Differential diagnosis in patients with suspected bile acid synthesis defects

Table 2 Electrospray ionization-tandem mass spectrometry operating parameters for bile acid intermediates

	Glycine conjugates (IS included)	Taurine conjugates	Sulfatides	Glucuronides
Nebulizer gas (au)	11	11	11	11
Curtain gas (au)	9	9	9	9
Collision gas (au)	5	5	5	5
Ion spray voltage (V)	-4100	-4100	-4100	-4100
Temperature (°C)	200	200	200	200
Declustering potential (V)	-35	-35	-35	-35
Focusing potential (V)	-31	-31	-31	-31
Entrance potential (V)	-10	-10	-10	-10
Prefilter (V)	23	23	23	23
Collision energy (V)	-55	-129	-60	-75
Collision cell exit potential (V)	-9	-9	-9	-9
Daughter ion (m/z)	74	80	97	85
Scan range of precursor ions (m/z)	430 to 550	490 to 590	460 to 490	600 to 630

The mass spectrometer was operated in a negative precursor ion scan mode with a step-size of 0.1 amu. Nitrogen was used as nebulizer, curtain and collision gases. au: Arbitrary units; IS: D₄-glycocholic acid.