ReactIR. Infrared spectroscopy revives in the age of NMR.
We have a brand new Mettler-Toledo ReactIR 15 sitting in my lab. It is rather simple to use- just dip the probe in your reaction mixture. It needs a little LN2 to chill the detector. The software is reasonable, bearing some resemblance to iControl of the RC1 sitting a few meters away.
The instrument is used to follow the progress of a reaction by monitoring the growth or extinction of IR absorptions. What is interesting for the user is that it is not necessary to identify any of the peaks in the course of an experiment. The software can integrate absorptions and plot their change over time. The fingerprint region of the IR spectrum is put to good use in that it is a fruitful region for numerous absorptions to appear.
The thing is still new to us, so we’re early in the learning curve. The probe in use has a wave number range from 2500 to about 650 reciprocal centimeters. It is possible to detect up to 3000 wave numbers with a different probe. The probe is connected to the interferometer by a fibre optic cable comprised of a silver bromide optical pathway.
The thing is the size of a coffee maker and costs as much as a used helicopter. The ATR probe tip is small enough to be immersed in experiments at the scale of a scintillation vial or a 5 liter flask.
What it brings to the table is the ability to follow the progress of reactions in real time for process optimization. Pulling samples and trudging over to the NMR for in-process checks is tiresome and time consuming.
One limitation is the electrical classification. As with other electrical devices you have pay attention to the NFPA classification of the space it sits in. The ReactIR 15 is class 1, but not division 1. If the instrument must be used in this space, there are ways to fashion an enclosure to get around this, according to Mettler. Have a look at your computer as well. If your computer throws sparks and coal cinders, you may want to keep it away from that pool of pet ether on the floor.