Redox tuning and species distribution in Maya Blue-type materials: a reassessment

ACS Appl Mater Interfaces. 2013 Aug 28;5(16):8134-45. doi: 10.1021/am402193u. Epub 2013 Aug 13.

Abstract

Maya Blue-type specimens prepared from indigo (1 wt %) plus kaolinite, montmorillonite, palygorskite, sepiolite, and silicalite are studied. Liquid chromatography with diode array detection, ultra-performance liquid chromatography coupled with mass spectrometry, and pyrolysis-silylation gas chromatography-mass spectrometry analyses of the extracts from these specimens combined with spectral and solid-state voltammetry, electrochemical impedance spectroscopy, and scanning electrochemical microscopy techniques provide evidence for the presence of a significant amount of dehydroindigo and isatin accompanying indigo and other minority organic compounds in all samples. Solid-state electrochemistry data permits the estimatation of indigo loading in archeological Maya Blue, which is in the range of 0.2 to 1.5 wt %. These results support a view of 'genuine' Maya Blue-type materials as complex polyfunctional organic-inorganic hybrids.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bentonite / chemistry
  • Bentonite / isolation & purification
  • Chromatography, High Pressure Liquid
  • Chromatography, Liquid
  • Electrochemistry
  • Humans
  • Indigo Carmine / chemistry*
  • Indigo Carmine / isolation & purification
  • Isatin / chemistry*
  • Isatin / isolation & purification
  • Kaolin / chemistry
  • Kaolin / isolation & purification
  • Magnesium Compounds / chemistry*
  • Magnesium Compounds / isolation & purification
  • Magnesium Silicates / chemistry*
  • Magnesium Silicates / isolation & purification
  • Mass Spectrometry
  • Oxidation-Reduction
  • Silicon Compounds / chemistry*
  • Silicon Compounds / isolation & purification

Substances

  • Magnesium Compounds
  • Magnesium Silicates
  • Silicon Compounds
  • Bentonite
  • Kaolin
  • Isatin
  • magnesium trisilicate
  • Indigo Carmine
  • attapulgite