Try piece of rigatoni as part of experiment (4,4)
I believe the answer is:
test tube
'experiment' is the definition.
(I've seen this before)
'try piece of rigatoni as' is the wordplay.
I cannot quite see how this works, but
'try' could be 'test' (synonyms) and 'test' is found in the answer.
'piece' could be 'tube' (tube is a kind of piece) and 'tube' is located in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
'part of' acts as a link.
Can you help me to learn more?
(Other definitions for test tube that I've seen before include "Hollow cylinder for the laboratory" , "Glass item in lab" , "Scientist's cylindrical glass" , "Lab vessel" , "Experimental glassware" .)