Many strong cation exchanger are being used, such as Bio-Rad AGMP-50, Chelex-100, Amberlite IR-120, and Amberjet 1200H Plus, for purification purpose of fulvic acids and DOM before freeze-drying.

Do you know which is the best in terms of both desalination efficiency and DOM recovery? Contamination from the resin should also be minimized.

Or do you have any suggested papers that investigated it?

For example, Miles et al (1983) Anal. chem. states that %recovery was >95% using Chelex-100, but many others don't give any details about recovery.

Thanks