Chemical Industry QC with NIR

Read this post, or watch the webinar instead!

Quality control for many labs involves a heavy dose of wet chemistry methods, things like titration and separation techniques that take skill, time and (even more) chemicals to execute. Luckily, some of these traditional testing methods can be replaced by simple, fast and safe NIR spectroscopy.

While this blog title indicates applicability to the Chemical Industry, “chemical” is one broad umbrella. There are myriad products and processes that fall under the chemicals category, from natural products like wood and pulp to personal care products to standard bulk chemicals. Reaching all of these audiences with one blog post seemed a little daunting until we broke it down to some common key themes for implementation of NIR for the chemical (or any!) industry:

• Raw material qualification
• Intermediate/in-process testing
• Finished product testing

Of course, the typical applications that might fall into any one of these categories will differ based on the products being produced. Some of the more common applications include:

• Material identification
• %-Moisture or %-solvent quantification
• Reaction extent or %-polymerization
• Hydroxyl and acid number determination

As with many other industries, the raw materials used for production of chemical products are often non-discrete, sourced from various parts of the galaxy, and labeled–sometimes correctly, sometimes not.  If you follow product recalls, you’ll find that millions of dollars have been lost due to mislabeled containers being poured into mixers, placed on trucks for distribution to other producers, or stocked on store shelves.

NIR is one quick tool used for identity testing of routinely received materials. There is potential to differentiate isomers, crystalline forms, chemical analogs, fatty acids, and even contaminated materials. Because identity testing with NIR takes seconds and can be done in the warehouse, more frequent testing can be accomplished without backlogging the QC guys and gals.

On the quantitative side, there is plenty to measure keeping in mind the inherent sensitivity of NIR to particular molecular bonds, including O-H, C-H, N-H and C-O bonds. So, if those bonds are changing in type or in number, NIR could be a great fit. This is the case in the typical chemical application of determining hydroxyl number, where we observe a decrease in NIR signal attributed to O-H bonds as those O-H end groups are consumed during polymerization. In fact, determining hydroxyl number of polyols by NIR is a standard practice per ASTM and ISO.

BUCHI Market Manager and former BUCHI NIR Applications Specialist Ryanne Palermo produced a short webinar on these topics, including a fiery example of tracking nitrogen substitution in nitrocellulose. Tune into the webinar by clicking here.

Find more free, streaming content on our BUCHI Webinar On-Demand page, including information about preparative chromatography, laboratory and industrial evaporation, drying, encapsulation and more.