Automated high-performance liquid chromatographic determination of plasma free fatty acids using on-line derivatization with 9-bromomethylacridine based on micellar phase-transfer catalysis.

The on-line use of micellar phase-transfer catalysis is described for the automated reversed-phase high-performance liquid chromatographic (RP-HPLC) determination of free fatty acids in plasma; minimum manual sample handling is involved. After diluting plasma ten-fold with the aqueous micellar system, which contains 25 mM of the non-ionic surfactant, Arkopal N-130 and 6 mM of the ion-pair agent tetrakis(decyl)ammonium bromide, the reaction of the fatty acids with the fluorophore 9-bromomethylacridine is complete within 5 min at 60 degrees C. Prior to RP-HPLC separation, interfering proteins are removed using an on-line filter and a column-switching unit. More than 100 samples can be injected onto a single pre-column. The detection limit is ca. 300 nM; the precision is better than 3% using an internal standard.