A comparative solid-phase extraction study for the simultaneous determination of fluoxetine, amitriptyline, nortriptyline, trimipramine, maprotiline, clomipramine, and trazodone in whole blood by capillary gas-liquid chromatography with nitrogen-phosphorus detection.

This paper reports the simultaneous detection of the seven antidepressants fluoxetine, amitriptyline, nortriptyline, trimipramine, maprotiline, clomipramine, and trazodone in whole blood at concentration levels of 100-2000 ng/mL by gas chromatography with a nitrogen-phosphorus detector (GC-NPD). A comparative and validation study using two solid-phase extraction (SPE) columns, Chem Elut and Bond Elut Certify, were developed regarding their recovery, precision, sensitivity, and matrix purification efficiency. The Chem Elut columns, a diatomaceous earth, are closely related to conventional liquid-liquid extraction. The Bond Elut Certify columns, more recently developed in the market, are a mixed SPE: reversed-phase and cation exchange sorbent. Recoveries of the compounds using Chem Elut columns at 500 ng/mL were in the range 30-50%, with intra- and interassay precisions of less than 9% and 17%, respectively. Limits of detection (LODs) and quantitation (LOQs) ranged from 13 to 146 ng/mL and from 44 to 485 ng/mL, respectively. Recoveries of the compounds using Bond Elut Certify columns at 500 ng/mL were in the range 59-84% with intra- and interassay precisions of less than 8% and 11%, respectively. LODs and LOQs ranged from 8 to 67 ng/mL and from 25 to 223 ng/mL, respectively. An excellent linearity was observed with both extraction procedures from the LOQs up to 2000 ng/mL. Higher recoveries, cleaner extracts, better sensitivity, better precision, and less solvent consumption and disposal were achieved for the screening of these antidepressants with the use of the mixed SPE Bond Elut Certify compared with Chem Elut columns.