| CPC G01N 1/405 (2013.01) [B01D 15/327 (2013.01); B01D 15/362 (2013.01); B01D 15/3847 (2013.01); B01D 15/426 (2013.01); B01J 39/05 (2017.01); B01J 39/26 (2013.01); G01N 33/92 (2013.01); G01N 2030/009 (2013.01); G01N 2030/062 (2013.01); G01N 2405/00 (2013.01)] | 10 Claims |

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1. A method of performing a sample enrichment procedure, the method consisting of:
(a) adding a sample fluid that comprises at least one phospholipid and at least one target analyte to an ammonium-modified sorbent comprising a hydrophobic component and a cation exchange component, wherein the cation exchange component comprises sulfonate groups and the cation of the cation exchange component is ammonium (NH4+), thereby resulting in the ammonium-modified sorbent adsorbed with phospholipid and adsorbed with target analyte;
(b) adding an organic solution consisting of a first organic solvent species to the ammonium-modified sorbent thereby desorbing at least a portion of the phospholipid from the ammonium-modified sorbent; and
(c) adding an elution solution consisting of a basic compound or salt species and a second organic solvent species to the ammonium-modified sorbent, thereby desorbing at least a portion of the target analyte from the ammonium-modified sorbent and forming a solution of the target analyte in the elution solution.
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