以香草素为内标之气相层析光谱法定量牛樟木精油指标成分松油醇的快速分析方法

牛樟精油具有独特浓郁的香气，其中以α-松油醇(α-terpineol)为牛樟精油主要成分。由于樟树精油制品可依种类、变种、亚种等不同而有不同成分，以松油醇最具独特性，可作为牛樟木精油品质重要指标成分，应用以区别牛樟树与冇樟以及香樟等木材精油的方法，因此建立市售牛樟木精油指标成分α-松油醇含量的简便快速又准确的检验方法便有其必要性。该研究拟以市售精油液体样品，不经任何前处理，加入适当之内标准溶液溶解后，直接注入气相层析光谱仪中，配合适当的分离管柱及气相层析条件，以期建立简便快速又准确的牛樟木精油指标成分α-松油醇之定量方法。毛细管柱气相层析具有高解析度及高灵敏度等优点，仍为现代最重要分析技术之一，因此研究建立了以香草素为内标准定量牛樟木精油指标成分α-松油醇(α-terpineol)之气相色谱层析法的快速分析方法。牛樟木精油液体样品，加入适当量之香草素内标准溶液混合溶解后，即可直接注入配有广口径之毛细管柱(megabore column)气相色谱仪中分析，相当简便，每分析一个样品仅需约30 min。结果显示松油醇之最低定量浓度（limit of quantitation, LOQ）为1 μg·mL-1左右。在添加回收试验中添加松油醇1.0及10.0 mg 于市售冇樟精油及牛樟精油中，其回收率在98%~103%，变异系数均在10.8%以下，显示该方法的精密度相当高。以该研究建立的方法分析15件市售牛樟精油中松油醇含量，结果显示，市售牛樟木精油的松油醇含量最高约51.6%及最低为21.3%左右，此结果显示以定量松油醇作为市售牛樟精油品质指标是一快速、准确且可行的方法。

Rapid Method for Analysis of Vanillin as the Internal Standard for Gas Chromatographic Quantitation of α-Terpineol—a Key Component of Stout Camphor Essential Oil

Stout camphor essential oil has a special scent due to its content of specific aromatic terpenoid compounds. Essential oils prepared from different species, varieties or subspecies have been shown to possess varied compounds. Of the major essential oil components extracted from the Stout Camphor tree, α-terpineol has been shown to be a key component, while essential oils prepared from other camphor species may not contain this terpene alcohol. Therefore, α-terpineol can be used as an index element to represent the purity of Stout Camphor essential oil. However, a method that can quantitatively examine the quality and purity of commercial Stout Camphor essential oils is necessary. By adding an internal standard to essential oil samples, this study aimed to develop a simple and reliable method for determining the level of α-terpineol in Stout Camphor essential oils on the market. Capillary column gas chromatography has the advantages of high resolution and high sensitivity, and is still one of the most important spectral analysis techniques in modern times. Therefore, this study developed a rapid method that used vanillin as an internal standard to determine the level of α-terpineol, a key component of the essential oil extracted from the stout camphor tree, using gas chromatography. The analysis of each sample only required 30 min. The lowest limit of quantitation was as low as 1 μg·mL-1. Add α-terpineol 1.0 and 10.0 mg to commercially available Cinnamomum micranthum Hayata essential oil and stout camphor wood essential oil, and the recovery rates were more than 98% (98%~103%) with a coefficient of variation below 10.8%. We then analyzed 15 commercially-available essential oil samples and one essential oil sample directly extracted from stout camphor wood. We found that the levels of α-terpineol in these samples were within the range of 21.3%～51.6%. In conclusion, this method has a high accuracy, and the α-terpineol levels can be used as an index to rapidly determine the quality of the stout camphor essential oil on the market.