Twentieth century Iranian carpets: investigation of red dye molecules and study of traditional madder dyeing techniques

Heritage Science

Table 4 Chromophores of Iranian madder detected by RP-HPLC–DAD at 255 nm

	Name	%	RT	Area_c
1	Ø	5.35	1.046	5.54
2	Ø	4.07	2.036	4.21
3	Unknown spectrum with max absorbance peaks 213–254–285–357	1.18	9.512	1.22
4	Unknown spectrum with max absorbance peaks 213–256–282–352	1.55	9.995	1.6
5	~ Ruberythric acid (= very similar to rubetythric acid)	0.40	10.305	0.41
6	Ruberythric acid	1.80	11.732	1.86
7	Unknown spectrum with max absorbance peaks 251–278–344	0.47	13.012	0.49
8	Unknown spectrum with max absorbance peaks 219–258–272–339–410	0.65	15.211	0.67
9	Xanthopurpurin	0.70	15.988	0.72
10	Anthragallol	0.56	17.123	0.58
11	Pseudopurpurin + munjistin	11.28	17.772	11.67
12	Alizarin	39.54	18.873	40.92
13	Unknown spectrum with max absorbance peaks 223–252–284–436	0.87	19.905	0.9
14	Purpurin	1.22	22.46	1.26
15	~ Rubiadin	0.68	25.291	0.7
16	Nordamnacanthal	29.36	26.84	30.38
17	Unknown spectrum with max absorbance peaks 214–245–270–280–391	0.19	28.756	0.2
18	~ Xanthopurpurin	0.14	29.332	0.15

Area_c Sum of peak areas (only identified peaks), RT retention time, Relative ratio (%) individual peak area divided by sum of peak areas multiplied by 100