I think thats a great idea. Players would have to think about that things in advance.
Morover - I think the battery must be recharged from time to time, like the drill.
EDIT:
I think that players should decide themselves whether they want to use
Porta-LIBS in the field or to take a
sample container instead.
Using PLIBS has an obvious advantages if you want to pinpoint exact location of the resource or when you explore far away from the base.
Taking sample container would be better if you make wide field study (for instance - you wish to map geologicaly the entire map). You just save the samples for later, and then use the HUB's normal-LIBS to determine they'r composition one-by-one.