The Little FTIR That Could

The Little FTIR That Could

I seem to have an obsession with pint-size FTIRs lately given my recent blog posts about handheld FTIRs. The folks at Bruker Optics (Billerica MA) were recently kind enough to loan me one of their Alpha FTIRs. It has by far the smallest footprint of any laboratory FTIR I have ever seen. According to the Bruker website the instrument’s footprint is about 8” by 11”; smaller than a lab notebook, and it is only 5” tall. The instrument contains a small version of Bruker’s “RockSolid™” interferometer. This design has two gold coated cube corner mirrors that straddle the beamsplitter and are attached to a single rocker arm. A flex pivot causes the arm to tilt alternately to the left and right to generate an optical path difference. My version of the instrument has an air cooled silicon carbide source and DTGS detector.

My understanding is that part of the reason they were able to make this FTIR so small is by getting rid of the He-Ne laser that has been such an important part of FTIRs for decades. This laser and its power supply, as you may know if you have ever looked inside of an FTIR, takes up a good bit of space. Instead, the Bruker Alpha has a small diode laser that gives off light at 11734 cm-1. This may seem sacrilegious to some spectroscopists, but remember we only need to know the wavenumber of the laser we use to measure the optical path difference of the interferometer. It does not matter all that much what wavenumber that laser gives off.

I am teaching my series of 5 public FTIR courses in the Philadelphia area this week (it’s not too late to attend, details here: http://www.spectros1.com/schedule.html ). When I teach these courses I always bring an FTIR with me, which is particularly important for the hands-on sample prep. course where students learn to prepare and run their own samples. My previous instrument was a “full sized” FTIR which worked fine but was cumbersome to move around and ship. It weighed over 40 lbs. and got damaged so frequently during shipping that I had a special padded case designed and built for it. The shipping costs for this were getting out of control, and had me wondering if there was not a smaller, lighter instrument I could find that would be easier and cheaper to ship.
The Bruker Alpha FTIR has solved this problem for me. The way I got it to Philadelphia was by wrapping it in bubble wrap, putting it in my suitcase, and bringing it with me. When I got to my destination I unwrapped the bubble wrap, plugged it in, and it is working fine. It did an excellent job today measuring spectra of a variety of samples in the FTIR sample prep. course. So my shipping costs are reduced from hundreds of dollars per seminar series to zero! For more information on the Alpha, click here: http://www.brukeroptics.com/alpha.html .