商品化正相硅胶固相萃取柱-气相色谱法检测 橄榄油中的蜡含量

Determination of wax content in olive oils by gas chromatography using a commercial normal phase silica gel solid phase extraction column

中文关键词:  商品化正相硅胶固相萃取柱  橄榄油  蜡含量

英文关键词:commercial normal phase silica gel solid phase extraction column  olive oil  wax content

中文摘要:

      目的 建立一种前处理简单快速、环保且重复性好的橄榄油中蜡含量的检测方法。方法 采用商品化正相硅胶固相萃取柱(硅胶含量为500 mg)替代国际和国家标准中推荐的自制硅胶固相萃取柱, 对橄榄油中的蜡酯组分进行分离, 然后通过气相色谱-氢火焰离子法检测分析。结果 本研究建立的方法仅需50 mg样品, 试剂总用量不到30 mL, C40酯、C42酯、C44酯和C46酯的检出限分别为0.10、0.12、0.14、0.17 μg/mL, 相对标准偏差小于8%, 加标回收率为83.3%~93.3%。结论 本研究建立的方法简单, 重复性好, 准确度高, 有效解决了国家标准中橄榄油蜡含量检测中前处理繁琐耗时、试剂损耗大、样品回收率低以及结果稳定性较差的问题。并可以成功应用于不同等级橄榄油样品的检测, 为特级初榨橄榄油、初榨橄榄油和油橄榄果渣油的鉴别奠定基础。

英文摘要:

      Objective To establish a method for the determination of wax content in olive oils which is simply operated, environmental conservation and repeatable. Methods The homemade silica gel solid phase extraction column recommended in current international and national standards was replaced by the commercial normal phase silica gel solid phase extraction column (SupelcleanTM LC-Si SPE, 500 mg) which was used to isolate wax ester fractions, and then their separation effects were compared by gas chromatography detection which equipped with a flame ionisation detector. Results Under the optimal condition, only 50 mg samples and less than 30 mL organic solvents were needed for each single analysis. And the wax ester fractions were well separated and detected while the detection limits for C40, C42, C44, and C46 esters were 0.10, 0.12, 0.14 and 0.17 μg/mL, respectively. And the average recoveries at 3 spiked levels (5, 10 and 20 mg/kg) were in the range of 83.3%~93.3% with the relative standard deviations (RSDs) lower than 8.0%. Conclusion The proposed method is simple, and has high accuracy and good repeatability which effectively solves the time and solvent consuming, lower recovery, poor stability of results and other problems in the recommended method of national standards for wax content detection in olive oils. Meanwhile, this method can also be used for the determination of different grades of olive oils, and provide a firm foundation for further authentication of extra virgin olive oil, virgin olive oil and olive-pomace oil.