GC法测定拟黑多刺蚁中棕榈酸和油酸的含量

目的:建立拟黑多刺蚁中棕榈酸和油酸含量的测定方法。方法:使用氢氧化钾甲醇溶液将拟黑多刺蚁中的脂肪酸甲酯化,采用正十八烷作为内标物,用气相色谱法测定拟黑多刺蚁中棕榈酸和油酸。色谱条件:色谱柱为Rtx^®-5毛细管柱(30 m×0.32 mm×0.25μm);柱流量2.0 mL·min^-1;总流量25.0 mL·min^-1;柱温采用程序升温方式, 80℃保持1 min, 15℃·min^-1升到220℃保持5 min; FID检测器温度250℃;载气为N₂(30.0 mL·min^-1), H₂(40.0 mL·min^-1),空气(400.0 mL·min^-1);进样口温度230℃;进样量1μL,分流进样,分流比为10:1。结果:棕榈酸甲酯进样量在0.0399~1.597μg范围内呈良好线性关系,回归方程为Y=0.9808X-0.1563(r=0.9994),平均回收率为100.1%(RSD=1.4%);油酸甲酯进样量在0.0394~1.576μg范围内呈良好线性关系,回归方程为Y=1.1033X+0.1467(r=0.9994),平均回收率为92.4%(RSD=1.5%)。广西横县、桂林、贵港、灵山、上林、都安6个产地的拟黑多刺蚁样品中,棕榈酸的含量分别为20.86、5.34、11.55、22.66、21.61、22.23 mg·g^-1,油酸的含量分别为48.52、18.62、33.09、53.75、50.36、52.48 mg·g^-1。结论:本方法经方法学验证,可用于拟黑多刺蚁中油酸和棕榈酸的含量测定。

Objective:To establish a GC method for content determination of palmitic acid and oleic acid in Poryrhaehis vicina Roger. Methods:Palmitic acid and oleic acid were determined by GC method after saponification and methylation, with potassium hydroxide-methanol as methylated reagent and octadecane as internal standard. The chromatographic condition was as follows:Rtx^®-5 restek capillary column(30 m×0.32 mm×0.25μm)was adopted; Pillars flow was 2.0 mL·min^-1, and total flow was 25.0 mL·min^-1. Column temperature was first kept at 80℃ for 1 min, and then raised to 220℃ with rate of 15℃·min^-1 and maintained for 5 min; FID was used as detector and the temperature was 250℃;nitrogen(30.0 mL·min^-1),hydrogen(40.0 mL·min^-1)and air(400.0 mL·min^-1)were used as carrier gas; injection port temperature was 230℃;sample size was 1μL;split injection and diversion ratio was 10:1. Results:Methyl palmitate had good linear relationship in the range of 0.0399-1.597μg,the regression equation was Y=0.9808X-0.1563(r=0.9994), the average recovery was 100.1% with RSD of 1.4%; methyl oleate had good linear relationship in the range of 0.0394-1.576μg, the regression equation was Y=1.1033X+0.1467(r=0.9994), the average recovery was 92.4% with RSD of 1.5%. The contents of palmitic acid in Poryrhaehis vicina Roger of six origin such as Hengxian, Guilin, Guigang, Lingshan, Shanglin and Du'an were 20.86, 5.34, 11.55, 22.66, 21.61, and 22.23 mg·g^-1, and the contents of oleic acid were 48.52, 18.62, 33.09, 53.75, 50.36 and 52.48 mg·g-1, respectively. Conclusion:The method established in this paper conforms to the requirements of the methodology validation, and thus can be used for quality control of fatty acid of Poryrhaehis vicina Roger.