Complex sentence: EGTA (ethylene glycol tetraacetic acid) is a polyamino carboxylic acid, a chelating agent that is related to the better known EDTA, but has a lower affinity for magnesium compared to EDTA, making it more selective for calcium ions.
Split into simpler sentences: EGTA (ethylene glycol tetraacetic acid) is an aminopolycarboxylic acid, a chelating agent. Compared to EDTA, it has a lower affinity for magnesium, making it more selective for calcium ions.