Microwave-Assisted Derivatization of Bile Acids for Gas Chromatography/Mass Spectrometry Determination

Table 1

Fragmentation patterns of the bile acid TMS (oximes) derivatives obtained using gas chromatography and mass spectrometry (GC/MS) and the common ions in the fragmentation patterns of cholic acid (conventional and microwave-assisted derivatization) and ursodesoxycholic acid (MAD) presented as relative intensities.

Bile acid	𝑡𝑟 (min)	Selected fragment ions for identification and quantification		Frequent ion in fragmentation
		[𝑀]^+•	[𝑀−15]^+	Further abundant fragment ion, m/z	m/z	Relative intensity (%) microwave	Relative intensity (%) conventional
Cholic	17.19	696.5	681	[M − 2TMSOH]^+ = 516	253	100	100
				[M − (2TMSOH + SiCH4)]^+ = 428	426	47.94	56.74
				[M − 3TMSOH]^+ = 426	516	32.23	39.61
					681	15.76	14.87
Ursodesoxycholic	17.59	608.5	593	[M − 2TMSOH]^+ = 428	413	32
				[M − (15 + 2TMSOH)]^+ = 413	428	56
					518	100