GTP hydrolysis assay - please help me pass my qualifying exam!!! (Feb/21/2007 )

Please help with my silly question. Is there a good way to determine the rate of hydrolysis besides using P32 release from purified proteins. I don't work with GTPases or protein interactions in general and am really stuck please give me a hand!

you can determine phosphate release with a non-radioactive phosphate determination like: chen, marsh (micromarsh), fiske-subarow (sp?). you don't have to use a radioactive method.