Application of totally automated on-line sample clean up system for extraction and high-performance liquid...

We have developed a fully automated on-line extraction-purification method for peptide leukotrienes in biological fluids using a column-switching technique. Individual leukotrienes in HPLC-collected fractions are determined by immunoassay techniques. Leukotrienes were extracted from nasal lavage samples and eluted from the solid-phase extraction cartridge into the HPLC column with methanol-ammonium acetate buffer (60:40, v/v) pH 5.4, as a mobile phase. This method provides good recoveries, excellent resolution of leukotrienes and is suitable to be combined with off-line radioimmunoassay (RIA) or enzymoimmunoassay (EIA). The most important losses are observed after evaporation-concentration and lyophilization. We also have compared RIA with EIA determination. Significant differences are found between RIA values and EIA values.