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 resi ns were arranged in varying sequences, which proved to be critical for determining the efficiency of DOC isolation. The sequence XAD7/2/4 al lowed the isolation of a very high percentage of DOC (65%) from the se awater matrix. A mixed bed of the same resins showed a significantly l ower recovery (39%). Varying amounts of the material adsorbed by the i ndividual 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.