Table 1.

MRM conditions for the estrogen steroids and deuterium-labeled internal standard in negative ion mode

Period (min)	Estrogen steroid	MRM transition	Retention time (min)	DP	EP	CE	CXP
Period I (5.5)	Estriol	287/171	4.46	−120	−10	−55	−15
	Estriol (2nd)	287/145	4.46	−120	−10	−55	−15
	Estriol-d₂	289/147	4.45	−120	−10	−55	−15
	16-Hydroxyestrone	285/145	4.77	−120	−10	−55	−15
	16-Hydroxyestrone (2nd)	285/143	4.77	−120	−10	−78	−17
	Aldosterone-d₆	365/337	4.63	−60	−10	−23	−15
Period II (2.5)	Estrone	269/145	6.88	−120	−10	−55	−15
	Estrone (2nd)	269/143	6.88	−120	−10	−55	−15
	Estrone-d₄	273/147	6.86	−120	−10	−55	−15
	Estradiol	271/145	6.93	−120	−10	−55	−15
	Estradiol (2nd)	271/183	6.93	−120	−10	−55	−15
	Estradiol-d₄	275/147	6.89	−120	−10	−55	−15

Note: for estriol, 16-hydroxyestrone, estrone, and estradiol, the first MRM transitions were listed for quantitation, and the second transitions were added for confirmation.