VSI Automatic Air Samplers. Automatic air samplers are devices used for collecting air samples from the atmosphere - both from ambient air and experimental Teflon chambers or PMMA respiration chambers used for gas flux measurements. Measuring the gas and volatile composition and/or isotopic signature of air reveals crucial information about water use, carbon balance, greenhouse gas emissions or other pollutants in natural or managed ecosystems or urban environments, and generally plant and/or soil interactions with the atmosphere. To support cost-effective air sampling campaigns in the laboratory and field, we developed the
Both highly portable air sampling devices originate from a range of research projects ("Iso-Drone") with academic partners and are fully lab tested. See Leitner et al. (2023) (https://doi.org/10.5194/amt-16-513-2023) for details on both VSI air autosamplers adapted to UAVs.
The VSI AS-100 Multiple Vial Whole Air Sampler and AS-110 Multiple Sorbent Tube Sampler for laboratory and field use allow sampling from up to 12 vials (20 ml) or sorbent tubes.
To take air sampling to "new heights", have a look at our UAV air samplers. They have been modified to be mounted and operated on unmanned aerial vehicles.
AS-100 Whole Air Vial Sampler Lab. The VSI AS-100 air sampler is both lab and field operable (12V) for highest versatility in a large range of experimental settings. For example, the whole air sampler system is mountable on (eddy flux) towers, in tree canopies and on the ground (e.g. attached to soil sampling rings). Automatic sampling can be triggered according to a predefined time schedule for 24/7 measurements, or sampling can be triggered remotely - avoiding e.g. contamination by exhaled human breath. With the systems, air samples are stored in 12 pre-evacuated, vacuum vials for later routine analyses of gas composition (with a gas chromatograph, mass spectrometer). Sample collection from the immediate vicinity occurs via needle puncture through a septum, minimising contamination. Optional, a ventilation system for circulating air over longer distances, thus allowing for several sampling points at distance to the device, can be added. The suitability of the sampling system to measure e.g. isotopic signatures at relevant concentration of CO2 in ambient air samples has been confirmed. Our whole air samplers are easy to use and require minimal training.
An automatic vial evacuator (VSI EV-101) to evacuate/reuse vials (incl. e.g. helium flushing and a strong vacuum pump) is available as option, allowing to easily prepare vacuum tubes both in the lab (220V) and the field (12V).
AS-101 Sorbent Tube Sampler Lab. At the current configuration, the VSI AS-101 sorbent tube air sampler (weight: c. 1100 g) for laboratory and field measurements (12 V) can be loaded with four sorbent tubes. The sampler can be factory modified to hold at least 12 sorbent tubes (depending on total inflow air required). The sample gas inlet can be set with a manually adjustable pinch valve and adjusted to the sorbent tubes installed (e.g. 50 mL min-1). All tubing is made out of 4 or 6-mm PTFE, and tube connections out of polyethylene terephthalate (PET) or metal. Passing the restriction valve at the sampler inlet, the gas flow is split in two and forwarded to the two inlet ports of an electric four-port gas distribution manifold. The gas manifold enables switching between different sampling modes, either
The sorbent tubes are fitted to the outlets of the gas manifold using straight push-in fittings. At the outlet of the sorbent tubes, the gas flow is divided into two streams. Each stream then passes through a flow sensor, which records the actual flow rate. Finally, the gas streams are combined and directed to the suction pump. To circumvent the unregulated suction pressure of the pump, a T-piece is installed upstream of the pump inlet to equalise the different flow rates set on the gas inlet restriction valve. This effectively eliminates the exposure to pressure differentials that can lead to altered flow readings, the development of leaks and overuse of sampler components. The AS-101 Sorbent Tube Air Sampler can be fitted with a wide range of different sorbent tubes for different air sampling purposes (see below for sorbents) such as volatile emissions (especially for sesquiterpene and monoterpene sampling), pollen and particulate matter (PM2.5, PM10) concentrations (see below for applications).
The VSI AS-101 Sorbent Tube Sampler for laboratory and field use is equipped with a memory card that records the actual flow rate, temperature, air pressure, humidity, activated sample port number and time over the sampling event. The sampler can be triggered
The AS-101 is powered by 12V DC and can be fully used in the field (on batteries), and in the laboratory on a 110-230V mains supply. The automatic sorbent tube sampler is easy to use and requires minimal training for achieving accurate sampling.
Overall, automatic whole air samplers are an important tool for atmospheric research, allowing accurate, quantitative and long-term sampling of multiple gases in a variety of locations. Related applications include climate change and environmental research, air quality monitoring, and atmospheric chemistry studies.
For example, collected whole air samples can be easily analysed with our gas analysers in "injection mode", where the small gas aliquot to be analysed is injected into a carrier gas stream with a syringe or similar device for subsequent gas analysis. The example is for CO2.
Overall, automatic sorbent tube samplers are an important emerging tool for monitoring air quality and investigating indoor and outdoor air pollution. They are highly sensitive, provide time-integrated sampling (of different time periods), preserve sample integrity, and are versatile and easy to use. Automated sorbent tube samplers can be used for a variety of applications, including occupational health and safety assessments, industrial hygiene and indoor air quality investigations, and environmental and plant research. See below for a brief overview on sorbent tubes types supporting different applications.
Sorbent tubes are the most widely used collection media for sampling hazardous gases and vapors in air in research and environmental monitoring settings but also civil and military gas defense strategies. Sorbent Tubes are available from multiple manufacturers incl. CARO Analytical Services, SKC Inc., 7Solutions BV, Uniphos Ltd., SKC Ltd, Zefon International, Sigma-Aldrich/Supelco and Markes International, or can be custom-made by individual laboratories. The sorbent in the tubes can hold various types of sampling media, onto which the volatile substance / contaminant is collected by passing air through the sorbent tubes. The VSI Sorbent Air Sampler AS-101 for laboratory and field use fits most common sorbent tube dimensions (diameter and length) on the market, however, please discuss specific needs (very long tubes, very high flow rates, etc.) with the engineers at Vienna Scientific.
Classical sorbent tubes hold e.g. the following material:
In addition, many other sorbents have been used in sorbent tube samplers, including carbon beads, drying tubes, firebrick sorbent, florisil sorbent, molecular sieve sorbent, oxidiser sorbent, soda lime sorbent, and volatile organic sampling traps. Sorbent tubes are attached to a pump or air sampler with a calibrated flow rate for sample collection. Automatic air samplers, such as the VSI AS-101, for sorbent tubes have the advantage of being able to set up sampling schedules or take technical replicates compared to traditional permanently running pump systems.
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