Hey
Yeah you can do that
I chuck 6 Massive scoops of Whey in a blender, (amounts to 150 GM Protein) and blend with water.
Put it ALL in a 2 Litre bottle, leave it in the refridgerator over nite then you be ok for around 8-10 hours
I take mine out at 8am prior to work, and take my last swig from the bottle at about 430pm and its all good to go