SPOT SAMPLER
Aerosol Particle Collector
What it does:
The Spot Sampler captures fine and ultrafine particles in a concentrated manner for easy, off-line analysis. Its moderated condensational technology enlarges particles without temperature extremes, making it ideal for volatile or biological applications.
Features:
Centerline saturation ratios reach 1.4 while maintaining temperatures below 25°C.
Dry sample deposits measure just over 1 mm in diameter.
High collection efficiency down to <8nm, with no particle bounce
How It Works:
Aerosol is sampled through a wet walled tube, the middle section of which is warm
In the first, Conditioner section, the flow is cooled and humidified.
In the warm-walled Initiator section, water evaporates from the wet walls faster than the flow warms. The flow becomes supersaturated, initiating the condensational growth of particles >5nm.
In the final, Moderator section, heat and water vapor are removed from the flow while maintaining supersaturated conditions that allow continued growth to form ~3µm droplets.
The droplets are collected by impaction, and warmed to make a concentrated, dry spot. Collection into liquid is also possible.
Extraction by the autosampler
Samples are collected as a sequence of ~1-mm diameter dry spots on a multiwall plate. Upon return to the laboratory, the plate is placed on an auto-sampler which handles all the sample extraction and HPLC or IC injection. Concentrated spots are also amenable to many analytical approaches, such as nano-DESI and LIBS, etc.
Dotted lines are for high particle concentration.
Collection efficiency
Twice-daily nitrate, sulfate and PAHs in Stockton, CA
