Researchers from Sorbonne University in Paris, France, led by Malak Rizk-Bigourd, analyzed volatile organic compounds using a miniaturized system that incorporates gas chromatography (GC), publishing their findings in the Journal of Chromatography Open (1).
Latin Quarter, Paris, historic building of University of Sorbonne, Chapel of Sorbonne, the square with fountains in front. Paris, France. | Image Credit: © Telly - stock.adobe.com
In this study, the researchers created and optimized MAVERIC, a miniaturized and autonomous gas chromatography (GC) system coupled to a nano-gravimetric detector (NGD) based on a NEMS (nano-electromechanical-system) resonator. An easily removable homemade preconcentrator was used, which enables changing of used sorbents and either extending or changing the panel of target compounds. Additionally, a mixture of isoprene, benzene, toluene and α-pinene was used to optimize experimental conditions.
Volatile organic compounds (VOCs) are compounds that have high vapor pressure and low water solubility (2). Many are human-made chemicals that are used and produced in the manufacture of paints, pharmaceuticals, and refrigerants. VOCs are emitted as gases from different solids or liquids, and some can have short- and long-term adverse health effects. Outdoors, the atmospheric mixing ratios and chemical nature of VOCs are all critical for estimating, anticipating, and mitigating their impacts. Indoors, monitoring VOCs and determining the emissions sources (such as materials or human activities) and sorption processes on surfaces can help improve indoor air quality.
Monitoring VOCs at sub-parts per billion (PPB) level can be challenging, whether online or offline methods are used. While offline methods can have low detection limits (parts per trillion [ppt] levels), be cost-effective, can easily implement sampling units, and have compact volume, they also have poor time resolution and logistics, meaning there can be necessary delays to getting accurate results (1). Online techniques can allow real-time measurements with high temporal resolution and low detection limits (ppt), but these instruments can be expensive, heavy (120–280 kg), and bulky. To overcome these issues, there have been investigations to create laboratory miniaturized GC or commercial GC systems that have been presented and reviewed in different works (1).
In this study, the detection limit, the stability, the repeatability and the linearity of the analytical system were assessed. This software also helped to control both the instrument and the electronics modules, operating at a low flow rate (2 mL.min-1) of helium used as carrier gas. The system enables the measurements of VOCs in less than 20 minutes, particularly regarding compounds that bear between 5–10 carbon atoms. It is standalone, portable, and fully controlled using the homemade software using automatic synchronize with NGD detector software. Additionally, the system can connect to the Internet and be remotely controlled, being adaptable for long-period field campaign tests or environmental monitoring and air quality surveys.
Optimal experimental conditions of the MAVERIC system were successfully determined at sub-parts per billion (ppb) to few parts per trillion (ppt) levels, with the system allowing reliable detection of complex compound mixtures. Compared to other instruments, MAVERIC presents a good compromise between portability, gas consumption, time analysis and limits of detection (LODs). However, this instrument should be validated in comparison with other online analytical instruments during laboratory tests and during field campaign measurements. Future works will aim to validate MAVERIC performances using real sample analysis and in situ conditions.
Overall, the scientists hope to mainly use their MAVERIC system for outdoor air monitoring and during field campaigns in extreme environments. To reach this goal, they propose new additions to their system to avoid the effects of humidity present in outdoor samples. Further, fine calibrations of instruments are required for all tested compounds to perform quantitative measurements, because NGD response is analyte-dependent. The scientists also hope to use NGD under a temperature ramp to have the same sensitivity for compounds having a growing number of carbon atoms to avoid calibration for all compounds.
(1) Rizk-Bigourd, M.; Gaimoz, C.; Colinet, E.; Pineau, J-P.; et al. Development of Miniaturized Autonomous and Versatile Gas Chromatograph for Volatile Organic Compounds Monitoring Using Nano-Gravimetric-Detector. J. Chromatogr. Open 2025, 7, 100202. DOI: 10.1016/j.jcoa.2024.100202
(2) What Are Volatile Organic Compounds (VOCs)? EPA 2025. https://www.epa.gov/indoor-air-quality-iaq/what-are-volatile-organic-compounds-vocs (accessed 2025-4-16)
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