In article <rose.486.3056EFC4 at alf1.ngate.uni-regensburg.de>,
rose at alf1.ngate.uni-regensburg.de (Andreas Rose t3077) says:
>>I study the host-finding of a blood-sucking bug (Reduviidae -
>I want to collect odors from the headspace of a sleeping person and see
>whether these are attractive in a behavioral test.
>>For the collection of the odors, I want to construct a cold trap.
A dry ice-acetone trap should do the job. I would not use liquid
nitrogen because it is cold enough to condense a trap full of
liquid oxygen and solid CO2.