Portable and Wearable Spectrometers in Our Future

The future portable and wearable technology © Nicolas - stock.adobe.com

Spectrometers in Wonderland: Shrinking, Shrinking, Shrinking

A feature paper gives a brief overview of the major portable techniques: those based on optical spectroscopy techniques, including near-infrared (NIR), mid-infrared (mid-IR), and Raman spectroscopy; mass spectrometry (MS) systems, including high-pressure MS (HPMS), gas chromatography–MS (GC–MS), ion mobility spectrometry (IMS); elemental techniques, such as X-ray fluorescence (XRF) and laser-induced breakdown spectroscopy (LIBS); and emerging miniaturized techniques like nuclear magnetic resonance (NMR) (1). The above are all “conventional” spectroscopic techniques and reduced to a rugged portable format, containing self-contained data systems. They provide specific and actionable information to their operators working with them outside the laboratory—in the field—and these instruments have well-defined value propositions. A recent development is the availability of low cost (<$100) multispectral sensors operating in the visible and NIR regions. This low cost enables the sensors to be embedded into consumer products, such as smart “white goods” appliances, personal care, fitness products, and even “wearables” products. In the future, miniature and portable spectrometers will be ubiquitous—outside the laboratory, and in your home and pocket (1).

Portable Raman Spectrometers: How Small Can They Get?

Portable Raman spectrometers have become smaller over the last 20 years, while their performance has increased. This has been made possible by closer coupling of all the components, use of transmission gratings rather than reflection gratings, and due to general advances in electronics, displays, and battery technologies. An obvious question to ask is whether this trend can continue. This article describes the technologies and development of these instruments, existing limitations, the current landscape of miniature Raman spectrometers, and the state of the art. Finally, the article also looks at what emerging technologies could be applied in this area, and how those could lead to new applications (2).

Portable Spectrometer Market to Grow Past $4 Million by 2030

The global portable spectrometer market size was valued at $1,675.7 million in 2020. Now, a new report finds that it is projected to reach $4,065.7 million (over $4.0 billion) by 2030, registering a compound annual gross rate (CAGR) of 9.1% from 2021 to 2030, according to a new report published by Allied Market Research, a market research firm based in Wilmington, Delaware (3). Portable spectrometers allow the equipment to be taken to the sample, as opposed to the sample to the spectrometer, thus moving the laboratory to the point of need—the location of the sample. That portability, combined with algorithms and libraries for identification and quantification, provide a transformative experience to researchers and data alike, changing the way in which people work, by enabling on-site analyses, followed by informed decision-making (3).

How Google is Using Optical Sensors in its Wearable Technology

Wearable health technology is all the rage right now. Research shows that almost one in three adults are using a wearable device like a smart watch to track health and fitness, according to the National Heart, Lung, and Blood Institute. Companies like Google and Apple are investing in wearable technologies to help consumers track biometric health-related data. Spectroscopy spoke with Pete Richards, senior staff research scientist, at Google to discuss how the company is using light technology in its Fitbit and other wearable devices (4).

Wearable Near-Infrared Technology Tested for Monitoring Athletic Performance

Researchers from the University of Saarland in Germany investigated the reliability and side differences in muscle oxygen saturation (SmO₂) measurements using a wearable near-infrared monitor on trained cyclists. The study found that the device shows good reliability but highlighted significant side differences, which must be considered in practical applications (5).

As endurance training advances, the use of wearable technology for precise training monitoring has become increasingly prevalent. One such technology is near-infrared spectroscopy (NIRS), which measures muscle oxygenation (SmO₂) in real time. A recent study by Philip Skotzke, Sascha Schwindling, and Tim Meyer from the Institute of Sport and Preventive Medicine at the University of Saarland in Germany, delves into the reliability and side differences of SmO₂ measurements using a commercially available Moxy muscle oximeter during cycling training (5).

Flexible Near-Infrared Photodetectors Pave the Way for Advanced Wearable Technology

A team of researchers from RIKEN and The University of Tokyo have developed flexible near-infrared organic photodetectors (OPDs) with significant implications for wearable technology. These devices promise enhanced non-invasive biosensing and bio-imaging capabilities, paving the way for more responsive and intelligent wearable applications 6). In the rapidly advancing field of wearable technology, a significant breakthrough has emerged from a collaboration between multiple researchers, which focuses on the development of flexible near-infrared organic photodetectors (OPDs) designed for next-generation wearable applications (6).The rise of Industry 4.0—the Fourth Industrial Revolution, which is the integration of cyber-physical systems, the Internet of Things (IoT), cloud computing, and cognitive computing into manufacturing)—has placed a spotlight on the potential of organic electronic sensors in creating high-performance, flexible, and integrative devices. OPDs, specifically those designed to operate in the near-infrared (NIR) spectrum, stand out for their application potential in non-invasive biosensing and bio-imaging (6).

Affordable Near-Infrared Open-Source Wearable Brain-Monitoring Device Revolutionizes Neuroscience.

