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目的:建立气相色谱法测定不同禽类蛋蛋黄中胆固醇含量的方法,并对不同烹饪方法鸡蛋中胆固醇的含量进行比较。方法:2.0 mol·L-1的氢氧化钾-乙醇溶液水浴皂化,石油醚萃取后采用气相色谱法分析检测。柱程序升温:200℃保持4min,以12℃·min-1升至300℃,保持10 min;进样口温度260℃,FID检测器温度:300℃;氮气流速30 mL·min-1,氢气流速47 mL·min-1,空气流速400 mL·min-1。结果:胆固醇在20 min内检出,胆固醇在1.2～7.2μg线性关系良好(r=0.999 4。该方法的精密度(RSD=0.16%),重复性(RSD=2.5%)良好;加样回收率在100.24%～103.89%;不同禽类蛋中,胆固醇含量为:土鸡蛋>普通鸡蛋>鸭蛋,本鸡蛋,鹌鹑蛋(三者差异不大);并比较了不同烹饪方法鸡蛋中胆固醇含量,结果为白煮蛋>鸡蛋>茶叶蛋。结论:气相色谱法作为蛋黄中胆固醇含量的快速测定方法,具有试剂用量少,操作简单,结果准确、可靠,重复性良好等特点。
Objective: To establish a method for the determination of cholesterol in egg yolk of different poultry by gas chromatography and to compare the cholesterol content in different cooking methods. Methods: 2.0 mol·L-1 potassium hydroxide-ethanol solution was saponified by water bath and analyzed by gas chromatography after petroleum ether extraction. The temperature of the column was kept at 200 ° C for 4 min, the temperature was raised to 300 ° C at 12 ° C min-1 for 10 min, the temperature of the inlet was 260 ° C, the temperature of the FID detector was 300 ° C, and the flow rate of nitrogen was 30 mL · min-1. The flow rate was 47 mL · min-1 and the air flow rate was 400 mL · min-1. RESULTS: Cholesterol was detected within 20 min. The linearity of cholesterol was good at 1.2-7.2 μg (r = 0.999 4. The precision (RSD = 0.16%) and repeatability (RSD = 2.5%) of the method were good. The rates of the two kinds of eggs were 100.24% -103.89%. The cholesterol content in different poultry eggs was: native eggs> common eggs> duck eggs, eggs and quail eggs (the difference was not significant); and the cholesterol content in different cooking methods was compared. As white boiled egg> egg> tea leaf.Conclusion: Gas chromatography is a rapid method for the determination of cholesterol in egg yolk and has the advantages of less reagent dosage, simple operation, accurate, reliable and reproducible results.