Paper spray ionization and portable mass spectrometers: a review
Mass spectrometry (MS) is one of the most effective analytical methods that provide information about molecular weights and chemical structures of analytes with high sensitivity and specificity. The requirement for in situ MS analysis has increased over the years. The hindrance preventing MS from in situ applications can be overcome by the coupling of ambient mass spectrometry (AMS) techniques to portable mass spectrometers. Paper spray ionization (PSI) is a well-established and easy-to-use AMS technique. In PSI, triangular paper is used as a substrate to generate analyte ions by applying a high voltage and a spray solvent onto the paper. Coupling the simplicity of PSI to the portability of mass spectrometers may take MS out of the laboratory and make feasible the MS analysis in demanding environments. Therefore, in this review, we will discuss the state of the art, applications, and advances of the PSI technique as well as the development of portable mass spectrometer systems and the coupling of PSI to portable mass spectrometers to enable real-time field analysis.