It's possible that your sample is washing the analyte out of the SPE cartridge. If you need a larger sample to drive down your detection limits, there are techniques to coax your analyte to "stick" to the substrate a little better. Sometimes the addition of a little acetic or formic acid to the sample will help, it depends on what you're analyzing for. Or you could try a different type of cartridge. A phone call to a Supleco or Waters sales rep could help; they're generous with samples.
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Topic: Recovery from SPE method (Read 3979 times)