Hello, I've seen and read alot about SPE columns as sample prep, but I'm not sure what it can do for me. I'm in the nutrition/supplement business, and not sure how this can help, say in a multivitamin tablet. What does SPE do exactly? Thanks all.

That's a pretty broad question, but I"ll take a general stab at it:

SPE as the acronym implies, is most often used for removing components from a simple which might otherwise contaminate your column or at least compromise your analysis. For example, in a multivitamin tablet you might find some of the components in the tablet formulation which are highly retained on your column and could potentially require an extensive wash with elevated solvent levels to remove this component from your column. Passing the sample solution over a SPE column can simply and effectively remove highly retained components while allowing your analytes to pass really through the SPE column (assuming you have arrange your sample composition appropriately). Alternatively, you might have some unretained components which interfere with the early part of your analysis. In this case, you could pass your sample solution through the SPE column under conditions where your analyte is retained on the SPE column and highly polar contaminants would pass through unretained. Afterward, you can elute your analytes from the SPE column with an eluent containing a higher solvent content.

The foregoing, of course, are just examples using a reversed phase SPE column but analogous applications have been developed for a variety of different situations using all types of different phases. Of course, covering this in more detail here is impractical but there are several good books on this topic and Waters has a very good handbook on the topic as well.

Thanks for your comments, I'll go to Waters. I think SPE is really a necessary thing for us. Especially for the analysis of herbs and tablets containing minerals. Thanks again.