ABSTRACT
This chapter presents some illustrative examples of applications of paper spray (PS)-mass spectrometry (MS), and its derived techniques, as effective alternatives for the analysis of complex food and environmental matrices. The development of electrospray ionization (ESI) in the 1980s was revolutionary in the MS field, as it made possible the effective ionization of analytes under atmospheric pressure conditions. Soft ionization sources comprise the atmospheric pressure methodologies, such as ESI, besides the ambient ionization methods. The solvents commonly used in ESI are suitable for PS ionization that is methanol or acetonitrile, either pure or mixed with water at different proportions. The simplicity of the PS ionization mechanism opened a range of possibilities for modifications that can further diffuse the use of this ambient ionization technique. Many of the advantages attributed to the PS technique, such as the minimization of matrix effects, are directly related to the physicochemical properties of the paper used as sample support.
