Table 3 The volatile aroma compounds detected and measured in the samples collected from different spatial positions of pit
Number | Aroma compounds | Retention time (min) | Identification | Contents of volatile aroma compounds of pit mud(µg/mg) | |||
|---|---|---|---|---|---|---|---|
U | M | D | B | ||||
Volatile acids | |||||||
AC1 | Propionic acid | 12.383 | MS, RI | 69.929 ± 2.214 | 56.783 ± 1.254 | 34.543 ± 1.987 | 6.254 ± 0.587 |
AC2 | Butyric acid | 14.547 | MS, RI | 135.802 ± 5.365 | 358.306 ± 6.321 | 469.598 ± 4.025 | 364.421 ± 3.587 |
AC3 | Pentanoic acid | 16.761 | MS, RI | ND | 12.452 ± 0.584 | 87.452 ± 5.026 | 79.444 ± 1.357 |
AC4 | 2-Benzylpropionic acid | 17.746 | MS, RI | ND | ND | 27.673 ± 1.025 | 38.215 ± 3.541 |
AC5 | 4-methyl-pentanoic acid | 18.351 | MS, RI | ND | 5.353 ± 0.325 | 13.488 ± 0.897 | 9.967 ± 0.869 |
AC6 | Caproic acid | 19.468 | MS, RI | 308.398 ± 12.321 | 783.231 ± 16.214 | 2421.936 ± 16.321 | 1652.168 ± 10.214 |
AC7 | Heptanoic acid | 21.72 | MS, RI | 328.312 ± 6.325 | 210.432 ± 4.321 | 95.562 ± 3.351 | ND |
AC8 | Octanol acid | 24.193 | MS, RI | 638.129 ± 8.369 | 907.256 ± 3.651 | 1006.955 ± 8.354 | 1142.957 ± 9.325 |
AC9 | Nonanoic acid | 26.735 | MS, RI | 24.469 ± 2.351 | 35.4226 ± 2.584 | 45.544 ± 2.102 | 20.342 ± 0.156 |
AC10 | n-Decanoic acid | 28.514 | MS, RI | 27.159 ± 1.695 | 61.789 ± 1.587 | 77.172 ± 1.650 | 29.683 ± 0.365 |
AC11 | Benzoic acid | 30.35 | MS, RI | 9.905 ± 0.895 | 22.745 ± 1. 021 | 40.110 ± 1.365 | 22.793 ± 0.201 |
AC12 | Decanoic acid | 31.025 | MS, RI | ND | ND | 12.919 ± 0.987 | 6.754 ± 0.965 |
AC13 | Benzeneacetic acid | 31.675 | MS, RI | ND | 21.556 ± 0.202 | 62.141 ± 2.036 | 15.169 ± 1.589 |
AC14 | Tetradecanoic acid | 32.956 | MS, RI | ND | ND | 14.0171 ± 0.876 | 8.432 ± 0.968 |
AC15 | n-Hexadecanoic acid | 34.615 | MS, RI | ND | 7.338 ± 0.658 | 8.357 ± 0.879 | 7.060 ± 0.756 |
Σ | 1542.103 ± 16.325 | 2482.6636 ± 12.354 | 4417.4671 ± 25. 362 | 3403.659 ± 21.021 | |||
Esters | |||||||
ES1 | Ethyl valerate | 2.176 | MS, RI | ND | 9.751 ± 0.768 | 41.516 ± 1.036 | 20.145 ± 1.879 |
ES2 | Ethyl acetate | 3.274 | MS, RI | 320.23 ± 7.558 | 516.276 ± 23.258 | 833.687 ± 22.369 | 670.564 ± 21.527 |
ES3 | Ethyl caproate | 4.012 | MS, RI | 210.21 ± 6.321 | 1102.194 ± 20.021 | 1534.301 ± 18.654 | 1210.365 ± 18.654 |
