In order to extract DNA from blood on FTA cards, Chelex-100 (BioRad) and FTA purification reagent (Whatman) seem to be the simplest, easiest, and, importantly, best-performing methods. I would appreciate a recommendation.

I found info on the principle of action of Chelex 100, but couldnot find any such information for the Whatman reagent. If anybody knows, please share your knowledge. Any responders, Thank you in advance.