反相液相色谱-质谱法使用甲酸甲胺改善甘油三酯电喷雾离子化检测灵敏度

发布时间：2018-10-22 12:17

【摘要】：提出使用甲酸甲胺作为新型电离增强剂改善反相液相色谱-电喷雾质谱(LC-ESI-MS)检测甘油三酯灵敏度的方法。使用反相C_(18)色谱柱,以玉米油的异丙醇溶液为样品,选择文献中常用的异丙醇-乙腈-甲醇-水,异丙醇-乙腈流动相,在考察甲酸、乙酸、甲酸铵、乙酸铵、甲酸丁胺、甲酸二丁胺、甲酸三乙胺、甲酸二乙胺、甲酸甲胺、甲酸乙胺等不同电离增强剂的基础上,比较了甲酸甲胺和常用的甲酸铵电离增强剂对LC-ESI-MS分析甘油三酯检测灵敏度的影响,结果表明,甲酸甲胺可以使其中三亚油酸甘油酯组分的质谱峰响应值和信噪比均约为使用甲酸铵的5倍。考察了使用甲酸甲胺时,甲酸甲胺电离增强剂的浓度、流动相流速以及雾化气流速对检测的影响。通过测定不同玉米油浓度与其中甘油三酯总离子流色谱峰面积的关系曲线,显示玉米油中甘油三酯组分在不同流动相的电喷雾过程中出现聚集的最小浓度相差不大,三亚油酸甘油酯峰面积与浓度在7×10~(-7)~2×10~(-4)mol/L范围内的线性关系较好,相关系数R~2=0.9997,在更高的浓度时则峰面积增加缓慢。根据实验数据分析甲酸甲胺改进检测的机理,提出含有疏水性基团的加合甲胺单电荷离子具有较低的溶剂化能,在雾滴表面富集的加合甲胺离子容易被蒸发,从而提高了电喷雾离子化效率。本方法为LC-ESIMS分析食用油中甘油三酯时提高检测灵敏度提供了有效途径。
[Abstract]:A method for improving the sensitivity of triglycerides by reversed phase liquid chromatography-electrospray mass spectrometry (LC-ESI-MS) using methylamine formate as a new ionization enhancer is proposed. Using reversed phase C _ (18) column and isopropanol solution of corn oil as the sample, the mobile phase of isopropanol-acetonitrile-methanol-water, isopropanol-acetonitrile, isopropanol-acetonitrile was selected, and the formic acid, acetic acid, ammonium formate, ammonium acetate and butylamine formate were investigated. On the basis of different ionization intensifiers such as dibutylamine formate, triethylamine formate, diethylamine formate, methylamine formate and ethylamine formate, the effects of methylamine formate and common ammonium formate ionization intensifier on the sensitivity of LC-ESI-MS determination of triglycerides were compared. The results show that the peak response and signal-to-noise ratio of trioleic acid glycerides are about 5 times as much as those of ammonium formate. The effects of the concentration of methylamine formate ionization enhancer, the mobile phase flow rate and the atomization flow rate on the determination of methylamine formate were investigated. By measuring the relationship between the concentration of different corn oil and the peak area of triglyceride total ion flow chromatography, it was found that the minimum concentration of triglyceride in corn oil showed little difference in the electrospray process of different mobile phases. The linear relationship between the peak area and concentration in the range of 7 脳 10 ~ (-7) ~ 2 脳 10 ~ (-4) mol/L was good, the correlation coefficient was 0.9997, and the peak area increased slowly at higher concentration. According to the experimental data, the mechanism of improving the detection of methylamine formate was analyzed. It was suggested that the adductive methylamine ion containing hydrophobic group had low solvation energy, and that the adductive methylamine ion enriched on the surface of droplet was easily evaporated. Thus, the efficiency of electrospray ionization is improved. This method provides an effective way to improve the detection sensitivity of triglycerides in edible oil by LC-ESIMS.
【作者单位】：上海应用技术大学化学与环境工程学院;
【基金】：国家自然科学基金(No.31671928) 上海市自然科学基金(No.15ZR1440800)资助项目~~
【分类号】：O657.63;TS227

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