Mass spectrometric method for distinguishing isomers of dexamethasone via fragment mass ratio: An HRMS approach

Abstract

The major challenge in identifying dexamethasone, betamethasone, and paramethasone from a mixture of these corticosteroids is difficulty in achieving an efficient separation. In this study, we aimed to develop an efficient technique to identify these co-eluting isomers based on the mass spectral patterns of them and their corresponding phase II metabolites after electrospray ionization. Fragmentation pathways in tandem mass spectrometry revealed acceptable specificity within the groups of conjugates. The method was validated using individual isomers and mixtures at various compositions. The effects of concentration and collision energies on fragmentation patterns were also studied extensively. Matrix-fortified equine urine and plasma samples were also included so that matrix effects and interferences on fragmentation ratios could be elucidated. Preliminary results using biological samples demonstrated the suitability of this analytical strategy for direct measurement from their fragmentation patterns. Possible fragmentation pathways for each isomer were proposed.

Liquid chromatography–quadrupole orbitrap and liquid chromatography–tandem mass spectrometry system for rapid identification and quantitation of thirty nonsteroidal anti‐inflammatory drugs and acetaminophen in illegal products

“…All these samples display fragment ion peaks with m / z values of 115.0327, 141.0117, and 184.0539, identical to those of the meloxicam standard, and the ratio between these peaks is also identical to that of the meloxicam standard (Figures 4A and 4B). Considering the MS 2 spectra, according to the literature, we inferred that the unknown compound exhibiting an m / z value of 393.2067 was dexamethasone 26 . Therefore, we analyzed the dexamethasone standard using LC‐Q‐Orbitrap/MS and compared the unknown compound with the dexamethasone standard in terms of RT, MS, and MS 2 spectra.…”

“…Considering the MS 2 spectra, according to the literature, we inferred that the unknown compound exhibiting an m/z value of 393.2067 was dexamethasone. 26 Therefore, we analyzed the dexamethasone standard using LC-Q-Orbitrap/MS and compared the unknown compound with the dexamethasone standard in terms of RT, MS, and MS 2 spectra. Figure 5 those of the dexamethasone standard, and the ratio between these peaks is also the same as that of the dexamethasone standard (Figures 5A and 5B).…”

Simultaneous analysis of 44 frequently abused corticosteroid drugs using polysaccharide‐based chiral column‐HRMS approach

“…To support drug metabolism and pharmacokinetic studies of chiral drugs, it is necessary to mix the physical phenomenon of HPLC with the sensitivity of mass spectrometric techniques. Recently, methods using LC‐MS/MS are found to be promising techniques for solving the matter of corticosteroid analysis 19–25 …”

“…Recently, methods using LC-MS/MS are found to be promising techniques for solving the matter of corticosteroid analysis. [19][20][21][22][23][24][25] Polysaccharide columns offer a large range of chiral separations of racemic components. [26][27][28][29][30]…”

Quantification of 17 Endogenous and Exogenous Steroidal Hormones in Equine and Bovine Blood for Doping Control with UHPLC-MS/MS

“…Genye et al developed a method to detect and analyze 13 steroids in human urine using a quadrupole-Orbitrap LC-MS/MS [ 14 ]. Tajudheen et al studied the separation of two anabolic substances using a reversed phase chiral chromatography approach [ 15 ]. Brian et al published an article regarding novel liquid chromatography-tandem mass spectrometry methods for measuring steroids [ 16 ].…”