grignard degradation at one time was a tool in structure identification (elucidation) in which a grignard rmgbr formed from a heteroaryl bromide hetbr reacts with water to het-h (bromine replaced by a hydrogen atom) and mgbroh. this hydrolysis method allows the determination of the number of halogen atoms in an organic compound. in modern usage, grignard degradation is used in the chemical analysis of certain triacylglycerols.