EXTRACTION OF MARINE ORGANIC-MATTER ON XAD-2 - EFFECT OF SAMPLE ACIDIFICATION AND DEVELOPMENT OF AN IN-SITU PRE-ACIDIFICATION TECHNIQUE

Dissolved organic materials in seawater were extracted on XAD-2 from b oth acidified and non-acidified samples. Nearly three times as much ma terial is extracted by acidification. The material extracted is chemic ally distinct from that extracted without acidification. Chelex-100 io n exchange resin was used as a solid phase pre-acidification device fo r organic matter extraction on XAD in situ. The compounds extracted on XAD using this means of pre-acidification are similar to those extrac ted using HCl as the pre-acidifier. The similar extraction efficiency and chemical nature of compounds separated using the traditional pre-a cidification technique and the Chelex-100 system suggests that the cat ion exchange technique may be a promising means of in situ acidificati on of seawater with subsequent extraction of humic materials on XAD.