【检测故事】芝麻香油香气的gcMS分析
1试验部分
1.1 仪器与装置
美国惠普HP5890plus/5972A气相色谱-质谱联用仪,带FID检测器。
1.2 样品和标样
样品:购于某超市。
所有香气化合物标准品均来自Sigma-Aldrich等主要试剂公司,少数为实验室内部精制标样。C6-C30正构烷混合标准物来自AccuStandard
1.3 gc/MS条件
1.3.1 色谱条件:
色谱柱:安捷伦HP-Innowax (60m×0.25 mm ( i.d.)×0.25μm)毛细管柱;
升温程序: 60℃,以3 ℃/min升至250℃,保持68 min;
载气(He,纯度99.999%以上)流速1.6 mL/min;
进样口温度250℃,分流进样,分流比40:1; 进样量:1μl。
1.3.2质谱条件:
电子轰击(EI)离子源;电子能量70eV;传输线温度280℃;离子源温度约180℃;四级杆温度150℃。SCAN扫描范围:29-400。EMV:2100V。
1.4样品处理及分析方法
表 芝麻香油成分表
No | Chemical Name | area% |
1 | pentane | 0.0622 |
2 | hexane | 1.2992 |
3 | carbon disulfide | 0.9290 |
4 | heptane | 0.9144 |
5 | octane | 1.8262 |
6 | acetone | 3.7072 |
7 | 2-methyl furan | 1.0984 |
8 | methyl ethyl ketone | 0.7269 |
9 | 2-methyl butanal | 1.9993 |
10 | 3-methyl butanal | 1.0000 |
11 | methyl isopropyl ketone | 1.8442 |
12 | nonene | 0.6550 |
13 | 2-pentanone | 0.9105 |
14 | valeraldehyde | 2.0968 |
15 | amyl mercaptan | 0.0500 |
16 | pentanethiol | 0.0500 |
17 | 2-methyl butanethiol | 1.1429 |
18 | thiophene | 0.6111 |
19 | toluene | 0.5903 |
20 | methyl thioacetate | 0.1161 |
21 | 3-methyl pentanone | 0.2423 |
22 | dimethyl disulfide | 0.8527 |
23 | hexanal | 2.4797 |
24 | 2-methyl thiophene | 0.4000 |
25 | 2-methyl 2-butenal | 0.5333 |
26 | 3-methyl thiophene | 0.0290 |
27 | 3-penten-3-one | 0.1270 |
28 | butanol | 0.0444 |
29 | 4,5-dimethyl oxazole | 0.0468 |
30 | pyridine | 0.9741 |
31 | methyl amyl ketone | 0.0700 |
32 | heptanal | 0.0700 |
33 | 2,4,5-trimethyl oxazole | 0.1826 |
34 | isoamyl alcohol | 0.0640 |
35 | pyrazine | 2.2414 |
36 | 2-methyl pyridine | 0.2000 |
37 | tr-2-hexenal | 0.1544 |
38 | 2-pentyl furan | 0.1557 |
39 | 2-methyl thiazole | 0.1000 |
40 | pentanol | 0.6000 |
41 | thiazole | 0.3178 |
42 | 2-methyl tetrahydrofuran-3-one | 0.0500 |
43 | 2-methyl pyrazine | 25.3797 |
44 | 4-methyl thiazole | 2.0000 |
45 | 2,4-dimethyl thiazole | 1.6890 |
46 | octanal | 0.0500 |
47 | acetol | 0.4511 |
48 | methyl lactate | 0.0500 |
49 | dimethyl thiazole isomer | 0.0638 |
50 | 2,5-dimethyl pyrazine | 4.7117 |
51 | 2,6-dimethyl pyrazine | 4.9223 |
52 | 2-ethyl pyrazine | 3.3213 |
53 | 2,3-dimethyl pyrazine | 0.7044 |
54 | hexanol | 0.4941 |
55 | 4,5-dimethyl thiazole | 0.0500 |
56 | dimethyl trisulfide | 0.0775 |
57 | 2-ethyl-5-methyl pyrazine | 0.4683 |
58 | dimethyl thiazole | 0.4806 |
59 | nonanal | 0.0311 |
60 | 2,3,5-trimethyl pyrazine | 0.9027 |
61 | 4-nonyne | 0.0474 |
62 | tr-2-octenal | 0.2720 |
63 | acetic acid | 2.9574 |
64 | 2-methyl-3(5or6)-dimethyl pyrazine | 2.5089 |
65 | furfural | 3.0000 |
66 | 2-furyl methyl ketone | 0.5441 |
67 | pyrrole | 0.8156 |
68 | 3-methyl-2-cyclopenten-1-one | 0.0500 |
69 | benzaldehyde | 0.2572 |
70 | propionic acid | 0.5819 |
71 | methyl 3-hydroxy propionate | 0.3000 |
72 | 4,5-dihydro-3(2H)-thiophenone | 0.0989 |
73 | dimethyl sulfoxide | 0.0500 |
74 | 5-methyl furfural | 1.3751 |
75 | 2-pentyl pyridine | 0.2764 |
76 | valeralactone gamma | 0.0312 |
77 | 2-formyl-N-methyl pyrrole | 0.0769 |
78 | butyrolactone gamma | 0.7000 |
79 | 2-acetyl pyridine | 0.6033 |
80 | p-tolyl aldehyde | 0.1385 |
81 | 2-acetyl thiazole | 0.0526 |
82 | acetophenone | 0.0960 |
83 | furfuryl alcohol | 1.9802 |
84 | 2-acetyl-5(6)-methyl pyrazine | 0.3423 |
85 | guaiacol | 0.3444 |
86 | 2-pyrrolaldehyde | 0.6264 |
SUM | 95.5392 |
从上述结果来看,从芝麻香油里一共鉴定测定了86个香气组分,占总量95.5%(其它也包含一些从萃取头解析的硅氧烷化合物等,所以实际总量大于95.5%。)。挥发性香气化合物包含醇,醛,酮,酸,酯,吡嗪,吡啶,吡咯,噻唑,呋喃,硫醚,硫醇类等。是一个各种香气化合物综合的香气。含氮和含硫化合物的香气可能更突出,恭喜更大。甲苯在其它文献上面也看到。