Patent ID: 8748194

Claim:
A method for extracting an analyte, comprising: a. providing a low dead volume extraction column, wherein the low dead volume extraction column is comprised of i) a column body having an open upper end for attachment to a pump, an open lower end for passing fluid into and out of the column body, and an open channel between the upper and lower end of the column body, wherein the column body comprises a pipette tip, ii) a bottom frit bonded to and extending across the open channel, the bottom frit having a pore volume, iii) a top frit bonded to and extending across the open channel between the bottom frit and the open upper end of the column body, the top frit having a pore volume, wherein the top frit or bottom frit are less than 350 microns thick, wherein the bottom frit is a membrane screen and the top frit is optionally a membrane screen and wherein the top frit or the bottom frit is comprised of nylon, polyester, polyamide, polycarbonate, cellulose, polyethylene, nitrocellulose, cellulose acetate, or polypropylene, and wherein the top frit, bottom frit, and channel surface define an extraction media chamber, and iv) a bed of extraction media positioned inside the extraction media chamber; b. passing a sample solution through the low dead volume extraction column; and c. passing a desorption solvent through the low dead volume extraction column.