Analysis of the Pigment Contents of Commercial Indigo Powders and Their Effect on the Color and the Antimicrobial Function of Dyed Cotton Fabrics

Abstract

Market available fermented indigo powders of Indian origin (FI1, FI2), Chinese origin (FC1, FC2), and raw indigo powders of Indian origin (R1, R2) were examined using TLC and HPLC analyses to investigate their pigment contents. TLC analysis gave Rf values of 0.81 and 0.72 for blue and red pigments, respectively. All the powder products and the synthetic and natural indigo standards eluted at 6.9 min and 8.3 min in the HPLC chromatograms, and the peaks showed the λmax at 610nm and 542nm, representing indigotin and indirubin, respectively. The pigment content calculated based on the area of indigotin and indirubin peaks in the HPLC chromatograms showed that the indigotin content was higher in FC1 and FC2, while FI1 and FI2 had a higher indirubin content. The relative percentage of indirubin was the highest in R2, but the HPLC peak intensity was quite low. Despite the higher indigotin content in FC1 and FC2, cotton dyed with FI1 and FI2 (versus cotton dyed with FC1 and FC2) showed a higher blue (B) hue, the highest K/S values, and the highest antimicrobial effect.

Simultaneous Analysis of the Coloring Compounds in Indigo, Phellodendron bark, and Madder Dye Using HPLC-DAD-MS

“…However, it was possible to distinguish indigotin and purpurin since the two pigment compounds exhibited different λmax at the visible range of DAD uv-vis absorption bands, owing to the difference in their color. The λmax of indigotin was 607nm which was close to the λmax reported in the literature using DMSO as the solvent (Oh & Ahn, 2013), exhibiting the blue color. The λmax of purpurin was 480nm which was close to the λmax reported by the manufacturer (Cayman Chemical, 2012), exhibiting the dark brown color (Sigma-Aldrich, 2012).…”

Study on the Improvement of Dyeability of Commercial Indigo Leaf Powder for the Purpose of Utilizing It in Indigo Dyeing

“…과거 우리나라의 쪽 생즙 염색방법은 염액의 가열 즉, 쪽잎을 물에 넣고 끓이는 방법임을 기록에서 찾을 수 있 다. Hong(as cited in Kim, 2008)이 지은『산림경제』 에 서는 쪽의 생즙과 익힌 즙을 섞어서 염색하는 방법을 쪽 생즙 염색과 비교하여 언급하였으며, 『규합총서』 (Yi, 1806(Yi, /1975 (Oh & Ahn, 2013;Stoker et al, 1998) 환원과정을 통해 수용성 류코 화합물로 만들어야 직물에 염착이 가능하다. 환원반응 을 위해서는 염액을 알칼리 상태로 만들어야 하는 것으 로 알려져 있다 (Choe et al, 1999;Etters, 1995;Torimoto, 1987;Yang et al, 2012).…”