柱前衍生-气相色谱法同时测定功能食品中8种有机酸

Simultaneous determination of 8 organic acids in functional foods by gas chromatography after precolumnderivatization

建立了功能食品中8种有机酸同时测定的方法。样品中的有机酸（乙酸、丙酸、丁酸、草酸、乳酸、丙二酸、丁二酸、柠檬酸）经体积分数15％的硫酸甲醇提取酯化，三氯甲烷萃取，最后用气相色谱法测定。色谱条件：SPB-5毛细管柱（30m×0．53mm×0．5μm）为分离柱，火焰离子化检测器检测，进样口温度为250oE，检测器温度为300℃，程序升温。载气（N2）流速为0．8mL／min，分流比为10：1，富马酸二甲酯内标法定量。8种有机酸衍生物达到基线分离，检测限范围为0．01～0．04mg／L，精密度（RSD）范围为2．4％～5．5％，平均回收率范围为79．5％～106％。方法适合于功能食品中8种有机酸的快速测定。

A method was established for simultaneous determination of 8 organic acids including acetic acid, propionic acid, butyric acid, oxalic acid, lactic acid, malonic acid, succinic acid and citric acid in functional foods by gas chromatography with pre-column derivatization and liquid phase microextraction. The organic acids in samples were extracted and esterified with 15% sulfuric acid in methanol, and microextracted with chloroform, and finally determined with gas chromatography. Chromatographic separation was performed on a SPB-5 capillary column（30 ×0.53mm×0.5μm）with FID as the detector. The injection temperature was 250 ℃, and the detector temperature was 300 ~C ,with temperature programming. N2was used as carrier gas with a flow rate of 0. 8 mL/min and split ratio was 10： 1. Dimethyl fumarate internal method was used for quantification. The baseline resolution was achieved for all the derivatives of eight organic acids. The detection limits were 0. 01 ~0. 04 mg/L, the precisions（RSDs） were 2. 4% - 5.5% , and the average recoveries were 79.5% ~ 106%. The method is accurate and rapid, and can be used for simulations determination of 8 organic acids in functional foods.