High-performance liquid chromatographic assay of ampicillin in plasma and broncho-alveolar lavage fluid,using fluorescence detection

Summary A high performance liquid chromatographic analysis of ampicillin in plasma and broncho-alveolar lavage fluid, using amoxicillin as internal standard, is described. The samples are deproteinated with trichloroacetic acid. For both ampicillin and amoxicillin, a fluorescent degradation product is formed in the presence of mercury(II)-chloride, after alkaline degradation and acid hydrolysis. Chromatography is done on a Spherisorb 5 ODS column using methanol-water (6040) with Pic^RB-7 (1-heptane sulphonic acid) as mobile phase and fluorescence detection (Ext 345 nm, Em 425 nm). Calibration curves for ampicillin were linear over the concentration range 1–100 g/ml in 100 l plasma samples and over the concentration range 20–2000 ng/ml in 0.5 ml samples of broncho-alveolar lavage fluid.Quantitative analyses with relative standard deviations of less than 10% are achieved.Presented at the 17th International Symposium on Chromatography, September 25–30, 1988, Vienna, Austria.