食品科学

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NMR氢谱定量测定奶酪中总共轭亚油酸的含量

李 玮,姜 洁,路 勇,何 涛,李 龙,王 振   

  1. 北京市食品安全监控和风险评估中心,北京 100041
  • 出版日期:2015-05-25 发布日期:2015-05-08
  • 基金资助:

    首都食品安全科技创优培育专项(Z141100002614013);北京市优秀人才培养资助项目(20140000204400001)

Determination of Total Conjugated Linoleic Acid Content in Cheeses by Quantitative Nuclear Magnetic Resonance (QNMR)

LI Wei, JIANG Jie, LU Yong, HE Tao, LI Long, WANG Zhen   

  1. Beijing Municipal Center for Food Safety Monitoring and Risk Assessment, Beijing 100041, China
  • Online:2015-05-25 Published:2015-05-08

摘要:

目的:建立用核磁共振定量法测定奶酪中总共轭亚油酸含量的方法,并与紫外分光光度法进行比较。方法:以1,2,4,5-四甲基苯为内标,采用5 mm BBO探头、脉冲序列noesyig1d、探头温度300 K、扫描次数128 次、脉冲延迟时间(D1)10 s。结果:该方法的加样回收率为93.33%,相对标准偏差(relative standard deviation,RSD)为4.20%;精密度RSD为0.99%,重复性RSD为3.17%,稳定性RSD为1.81%。结论:该方法前处理简单,无需标准品做参比,在对目标物完成定性、定量分析的同时还可以实现对非目标物的定性分析。与紫外分光光度法相比,该方法具有更好的专属性。

关键词: 核磁共振定量法, 奶酪, 共轭亚油酸, 定量测定

Abstract:

Objective: To establish a method for the determination of total conjugated linoleic acid (CLA) content
in cheeses by quantitative nuclear magnetic resonance (QNMR) and to compare its effectiveness with that of
ultraviolet spectrophotometry. Methods: The analysis employed 1,2,4,5-tetramethylbenzene as internal standard, and a
5-mm Bruker broadband observe (BBO) probe, working at 300 K with a pulse sequence of Noesyig1d, 128 scans and a
pulse delay time (D1) of 10 s. Results: The recovery rate was 93.33% with relative standard deviation (RSD) of 4.20%. The
precision RSD was 0.99%, the reproducibility RSD was 3.17% and the stability RSD was 1.81%. Conclusion: This method
enables direct determination of target and non-target compounds in foods without using standard reference. Compared with
ultraviolet spectrophotometry, it had a higher specificity.

Key words: quantitative nuclear magnetic resonance (QNMR), cheeses, conjugated linoleic acid (CLA), quantitation

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