Some American university governors welcoming head of academy employed in the science laboratory (8)
I believe the answer is:
reagents
'head of academy employed in the science laboratory' is the definition.
I can't judge whether this definition defines the answer.
'some american university governors welcoming' is the wordplay.
'some american university' becomes 'a' (I can't justify this - if you can you should give a lot more credence to this answer).
'governors' becomes 'regents' (I've seen this in another clue).
'welcoming' is an insertion indicator.
'a' inserted into 'regents' is 'REAGENTS'.
Can you help me to learn more?
(Other definitions for reagents that I've seen before include "Laboratory chemicals used in analyses" , "They produce chemical reactions in sergeant" , "Chemicals used in analysis or reactions" , "Chemicals for testing" , "Chemical substances" .)