Indigo chemical structure

Both HPLC and GC-MS were employed for the separation, identification and quantitation of the decomposition products of indigo and indigo carmine. The chemical structures of the dyes are shown in Fig. 3.73. Carboxylic acids were preconcentrated before HPLC analysis either by ion-exchange SPE or by solid-phase microextraction. HPLC measurements were performed in a Sarasep column (300 X 7.8 mm i.d.) using 5 mM H2S04 at a flow rate of 0.7 ml/min. Analytes were detected at 215 nm. The main intermediates formed during the photocatalytic decomposition are compiled in Table 3.26. The results demonstrated that... 

Adolf von Baeyer reported the chemical structure of indigo in 1883, having already prepared the first synthetic indigo from isatin (2) in 1870. Until then, isa-tin had only been obtainable by oxidation of indigo. It was not until 1878 that von Baeyer first synthesized it from phenylacetic acid, making a complete synthesis of indigo possible [1],... 

From the seeds, trichotomine was isolated as a deep blue pigment and its chemical structure determined [IJ.The skeleton of this alkaloid is, as in the case of nigakinone, formed by the addition of a C4 unit to a tryptamine moiety. However, in this instance, the direction of the ring formation is towards Ni, rather than N. Trichotomine is considered to be formed by a dimerization reaction, as in the case of indigo (Section 2.4) [1]. 

Examples of redox indicators are Indigo Carmine (C.I. 73015 [ 860-22-0] 8), which is frequently employed, and ferroin, an iron(n) complex with three 1,10-phenanthroline ligands (14), which is widely used in water and wastewater analysis in the determination of chemical oxygen demand (COD) in an internationally standardized procedure. For the structure of the organic ligand, see p. 539. 

Previous research aimed at removing pesticide residues from contaminated fabrics has been directed at removal of a particular pesticide chemical and/or formulation of pesticide, with no effect toward comparing the pesticide residue s composition to that of common soil. Fabric selection for this study allowed a comparison of both hydrophilic and hydrophobic fibers and the effect of fabric type on soil removal. Two fabrics were identified for the study. Denim was 100% cotton fabric of twill weave dyed with indigo dyes. This fabric was 14 ounce, comparable to the heavy weight denim found in jeans. The second fabric was Gore Tex, a three layer structure consisting of an outer layer of rip-stop nylon and an inner layer of nylon tricot laminated to a film. The film was a micro-porous, polymeric film or polytetrafluoroethylene (PTFE). Previous studies on pesticide penetration found Gore Tex to be impermeable to pesticides. Thermal comfort studies found it to be relatively comfortable, similar In comfort to the commonly worn denim jeans and a chambray shirt. 

More than half a century passes from initial research the pharmacist Otto Paul Unverdorben (1806-1873) had conducted in 1826 to elucidate the structure, when Adolf von Baeyer was able to dispose of the final uncertainties regarding indigo s chemical constitution in 1883. 

Recently, the leuco-peracetate (54) of thelephoric acid has been isolated from sporophores of Boletopsis leucomelaena (386). The leuco-permethyl ether (67) of thelephoric acid occurs in minute amounts in the indigo blue coloured mycelial mats of Pulcherricium caeruleum ( = Corticium caeruleum) and its structure has been established by an X-ray crystal analysis (581, 711). The chemical nature of the blue pigment from this organism is a matter of dispute. Briggs et al. (135) obtained blue solutions (A, ax = extraction of the mycelium... 

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