School of Chemistry and Biochemistry, Georgia Institute of Technology , Atlanta, GA 30332, United States.
Anal Chem. 2014 Apr 15;86(8):3756-63. doi: 10.1021/ac5007816. Epub 2014 Mar 31.
Mass spectrometry imaging (MSI) performed under ambient conditions is a convenient and information-rich method that allows for the comprehensive mapping of chemical species throughout biological tissues with typical spatial resolution in the 40-200 μm range. Ambient MSI methods such as desorption electrospray ionization (DESI) eliminate necessary sample preparation but suffer from lower spatial resolution than laser-based and vacuum techniques. In order to take advantage of the benefits of ambient imaging and to compensate for the somewhat limited spatial resolution, a secondary orthogonal separation nested in the imaging scheme was implemented for more selective discernment of tissue features in the spectral domain. Differential mobility spectrometry (DMS), an ion mobility-based separation that selectively transmits ions based on their high-to-low electric field mobility differences, can significantly reduce background chemical interferences, allowing for increased peak capacity. In this work, DESI DM-MSI experiments on biological tissue samples such as sea algae and mouse brain tissue sections were conducted using fixed DMS compensation voltages that selectively transferred one or a class of targeted compounds. By reducing chemical noise, the signal-to-noise ratio was improved 10-fold and the image contrast was doubled, effectively increasing image quality.
在环境条件下进行的质谱成像（MSI）是一种便捷且信息丰富的方法，可实现对生物组织中化学物质的全面映射，其典型的空间分辨率在 40-200μm 范围内。解吸电喷雾电离（DESI）等环境 MSI 方法消除了对样品制备的需求，但与基于激光和真空的技术相比，空间分辨率较低。为了利用环境成像的优势并弥补空间分辨率的限制，在成像方案中嵌套了二次正交分离，以在谱域中更有选择性地辨别组织特征。差分迁移谱（DMS）是一种基于离子迁移率的分离方法，可根据其高低电场迁移率的差异选择性传输离子，它可以显著减少背景化学干扰，从而提高峰容量。在这项工作中，对海洋藻类和小鼠脑组织切片等生物组织样本进行了 DESI-DM-MSI 实验，使用固定的 DMS 补偿电压选择性传输一种或一类靶向化合物。通过降低化学噪声，信噪比提高了 10 倍，图像对比度提高了一倍，有效地提高了图像质量。
