70539-42-3 Butanoic acid, 4-((2,5-dioxo-1-pyrrolidinyl)oxy)-4-oxo-, 1,2-ethanediyl ester EGBSS Ethylene glycol bis(succinimidyl succinate) Ethylene glycolyl bis(succinimidylsuccinate) ethylene glycolylbis(succinimidyl succinate)