Identifying Pig Residue in a Ding Pottery Sherd: A Gas Chromatography-Mass Spectrometry, Gas Chromatography-Isotope Ratio-Mass Spectrometry, Nuclear Magnetic Resonance Spectroscopy, and LC-MS-MS Metabolomics Analysis
Introduction
Three spectrometric methods and one spectroscopy method are used on the same samples, a ding sherd from the Longshan site of Liangchengzhen, Shandong, China (see Figs. 1 & 2), and modern cooked pig bone from the Shandong area, to demonstrate alternative yet compatible perspectives of interpretive measures.
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Gas chromatography-mass spectrometry (GC-MS)
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Gas chromatography-isotope ratio-mass spectrometry (GC-IR-MS)
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Nuclear magnetic resonance spectroscopy (NMR)
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Liquid chromatography-tandem mass spectrometry (LC-MS MS) metabolomics
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Figure 1. A ding rim containing pig residue from ritual pit H31, Liangchengzhen, Shandong, China (Photo by R. Lanehart)
Figure 2. 3D animation of a portion of the ding rim in Fig. 1. (Digitization by Laura Harrison at Access 3D Lab, University of South FL. Colorization and animation by Elliot Alvarez, Access 3D Lab).
GC-MS and GC-IR-MS Analysis using the n-alkane fraction.
For GC-MS analysis, the alkane fraction was run on a Varian 320 GC equipped with a 30 m x 0.25 mm (i.d.) Zebron Zb-5MS fused silica capillary column coated with a 5% diphenyl/95% dimethyl polysiloxane stationary phase (film thickness 0.25 μm). Helium was used as the carrier gas with a flow rate of 1ml/min. Run parameters for the reference and pottery samples included an initial temperature of 80° C, a hold for 2 minutes, an increase to 310° C @ 4° C/min which was held for 4 minutes for a total of 63.54 minutes/run. The Varian 320 mass spectrometer operated in the electron impact ionization mode (70eV) in the 40-500 m/z mass range with a source temperature set at 200° C. The injector and transfer line temperature were set at 250° C (see Table 1).
For GC-IR-MS analysis, the GCMS samples were cleaned (see Grice, et al., 2008; Plet, et al., 2016) and sent to the Center for Applied Isotope Studies (CAIS) located at the University of Georgia in Athens. Samples were run on a Finnigan MAT 253 Isotope Ratio Mass Spectrometer. Stable isotope values were obtained for the C15 and C17 peaks to support the findings from the GC-MS analysis. Results are reported on a per mil (‰) basis relative to the PDB standard (see Fig. 2).
Table 1. δ13C15.0 and δ13C17.isotope values and standardized residue quantities
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