Table 1. Retention time (t_R), retention factor (k), separation factor (α), peak purity (pp) and contents of various carotenoids in carotenoid fraction isolated from R. nasutus extract along with their absorption and mass spectra data for identification.

Peak No.	Carotenoid	tR (min)	k	α	pp (%)	Absorption data (nm)						Mass data (m/z)i		Content (μ g/mL)
						Online λmaxf			Reported λmaxh			Online [M + H]+	Reported [M + H]+h
1	all-trans-neoxanthina	8.25	1.16	2.27 (1, 2)e	98.8	418	440	468	418	440	468	601	601	1.03  ±   0.01
2	all-trans-violaxanthina	13.88	2.63	1.54 (2, 3)e	96.4	416	440	468	416	440	468	601	601	8.26  ±   0.74
3	13- or 13′ -cis-luteinb	19.35	4.07	1.09 (3, 4)e	95.6	416	440	464	416	438	464	569	569	5.59  ±   0.88
4	13- or 13′ -cis-luteinb	20.73	4.43	1.14 (4, 5)e	91.5	414	438	466	414	438	466	569	569	3.35  ±   0.78
5	all-trans-luteinc	23.07	5.04	1.50 (5,IS)e	99.3	424	446	474	422	446	474	569	569	50.3  ±   2.69
6	β -apo-8′ -carotenal (IS)d	32.74	7.57	1.40 (IS, 7)e	99.4	–g	464	–g	–g	464	–g	417	417	–g
7	all-trans-β -cryptoxanthinc	44.24	10.58	1.04 (7, 8)e	97.2	428	456	480	428	456	480	553	553	1.99  ±   0.91
8	13- or 13′ -cis-α -caroteneb	45.77	10.98	1.03 (8, 9)e	97.7	334	442	468	334	442	468	537	537	2.95  ±   0.32
9	13- or 13′ -cis-α -caroteneb	46.96	11.29	1.03 (9, 10)e	94.2	334	442	468	334	442	468	537	537	2.44  ±   0.06
10	15- or 15′ -cis-β -caroteneb	48.31	11.65	1.04 (10, 11)e	98.6	340	454	478	340	452	478	537	537	2.70  ±   0.15
11	13- or 13′ -cis-β -caroteneb	49.88	12.06	1.05 (11, 12)e	99.6	342	448	474	342	448	474	537	537	12.8  ±   0.92
12	all-trans-α -carotenec	52.17	12.66	1.12 (12, 13)e	99.7	424	448	476	424	450	476	537	537	49.2  ±   2.69
13	all-trans-β -carotenec	57.82	14.14	1.04 (13, 14)e	99.9	428	454	482	428	456	482	537	537	144  ±   7.78
14	9- or 9′ -cis-β -caroteneb	60.07	14.73	1.04 (13, 14)e	99.6	346	450	474	340	450	476	537	537	19.6  ±   1.34

^aIdentification based on absorption and mass spectra of samples isolated from spinach by thin-layer chromatography.

^bIdentification based on absorption and mass spectra of HPLC chromatogram obtained for photoisomerized all-trans standards as shown in Fig. 2.

^cIdentification based on absorption and mass spectra of commercially obtained reference standards.

^dInternal standard.

^eNumbers in parentheses represent values between two neighboring peaks.

^fA gradient mobile phase of methanol-acetonitrile-water (82:14:4, v/v/v) and methylene chloride (from 95:5, v/v to 69:31, v/v) was used.

^gData not available.

^hBased on a gradient mobile phase of methanol-acetonitrile-water (82:14:4, v/v/v) and methylene chloride (from 100:0, v/v to 55:45, v/v) used by Kao et al.¹⁸

ⁱm/z is mass-to-charge ratio.