Accurate and sensitive detection of hazardous gases is critical for public safety, but it poses logistical and analytical challenges. To minimize risk, work is underway to develop mobile detection systems—some inspired by our four-legged friends.
Testing the air in risky workplaces or after an accident is important but dangerous work. Various hazardous volatile organic compounds (VOCs) can be released during accidents, and they may represent a hazard to ecosystems and humans. The traditional workflow to assess these emissions is labor intensive, and there are limits to what can be achieved on-site in real time. But rapid identification of hazardous VOCs in risky environments such as wars, fires, or industrial accidents is critical to inform appropriate rescue and clean-up operations.
To minimize risk to humans, work is underway to develop mobile detection systems. Approaches include gas sensors, electronic noses, spectroscopic methods, miniaturized gas chromatography, portable ion mobility spectrometry, and portable mass spectrometry, as well as their coupling techniques. Of these, portable mass spectrometry is promising due to its high sensitivity, reliability, fast signal response, and unique environmental suitability. A team working in Guangzhou, China, previously designed a microextraction sampler array, in which a solid-phase microextraction fiber was mounted on drones for remote-control air sampling and coupled with a portable gas chromatography-mass spectrometry approach for quick identification of hazardous air pollutants.1 In another study, they trialed a miniaturized mass spectrometer in a unmanned floating ship-like device, which achieved real-time detection of hazardous VOCs in water via a liquid/gas exchange membrane.2
To turn this chemical sniffing solution into man’s best friend, the same team have now created a dog-like robot with an articulated testing arm on its back.3 In the new work, the arm is loaded with three needle trap devices that can collect air samples at any point, and which can be controlled independently. This sounds simple, but unmanned manipulation of ground environments is in fact very complicated due to the presence of unknown obstacles, and few robotic analytical systems exist that integrate samplers and portable mass spectrometry.
Portable Mass Spectrometry for On-site Detection of Hazardous Volatile Organic Compounds via Robotic Extractive Sampling
DOI: 10.1021/acs.analchem.4c01555
The results, published in Analytical Chemistry, showcase the potential for the new system, with captured samples identified within minutes. This was possible for various VOCs including toxicants, chemical warfare agents, and burning materials from different environments. As well as demonstrating low detection limits, good reproducibility, excellent quantitative ability, and detection speed, the results showed that the quadruped robot had excellent performance including safety, controllability over distances greater than 500 meters, and robustness under dangerous chemical conditions. In the researchers' videos (you can watch them all in the "Supporting Information" section of the article), you can see that the robot was able to navigate stairs and narrow areas, as well as uneven ground such as grass.
Watch it smoothly travel up two flights of stairs below:
The authors believe this is a smart and person-centered approach for detecting hazardous VOCs from unknown and risky environments. However, they also point out that more work is needed to develop a system that can cope with all weather conditions—since the current model cannot operate in rain or snow—and to be able to also detect non-volatiles.
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References
- Chen, W. et al. Onsite Identification and Spatial Distribution of Air Pollutants Using a Drone-Based Solid-Phase Microextraction Array Coupled with Portable Gas Chromatography-Mass Spectrometry via Continuous-Airflow Sampling. Environ. Sci. Technol. 2022, 56, 23, 17100–17107.
- Zhang, J. et al. Real-Time and Online Monitoring of Hazardous Volatile Organic Compounds in Environmental Water by an Unmanned Shipborne Mass Spectrometer System. Environ. Sci. Technol. 2023, 57, 49, 20864–20870.
- Liu, X. et al. Portable Mass Spectrometry for On-site Detection of Hazardous Volatile Organic Compounds via Robotic Extractive Sampling. Anal. Chem. 2024, 96, 23, 9325–9331.