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MIP with Purge and Trap:
Analytical sampling with MIP can be enhanced by
incorporating a second component to include a gas chromatograph for
separation, identification, and quantification. Prior to the MIP
carrier gas line entering the PID/ECD detectors, a valve is used to
split the carrier gas with half going to the detectors and half
going into a trap containing Tenax material. The trap sorbs VOCs which effectively concentrates the contaminates. Changing
the trap at known intervals and for set times allows a more complete
analysis to be accomplished by thermally desorbing the VOCs directly
into the gas chromatograph. This new approach to direct vapor sensing
significantly increases
system sensitivity and provides more information for the identification of
VOCs.
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