Zhao Haizhen, Lu Zhaoxin, Bie Xiaomei, Lü Fengxia
Key Laboratory of Processing and Quality Control of Agricultural Products of Ministry of Agriculture, College of Food Science & Technology, Nanjing Agricultural University, Nanjing 210095, China.
Se Pu. 2005 Mar;23(2):142-5.
A high performance liquid chromatographic (HPLC) method for the determination of fatty acid positional distribution on triacylglycerols from lard has been established. The analysis was carried out with an sn-1, 3 specific lipase to deacylate the fatty acid residues esterified at sn-1 and sn-3 positions of triacylglycerols, forming sn-2 monoglycerides and free fatty acids. After lipase action, it was possible to determine the fatty acid esterified at the sn-2 position by the substraction of the results of the sn-1, 3 analysis from an overall composition analysis based on complete saponification of the original sample. The free fatty acid mixtures were converted to phenacyl esters via 2-bromoacetophenone and analyzed on an Agilent 1100 series high performance liquid chromatograph, equipped with a ZORBAX SB C18 column (4.6 mm i.d. x 250 mm, 5 microm) and a UV detector. Elution was performed at a flow rate of 1 mL/min, with a gradient of methanol-acetonitrile-water starting at 80: 10: 10 (v/v), increasing linearly to 86: 10: 4 (v/v) in 35 min, then returning'to the initial conditions in 5 min. Elution of phenacyl esters was monitored by absorbance at 254 nm. Pentadecanoic acid was used to be an internal standard. The results showed that palmitic and oleic acids were the major components in lard, accounting for 26.61% and 43.18% respectively. Among these, palmitic acid mainly locates at sn-2 position, while oleic acid at sn-1, 3 positions. These results were consistent with those obtained via gas chromatographic method. The new method is simpler and easier to use as it eliminates time-consuming thinner-layer chromatography used in standard regioselective analysis. It is possible to be an effective laboratory analytical method.
已建立一种高效液相色谱（HPLC）方法，用于测定猪油中三酰甘油的脂肪酸位置分布。分析时使用一种sn - 1,3特异性脂肪酶使三酰甘油sn - 1和sn - 3位酯化的脂肪酸残基脱酰基，形成sn - 2单甘油酯和游离脂肪酸。脂肪酶作用后，通过从基于原始样品完全皂化的总体组成分析结果中减去sn - 1,3分析结果，可确定sn - 2位酯化的脂肪酸。游离脂肪酸混合物通过2 - 溴苯乙酮转化为苯甲酰酯，并在配备ZORBAX SB C18柱（内径4.6 mm×250 mm，5 µm）和紫外检测器的安捷伦1100系列高效液相色谱仪上进行分析。以1 mL/min的流速进行洗脱，甲醇 - 乙腈 - 水的梯度从80:10:10（v/v）开始，在35分钟内线性增加至86:10:4（v/v），然后在5分钟内恢复到初始条件。通过254 nm处的吸光度监测苯甲酰酯的洗脱。十五烷酸用作内标。结果表明，棕榈酸和油酸是猪油中的主要成分，分别占26.61%和43.18%。其中，棕榈酸主要位于sn - 2位，而油酸位于sn - 1,3位。这些结果与通过气相色谱法获得的结果一致。新方法更简单、更易于使用，因为它省去了标准区域选择性分析中耗时的薄层色谱法。它有可能成为一种有效的实验室分析方法。
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