Recent advances in ambient mass spectrometry imaging

The emerging ambient mass spectrometry imaging (MSI) enables to acquire molecular images and information directly on the sample surface under the atmospheric environment without labelling and staining. The appealing and unique advantages of ambient MSI drive the active development of novel ambient ionization techniques and their wide applications in different research areas. This paper first gives the overview of ambient ionization techniques capable of MSI from different point of view, including the ion source setup, the desorption/extraction, the spatial resolution etc. On this basis, some critical issues during ambient MSI, for example, spatial resolution, compounds identification, matrix effects, quantitative analysis, sensitivity and specificity etc., are discussed in detail. After briefly introducing the frontier three-dimensional ambient MSI, the applications of ambient MSI in different field are summarized, focusing on various types of analytes (e.g., proteins, lipids, natural produces, polymers etc.). Finally, the challenges and the perspectives of ambient MSI are concluded and proposed. (c) 2019 Elsevier B.V. All rights reserved.