摘要
采用核磁共振氢谱定量法(q1H-NMR)研究樟树籽油的甲酯化率。以氘代三氯甲烷为溶剂、四甲基硅烷为内标,对不同质量浓度的月桂酸甲酯和甘油三月桂酸酯混合标准品的核磁共振氢谱(1H-NMR)进行分析,根据定量关系,建立标准曲线;并对不同反应时间的樟树籽油甲酯化率进行测定。结果表明:以月桂酸甲酯特征峰(δ=3.67)为定量峰时,甲氧基(-OCH3)峰面积与月桂酸甲酯含量的线性回归方程为y=-0.97+0.61x(R2=0.9991);以甘油三月桂酸酯特征峰(δ=4.13~4.18和δ=4.28~4.34)为定量峰时,甘油骨架上亚甲基(-CH2-CH-CH2-)峰面积与月桂酸甲酯含量的线性回归方程为y=34.6-0.35x(R2=0.9998)。樟树籽油甲酯化衍生过程中,随着衍生时间增加,-CH2-CH-CH2-信号峰强度逐渐减弱,-OCH3信号峰强度逐渐增强;当衍生时间为10 min时,甲酯化率达到99.1%。q1H-NMR法的定量分析结果与GC-MS法基本一致,无显著性差异(P>0.05),因此可用于樟树籽油衍生过程中甲酯化率的分析,且本方法具有前处理简单、分析时间短、准确度高等优点。
The conversion rate of methyl esterification of camphor tree seed oil was studied by quantitative proton nuclear magnetic resonance spectroscopy(q1H-NMR).The 1H-NMR spectra of standard trilaurin and methyl laurate were obtained by nuclear magnetic resonance spectrometer using deuterated chloroform as the solvent and tetramethylsilane as the internal standard.Meanwhile,standard curves were established based on the quantitative relationship to analyze the methyl esterification rate of camphor tree seed oil at different reaction times.The results indicated that the methoxy(-OCH3)at chemical shiftδ=3.67 was as the quantitative peak of methyl laurate,the linear regression equation of the methoxy peak area and methyl laurate content was y=-0.97+0.61x(R2=0.9991).Similarly,the methylene of glycerol backbone(-CH2-CH-CH2-)at chemical shiftδ=4.13~4.18 andδ=4.28~4.34 was as the quantitative peak of trilaurin,the linear regression equation of the methylene peak area and trilaurin content was y=34.6-0.35x(R2=0.9998).The intensity of-CH2-CH-CH2-signal peak gradually decreased,while the intensity of-OCH3 signal peak gradually increased with the increasing of reaction time.And the methyl esterification rate reached 99.1%after reacting for ten minutes.Quantitative analysis results of q1H-NMR agreed with those of GC-MS,and there was no significant difference between them(P>0.05).Therefore,q1H-NMR method could be used to analyze the methyl esterification rates of camphor tree seed oil,with advantages of simple pretreatment,short analysis time and high accuracy.
作者
王云鹏
徐华
杨德孟
楼乔明
张进杰
杨文鸽
Wang Yunpeng;Xu Hua;Yang Demeng;Lou Qiaoming;Zhang Jinjie;Yang Wenge(College of Food and Pharmaceutical Sciences,Ningbo University,Ningbo 315211)
出处
《中国粮油学报》
EI
CAS
CSCD
北大核心
2020年第2期159-164,共6页
Journal of the Chinese Cereals and Oils Association
基金
浙江省自然科学基金(LQ15C200002)
关键词
核磁共振氢谱定量法
樟树籽油
甲酯化率
定量分析
quantitative proton nuclear magnetic resonance spectroscopy
camphor tree seed oil
methyl esterification rate
quantitative analysis
