Spectrometric study on the interaction of Sn(Ll) and Fe(Ll) with natural pigment of hibiscus rosa-sinensis / Masni Hassan

Hibiscus rosa-sinensis flowers of different colors (pink, peach and red) were chosen in these spectrophotometric studies. The natural pigments were extracted in acidified water with hydrochloric acid at different pH (1, 3, and 5). The crude extract was then analyzed by using UV-VIS Spectrophotometer over the range of 400 nm to 700 nm. The maximum absorbance of red, pink and peach flowers were 6.363, 0.3602 and 0.4212 and detected at 520.96 nm, 514.73 nm and 513.78 nm respectively. The metal cation of Fe(II) and Sn(II) ion were applied in order to study their interaction with natural pigment. The interaction of pink flower crude extract with Fe(II)ion gives hypsochromic shifts. Whereas the interaction between both metal cations and other crude extracts give bathochromic shifts. The percent decreased in absorbance was in the range of 14.79 % to 69.25% for the interaction of metal cation with crude extract of natural pigment. Different shades of color were obtained on silk fabric when the cations solution mixed with crude extract of each flower.