信阳毛尖挥发油的热裂解产物分析

Analysis of Pyrolyzed Constituents in Essential Oil of Xinyang Maojian Tea

摘要:

采用水蒸气蒸馏法提取信阳毛尖挥发油。用热失重（TG）技术以及在线热裂解（Py）技术对信阳毛尖挥发油热裂解产物进行了研究。TG曲线显示主要失重区间在25~443.4 ℃，质量损失高达93%，选取了失重比较大的2个温度点（200、500 ℃）和800 ℃作为裂解温度，以气相测谱/质谱法（GC/MS）分析其在不同温度下的裂解产物。结果表明，信阳毛尖挥发油经GC/MS测定共鉴定出45种化学成分，主要是醇、酮、萜烯类物质；裂解实验中，挥发油在200 ℃热裂解后共分离鉴定出31种化合物，500 ℃热裂解后共鉴定出30种化合物，并出现稠环芳烃类物质。800 ℃热裂解后共分离鉴定出45种化合物，且稠环芳烃类物质的含量随温度的升高而增加。

Abstract:

The essential oil of Xinyang Maojian tea was extracted with steam distillation extraction. The pyrolyzed products of the Xinyang Maojian tea extract was investigated by thermogravimetric analysis and on-line pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The TG curve shows that between 25~443.4 ℃ the largest weight loss occurs, and the total weight loss was about 93%. Py-GC/MS was used for the qualitative and semi-quantitative analysis of the pyrolysis products at the main weight loss temperature(200, 500 and 800 ℃).The results showed that 45 volatile compositions were identified from Xinyang Maojian tea by GC/MS. Alcohols, ketones and terpenes were the main efficacious ingredients in the essential oil. Pyrolysis products of the essential oil at 200 ,500 and 800 ℃ were compared. 31 compounds were identified at 200 ℃ and 30 compounds were identified at 500 ℃. Polycyclic aromatic hydrocarbons occurred when hydrolysis at temperature higher than 500 ℃ and 45 compounds were identified at 800 ℃. Its quantity increased with the rise of temperature.