“…Mass spectrometry combined with chromatographic techniques has become very popular owing to its sensitivity and selectivity [9]. The analysis of steroids has been carried out by gas chromatography-mass spectrometry (GC-MS) [10][11][12][13][14][15][16], liquid chromatography-mass spectrometry (LC-MS) [17][18][19], electrospray mass spectrometry (ESI-MS) [20][21][22][23][24], atmospheric pressure chemical ionization mass spectrometry (APCI-MS) [25], matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) [26][27][28], and immunoassay [29]. Although GC-MS approaches are highly sensitive, they have some limitations due to the need for multistep derivatization procedures for these thermally-labile compounds, especially those that contain large numbers of hydroxyl groups [9,30,31].…”