Direct Analysis of Xanthine Stimulants in Archaeological Vessels by Laser Desorption Resonance Enhanced Multiphoton Ionization

Owens, Shawn C.; Berenbeim, Jacob A.; Ligare, Marshall R.; Gulian, Lisa E.; Siouri, Faady M.; Boldissar, Samuel; Tyson-Smith, Stuart; Wilson, Gregory D.; Ford, Anabel; Vries, Mattanjah S. de

doi:10.1021/acs.analchem.6b03932

Cited by 2 publications

(1 citation statement)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…REMPI-TOFMS is applied in a wide variety of fields, such as spectroscopic studies and environmental monitoring. [21][22][23][24][25][26][27][28] This method is normally used for the detection of samples in the gas phase with fewer applications to liquid samples. 29 In order to apply the unique features of this method to the measurement of an emulsion, we developed a sample introduction technique for REMPI-TOFMS that is based on the use of a pair of concentric capillaries.…”

Section: Introductionmentioning

confidence: 99%

Resonance-enhanced Multiphoton Ionization Time-of-Flight Mass Spectrometry for Evaluating Emulsion Inversion via Temperature Change

Iwata

Uchimura

2019

ANAL. SCI.

View full text Add to dashboard Cite

This study used resonance-enhanced multiphoton ionization time-of-flight mass spectrometry (REMPI-TOFMS) to evaluate the phase inversion that is driven via temperature change. A change in temperature prompts phase inversion in an oil-in-water (O/W) emulsion that uses a nonionic surfactant as an emulsifier. In this study, an O/W emulsion was prepared containing Triton X-100 as an emulsifier. To promote emulsion inversion, we heated only the outlet of a capillary column that was used for sample introduction during REMPI-TOFMS. When the emulsion was continuously measured at 40 C, several intense spikes could be detected on a time profile for the analyte, toluene, constructed by extracting the peak areas from a series of obtained mass spectra. This indicated the presence of toluene droplets in the O/W emulsion. No intense spikes appeared at 80 C, however, which suggested the shrinkage or even disappearance of the oil droplets following phase inversion. Using this technique, an emulsion can be measured without affecting the influence of vaporization even at elevated temperatures, which surely is a serious concern when using other analytical techniques. Therefore, this technique would be quite useful for evaluating the phase inversion of an emulsion at elevated temperatures.

show abstract

Section: Introductionmentioning

confidence: 99%

Resonance-enhanced Multiphoton Ionization Time-of-Flight Mass Spectrometry for Evaluating Emulsion Inversion via Temperature Change

Iwata

Uchimura

2019

ANAL. SCI.

View full text Add to dashboard Cite

show abstract

New light on the use of Theobroma cacao by Late Classic Maya

Ford

Williams

Vries

2022

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Cacao seeds, Theobroma cacao , provide the basis for a ceremonially important Mesoamerican food. Past efforts to identify cacao in ceramics focused on highly decorative vessel forms associated with elite ceremonial contexts, creating assumptions as to how cacao was distributed and who could access it. This study examines 54 archaeological ceramic sherds from El Pilar (Belize/Guatemala) of Late Classic (600 to 900 CE) residential and civic contexts representing a cross-section of ancient Maya inhabitants. Identification of cacao in ancient sherds has depended on the general presence of theobromine; we used the discrete presence of theophylline, a unique key biomarker for cacao in the region. Analysis was done by grinding off all outside surfaces to reduce contamination, pulverizing the inner clay matrix, extracting absorbed molecules, and concentrating the extractions. In order to obtain especially high selectivity and low limits of detection, our study utilized the technique of resonance-enhanced multiphoton ionization coupled with laser-desorption jet-cooling mass spectrometry. This technique isolates molecules in the cold gas phase where they can be selectively ionized through a resonant two-photon process. Of the sherds analyzed, 30 samples (56%) were found to contain significant amounts of theophylline and thus test positive for cacao. Importantly, cacao is present in all contexts, common to all Maya residents near and far from centers.

show abstract

Direct Analysis of Xanthine Stimulants in Archaeological Vessels by Laser Desorption Resonance Enhanced Multiphoton Ionization

Cited by 2 publications

References 44 publications

Resonance-enhanced Multiphoton Ionization Time-of-Flight Mass Spectrometry for Evaluating Emulsion Inversion via Temperature Change

Resonance-enhanced Multiphoton Ionization Time-of-Flight Mass Spectrometry for Evaluating Emulsion Inversion via Temperature Change

New light on the use of Theobroma cacao by Late Classic Maya

Contact Info

Product

Resources

About