Studies on structure characterization of tryptophan melanin: Comparison between filament and curie-point pyrolysis gas chromatography/mass spectrometry

✍ Scribed by Karoly Vèkey; József Tamás; Arpád Somogyi; Antonella Bertazzo; Carlo Costa; Graziella Allegri; Roberta Seraglia; Piero Traldi

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 390 KB
• Volume: 27
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/oms.1210271111

✦ Synopsis

Structural studies of a synthetic melanin, obtained by means of performic acid oxidation of tryptophan, were carried out by pyrolysis gas chromatography/mass spectrometry (Py-GC/MS). To identify the best pyrolysis conditions, both Curie-point pyrolysis and filament pyrolysis were employed and the effects of pyrolysis temperatures and times were studied. Using the first approach, various compounds were identified: toluene, ethylbenzene, styrene, indole, methylindole, ethylindole, phenol, cresol and ethylphenol. Using filament pyrolysis some interesting differences could be observed. Whereas toluene, ethylbenzene, phenol, cresol and methylindole were found, neither indole nor ethylindole was detected. Instead, new pyrolysis products were evident, such as methylpyrrole and indolin-&one. Hence filament pyrolysis seems to activate different thermal decomposition pathways of the melanin under study. It is suggested that tryptophan melanin is a polymer containing indole and hydroxyindole derivatives as subunits.