Effective desorption of humic substances from amberlite XAD-2 resin with sodium dodecyl sulfate

The adsorption and desorption of humic and fulvic acids on a non-ionic macroreticular resin, Amberlite XAD-2, were studied from the view point of the concentration of aquatic humic substances. Microgram: or milligram quantities of humic and fulvic acids were collected on a small column of pulverized XAD-2 (16 mm in diam.x5 mm height) and then desorbed with 10 cm(3) of 0.1 mol dm(-3) sodium hydroxide solution containing 200 mg of sodium dodecyl sulfate (SDS). The resulting humic solution contained appreciable amounts of SDS (ca. 100 mg), which were removed by introducing the solution onto another XAD-2 column (7 mm in diam.x60 mm height, unpulverized resin). The SDS was completely retained on the resin because of the strong affinity, even in an alkaline solution, whereas nearly all humic substances were passed through the column. The validity of the proposed separation method was evaluated by using synthetic sample solutions.