH HH 2,4-Dihydroxybenzoic acid 16 HOHHH 3-Hydroxybenzoic acid 18 OHHHH 2,6-Dihydroxybenzoic acid 21 HOCH 3 HH 3,4-Dimethoxybenzoic acid 25 HOCH 3 HHH o-Anisic acid 27 OHHHHH Salicylic acid 29 HHHHH Benzoic acid 30 StructureR2R2 R3R3 R4R4 R5R5 NameNumber OHHH Homogentisic acid2 HOH H3,4-Dihydroxyphenyl acetic acid 4 HOCH 3 OHHHomovanillic acid17 StructureR2R2 R3R3 R4R4 R5R5 NameNumber HOH HCaffeic acid12 HHOHHp-Coumaric acid22 HOCH 3 OHOCH 3 Sinapic acid23 HOCH 3 OHHFerulic acid24 HOHHHm-Coumaric acid/ trans-3-Hydroxycinnamic acid 26 OHHHHtrans-2-Hydroxycinnamic acid 28 HHHHCinnamic acid31 HHOCH 3 H4-Methoxycinnamic acid32

3. Resorcinol (7) (R 3 =H) 4-Hydroxyphenylpropionic acid (19) (R 3 =OH) 3,4-Dihydroxyphenylpropionic acid (20) Catechol (13) Chlorogenic acid (5) (+)-Catechin (6); (-)-Epicatechin (10) Caffeine (33) Coumarin (34) Fig. 1S. Structures of phenolic compounds analyzed

4. Fig.2S Extracted ion chromatograms obtained for the calibration solutions containing 34 compounds at two concentration levels: 1.0 and 2.5 mg l -1 each. Individual compounds are numbered according to Fig. 1S (a) negative ESI mode, extracted m/z values: 109, 121, 169, 167, 153, 289, 353, 137, 179, 181, 165, 147, 163, 151, 193, 223, 177, 197 (b) positive ESI mode, extracted m/z values: 195, 151, 147 (a) (b) Intensity x 10 6 Intensity x 10 7 24681012 0 2.5 5 10 12.5 14 Time,min 0 33 27 34

5. Table 1S. Analytical parameters evaluated for 34 phenolic compounds using HPLC-ESI-ITMS procedure. a - A – peak area, c –  g l -1 b - relative standard deviation of the slope evaluated for three replicates of calibration, carried out in different days; c - on-column detection limit (pmol) evaluated based on S/N 3:1, as explained in the main text; d - on-column quantification limit (pmol) evaluated based on S/N 10:1; e - coefficient of variance evaluated based on 5 succesive replicates of calibration standard (0.1 mg l -1 ).

6. Table 2S. Concentrations of individual phenolic compounds determined in white, rested and aged tequilas (B1 - B6, R1 - R12, A1 - A4, respectively); mean values for three replicates are presented in  g l -1 and empty cells indicate that the compound was not detected.