www . AmericanSecurityToday . com 2022 CHAMPIONS - Edition 66
and diethyl methyl phospho- nate ( DEMP ).
Vapor buildup was relatively quick in a span of 100 minutes and the next set of measure- ments were done later which showed a clear decrease of concentration inside the con- tainer .
DPGME concentration contin- ued to decrease over time but still the vapor was detect- ed even after approximately 26.7hours .
DEMP concentration re- mained steady but started to decrease after roughly 20 hours of incubation or soak time .
Modeling the evaporation of DPGME based on its vapor pressure at inside container temperature produced rough- ly 2.4ng / sec evaporation rate into a container volume of 33m3 at different times .
For example , after 2 hours , con- centration buildup inside the container would be roughly 0.5ng / L , assuming no losses to the walls and surrounding sur- faces .
The signal obtained after 2 hours was 299dc or the equiv- alent of 10ng ( see calibration curve ). The sampling flow rate was at 100L / min , and sampling done in 1 minute with a collection efficiency of approximate- ly 10 % would mean the vapor concentration of DPGME at roughly 1ng / L , which is in close agreement with the predicted
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