長鏈二元酸分子定性與定量方法的建立與評估

Establishment of Qualitative and Quantitative Methods for Long-chain Dicarboxylic Acids

吳柏龍(Po-Long Wu) ； 陳錦坤(Jeen-Kuen Chen) ； 涂茂園(Mao-Yuan Tu) ； 黃維寧(Wei-Ning Huang) ； 莊路德(Lu-De Chuang)

《石油季刊》 50卷4期 (2014/12) Pp. 93-105

摘要

長鏈二元酸具有非常廣泛的用途，如香料合成、潤滑劑、大環內酯類抗生素、粘合劑與各種的聚合物。鏈長超過十二碳的二元酸目前多是使用石化烴烷原料透過微生物醱酵而獲得。本研究主要以基因改良後的Candida tropicalis酵母菌ATCC20962醱酵獲得之二元酸，利用不同的量測方法如（一）紫外光吸收光譜（UV）、（二）氣相層析結合火焰游離偵測器（GC-FID）、）三）高效液相層析（HPLC）結合紫外光偵測器、（四）酸鹼滴定法及（五）衰減全反射紅外光譜法（ATR-FTIR）多項技術來進行分析並比較其結果。結果顯示除傳統氣相層析結合火焰游離偵測器可精準定量二元酸外，高效液相層析結合紫外光偵測器也可以準確地用於定量及鑑定不同碳鏈長二元酸，此方法還兼具不需前處理樣品之快速優點。此研究中我們第一次以衰減全反射紅外光譜法來測定醱酵二元酸的樣品分析，除了可以對烴烷類酸定量外，還可快速的鑑定樣品中的不純物成份（如醣類或蛋白質），但是在不同鏈長及單元的二元酸上是無法以此法加以區別，紫外光吸收光譜及酸鹼滴定法所獲得的二元酸含量較為不準確，主要的原因來自於樣品前處理的純度不高所造成。綜合以上結果，樣品經過簡單的酸沉澱及過濾後以高效液相層析結合兩波段UV偵測器，將可以補足以上不同方法的缺點，又可避免使用GC-FID方法需要煩瑣的樣品前處理步驟，而當作醱酵與純化二元酸的製程改良中的快速及精確的分析利器。

關鍵字

長鏈二元酸 ； 氣相層析結合火焰游離偵測器 ； 衰減全反射紅外光譜法 ； 高效液相層析

並列摘要

Long-chain α, ω-dicarboxylic acid has a very wide range of uses, such as perfume synthesis, lubricants, macrolide antibiotics, adhesives, and a variety of polymers. The manufactured long-chain dicarboxylic acids, chain length of more than 12 carbons, mainly obtained through microbial fermentation by using petrochemical feedstock n-alkanes as the original source nowadays. In this study, different dicarboxylic acid samples were obtained by fermentation with genetically modified yeast (Candida tropicalis ATCC 20962). We systematically analyzed and compared the results obtained by different methods including (a) UV absorption spectrum, (b) gas chromatography with flame ionization detector (GC-FID), (c) High-performance liquid chromatography combined with ultraviolet detector (HPLC-UV), (d) Acid-base titration and (e) Attenuated total reflection infrared spectroscopy (ATR-FTIR). The results indicated that the traditional GC-FID method could accurately quantifieddicarboxylic acids and HPLC-UV method could also be used to identify quantitatively and accurately dicarboxylic acids with different chain lengths. This method also takes the advantages of fast without pre-treatment samples. In this study, the ATR-FTIR method for dicarboxylic acid analysis was applied in the first time. The ATR-FTIR method not only can quantitate dicarboxylic acids but also in rapid sample identification of impurities components (such as sugars or protein). However, the dicarboxylic acids with different chain lengths or monocarboxylic acids were unable to distinguish by this method. In contrary, dicarboxylic acids measured by both UV absorption spectra and acid-base titration were relatively inaccurate due to impurities of the purified samples. Taken together, unlike GC-FID method requires tedious sample preparation before analysis; HPLC-UV method can be used to identify quantitatively and accurately dicarboxylic acids with simple pre-treatment samples.

並列關鍵字

Long Chain Dicarboxylic Acids ； GC-FID ； ATR-FTIR ； HPLC-UV