Sensitive flow-injection method with peroxyoxalate chemiluminescence detection combined with preparative high-performance liquid chromatography for determination of choline-containing phospholipids in human serum.

A sensitive and rapid flow-injection analysis (FIA) of total choline-containing phospholipids (PLs) and a selective FIA method for the class assay of choline-containing PLs combined with preparative HPLC were described. The FIA method is based on peroxyoxalate chemiluminescence (PO-CL) detection of hydrogen peroxide enzymatically formed from choline-containing PL. The linear standard curves were obtained up to 1 nmol/20-microliters injection (r > 0.999) with the detection limits of 1.3-1.6 pmol at a signal-to-noise ratio of 2. The total amounts of choline-containing PLs in human serum were ranged from 1.63 to 3.19 mg/ml. The HPLC separation of choline-containing PLs was achieved with an aminopropyl-modified silica gel column using a mixture of acetonitrile-methanol-10 mM ammonium phosphate buffer pH 5.8 as eluent. The eluate corresponding to each choline-containing PL was collected, evaporated, dissolved in 0.1% Triton X-100 aqueous solution, and then injected into FIA system. The FIA method combined with preparative HPLC was applied to the assay of human serum.