Advantages of Canisters Over Tubes

Canisters Tubes
Preconcentrator Performed Under Controlled Conditions Yes No
Traps Checked for Blank and Analyte Recovery Yes No
Allow Repeat Analyses Yes No
Chance for Post Cleaning Contamination Minor Yes
Permits Sample Screening Yes No
Allows Mild Trapping/Desorption Conditions to Maximum Yes No
Requires Power for Sampling No Yes(?)
Long Integrated Sampling Times Yes No
Tailoring of Sample Size After Collection Yes No
Recovery Effects After Exposure to Ozone, NOx, SOx Minor ?
Analysis of Reactive Compounds (Sulfur, etc.) Yes No

Advantages of Canisters Over Bags

Canisters Tubes
Holding Time in Weeks, Not Hours Yes No
Usable to Part Per Trillion Levels Yes No
Shippable by Air Yes No
Totally Impermeable to VOC’s Yes No
Field Sampling Performed without Power Yes No
Prevents Photolytic Reactions Yes No
Capable of Storing H2S and Mercaptants Yes No