Infrared imaging aids combinatorial chemistry analysis

17 Jun 2002

Chemical engineers at Purdue University in Indiana, US have developed an infrared imaging instrument that they say screens chemical samples up to 5 000 times faster than conventional analytical methods.

Jochen Lauterbach has used the instrument to analyse thousands of samples produced using combinatorial chemistry - a technique used to synthesize a large array of chemical products simultaneously.

At the heart of the rapid-scan Fourier transform infrared imager is a Globar mid-infrared source. Emission from the source passes through a calcium fluoride lens, which restricts the frequency range to 4000 to 1300 cm-1.

A lens configuration provides a wide field of view, so that the hundreds of samples produced on support beads with the combinatorial technique could be analysed simultaneously. In the combinatorial technique, thousands of the tiny plastic beads are each coated with an individual catalyst, upon which the reaction takes place.

Characteristic molecular absorptions of functional groups in the emitted spectral region allow chemists to identify the products formed, as well as study reaction kinetics, with the instrument.

Unlike conventional, destructive analytical techniques like mass spectrometry, where chemical products must be cleaved from the support beads, the new instrument enables non-destructive, in situ analysis.

Lauterbach has also used the instrument to analyse the stream of gas passing over gas-solid catalysts that are used in car engines and industrial chemical manufacture. Slight differences in the combinations of metals used in such catalysts, such as platinum, palladium and rhodium, can improve manufacturing efficiency, and lead to substantial cost savings for the manufacturer. The new instrument enables screening of hundreds of catalyst combinations simultaneously.

Putting all the parts of the instrument together cost an estimated USD 80 000. Lauterbach says that after filing two patents and copyrighting the data collection and processing software, he is now looking for partners to commercialize the instrument.

Story courtesy of Opto and Laser Europe magazine.