I am planning on using a pretty low-tech protocol for collecting emitted plant volatiles in the field, and I want to use PET bags to enclose my target plants, as is usual. However, I can't ascertain from the literature whether or not these PET enclosures are reusable. I need to do a fair amount of sampling and I don't want to have to use an inordinate amount of the stuff, although, obviously if the material becomes contaminated with bVOCs, that's a clearly a huge issue.
Does anyone know what kind of affinity different bVOCs have for PET, or if PET can be 'cleaned' of VOCs after use?
I would really, really appreciate the benefit of some solid technical experience, so please pitch in!
I have to say, I am not sure if PET bags may hold some residuals after used or if it is possible to clean them with methanol and water afterward to eliminate remnants. However, I could suggest having a look into PDMS tubes for volatile collection, see Article A robust, simple, high-throughput technique for time-resolve...
. It is a relatively cheap alternative. Cheers
PET is probably not a good choice. It is not dishwashing machine safe, breaking down in hot water and under moderately high water jet stress, releasing plasticizers and polymer fragments. Methanol would add a harsher chemical level of treatment that the PET might not survive, at least over time. You may only use cold or warm water in your cleaning procedure, not very hot water as found in dishwashing machines, but I suspect that methanol would still cause problems, as would warm water over time. This is not a definitive answer but is based on how commercial PET water bottles behave in a home environment (this is why bottled water containers should not be cleaned in dishwashers). Check with the PET plastic bag manufacturer for more information about durability. Best wishes!
Sure, your bags will get contaminated. Like all plastics, PET can absorb volatiles. But it is also true that these volatile substances can be removed. To do this, you can use the vacuum of an oil pump (~ 0.001-0.0003 Torr) and a moderate heating (60-80oC). The time is usually about an hour is enough even for relatively thick products (several mm). But you can’t pack your bags tightly, because in narrow holes the air flows slowly and vacuum is slowly established.
Thanks everyone for your detailed and considered responses, I will continue to look for a material to enclose my tree branches in, that is hopefully not to 'attractive' to VOCs, or that can be easily cleaned of said VOCs, so any ideas gratefully received!
I really, really don't want to use reams and reams of single use plastic!!
Hi Laura,
You may have already found a solution, but if not, it is common to use oven bags to sample tree (and other plant) VOCs. They are typically made from nylon, which is quite inert and can withstand cleaning much better than PET bags. I hope this helps!
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