高效液相色谱法测定食用油中抗氧化剂的国家标准方法的优化研究

Optimization of the National Standard Method for the Determination of Antioxidants in Edible Oils by High Performance Liquid Chromatography

对国家标准GB 5009.32-2016中测定食品中抗氧化剂的高效液相色谱法进行了优化。优化的试验条件如下:样品用乙腈饱和的正己烷溶液溶解,再用含L-抗坏血酸棕榈酸酯的正己烷饱和的乙腈溶液提取(10 mL×3);采用C_(18)固相萃取柱净化;以Agilent Eclipse XDB-C_(18)色谱柱(250 mm×4.6 mm,5μm)为固定相,以不同体积比的0.1%(体积分数)甲酸溶液-乙腈混合液为流动相进行梯度洗脱。优化结果表明:9种抗氧化剂在30 min内完全分离,峰形对称,分离度较好,解决了国家标准方法中没食子酸丙酯(PG)峰形较差、2,4,5-三羟基苯丁酮(THBP)和叔丁基对苯二酚(TBHQ)未能达到基线分离等问题;加标回收率由标准方法的31.4%~90.1%提高至62.0%~104%,测定值的相对标准偏差(n=6)均小于13%。

A method of high performance liquid chromatography for the determination of antioxidants in food in the national standard GB 5009.32-2016 was optimized.The optimized test conditions were as follows:Samples were dissolved in n-hexane saturated with acetonitrile,and the antioxidants were extracted 3 times by 10 mL of acetonitrile saturated with n-hexane(containing Ascorbyl Palmitate);the C_(18) solid phase extraction column was used for purification.The Agilent Eclipse XDB-C_(18) column(250 mm×4.6 mm,5μm)was used as stationary phase,and 0.1%(volume fraction)formic acid-acetonitrile mixtures in different volume ratios were used as mobile phase for gradient elution.The optimized results showed that the 9 antioxidants were completely separated within 30 min,the peak shapes were symmetrical,and the resolution was better,which solved the problems including the poor peak shape of PG and the failure of the baseline separation of THBP and TBHQ in the national standard method.The spiked recovery increased from 31.4%-90.1%of the national standard method to 62.0%-104%,and RSDs(n=6)of the determined values were all less than 13%.