An Insight to the Composition of Pre-Hispanic Mayan Funerary Pigments by 1H-NMR Analysis

The funerary rites of particular members of the pre-Hispanic Mayan society included the pigmentation of the corpse with a red color. In order to understand this ritual, it is first necessary to identify the constituents of the pigment mixture and then, based on its properties, analyze the possible form and moment of application. In the present approach, 1H-NMR analysis was carried to detect organic components in the funerary pigments of Xcambó, a small Maya settlement in the Yucatan Peninsula. The comparison of the spectra belonging to the pigment found in the bone remains of seven individuals, and those from natural materials, led to the identification of beeswax and an abietane resin as constituents of the pigment, thus conferring it agglutinant and aromatic properties, respectively. The 1H-NMR analysis also allowed to rule out the presence of copal, a resin found in the pigment cover from paramount chiefs from the Mayan society. Additionally, a protocol for the extraction of the organic fraction from the bone segment without visible signs of analysis was developed, thus broadening the techniques available to investigate these valuable samples.

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Polyhydroxyalkanoate quantification in organic wastes and pure cultures using a single-step extraction and 1H NMR analysis

Water Science & Technology ◽

10.2166/wst.2012.273 ◽

2012 ◽

Vol 66 (5) ◽

pp. 1000-1006 ◽

Cited By ~ 12

Author(s):

Elisabeth Linton ◽

Asif Rahman ◽

Sridhar Viamajala ◽

Ronald C. Sims ◽

Charles D. Miller

Keyword(s):

1H Nmr ◽

Azotobacter Vinelandii ◽

Nile Blue ◽

Agricultural Waste ◽

Accurate Method ◽

Single Step ◽

Proton Nuclear Magnetic Resonance ◽

Copolymer Composition ◽

Nmr Analysis ◽

Nmr Method

In this study, a proton nuclear magnetic resonance (1H NMR) method was developed to quantitatively analyze polyhydroxyalkanoate (PHA) content in Cupriavidus necator H16, Azotobacter vinelandii AvOP, and mixed microbial cultures from the effluent of an agricultural waste treatment anaerobic digester. In contrast to previous methods, a single-step PHA extractive method using deuterated chloroform was established, thereby facilitating direct 1H NMR analysis. The accuracy of the method was verified through comparison with well-established gas chromatography (GC) methanolysis techniques. Nile blue fluorescence staining was also carried out to serve as an independent and qualitative indicator of intracellular PHA content. The results indicate that the 1H NMR method is appropriate for rapid and non-destructive quantification of overall PHA content and determination of PHA copolymer composition in a variety of cultures. Notably, this technique was effective in measuring PHA content in full-strength waste samples where high concentrations of background impurities and organic compounds are present. The straightforward procedures minimize error-introducing steps, require less time and materials, and result in an accurate method suitable for routine analyses.

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Iridium-Catalyzed Triborylation of 3-Substituted Indoles

Australian Journal of Chemistry ◽

10.1071/ch15393 ◽

2015 ◽

Vol 68 (12) ◽

pp. 1810 ◽

Cited By ~ 7

Author(s):

Andrew S. Eastabrook ◽

Jonathan Sperry

Keyword(s):

1H Nmr ◽

Nmr Analysis ◽

One Pot ◽

Substitution Pattern ◽

The Third

Readily available 3-substituted indoles undergo a one-pot iridium-catalyzed triborylation at the C2, C5, and C7 sites. 1H NMR analysis indicates borylation at C2 and C7 occurs first (no monoborylated product is observed), with the third borylation occurring as a separate, distinct step that is sterically directed to C5 by a combination of the substituent at C3 and the boronate at C7. The resulting tetrasubstituted indoles possess a substitution pattern that is cumbersome to prepare using existing methods.

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