Researchers from Vanderbilt University and Stanford University School of Medicine have developed a low-cost, wearable functional near-infrared spectroscopy (fNIRS) headband (7). This device, described as the first open-source, wireless fNIRS headband system, enables neuroimaging in naturalistic settings, making brain monitoring more accessible and versatile. Functional near-infrared spectroscopy (fNIRS) is a non-invasive neuroimaging technique that measures brain activity by detecting changes in blood oxygenation. Functional neuroimaging technology has made significant strides in understanding brain activity. However, most traditional devices are bulky and expensive, limiting use to laboratory environments. Addressing this gap, researchers have demonstrated a leading-edge low-cost, wearable fNIRS headband system that is fully integrated and wireless, allowing for brain monitoring in everyday settings (7).

Portable Near-Infrared Detection of Melamine in Sports Supplements: A Breakthrough in Rapid Testing

A research team has developed rapid quantification models to detect melamine adulteration in sports nutrition supplements using benchtop and portable near-infrared (NIR) spectroscopy instruments (8). One study highlights the efficiency of these methods in ensuring the safety and quality of sports supplements. In the quest for enhanced athletic performance and better health, sports nutrition supplements (SNS) have become indispensable. These products, ranging from protein powders to amino acids, cater not only to elite athletes but also to a growing number of fitness enthusiasts and casual gym-goers. However, the burgeoning market for SNS has also opened doors to fraudulent practices, particularly adulteration with harmful substances like melamine to falsely boost protein content. A specialized study addresses the urgent need for rapid, effective, and sensitive methods to detect such adulteration (8).

Miniaturized Near-Infrared Spectrophotometers in Forensic Analytical Science

Spectroscopy plays a crucial role in forensic analysis by enabling the identification and characterization of substances at crime scenes. Forensic analysis is the scientific detection, evaluation, and examination compiled from crime scenes to support the investigation of legal cases (9). The introduction of miniaturized near-infrared (NIR) instruments has transformed the use of technology in the field of forensics. A recent research paper examines the main aspects and provides a comprehensive, critical review of this equipment. Be they referred to as compact, portable, or handheld, the introduction of miniaturized near-infrared (NIR) instruments has transformed the use of technology in the field of forensics. With miniaturized equipment, researchers and analysts now can perform their studies in the field, thus producing objective, easy-to-use, tailored, and accurate qualitative and quantitative forensic results in a fraction of the time and cost for comparable laboratory instruments. A recent research paper examines the main aspects and provides a comprehensive, critical review of this equipment. Spectroscopy had the opportunity to discuss research on this topic with Celio Pasquini (9).

Exploring the World of Spectroscopy for Portable and Wearable Systems: Technology and Applications

In Episode #27 of the Analytically Speaking podcast series, host Jerry Workman speaks with guest Richard Crocombe of Crocombe Spectroscopic Consulting, about the world of ever shrinking spectrometers. We explore the technologies and applications for such portable and wearable systems and the future of spectroscopy in our everyday lives (10).

Handheld X-Ray Technology Unveils New Forensic Tool

A recent study by researchers at the University of Porto demonstrates the potential of handheld X-ray fluorescence spectrometers to analyze cigarette ash, providing a new method for forensic investigation (11). This non-destructive technique can differentiate between various tobacco brands based on the elemental composition of their ash. In a leap forward for forensic analysis, a study by researchers at the University of Porto has revealed that handheld X-ray fluorescence spectrometers (HHXRF) can be used to analyze cigarette ash. This innovation offers a new way to identify suspects and witnesses in criminal investigations. The study demonstrates how XRF can distinguish between different tobacco brands based on their ash’s elemental concentration, providing valuable forensic evidence while preserving the integrity of the sample (11).

Compact LIBS Sensor Modernizes Crime Scene Forensics

Researchers have developed a cutting-edge, portable LIBS sensor designed for crime scene investigations, offering both handheld and tabletop modes. This device enables on-the-spot analysis of forensic samples with unprecedented sensitivity and depth, potentially transforming forensic science. A team of researchers has unveiled a novel laser-induced breakdown spectroscopy (LIBS) sensor. This tool, designed to meet the stringent demands of law enforcement, promises to modernize how forensic evidence is analyzed at crime scenes. The sensor, which can operate in both handheld and tabletop modes, is set to offer law enforcement agencies a versatile, portable, and highly sensitive tool for on-the-spot forensic analysis (12).

Portable Spectroscopy and Forensic Analysis: Trends and Emerging Technologies

Handheld instrumentation allows for on-site analysis without transporting samples to a laboratory, helping to reduce the cost and time of forensic investigations.