ES4 | Ethyl butyrate | 6.125 | MS, RI | 118.356 ± 8.943 | 469.735 ± 26.793 | 632.441 ± 21.786 | 535.436 ± 20.894 |
ES5 | Ethyl heptanoate | 6.529 | MS, RI | 218.620 ± 8.32 | 243.079 ± 2.065 | 428.677 ± 10.365 | 321.845 ± 9.587 |
ES6 | Ethyl benzoate | 9.140 | MS, RI | 17.566 ± 0.987 | 24.534 ± 1.231 | 48.611 ± 0.986 | 36.397 ± 2.654 |
ES7 | Ethyl nonanoate | 12.301 | MS, RI | 11.324 ± 1.032 | 19.631 ± 1.032 | 28.086 ± 0.986 | 23.254 ± 1.841 |
ES8 | Ethyl lactate | 12.418 | MS, RI | 991.863 ± 27.32 | 787.467 ± 11.236 | 357.324 ± 10.587 | 465.320 ± 21.695 |
ES9 | Ethyl caprate | 14.137 | MS, RI | ND | 47.389 ± 2.365 | 230.889 ± 6.354 | 118.558 ± 1.005 |
ES10 | Ethyl undecanoate | 17.569 | MS, RI | ND | 7.167 ± 0.865 | 22.000 ± 0.864 | 10.235 ± 0.986 |
ES11 | Benzeneacetic acid | 18.099 | MS, RI | ND | 44.595 ± 1.036 | 63.735 ± 1.032 | 46.626 ± 0.653 |
ES12 | Ethyl 3-phenylpropanoate | 19.990 | MS, RI | 52.648 ± 1.365 | 70.878 ± 2.351 | 88.514 ± 4.235 | 80.603 ± 4.658 |
ES13 | Ethyl tridecanoate | 20.559 | MS, RI | 12.576 ± 0.989 | 9.563 ± 0.897 | ND | ND |
ES14 | Ethyl phenylacetate | 22.372 | MS, RI | ND | ND | 9.684 ± 0.945 | 6.626 ± 0.876 |
ES15 | Ethyl myristate | 26.401 | MS, RI | ND | 7.743 ± 0.852 | 23.838 ± 3.621 | 19.523 ± 1.894 |
ES16 | Ethyl Palmitate | 28.212 | MS, RI | 31.831 ± 3.025 | 114.508 ± 6.321 | 157.149 ± 9.362 | 183.678 ± 4.658 |
Σ | 1985.224 | 3474.51 | 1985.224 ± 8.980 | 3474.51 ± 2.125 | 4500.452 ± 1111 | 3789.175 ± 17.879 | |
Alcohols | |||||||
AL1 | Hexanol | 7.28 | MS, RI | 5.211 ± 0.421 | 11.036 ± 1.982 | 27.368 ± 3.659 | 16.124 ± 2.033 |
AL2 | Enanthol | 11.241 | MS, RI | 6.263 ± 0.206 | 3.955 ± 0.057 | 2.775 ± 0.082 | 1.187 ± 0.032 |
AL3 | Isobutanol | 11.342 | MS, RI | 16 0.215 ± 0.596 | 9.356 ± 0.163 | 7.625 ± 0.355 | 4.845 ± 0.085 |
AL4 | Isooctanol | 12.105 | MS, RI | 8.389 ± 0.732 | 4.279 ± 0.389 | 2.207 ± 0.303 | 0.875 ± 0.069 |
AL5 | 1-Butanol | 12.675 | MS, RI | 0.786 ± 0.462 | 4.268 ± 0.863 | 7.441 ± 0.986 | 5.079 ± 0.458 |
AL6 | 2,3-butanediol | 13.432 | MS, RI | ND | 1.487 ± 0.354 | 3.096 ± 0.855 | 2.0154 ± 0.019 |
AL7 | 1-Pentanol | 15.090 | MS, RI | 0.897 ± 0.101 | 3.653 ± 0.563 | 6.143 ± 0.996 | 5.321 ± 0.686 |
