Ion Soft Landing

Ion soft-landing (or briefly soft-landing) is one of the competitively occurring basic processes associated with collisions of hyperthermal polyatomic ions at surfaces. Soft-landing is characterized by deposition of intact species on surfaces at low kinetic energies. It is important to distinguish two processes that are both described as soft landing; in one the landed ion is trapped as the ion itself, in the other the molecule remains structurally intact but the trapped product is neutralized.

From the applicational point of view soft-landing represents method of extracting species of interest from the gas phase by gently landing intact polyatomic ions onto a suitable surface at room temperature. It has become the basis for recent novel experiments in preparative mass spectrometry and surface modifications.


  • understanding of soft-landing process and cognate phenomena on the molecular level
  • design of high-throughput mass spectrometry instruments
  • practical applications in the areas of:
    1. purification of biomolecules and preparation of protein microarrays ("protein chips")
    2. design of novel catalytically active surfaces


Key Findings
  • gas-phase ions produced from large biopolymers can be non-destructively landed from vacuum onto surfaces and recovered with retention of biological activity
  • soft-landed peptides can be recovered from the surface in preparatively relevant quantities and re-analyzed by suitable mass spectrometry techniques
  • a new family of mass spectrometers capable of ion soft-landing was developed
  • soft landing yields can be improved by achieving more efficient ion transport
  • The Indiana 21st Century Research and Technology Fund
Key Publications
  1. V. Franchetti, B.H. Solka, W.E. Baitinger, J.W. Amy and R.G. Cooks, "Soft Landing of Ions as a Means of Surface Modification", Int. J. Mass Spectrom. Ion Phys., 23, (1977) 29.
  2. S. A. Miller, H. Luo, S. J. Pachuta and R. G. Cooks, "Soft-Landing of Polyatomic Ions at Fluorinated Self-Assembled Monolayer Surfaces", Science, 275 1447 (1997).
  3. Zheng Ouyang , Zoltan Takats, Thomas A. Blake, Bogdan Gologan, Andy J. Guymon, Justin M. Wiseman, Justin C. Oliver, V. Jo Davisson, R. Graham Cooks “Preparing Protein Microarrays by Soft Landing of Mass-Selected Ions” Science 2003, 301, 1351-1354. doi: 10.1126/science.1088776
  4. Thomas A. Blake, Zheng Ouyang, Justin M. Wiseman, Zoltan Takats, Andrew J. Guymon, Sameer Kothari and R. Graham Cooks. “A Preparative Linear Ion Trap Mass Spectrometer for Separation and Collection of Purified Proteins and Peptides in Arrays using Ion Soft Landing.” Anal. Chem. 2004, 76 (21), 6293-6305. doi: 10.1021/ac048981b

Full publications list


Ion Soft-landing in other Research Groups