Table 2.

Results of column screening. Injection of PTAD-derivatized individual solutions (100 ng/mL, 3 μL). Gradient elution, methanolwater (98:2) containing 10 mM ammonium formate into carbon dioxide. Retention times of each of the compounds in minutes, where two isomers of the PTAD derivative were separated the two values are shown. Column 1: Waters Torus^TM 1-AA, column 2: Waters BEH C18, column 3: Waters CSH^TM Fluoro Phenyl, column 4: Waters HSS C18 SB, column 5: Waters Torus^TM Diol, column 6: Waters BEH 2-EP, column 7: Nacalai Tesque cosmocore 2,6 cholester, column 8: Thermo Fischer Acclaim^TM C30, column 9: Chiral Technologies Chiralpak® AD-3

Column number		1	2	3	4	5	6	7	8	9
Particle size (μm)		1.8	1.7	1.7	1.8	1.7	1.7	2.6	3	3
ID (mm)		3	3	3	3	3	3	2.1	2.1	4.6
L (mm)		100	100	100	100	100	100	150	150	150
	Precurson ion (m/z)	Retention time (min)
D2	572.4	3.60–3.71	3.02–3.04	2.54	3.18–3.30	2.82	3.74–3.77	6.44–6.68	2.76–2.89	5.30–5.80
D3	560.4	3.58–3.69	3.01–3.04	2.55	3.18–3.31	2.82	3.73–3.77	6.48–6.70	2.77–2.91	5.44–6.99
25OHD2	570.4	4.04–4.22	3.39	2.87	3.24–3.32	3.26	3.94–3.98	4.07–4.16	2.58–2.71	6.45
3epi25OHD2	570.4	4.18	3.36–3.39	2.81–2.91	3.25–3.32	3.25–3.28	3.96	4.38–4.44	2.61–2.76	6.80
25OHD3	558.4	4.06–4.26	3.41–3.43	2.94	3.27–3.35	3.32	3.96–4.02	4.07–4.16	2.61–2.75	6.48
3epi25OHD3	558.4	4.21	3.41–3.43	2.90–2.96	3.28–3.34	3.30–3.34	3.98–4.01	4.38–4.44	2.64–2.78	6.66
1,25diOHD2	586.4	4.47	3.70	3.11	3.32	3.55–3.60	4.17	5.60	2.91	8.00
24,25diD2	586.4	4.35–4.57	3.57–3.59	3.06	3.30–3.37	3.48	4.07–4.12	4.94–5.03	2.60–2.75	8.10
1,25diOHD3	574.4	4.51	3.70	3.15	3.32	3.59–3.63	4.20–4.27	5.60	2.93	8.40
24,25diOHD3	574.4	4.41–4.66	3.58–3.63	3.08–3.11	3.31–3.40	3.53	4.12–4.18	4.94–5.02	2.67–2.83	7.97–8.90