Near-infrared spectroscopy at Pittcon 2023

Abstract

The Pittsburgh Conference (Pittcon) was held in Chicago in March 2020, immediately before worldwide coronavirus disease 2019 (COVID-19) restrictions came into place. The attendance then was down from previous years, and it was noticeable that airports were deserted. Therefore Pittcon 2023, held in Philadelphia, Pennsylvania was the first chance for many people to get together in more than three years. The Philadelphia Convention Center is built around a former railway terminus, with reminders of its older purpose still visible, and part of it sits above a large, very popular indoor market (Figure 1). The Symposium “Frontiers of Near-Infrared Spectroscopy in Analytical Applications” was organized by Krzysztof Bec and Christian Huck (University of Innsbruck). Unfortunately, COVID-19 still affected the Symposium and three of the speakers were unable to attend. At short notice the author of this summary (Figure 2) was asked to step in to chair the session, and he used the available time to allow the speakers to overrun their normal time allocation, and to have a fruitful panel discussion, so that there were no gaps in the schedule (Figure 3). Richard Crocombe’s (Crocombe Spectroscopic Consulting) talk was about “Miniature Optical Spectrometers and Multispectral Sensors in Consumer Goods and Wearables”. He described the latest development in portable spectroscopy, the availability of very low-cost multispectral sensors, about the size of computer chips, leading to the possibility of embedding them into consumer goods. Multispectral devices can be produced in volume via semiconductor and optical coating techniques, at very low cost – less than $10 each. Multispectral sensors can now not only be incorporated into ‘white goods’ like washing machines and dryers, but also into ‘fitness’ products like smart watches and sports watches, and as photonic miniaturization increases, into ‘wearables’ like smart rings, providing the user with health information. Silicon photonics and photonic integrated circuits, produced en masse using semiconductormanufacturing techniques, are the ideal next step. The presentation surveyed the field, and highlighted some ‘smart’ consumer device possibilities, from toothbrushes to toilets. Boris Mizaikoff’s (Ulm University and HahnSchickard) talk was on “Midvs. Near-Infrared Spectroscopy: Challenges and Potential”. He discussed the miniaturization of spectrometers and advances in fiber-optic devices and spectral data processing which make NIRS a powerful analytical technology for its implementation at various points along the entire food chain to meet the growing demands of food product control. The portability of the latest generation miniaturized NIR systems makes their application for the quality and authentication control and monitoring of a wide range of food products feasible, to provide challenging solutions to specific demands of the food industry that were completely unthinkable and unaffordable before these developments. Some examples were shown of the use of NIRS directly in the field to give harvesting recommendation on horticultural products or in the analysis of live animals to assess specific quality parameters. Jerome Workman, Jr. (MJH Life Sciences) described solid-state near-infrared analysis: building multiple identical instruments with no moving parts, a 3D printed chassis and calibration transfer technology. He posed the question, how could one build a solid-state nearinfrared spectrophotometer that has high performance, low maintenance, and allows precise calibration transfer? Calibration transfer refers to a combination of instrument technology and chemometric techniques that are used to attempt to apply a single spectral database, and the calibration model developed using that database, for two or more instruments, with retained accuracy and precision. His presentation discussed the technical aspects and challenges associated with the development of a micro-electro-mechanical systems digital light processing (MEMS-DLP)-based spectrophotometer, combined with a 3D printed optical chassis, and an AI-type software capability for automated instrument alignment, to illustrate a model for future instrument design and manufacturing. Dolores (“Lola”) P erez Mar ın (University of Cordoba) discussed portable near-infrared spectral sensors for increasing solutions in the agri-food product control. She described how NIR sensors enable rapid, accurate, non-destructive, low-cost and