Browse Prior Art Database

Laser Desorption Transfer Sampling

IP.com Disclosure Number: IPCOM000104569D
Original Publication Date: 1993-May-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 60K

Publishing Venue

IBM

Related People

de Vries, MS: AUTHOR [+4]

Abstract

Disclosed is a process which permits spatially resolved chemical analysis by infrared absorption spectroscopy of surface deposits, in situations where the nature of the surface prohibits direct, in-situ application of the infrared technique. The surface deposits may be solid or liquid films, particles, or a combination thereof.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Laser Desorption Transfer Sampling

      Disclosed is a process which permits spatially resolved
chemical analysis by infrared absorption spectroscopy of surface
deposits, in situations where the nature of the surface prohibits
direct, in-situ application of the infrared technique.  The surface
deposits may be solid or liquid films, particles, or a combination
thereof.

      Laser ablation of surfaces, surface films, and particles, as
well as the directionality of these processes, have been described in
the literature [1-4].  Transfer sampling uses the laser ablation
process and its directional properties to transfer the surface
deposit onto an infrared-transparent substrate for analysis,
preserving spatial information.  A preferred embodiment of the
transfer sampling process is shown in the figure.  Sample 1, carrying
surface deposits marked as stripes in the figure, is mounted on a
sliding holder 2 in vacuum chamber 3 equipped with removable, blank
sodium chloride window 4a.  A 0.25 mm vacuum gap between sample and
window is maintained with a spacer, 5.  After evacuating the chamber,
a single pulse of 1064 nm radiation from a Q-switched Nd:YAG laser,
6, is fired through the window at the sample, transferring the
surface deposits from the sample to the window surface by explosive
laser ablation.  A spatially homogeneous laser beam profile is
preferred for this purpose.  The window carrying the transferred
deposits, 4b, is then removed and analyzed under an infrared
microscope by transmission infrared spectroscopy, 4c, to obtain its
spectrum, 7.  The spatial di...