激光解吸/激光后电离质谱法快速检测黄酒中酪胺

黄酒是中国特有的酒类,营养丰富,酒曲中酶的作用可产生酪胺,人体中酪胺含量高低会影响神经传递过程。使用高效液相色谱-质谱法（HPLC/MS）分析黄酒中的酪胺,灵敏度高但需要复杂的样品前处理。本研究建立了激光解吸/激光后电离质谱法（解吸激光波长532 nm,后电离激光波长266 nm）快速检测黄酒体系中的酪胺,通过对梯度浓度的酪胺纯样进行分析,计算酪胺纯样的检出限。将该方法直接用于黄酒样品的快速分析,使用标准加入法测定黄酒中酪胺含量。本方法对酪胺纯样的检出限为32 μg/L,标准加入法测得的黄酒中酪胺含量约为68 mg/L,在安全食用范围内。该方法无需任何样品前处理,快捷省时,且谱图简单清晰,信噪比高,适用于实际样品中酪胺成分的选择性快速检测。

Fast Determination of Tyramine in Yellow Rice Wine by Laser Desorption/Laser Postionization Time-of-Flight Mass Spectrometry

Yellow rice wine is a typical Chinese wine, which is famous for nutritive value. The enzymes in the yeast produce tyramine, which influences the neurotransmission in the body. High level of tyramine concentration in human body will lead to alert, elevation of blood pressure and neurological disorders. Undoubtedly, the concentration of the tyramine should be analyzed and controlled. High performance liquid chromatography-mass spectrometry (HPLC/MS) is applied as the common method to analyze the tyramine in complex system with high sensitivity but complicated preprocessing and derivatization. In this paper, mass spectrometry method was developed for fast determination of tyramine in yellow rice wine. The laser desorption/laser post ionization mass spectrometry (L2MS) setup was built in house, and the selectivity of the tyramine in L2MS method can be explained by the principle of resonant two-photon ionization (R2PI). Solutions of tyramine at gradient concentrations were analyzed by L2MS (wavelengths of the desorption and post ionization laser are 532 nm and 266 nm, respectively), and the limit of detection (LOD) of tyramine was calculated. Compared with laser desorption ionization mass spectrometry (LDI/MS, wavelength of the laser is 532 nm), L2MS method obtained distinct molecular ion peak (m/z 137) with little interference peaks. Yellow rice wine sample was directly analyzed, the tyramine content of which was estimated using standard addition method. The signal of tyramine in the yellow rice wine was obvious and intensive. The mass spectra were analyzed and the fragmentation pathways of tyramine were discussed in detail. The LOD of tyramine in pure sample is 32 μg/L, and the concentration of the tyramine in yellow rice wine is about 68 mg/L. Poor signals were obtained by the electron spray ionization mass spectrometry (ESI-MS) because of quality discrimination and lack of the selectivity of tyramine. This method offers direct detection of the tyramine in the yellow rice wine without time-consuming sample preparation. Besides, simple and explicit mass spectra with excellent sign-to-noise ratio can be obtained. This method can be applicable for the selective determination of tyramine in various practical samples such as white spirit, grape wine and soybean sauce.