ALUMINA CLEANUP

2.1 This method describes procedures for alumina cleanup of solvent extracts of environmental samples. It provides the option of using either traditional column chromatography techniques or solid-phase extraction cartridges. Generally, the traditional column chromatography technique uses larger amounts of adsorbent and, therefore, has a greater cleanup capacity. 2.2 In the column cleanup protocol, the column is packed with the appropriate amount of adsorbent, topped with a water adsorbent, and then loaded with the sample extract. Elution of the analytes is effected with a suitable solvent(s), leaving the interfering compounds on the column. The eluate may be further concentrated prior to gas chromatographic analysis. 2.3 The cartridge cleanup procedure uses solid-phase extraction cartridges containing 40 µm particles of alumina (60 D pores). Each cartridge is washed with solvent immediately prior to use. The sample extract is loaded onto the cartridge which is then eluted with suitable solvent(s). A vacuum manifold is needed to obtain reproducible results. The eluate may be further concentrated prior to gas chromatographic analysis. 2.4 The phthalate esters may be considered either the analytes of interest or the interferants, depending on which eluant fraction is analyzed.