Spectroscopy plays a crucial role in forensic analysis by enabling the identification and characterization of substances at crime scenes. Forensic analysis is the scientific detection, evaluation, and examination compiled from crime scenes to support the investigation of legal cases (13). Different spectroscopy techniques, such as infrared (IR), ultraviolet-visible (UV-vis), and Raman spectroscopy, are employed depending on the nature of the material being analyzed. IR spectroscopy is particularly useful for identifying organic compounds by examining the vibrational modes of molecules. UV-vis spectroscopy is often applied in cases involving colored substances, such as inks or dyes, to analyze their composition. Raman spectroscopy allows for rapid, non-invasive identification of both organic and inorganic substances, often complementing other forms of chemical analysis. The introduction of portable Raman spectrometers has also allowed Raman spectroscopy to become a technique of choice because it requires no sample preparation (13).

References

(1) Crocombe, R. A. Spectrometers in Wonderland: Shrinking, Shrinking, Shrinking. November 1, 2022. Spectroscopyonline.com. Available at: https://www.spectroscopyonline.com/view/spectrometers-in-wonderland-shrinking-shrinking-shrinking (accessed 2024-11-25).

(2) Crocombe, R. A.; Kammrath B. W. Portable Raman Spectrometers: How Small Can They Get? June 1, 2023. Spectroscopyonline.com. Available at: https://www.spectroscopyonline.com/view/portable-raman-spectrometers-how-small-can-they-get- (accessed 2024-11-25).

(3) Chasse, J. Portable Spectrometer Market to Grow Past $4 Million by 2030. May 9, 2024. Spectroscopyonline.com. Available at: https://www.spectroscopyonline.com/view/portable-spectrometer-market-to-grow-past-4-million-by-2030 (accessed 2024-11-25).

(4) Hroncich, C.; Workman, Jr., J. How Google is Using Optical Sensors in its Wearable Technology. May 14, 2024. Spectroscopyonline.com. Available at:https://www.spectroscopyonline.com/view/how-google-is-using-optical-sensors-in-its-wearable-technology (accessed 2024-11-25).

(5) Workman, Jr., J. Wearable Near-Infrared Technology Tested for Monitoring Athletic Performance. June 10, 2024. Spectroscopyonline.com. Available at: https://www.spectroscopyonline.com/view/wearable-near-infrared-technology-tested-for-monitoring-athletic-performance (accessed 2024-11-25).

(6) Workman, Jr., J. Flexible Near-Infrared Photodetectors Pave the Way for Advanced Wearable Technology. June 12, 2024. Spectroscopyonline.com. Available at:https://www.spectroscopyonline.com/view/flexible-near-infrared-photodetectors-pave-the-way-for-advanced-wearable-technology (accessed 2024-11-25).

(7) Workman, Jr., J. Affordable Near-Infrared Open-Source Wearable Brain-Monitoring Device Revolutionizes Neuroscience.Published: June 20, 2024 | Updated: June 21, 2024. Spectroscopyonline.com. Available at: https://www.spectroscopyonline.com/view/affordable-near-infrared-open-source-wearable-brain-monitoring-device-revolutionizes-neuroscience (accessed 2024-11-25).

(8) Workman, Jr., J. Portable Near-Infrared Detection of Melamine in Sports Supplements: A Breakthrough in Rapid Testing.July 17, 2024. Spectroscopyonline.com. Available at:https://www.spectroscopyonline.com/view/portable-near-infrared-detection-of-melamine-in-sports-supplements-a-breakthrough-in-rapid-testing (accessed 2024-11-25).

(9) Chasse, J. Miniaturized Near-Infrared Spectrophotometers in Forensic Analytical Science.September 16, 2024. Spectroscopyonline.com. Available at:https://www.spectroscopyonline.com/view/miniaturized-near-infrared-spectrophotometers-in-forensic-analytical-science (accessed 2024-11-25).

(10) Analytically Speaking Podcast: Exploring the World of Spectroscopy for Portable and Wearable Systems: Technology and Applications.August 15, 2024. Spectroscopyonline.com. Available at:https://www.spectroscopyonline.com/view/ep-27-exploring-the-world-of-spectroscopy-for-portable-and-wearable-systems-technology-and-applications (accessed 2024-11-25).

(11) Workman, Jr., J. Handheld X-Ray Technology Unveils New Forensic Tool. September 16, 2024. Spectroscopyonline.com. Available at: https://www.spectroscopyonline.com/view/handheld-x-ray-technology-unveils-new-forensic-tool (accessed 2024-11-25).

(12) Workman, Jr., J. Compact LIBS Sensor Modernizes Crime Scene Forensics. September 16, 2024. Spectroscopyonline.com. Available at: https://www.spectroscopyonline.com/view/compact-libs-sensor-modernizes-crime-scene-forensics (accessed 2024-11-25).

(13) Wetzel, W. Portable Spectroscopy and Forensic Analysis: Trends and Emerging Technologies. October 8, 2024. Spectroscopyonline.com. Available at: https://www.spectroscopyonline.com/view/portable-spectroscopy-and-forensic-analysis-trends-and-emerging-technologies (accessed 2024-11-25).