AL8 | 1-nonanol | 15.966 | MS, RI | 7.232 ± 0.203 | 6.167 ± 0.202 | 3.147 ± 0.303 | 2.847 ± 0.303 |
AL9 | 2-Heptanol | 16.620 | MS, RI | 3.827 ± 0.682 | 2.565 ± 0.063 | 1.897 ± 0.063 | 1.028 ± 0.013 |
Σ | 32.605 ± 1.641 | 35.730 ± 2.036 | 61.699 ± 4.233 | 39.321 ± 1.032 | |||
Aldehydes | |||||||
AD1 | 2-Heptenal | 7.879 | MS, RI | 4.715 ± 0.398 | 3.267 ± 0.368 | 1.132 ± 0.132 | 0.587 ± 0.0498 |
AD2 | Nonaldehyde | 9.453 | MS, RI | 0.765 ± 0.056 | 3.188 ± 0.296 | 6.132 ± 0.568 | 4.012 ± 0.365 |
AD3 | Benzaldehyde | 12.809 | MS, RI | 1.315 ± 0.980 | 2.332 ± 0.205 | 4.366 ± 0.396 | 3.254 ± 0.296 |
AD4 | 2-undecenal | 17.723 | MS, RI | 0.875 ± 0.056 | 1.925 ± 0.123 | 3.135 ± 0.268 | 2.015 ± 0.158 |
AD5 | Pentanal | 18.202 | MS, RI | 0.765 ± 0.063 | 1.897 ± 0.106 | 2.278 ± 0.260 | 1.968 ± 0.103 |
AD6 | 2-phenyl-2-butenal | 21.621 | MS, RI | 1.032 ± 0.012 | 1.378 ± 0.101 | 4.543 ± 0.385 | 2.014 ± 0.186 |
Σ | 9.467 ± 0.851 | 13.987 ± 0.998 | 21.586 ± 0.968 | 13.85 ± 1.103 | |||
Ketones | |||||||
KE1 | 2-octanone | 6.576 | MS, RI | 8.419 ± 0.098 | 3.251 ± 0.299 | 2.014 ± 0.203 | ND |
KE2 | 2-Heptanone | 9.354 | MS, RI | 13.902 ± 0.986 | 8.564 ± 0.787 | 3.214 ± 0.654 | 0.987 ± 0.088 |
KE3 | Undecanone | 17.689 | MS, RI | 3.564 ± 0.336 | 8.572 ± 0.796 | 13.715 ± 1.021 | 9.254 ± 0.087 |
Σ | 25.885 ± 1.035 | 20.387 ± 0.212 | 18.943 ± 1.036 | 10.241 ± 0.098 | |||
Alkanes | MS, RI | ||||||
AK1 | Dodecamethylcyclohexasiloxane | 7.784 | MS, RI | 6.269 ± 0.556 | 8.251 ± 0.774 | 14.340 ± 0.985 | 10.254 ± 1.213 |
AK2 | Decamethylcyclopentasiloxane | 2.239 | MS, RI | 24.768 ± 0.205 | 12.354 ± 0.105 | 8.657 ± 0.754 | 2.587 ± 0.302 |
AK3 | Decamethyltetrasiloxane | 19.247 | MS, RI | 23.010 ± 0.271 | 11.587 ± 0.989 | 6.587 ± 0.563 | 3.254 ± 0.289 |
AK4 | 2-phenyl-2-butenal | 21.556 | MS, RI | ND | 9.564 ± 0.785 | ND | ND |
Σ | 54.047 ± 4.058 | 41.756 ± 0.687 | 29.584 ± 0.587 | 16.095 ± 0.989 | |||
Volatile phenols | |||||||
VP1 | Phenol | 24.562 | MS, RI | ND | 1.871 ± 0.152 | 3.254 ± 0.285 | 2.012 ± 0.156 |
VP2 | 2-Methylphenol | 24.603 | MS, RI | 27.519 ± 1.996 | 35.602 ± 2.698 | 28.161 ± 1.365 | 32.985 ± 2.032 |
VP3 | 3-methylphenol | 24.799 | MS, RI | 10.701 ± 1.023 | ND | ND | ND |
Σ | 22.22 ± 1.354 | 37.473 ± 2.654 | 28.415 ± 2.023 | 21.997 ± 1.652 | |||