Aside from standard quantifiers(some, much, a bit, a little), I'm not sure of what partitive I would use for time. "A bit of time" is certainly acceptable but not "a pinch of time."
The only thing I can think of would be to say "A length of time.", though calling this a partitive would definitely be a stretch.
"We will be away from each other for only a short length of time."
Partiality in English is easily shown through our quantifiers and adjectives because we don't really have a robust count-word system or partitive case.
Hope this helps :)