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

  

   

 

Fig. 1S. Structures of phenolic compounds analyzed

Structure R2 R3 R4 R5 R6 Name Number

H OH OH OH H Gallic acid 1H OH OH H H Protocatechuic acid 3OH H H OH H 2,5-Dihydroxybenzoic

acid8

H H OH H H 4-Hydroxybenzoic acid 9OH OH H H H 2,3-Dihydroxybenzoic

acid11

H OCH3 OH H H Vanillic acid 14H OCH3 OH OCH3 H Syringic acid 15OH H OH H H 2,4-Dihydroxybenzoic

acid16

H OH H H 3-Hydroxybenzoic acid 18OH H H H OH 2,6-Dihydroxybenzoic

acid21

H OCH3 OCH3 H H 3,4-Dimethoxybenzoic acid

25

H OCH3 H H H o-Anisic acid 27OH H H H H Salicylic acid 29H H H H H Benzoic acid 30

Structure R2 R3 R4 R5 Name NumberOH H H OH Homogentisic acid 2H OH OH H 3,4-Dihydroxyphenyl

acetic acid 4

H OCH3 OH H Homovanillic acid 17

    

Structure R2 R3 R4 R5 Name NumberH OH OH H Caffeic acid 12H H OH H p-Coumaric acid 22H OCH3 OH OCH3 Sinapic acid 23H OCH3 OH H Ferulic acid 24H OH H H m-Coumaric acid/

trans-3-Hydroxycinnamic acid

26

OH H H H trans-2-Hydroxycinnamic acid

28

H H H H Cinnamic acid 31H H OCH3 H 4-Methoxycinnamic acid 32

Resorcinol (7)

(R3=H) 4-Hydroxyphenylpropionic acid (19)(R3=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

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

26

2324

28

22

6 21 315

0 2 4 6 8 10 120

1

2

3

191017

1 182 83 9

31

15

1611

14

27

12

14

1374

2025

29

3230In

tens

. X

107

Time, min

(a)

(b)

Inte

nsi

ty x

106

Inte

nsi

ty x

107

2 4 6 8 10 120

2.5

5

10

12.5

14

Time, min

0

33

27

34

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).

Analyte Linear regression functiona R RSD slopeb LDc, pmol

LQd, pmol

CVe, %

Negative ESI 1 A = (3.233c + 0.135)106 0.9918 2.2 0.14 0.45 2.3 2 A = (1.198c – 0.046)106 0.9985 7.4 0.16 0.54 3.5 3 A = (1.502c + 0.022)106 0.9991 0.4 0.17 0.56 1.2 4 A = (0.321c – 0.01)106 0.9988 5.1 0.66 2.20 1.9 5 A = (11.16c + 0.140)106 0.9980 3.9 0.07 0.25 0.9 6 A = (5.836c + 0.023)106 0.9998 0.9 0.10 0.32 2.7 7 A = (0.128c + 0.135)106 0.9976 0.3 6.09 20.3 3.9 8 A = ( 2.18c + 0.101)106 0.9991 3.8 0.51 1.69 3.2 9 A = (0.563c + 0.001)106 0.9993 6.5 0.79 2.63 2.8 10 A = (3.651c + 0.161)106 0.9977 1.4 0.11 0.37 3.1 11 A = (6.320c + 0.131)106 0.9973 2.5 0.38 1.25 2.8 12 A = (5.702c + 0.009)106 0.9986 5.6 0.17 0.56 3.3 13 A = (0.674c + 0.054)106 0.9999 4.4 1.63 5.43 4.7 14 A = (0.259c – 0.001)106 0.9997 3.4 1.14 3.79 5.2 15 A = (0.572c + 0.003)106 0.9989 0.7 0.50 1.68 2.6 16 A = (2.756c + 0.017)106 0.9997 2.4 0.13 0.44 2.4 17 A = (0.179c – 0.001)106 0.9987 6.1 0.45 1.50 5.1 18 A = (0.437c + 0.009)106 0.9993 5.9 0.70 2.34 4.2 19 A = (1.148c + 0.067)106 0.9978 6.0 0.17 0.56 3.2 20 A = (0.661c + 0.001)106 0.9999 7.3 0.57 1.88 5.0 21 A = (6.517c + 0.380)106 0.9953 1.5 0.15 0.50 1.9 22 A = (1.438c + 0.123)106 0.9937 2.7 0.30 0.99 1.7 23 A = (2.655c + 0.021)106 0.9994 3.1 0.10 0.34 1.1 24 A = (1.648c + 0.019)106 0.9994 2.4 0.09 0.31 2.4 25 A = (0.305c + 0.008)106 0.9982 2.5 1.41 4.68 4.8 26 A = (3.088c - 0.047)106 0.9997 5.8 0.08 0.26 1.9 27 A = (0.720c + 0.051)106 0.9975 0.4 4.93 16.5 4.2 28 A = (1.200c – 0.022)106 0.9993 1.0 0.16 0.55 3.2 29 A = (2.239c + 0.097)106 0.9942 2.3 0.67 2.22 1.1 30 A = (0.479c + 0.001)105 0.9991 3.7 4.62 15.4 4.1 31 A = (0.248c + 0.004)106 0.9917 1.0 1.89 6.30 7.2 32 A = (0.190c + 0.011)106 0.9903 0.8 1.40 4.66 8.1

Positive ESI 27 A = (2.724c + 0.118)108 0.9911 2.7 0.28 0.94 1.3 33 A = (0.961c + 0.011)108 0.9944 0.4 0.28 0.94 2.1 34 A = (0.250c - 0.001)108 0.9987 3.4 19.2 6.39 1.0

 

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.

Individual phenolic compounds in tequilas; mean values ± SD, g l-1

1 3 9 14 15 17 18 24 29 30

White tequilas

B1 39±2 39

B2 < QL 82±4 82

B3 26±2 107±9 21±1 154

B4 < QL 213±7 55±2 49±1 317

B5 301±6 107±3 408

B6 36±5 36

Rested tequilas

R1 39±3 236±11 390±12 27±2 47±1 935±45 1674

R2 116±11 679±12 157±12 788±14 1290±17 175±5 55±2 1036±37 4296

R3 82±3 < QL 760±12 940±21 36±3 < QL 175±21 1993

R4 213±10 172±15 467±12 96±4 < QL 948

R5 142±8 129±11 325±9 596±24 330±10 102±2 55±3 44±2 1723

R6 494±13 188±12 429±13 1090±45 139±4 < QL 2340

R7 48±3 195±14 351±24 222±8 64±1 880

R8 287±13 77±4 326±17 707±17 109±4 1506

R9 417±12 158±8 < QL 369±21 773±13 166±11 457±15 2340

R10 < QL 144±10 < QL 458±18 875±15 274±12 95±3 1846

R11 89±7 136±14 194±7 96±3 515

R12 26±2 105±10 290±21 630±18 128±7 < QL 1179

Aged tequilas

A1 277±15 186±12 453±16 860±10 191±10 32±2 49±2 2048

A2 106±11 208±10 764±16 1890±28 < QL < QL 2968

A3 421±12 667±16 732±15 1285±43 144±4 < QL 3249

A4 154±8 388±12 450±23 1161±25 162±5 45±3 2360