Table 1 Relative percentage of silylated compounds detected in beer residues from vats using GC-MS for primary metabolites analysis (n = 4).

From: Revealing the constituents of Egypt’s oldest beer using infrared and mass spectrometry

Peak Rt (min) RI Compound Name Class Average (Standard Deviation)
1 4.65 1030 Lactic acida Acid 3.08 (0.23)
2 4.66 1031 α-Hydroxyisobutyric acid Acid 0.72 (0.32)
3 4.66 1033 Malonic acid Acid 3.08 (0.23)
4 5.05 1041 Acetic acid Acid 0.63 (0.12)
5 5.08 1043 Hexanoic acid Acid 0.09 (0)
8 6.49 1085 Oxalic acida Acid 4.68 (2.96)
10 6.87 1095 β-Hydroxybutyric acid Acid 0.02 (0.01)
11 7.24 1105 Heptanoic acid Acid 0.06 (0.01)
14 8.07 1130 Hydroxyisovaleric acid Acid 0.08 (0.04)
16 9.34 1167 Benzoic acida Acid 0.60 (0.36)
19 10.88 1207 Succinic acida Acid 7.38 (3.19)
21 11.12 1214 Methyl succinic acid Acid 1.38 (0.25)
22 12.07 1236 Nonanoic acid Acid 0.02 (0.01)
23 12.37 1243 Citramalic acid Acid 0.56 (0.31)
25 13.23 1265 Glutaric acid Acid 0.85 (0.27)
27 13.68 1276 Methylglutaric acid Acid 0.29 (0.14)
28 14.49 1295 Citramalic acid Acid 0.06 (0.03)
29 15.06 1309 Malic acida Acid 0.38 (0.23)
30 15.69 1323 Adipic acid Acid 0.21 (0.15)
33 18 1378 Pimelic acid Acid 0.06 (0.03)
37 20.12 1429 Suberic acid Acid 1.00 (0.43)
39 22.26 1479 Azelaic acid Acid 0.08 (0.05)
Acids 27.76
17 9.56 1173 Glycerola Alcohol 1.60 (0.48)
Alcohols 1.60
12 7.51 1113 16-Heptadecenal Aldehyde 0.37 (0.18)
Aldehydes 0.37
13 8 1128 N-Trifluoroacetyl glycine Amino acid 1.07 (0.62)
20 11.12 1213 Proline Amino acid 25.33 (4.78)
24 12.99 1259 Homocysteine Amino acid 0.94 (0.69)
26 13.58 1271 Unknown Amino acid 0.01 (0)
31 16 1331 Pyroglutamic acida Amino acid 0.01 (0)
Amino acids 27.36
32 16.26 1337 Di-t-butyl-trimethylsilyloxytoluene Aromatic 0.61 (0.34)
34 19.77 1420 Di-t-butyl-trimethylsilyloxytoluene isomer Aromatic 1.03 (0.6)
36 19.92 1423 Phthalic acid Aromatic 0.94 (0.87)
40 22.41 1483 Protocatechuic acid Aromatic 0.09 (0.05)
Aromatics 2.67
6 5.4 1052 Acetal Ether 0.85 (0.45)
Ethers 0.85
42 27.2 1601 Palmitic acid Fatty acid 1.23 (0.12)
43 30.74 1693 Stearic acid Fatty acid 2.93 (0.64)
Fatty acids 4.16
18 9.66 1174 Phosphoric acida Inorganic 26.69 (8.19)
35 19.83 1421 Unknown Inorganic 4.99 (2.22)
Inorganics 31.68
44 36.18 1843 Monopalmitin Mono glyceryl ether 0.04 (0.03)
45 39.01 1925 Monostearin Mono glyceryl ether 0.01 (0)
Mono glyceryl ethers 0.04
7 5.71 1061 Hydroxylamine Nitrogenous compound 3.14 (1.24)
9 6.78 1092 Cadaverinea Nitrogenous compound 0.90 (0.16)
15 8.47 1141 Silanamine Nitrogenous compound 1.34 (0.19)
Nitrogenous compounds 5.37
38 21.66 1465 Deoxy mannose Sugar 0.01 (0)
41 22.92 1495 Myo-Inositol Sugar 0.64 (0.32)
Sugars 0.65
  1. Rt, Retention time; RI, Retention index. arepresents peaks confirmed by standards.
  2. The relative percentage was determined using the chromatographic peak area. The total percentile levels for each class is bolded. Number in brackets represents std deviation of measurements.