Graduate finds sodium repeatedly in fruit (6)
I believe the answer is:
banana
'fruit' is the definition.
(type of fruit)
'graduate finds sodium repeatedly' is the wordplay.
'sodium repeatedly' can mean two substitutions for 'sodium'.
'graduate' becomes 'ba' (someone with a Bachelor of Arts degree).
'finds' means one lot of letters go next to another.
'sodium' becomes 'NA' (chemical symbol).
'sodium' becomes 'NA' (chemical symbol).
'ba'+'na'+'na'='BANANA'
'in' acts as a link.
(Other definitions for banana that I've seen before include "Fruit grown in hands" , "6 Yellow fruit" , "plant" , "Another of 5 down" , "Fruity type" .)