ISOLATION OF MARINE DISSOLVED ORGANIC-MATTER - EVALUATION OF SEQUENTIAL COMBINATIONS OF XAD RESIN-2, RESIN-4, AND RESIN-7

The sorptive behavior of resins XAD2, -4, and -7 for dissolved organic carbon (DOC) derived from marine phytoplankton was compared. The resins were arranged in varying sequences, which proved to be critical for determining the efficiency of DOC isolation. The sequence XAD7/2/4 allowed the isolation of a very high percentage of DOC (65%) from the seawater matrix. A mixed bed of the same resins showed a significantly lower recovery (39%). Varying amounts of the material adsorbed by the individual resins could not be recovered by NaOH/methanol elution. The percentage of DOC firmly retained by each resin was 32, 21, and 2% in XAD2, XAD4, and XAD7, respectively.