Preparative mass spectrometry has become a diverse field that covers the spectrum of kinetic energy deposition. Of these methods, soft-landing mass spectrometry has many fundamental properties, which make it an advantageous technique for ion isolation and deposition. Its definition implies the preservation of ionic structural integrity after landing, which ensures the structure-function relationship of a molecule remains intact. Here the focus is on the instruments and applications of studying ion-surface landing in the hyperthermal and thermal kinetic energy regimes. Soft-landing preparative mass spectrometry covers the breadth of mass spectrometric ionization sources, instrumental configurations, and molecular families. Due to the diverse nature of soft landing, and to maximize readability, this review has been organized according to instrumental considerations and molecular families, with a discussion of theoretical work at the end.

Matrix-assisted laser desorption ionization (MALDI) imaging is gaining popularity, but matrix effects such as mass spectral interference and damage to the sample limit its applications. Replacing traditional matrices with silver particles capable of equivalent or increased photon energy absorption from the incoming laser has proven to be beneficial for low mass analysis. Not only can silver clusters be advantageous for low mass compound detection, but they can be used for imaging as well. Conventional matrix application methods can obstruct samples, such as fingerprints, rendering them useless after mass analysis. The ability to image latent fingerprints without causing damage to the ridge pattern is important as it allows for further characterization of the print. The application of silver clusters by soft-landing ion mobility allows for enhanced MALDI and preservation of fingerprint integrity.

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A charge carrier for a neutral organometallic complex was found in imidazolium salts, where the cation was observed as the ionizing agent. Differing ion intensities of the complex-adduct peak resulted from the anions ability to dissociate from the cation.

a b s t r a c tSub-eV ion deposition via soft-landing ion mobility has been utilized for a variety of applications. It has allowed for the deposition of a dielectric material onto graphene without introducing defects into the lattice structure. This deposition technique has also been used for surface enhanced Raman studies. Deposited silver has also been used as an alternative MALDI matrix for low mass compounds and shows promise for imaging applications.