Wavelength Tech Forum: FT-IR/NIR

This month’s Technology Forum looks at the topic of FT-IR/NIR and the trends and issues surrounding it. Joining us for this discussion are Simon Nunn and Chris Petty, with Thermo Fisher Scientific, Rob Morris, with Ocean Optics, Inc., and Richard Larsen, with JASCO, Inc.

What is the one FT-IR/NIR application area that you see growing the fastest?

(Nunn/Petty) This question is best answered by separating FT-IR from NIR. The FT-IR market remains dominated by generic materials identification applications. Occasionally, we do see specific applications areas grow quickly and then mature quickly. Recent examples of these include the determination of FAME content of biodiesel and the detection of fake or adulterated gemstones. However, while these may grow rapidly, they remain minor compared to the more general uses to which FT-IR is put. FT-IR microscopy and imaging applications show the broadest ongoing growth. These measurements stretch across a wide range of industries, however. There are common needs for people to analyze ever smaller contaminants and particles while increasing the confidence they have in the results.NIR is somewhat different. Here, specific applications can drive significant growth of the market. A classic early example of this was determination of moisture content in various materials. The development of more sophisticated instrumentation and chemometrics has significantly widened the applications potential of NIR. For example, composition analysis of powder blends prior to tableting in pharmaceutical processes has been an area of recent rapid growth for NIR.

(Morris) There doesn’t seem to be any one NIR application that is emerging; we don’t handle FT-IR. However, one of the newer applications we’ve seen recently is characterizing waste materials (plastics and carpeting in particular) for recycling. Also, with such attention on keeping food supplies safe, we get a lot of interest in folks in the food and beverage industries.

(Larsen) There are so many application areas that require FT-IR/NIR instrumentation, it is indeed difficult to single out one area. If pressed, I would say that I have personally seen a growth in the QC markets. Those industries that require ‘perfection’ in the appearance of a final product, specifically, blemishes in polymer films, coatings and finishes, etc. As the final consumer becomes more discriminating with respect to the quality of goods, manufacturers are turning to analytical methods for the identification of problems with appearance and the resolution of production problems that produce the imperfections in the appearance of a product. FT-IR and FT-NIR are uniquely suited to provide an identification of materials causing the imperfections as well as improving the ability to provide consistent manufacturing processes with respect to mixtures of materials.

In what ways have FT-IR/NIR positively impacted the agriculture and food markets?

(Nunn/Petty) Although something of a generalization, FT-IR has improved the quality of the wrapper while NIR has improved the quality of the food within. The shelf life of many food products is achieved through sophisticated polymer-based packaging systems. FT-IR has been used widely to understand the performance and structure of such systems. This improves food safety, allows product to reach consumers far from the point of manufacture and significantly reduces costs. NIR assures that the product within that sophisticated package is of consistent quality. Determination of moisture and fat content of foodstuffs are classic applications for NIR.

(Morris) As these spectral systems have become more affordable and portable, they’ve allowed QC managers to integrate more effective sensing systems into their processes. More powerful technology at lower costs potentially can affect product yield and safety, among other things.

(Larsen) The ability to monitor trans-fatty acid content as well as the well-established methods for analysis of fats, proteins, etc. in grains and other foods has offered the agriculture and food markets the ability to refine manufacturing/production methods as well as comply with the various FDA and USDA regulations. There will continue to be additional applications developed for these industries as instrument vendors supply application-oriented solutions to the requirements of these industries.

How have FT-IR/NIR applications affected homeland security?

(Nunn/Petty) The ability of FT-IR to identify a broad range of suspect materials, including ‘unknown white powders’, quickly and with minimal training, equips it well as a tool for improving homeland security. Simple spectrometers can be deployed in the field allowing their use at incident sites. More sophisticated equipment is used in forensic laboratories, often in pursuit of the perpetrators of such incidents. It is interesting to reflect that a significant benefit of having such an arsenal of instrumentation deployed in homeland security is how it can limit the impact of false alarms. Dropping a bag of flour from your groceries is now unlikely to bring your downtown area to a standstill.

(Morris) We’ve been so focused on our LIBS-based technology for homeland security applications that NIR hasn’t crossed our radar too much in this area. One might deduce that detection of chemical and biological warfare agents would make sense for these technologies.

(Larsen) Very little, if at all. The difficulty with FT-IR/NIR is the sample preparation issue. NIR spectra do not necessarily provide unambiguous identification of materials, even though the sample preparation is minimal. Mid-IR spectra do provide identification of materials (e.g., explosives, contraband materials, etc.), but the technique does not offer the ease of sampling compared to other analysis methods such as Raman spectroscopy or mass spectroscopy.

In our previous Question of the Month, “Which area do you believe will see the most growth for FT-IR?” none of our readers voted for the environmental field. Are the prospects of FT-IR for environmental applications as bright as some believe?

(Nunn/Petty) The sensitivity of FT-IR undoubtedly limits its application in environmental sciences. Once a problematic material is released into environment it usually becomes rapidly diluted by air or water to below the limits of infrared detection on a ‘standard’ instrument. Thus, FT-IR finds limited applicability in the testing of the air that we breathe or the water that we drink. However, FT-IR can be and is used at the point of origin of such pollutants to control emissions prior to downstream environmental dilution. A good example of this is the monitoring the composition of stack gases emitted from incinerators.

(Morris) It seems logical, what with various site remediation applications that lend themselves to this kind of approach, but we have no indications about the prospects for environmental applications.

(Larsen) Personally, I do not believe so. Infrared spectroscopy is extremely difficult to perform for aqueous samples, does not have the sensitivity to provide quantitative results for extremely low levels of chemicals, and requires fairly extensive sample preparation. Thus, I do not see extensive application of FT-IR for environmental analyses. Certainly, there are selected methods that are performed using infrared spectroscopy, but there are a larger number of environmental methods that utilize HPLC, HPLC/MS and the AA and ICP instruments.

Do you foresee rapidly decreasing costs for infrared instrumentation?

(Nunn/Petty) FT-IR currently represents a very cost-effective way of quickly measuring an infrared spectrum with high resolution over a broad wavelength range. I do not foresee rapidly decreasing costs for FT-IR. However, it is likely that the capabilities and value of spectrometer systems will continue to increase at current price points. There are some interesting technologies that can provide some aspects of the capability of FT-IR at potentially lower cost. However, the compromises in wavelength range or resolution that such technologies make compared to FT-IR equip them better for niche application-specific instrumentation than as a serious competitor for the more generally-applicable FT-IR. The challenge is to find a niche application of such size that it is economically viable to create such instrumentation.

(Morris) It’s inevitable. The major hurdle has always been the relatively high cost of the detectors typically associated with NIR analysis, such as indium gallium arsenide. But the emergence of less costly NIR sensing technologies, MEMs devices, for example, should spur the market to come up with lower-cost approaches. The Holy Grail seems to be to lower the retail price to less than $5,000.

(Larsen) Not especially. Yes, the cost of the instrumentation will continue to decrease slowly, but the essential hardware for an infrared instrument will still require those components necessary to provide quality results. The source, laser and detector elements as well as the window and beamsplitter materials are about as inexpensive as can be achieved with modern production methods. There have been interesting developments in other types of infrared instrumentation that do not require an interferometer, but these instruments have yet to prove themselves in the industry.

What do you think?

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