CHEMICAL IMAGING OF SURFACES WITH LASER-DESORPTION MASS-SPECTROMETRY

Mass spectrometric imaging of surfaces can reveal features not evident in micrographs. The use of two lasers, one to desorb atoms and molecu les and a second to ionize them in the gas phase, produces a reasonabl y steady ion yield as the desorption spot is rastered across a surface . When combined with a time-of-flight mass analyzer, the result is a s imple instrument capable of molecular imaging with micron resolution.