Column: IR Spectral Interpretation Workshop

, is the founder and CEO of Big Sur Scientific, a maker of portable mid-infrared cannabis analyzers. He has over 30 years experience as an industrial infrared spectroscopist, has published numerous peer-reviewed papers, and has written three books on spectroscopy. As a trainer, he has helped thousands of people around the world improve their infrared analyses. In addition to writing for Spectroscopy, Dr. Smith writes a regular column for its sister publication Cannabis Science and Technology and sits on its editorial board. He earned his PhD in physical chemistry from Dartmouth College.

Articles

An examination of halogenated compounds and some common halogenated polymers is explored here.

Halogenated Organic Compounds

The structure and infrared spectra of polyurethanes and polymeric amides are similar, but there are several key differences worth calling attention to.

Infrared Spectroscopy of Polymers XIII: Polyurethanes

Slip agents are commonly used amide small molecules that lubricate the molds in injection molding processes. By studying the spectra of a primary amide, we can see how they can contaminate the spectra of polymeric materials.

Infrared Spectroscopy of Polymers XII: Polyaramids and Slip Agents

We study the spectra of organic nitrogen polymers with a particular focus on polyamides.

Infrared Spectroscopy of Polymers, XI: Introduction to Organic Nitrogen Polymers

We study the spectrum of polymethyl methacrylate (PMMA)—otherwise known as plexiglass—and the spectra of PMMA mixtures and copolymers.

Infrared Spectroscopy of Polymers X: Polyacrylates

We continue our survey of the spectra of carbonyl-containing polymers by looking at cellulose acetate and the economically important polycarbonate Lexan.

Infrared Spectroscopy of Polymers, IX: Pendant Ester Polymers and Polycarbonates

An exploration of polyethylene terephthalate (PET), one of the most important polymers, is presented.

Infrared Spectroscopy of Polymers, VIII: Polyesters and the Rule of Three

We continue our survey of the infrared (IR) spectra of polymers with a look at the spectra of polymers that contain carbonyl or C=O bonds. Our long-term goal is to examine the spectra of polymers that contain ketone, carboxylic acid, ester, and carbonate linkages. Studying these spectra is vital, because these molecules are important economically and are ubiquitous in society. 

The Infrared Spectra of  Polymers, VII: Polymers with  Carbonyl (C=O) Bonds 

An examination of polymers with C-O bonds, focusing on the spectra of polyvinyl alcohol, cellulose, starch, and copolymers.

The Infrared Spectra of Polymers, VI: Polymers With C-O Bonds

Epoxies are perhaps the most economically important functional group of polymers. We explain how to interpret their spectra.