HPLC-MS/MS Determination of Trace Amount of Celastrol in Urine After Purification with Solid-Phase Extraction

A method for the determination of celastrol in urine by high-performance liquid chromatography hyphenated with tandem mass spectrometry (HPLC-MS/MS) was proposed. Celastrol in samples was enriched and purified on Waters Oasis HLB SPE column. The eluate was used for HPLC-MS/MS determination,in which the XDB C18 reserved-phase column (150 mm×4.6 mm,5 μm) was used as chromatographic column,and a mixture of 0.5 g·L-1 acetic acid solution and acetonitrile (25+75) was used as mobile phase. Hydrocortisone was used as internal standard. Abnospheric pressure chemical ionization source with negative ionization mode as well as multiple reaction monitoring mode was used in the detection. Ion pairs used for the quantitative analysis were m/z 449/405 for celastrol and m/z 419/329 for internal standard. Linearity range was found between 0.2-50.0 μg·L-1,and the detection limit (3S/N) found was 0.07 μg·L-1. Values of RSD′s of intra-day (n=6) and inter-day (n=15) found were less than 9.3% and 11.4%,respectively.