General Extraction Protocol: Ion Exchange

• Rinse packing bed with 5 mL deionized water or low-ionic strength buffer.

• Apply sample solution to the top of the packing bed. Push or draw through the bed at 1 - 2 mL/min. Collect sample for analysis if desired compound has passed through the bed without being retained.

• If desired compound was retained, wash off weakly retained interfering compounds with deionized water or low-strength buffer.

• Elute analyte with 1 - 5 mL of a high salt concentration solution, or change elution buffer pH so analyte is no longer ionized.