甜蜜素的电喷雾串联质谱行为及其在酒类分析检测中的应用研究

Sodium cyclamate detection by electrospray ionization tandem mass spectrometry and its application in wine

采用国家标准规定的液相色谱-串联质谱法检测酒类甜蜜素过程中,常很难优化出正离子模式下所监测的202>122(ESI+)离子对。本论文比较正/负离子模式下甜蜜素在不同流动相体系中的电喷雾串联质谱行为。结果发现,负离子模式下,甜蜜素在不同流动相体系离子对较为稳定,为178>80(ESI-),但响应值有所差异;而正离子模式,甜蜜素所呈现的离子对会随流动相的变化出现加钠、脱钠加氨等现象。研究表明,在甲醇/5mmol乙酸铵(v/v=10/90)的条件下,正离子模式所呈现的离子对197>100(ESI+)信号强度较大,更适合质谱法分析检测中佐证使用。运用本文所优化的质谱条件,建立了酒类甜蜜素的检测方法,其线性范围在2.5~100μg/L内,标准曲线方程为Y=900.952X+391.716,所得线性相关系数为0.9990,经计算该方法检出限为0.66μg/L,定量限为2.2μg/L。不同浓度水平下样品加标回收率介于89.8%~98.6%,相对标准偏差均在5%以内。本研究为运用质谱法开展酒类中的甜蜜素的检测提供了更好的确证依据。

The national standards of sodium cyclamate detection in wine by HPLC-MS/MS often shows the difficulty in optimizing specific 202 〉 122（ESI＋）ion pair. Electrospray ionization tandem mass spectrometry was used in sodium cyclamate detection and compared under different mobile phase in this study. It is found that the under the negative ion mode,ion pair was 178 〉80（ESI-）and was stable with a difference response value;under the positive ion mode,ion pairs was changed with the mobile phrase such as adding sodium,removing sodium and adding ammonia actions. The results showed that the ion pair of 197 〉 100（ESI＋）with a stronger mass spectrum abundance in the mixture of 5 mmol ammonium acetate and methanol（v/v=10/90）,was more suitable for mass spectrometry analysis. A new method of sodium cyclamate detection in wine was established by using the optimized mass spectrometry conditions. The linear range was 2.5 ～ 100 μg/L,standard curve was Y=900.952 X＋391.716 and the linear correlation coeffi cient was 0.9990. The detection limit and the quantitative limit were 0.66 μg/L and 2.2 μg/L by calculation,respectively.The recovery rate of the sample was between 89.8 % and 98.6%,and the relative standard deviation was within 5%. This study provides a reference for using the mass spectrometry in the detection of sodium cyclamate in alcohol.