Specifications of glutaraldehyde are:
OCHCH2CH2CH2CHO F.W. 100.12 CAS #111-30-8
Specific gravity @20/20°C: 1.131
EM grade aqueous glutaraldehyde if stored in volume greater than 100ml, with repeated defrosting and recapping will polymerize in time. This reduces the absorption peak from 280nm to 235nm. Presence of polymers reduces the efficiency of Glutaraldehyde as a cross-linking agent preventing proper fixation.