Liquid chromatography sample recovery from columns

The second method uses preconcentration to increase the analyte concentration in the absorption solution to detectable levels prior to analysis. One example is the use of solid-phase extraction with an anion exchange column as a pretreatment technique to remove interference from the sample matrix and to enhance the detection sensitivity prior to determination of the concentrated iodide anion through reversed phase high-performance liquid chromatography (HPLC) using an ultraviolet (UV) detector. The results show more than 90% recovery and good reproducibility for the determination of trace iodine in iodine-enriched eggs. 

Despite these applications, disadvantages such as requirement of large sample amounts may restrict the use of TLC compared to column methods because such amounts are not always available. On the other hand, recovery of the antioxidant from TLC plates could also be challenging. In this sense, most TLC applications are restricted to the fractionation and preliminary separation of antioxidant flavonoids before they are separated, quantified, and identified by high-performance liquid chromatography (HPLC) or other high-performance separation techniques. 

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