Determination of the glucocorticoids prednisone, prednisolone, dexamethasone, and cortisol in human serum using liquid chromatography coupled to tandem mass spectrometry

Simultaneous determination of cortisol, dexamethasone, methylprednisolone, prednisone, prednisolone, mycophenolic acid and mycophenolic acid glucuronide in human plasma utilizing liquid chromatography–tandem mass spectrometry

“…Previous comparison of the positive and negative ionization modes for corticosteroids indicated that negative ionization produced better signal-tonoise ratio and a reduced number of fragments. This is in agreement with other published literature [16,30]. Collisioninduced dissociation with nitrogen gas produced fragments that MPA and MPAG.…”

Determination of prednisolone in human adipose tissue incubation medium using LC–MS/MS to support the measurement of 11β-hydroxysteroid dehydrogenase activity☆

“…In a comparison using neat solution, it was observed that negative ionization produced less fragmentation than positive ionization for both prednisolone and d4-cortisol (Figs. 2 and 3), which was in agreement with previous reports [18][19][20]. However, positive ion mode produced a much better signal-to-noise ratio (S/N) than negative ion mode when both were optimized for the glucocorticoids.…”

Critical Review of Development, Validation, and Transfer for High Throughput Bioanalytical LC-MS/MS Methods

“…Huang et al used LC-UV to detect the down-field matrix peaks that caused ion suppression for the analyte of interest and modified the chromatographic condition [113]. Another approach for assessing consistent matrix effect among the individual matrix lots is to measure the consistency for the results obtained from sample from individual matrix lot (typically n > 6) [114][115][116][117][118][119][120][121][122][123]. One could argue that as long as the results (both back-calculated concentration and MS response) are consistent among the tested lots, matrix effects would not likely contribute negatively to the quantitation.…”