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 Robert Mattes, Applications Scientist with FOSS NIRSystems, Inc.; Paul Scholl, Head of Reaction Analysis Technology and Applications Consulting Group, and Brian Wittkamp, Ph.D., Reaction Analysis Market Manager, with Mettler Toledo, Inc.; and Federico Izzia, Product Manager, Thermo Scientific FT-IR Spectrometers and Microscopes.

What effect has the evolution of imaging had on FT-IR/NIR?

(Mattes) There is not too great an impact on NIR yet because the imaging instruments are very expensive, have very large file sizes, and very little depth penetration into the sample. In the one application that has been highly promoted, tablet analysis, dust on the tablets can adversely affect the measurements when using imaging.

(Scholl/Wittkamp) Imaging, through the use of an integrated microscope has demonstrated that very portable devices can be used to quickly analyze and identify the composition of a small size of material. This has proven to be quite effective for hazmat, forensic, and counter-terrorism applications. Having such a device be so portable and the ability to focus on a pinpoint sample size to identify its composition rather quickly is a valuable tool.

(Izzia) Imaging has opened up different perspectives to material scientists in that it has found a new way to analyze the spatial distribution of materials in sample areas quickly and with acceptable resolution. Imaging still does not bridge the gap between a seasoned microscopist and those you wish to use the technique but do not have training and experience. The ease of use of imaging will be resolved when even the unskilled scientist – knowledgeable in his/her field, but not in analytical instruments – will be capable of obtaining the answers with limited learning time.

How have improvements in software made the FT-IR/NIR field better?

(Mattes) With perhaps the exception of the filter-based instruments, without modern chemometric software, NIR would still be used only by a handful academics.

(Scholl/Wittkamp) Software has had a critical impact on the usability of the technology. In particular, the development of an intuitive user interface has reduced or removed the barrier for the non-spectroscopist to utilize the instrumentation and to generate high value information. Another important contribution in the area of software has been the development of modules that automate data analysis. Moving forward, particularly in the area of reaction analysis, software modules that automate the conversion of data to information are going to play a significant role in further adoption of the technology.

(Izzia) FT-IR is universally considered one of the quickest and easiest tools in the analytical instruments laboratory. Software has played a major role in the successful global utilization of these products, by introducing multiple perspectives including the monitoring and verifying of instrument performance, rapid material identification, and the verification of material consistency. Software developments enable and accelerate conversion of sample data into useful information.

How has diamond ATR technology affected the FT-IR/NIR field?

(Mattes) ATR works well in the mid-infrared, but has little practical application in NIR.

(Scholl/Wittkamp) If you consider how many companies now offer sampling technologies using a diamond ATR element, I believe we can conclude that the development of diamond as an ATR element has made a major contribution. Diamond has allowed the analysis of not only chemically aggressive samples, but also physically challenging samples such as extremely hard materials. As diamond was integrated into probes that could withstand a wide range of temperature and pressure conditions it also allowed a wide range of applications for in-situ analysis of reactive chemistry. Diamond is not the only ATR sensor that has proven invaluable in this field. Another senor type such as silicon has complementary value where it is highly efficient in the carbonyl region where the diamond has a "blind spot." Coordinated use of these ATR sensors allows for use in an even wider range of chemistry and applications.

(Izzia) Diamond ATR technology has had a dramatic effect on the FT-IR market. It is a reliable, robust technology that involves 15% to 25% higher expense on the initial investment – depending on the spectrometer price range – but protects the user from the risk of system downtime and removes the need to routinely purchase consumables. This means that the cost of ownership variability related to the main sampling device of FT-IR is well defined upfront at the time of purchase. As with any ATR, the technique offers extraordinary ease of use and data reproducibility, which explains the large success, due in large part to the day-to-day challenges of keeping cost per analysis as low as possible while guaranteeing the highest quality.

What impact has FT-IR/NIR had on chemometrics?

(Mattes) The field of chemometrics has greatly expanded due to its required use in the NIR analysis. The use of chemometrics with NIR has brought the former into the real world of chemical analysis and demonstrated its utility with a range of analytical techniques beyond just NIR.

(Scholl/Wittkamp) Chemometrics has become the major enabling technology, particularly for dynamically changing samples. Today's software allows the collection of complex data sets and chemometric algorithms and has enabled the automatic and real time deconvolution of the data. What used to take hours or days to analyze can now be accomplished near real-time, thereby providing the chemist with an up to date analysis of their chemistry that could be considered as a "molecular video" of the reaction.

(Izzia) It is probably the opposite. Chemometrics enables FT-IR and NIR (especially the latter) to extract the hidden information from spectral data where basic peak integration based methods were not capable. Chemometric algorithms are more reliable, stable, and accurate than old spectroscopy methods where sample complexity becomes higher or dilution is quite high. In the industrial material verification process FT-IR and NIR should guarantee consistent spectral quality and reliability, but the answers are delivered by the next step, which in many cases is chemometrics.

What do you see in the future for quality control in FT-IR/NIR?

(Mattes) There will be more dedicated analytical solutions for real-time monitoring of processes especially with NIR because there is no need for sample preparation. FT-IR is inherently more limited because extensive sample preparation is needed. The FDA Process Analytical Technology (PAT) initiative encourages manufacturers to monitor processes before the final product stage. NIR is particularly well suited to in-line, real-time analysis because it can be utilized with no sample preparation, used with multiplexed fiber optic probes and is robust in industrial environments.

(Scholl/Wittkamp) Traditionally, quality control applied mainly to incoming material and final product analysis. The PAT initiative in the pharmaceutical industry can also be viewed as an integral part of quality control. As we move into the future, PAT can be moved further upstream to the synthetic organic chemist. Using FT-IR to understand the critical control parameters that affect the quality of the chemical process and final product is a very powerful way to take advantage of the power of spectroscopy.

(Izzia) Instruments that deliver reliability, ease of use, and speed are already "mature" products in the marketplace. New developments will be in the direction of guaranteeing confidence on results, especially from the software side. The fast-growing new economies will drive for large quantities with less specifications and automations. The major occidental economies challenged by competitive markets will drive through automations and near-line/at-line faster controls during production.

What do you think?

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