High-performance liquid chromatographic assay of carbenicillin, ticarcillin and sulbenicillin in serum and urine using pre-column reaction with 1,2,4-triazole and mercury(II) chloride

Abstract

A high-performance liquid chromatographic method has been developed for the assays of carbenicillin (CBPC), ticarcillin (TIPC) and sulbenicillin (SBPC) in serum and urine. These penicillins were reacted with 2 M 1,2,4-triazole and 10^–3M mercury(II) chloride in solution (pH 9.0) at 60 °C for 10 min. The resulting products were separated on a C₁₈ column using a mobile phase containing tetrabutylammonium bromide and sodium thiosulphate, and were detected at between 327 and 331 nm. The method has been applied to the assays of these penicillins in serum and urine samples, which were ultra-filtered with a YMT membrane, or filtered with an acrylate copolymer membrane. The procedure permits the accurate determination of penicillin concentrations in serum down to 0.05 µg ml^–1 for SBPC and 0.1 µg ml^–1 for CBPC and TIPC, and is specific to intact penicillins without interference from corresponding penicilloic acids.