以超高效液相層析串聯質譜法分析油脂中三酸甘油酯及固醇化合物特徵

Abstract

摘要 三酸甘油酯為食用油中最主要的成分，不同來源油脂除脂肪酸組成外，其脂肪醯基分布在甘油酯上的位置亦為重要的特徵。本研究目的以液相層析串聯質譜法分析固醇類化合物並建立三酸甘油酯組成及脂肪酸分布資訊。逆相液相層析採用 Accucore C30 管柱，整體分析時間為25分鐘，可將三酸甘油酯依據碳當量數 (equivalent carbon number, ECN) 將其分群並能將部分具有相同碳當量數的三酸甘油酯異構物分離，經電噴灑游離後，三酸甘油酯的銨加成離子([M+NH4]+)為其特徵離子訊號，二次質譜分析可辨別脂肪酸的組成及甘油酯sn-2位置上脂肪酸的資訊。以市售食用油中三酸甘油酯的組成可建構出油品的指紋特徵，以主成分分析可將市售食用油做分群，另外，以液相層析串聯大氣壓游離質譜法分析食用油中固醇類化合物，動物油主要特徵為膽固醇，市售油植物固醇以β-sitosterol、stigmasterol與campesterol為主，玄米油中另外含有酚酸酯化態固醇(米糠醇)，而麻油中的seasmin、seasmolin，橄欖油中的squalene、苦茶油中的β-ayrmin為具有特徵的化合物，可做為食用油特徵辨別的依據。

Triacylglycerols are the major component of edible oils. In addition to fatty acid composition, distribution pattern is an essential characteristics for each botanic source of edible oil. An ultra-performance liquid chromatography-electrospray tandem mass spectrometry was developed for fingerprint recognition of edible oils. Triacylglycerols were separated and grouped according their equivalent carbon number (ECN). The MS data recorded for ammonium adducts ([M+NH4]+) of triacylglycerols and the signals of onium ion of diacylglycerol in MS2 were used to differentiate the fatty acid on the sn-2 position of original triacylglycerols. The major phytosterols in commercial edible oil were -sitosterol, stigmasterol and campesterol. The -oryzanol, ferulate esters were found in rice bran oil. Seasmin、seasmolin in sesame oil, squalene in olive oil and β-ayrmin in camellia oil can be used as characteristic compounds.