Chen Huanwen, Zenobi Renato
Department of Applied Chemistry, College of Chemistry, Biology and Material Sciences, East China Institute of Technology, Fuzhou 344000, People's Republic of China.
Nat Protoc. 2008;3(9):1467-75. doi: 10.1038/nprot.2008.109.
Extractive electrospray ionization mass spectrometry (EESI-MS) allows the real-time, direct analysis of complex gaseous and liquid samples without any sample pretreatment under ambient conditions. By using a neutral desorption (ND) sampling gas beam to gently impact a surface, the analyte present on a surface can be efficiently sampled and then transported to the EESI source for soft ionization without any previous work-up. By separating the sampling process and the ionization process in both space and time, ion suppression effects are significantly decreased in ND-EESI-MS. Therefore, virtually any surface can be gently sampled in real time, allowing in vivo analysis of living objects while maintaining the native conditions of the sample. This greatly simplifies the procedure for the characterization of complex surfaces (e.g., plants, food, skin) and prevents potential chemical contamination, providing a unique platform for wide applications in multiple disciplines such as chemistry, biology and the life sciences. Here we present a complete description of a protocol for ND-EESI-MS for in vivo analysis of living objects, including equipment setup, reagent preparation, data acquisition and analysis steps. The data collection can be completed within a few minutes even though the time required for the entire analytical process, which largely depends on the preparation of samples and materials, takes slightly longer.
萃取电喷雾电离质谱法（EESI-MS）能够在环境条件下对复杂的气态和液态样品进行实时、直接分析，无需任何样品预处理。通过使用中性解吸（ND）采样气束轻轻撞击表面，表面上存在的分析物能够被高效采样，然后输送到EESI源进行软电离，无需任何预先处理。通过在空间和时间上分离采样过程和电离过程，ND-EESI-MS中的离子抑制效应显著降低。因此，几乎任何表面都能被实时轻柔采样，从而在维持样品原始条件的同时对活体进行体内分析。这极大地简化了对复杂表面（如植物、食物、皮肤）进行表征的程序，并防止潜在的化学污染，为化学、生物学和生命科学等多个学科的广泛应用提供了一个独特的平台。在此，我们完整描述了一种用于对活体进行体内分析的ND-EESI-MS方案，包括设备设置、试剂制备、数据采集和分析步骤。即使整个分析过程所需的时间（很大程度上取决于样品和材料的制备）稍长，但数据收集可在几分钟内完成。
