Analysis of 11-dehydrothromboxane B2 in human urine improved by use of gas chromatography/high-resolution selected ion monitoring with18O2-labelled analogue as an internal standard

Abstract

Gas chromatography/high-resolution selected ion monitoring (GC/HR-SIM) for the determination of 11-dehydrothromboxane B2 (11-dehydro-TXB2) in human urine is described. Combined use of the lactone ring opening reaction and dimethylisopropylsilylation has been adopted for the analysis of 11-dehydro-TXB2, to give a new chemically stable derivative. The feasibility of using this derivative for the analysis of 11-dehydro-TXB2 in human urine has been evaluated. Following the addition of 18O2-labelled analogue, for use as an internal standard, the samples were extracted using chromatographic separation with Bond Elut C18 and silica gel. Derivatization of the extracted 11-dehydro-TXB2 was followed by GC/SIM at resolution of 5000. This method enables selective detection of 11-dehydro-TXB2 in human urine without serious interference from other endogenous substances. In 11 volunteers, the mean urinary excretions of 11-dehydro-TXB2 was 547.6 +/- 217.6 ng per day.