Copper and tin isotopic analysis of ancient bronzes for archaeological investigation: development and validation of a suitable analytical methodology

Although in many cases Pb isotopic analysis can be relied on for provenance determination of ancient bronzes, sometimes the use of “non-traditional” isotopic systems, such as those of Cu and Sn, is required. The work reported on in this paper aimed at revising the methodology for Cu and Sn isotope ratio measurements in archaeological bronzes via optimization of the analytical procedures in terms of sample pre-treatment, measurement protocol, precision, and analytical uncertainty. For Cu isotopic analysis, both Zn and Ni were investigated for their merit as internal standard (IS) relied on for mass bias correction. The use of Ni as IS seems to be the most robust approach as Ni is less prone to contamination, has a lower abundance in bronzes and an ionization potential similar to that of Cu, and provides slightly better reproducibility values when applied to NIST SRM 976 Cu isotopic reference material. The possibility of carrying out direct isotopic analysis without prior Cu isolation (with AG-MP-1 anion exchange resin) was investigated by analysis of CRM IARM 91D bronze reference material, synthetic solutions, and archaeological bronzes. Both procedures (Cu isolation/no Cu isolation) provide similar δ 65Cu results with similar uncertainty budgets in all cases (±0.02–0.04 per mil in delta units, k = 2, n = 4). Direct isotopic analysis of Cu therefore seems feasible, without evidence of spectral interference or matrix-induced effect on the extent of mass bias. For Sn, a separation protocol relying on TRU-Spec anion exchange resin was optimized, providing a recovery close to 100 % without on-column fractionation. Cu was recovered quantitatively together with the bronze matrix with this isolation protocol. Isotopic analysis of this Cu fraction provides δ 65Cu results similar to those obtained upon isolation using AG-MP-1 resin. This means that Cu and Sn isotopic analysis of bronze alloys can therefore be carried out after a single chromatographic separation using TRU-Spec resin. Tin isotopic analysis was performed relying on Sb as an internal standard used for mass bias correction. The reproducibility over a period of 1 month (n = 42) for the mass bias-corrected Sn isotope ratios is in the range of 0.06–0.16 per mil (2 s), for all the ratios monitored

Solar System Abundances of the Elements

Representative abundances of the chemical elements for use as a solar abundance standard in astronomical and planetary studies are summarized. Updated abundance tables for solar system abundances based on meteorites and photospheric measurements are presented.Comment: 46 pages; 5 figures; 8 tables; In: Principles and Perspectives in Cosmochemistry.Lecture Notes of the Kodai School on 'Synthesis of Elements in Stars' held at Kodaikanal Observatory, India, April 29 - May 13, 2008 (Aruna Goswami and B. Eswar Reddy eds.) Astrophysics and Space Science Proceedings, Springer-Verlag Berlin Heidelberg, 2010, p. 379-417 (ISBN 978-3-642-10351-3), 201

Metabolomics approach for determining growth-specific metabolites based on Fourier transform ion cyclotron resonance mass spectrometry

Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR/MS) is the best MS technology for obtaining exact mass measurements owing to its great resolution and accuracy, and several outstanding FT-ICR/MS-based metabolomics approaches have been reported. A reliable annotation scheme is needed to deal with direct-infusion FT-ICR/MS metabolic profiling. Correlation analyses can help us not only uncover relations between the ions but also annotate the ions originated from identical metabolites (metabolite derivative ions). In the present study, we propose a procedure for metabolite annotation on direct-infusion FT-ICR/MS by taking into consideration the classification of metabolite-derived ions using correlation analyses. Integrated analysis based on information of isotope relations, fragmentation patterns by MS/MS analysis, co-occurring metabolites, and database searches (KNApSAcK and KEGG) can make it possible to annotate ions as metabolites and estimate cellular conditions based on metabolite composition. A total of 220 detected ions were classified into 174 metabolite derivative groups and 72 ions were assigned to candidate metabolites in the present work. Finally, metabolic profiling has been able to distinguish between the growth stages with the aid of PCA. The constructed model using PLS regression for OD600 values as a function of metabolic profiles is very useful for identifying to what degree the ions contribute to the growth stages. Ten phospholipids which largely influence the constructed model are highly abundant in the cells. Our analyses reveal that global modification of those phospholipids occurs as E. coli enters the stationary phase. Thus, the integrated approach involving correlation analyses, metabolic profiling, and database searching is efficient for high-throughput metabolomics

Seven Golden Rules for heuristic filtering of molecular formulas obtained by accurate mass spectrometry

BACKGROUND: Structure elucidation of unknown small molecules by mass spectrometry is a challenge despite advances in instrumentation. The first crucial step is to obtain correct elemental compositions. In order to automatically constrain the thousands of possible candidate structures, rules need to be developed to select the most likely and chemically correct molecular formulas. RESULTS: An algorithm for filtering molecular formulas is derived from seven heuristic rules: (1) restrictions for the number of elements, (2) LEWIS and SENIOR chemical rules, (3) isotopic patterns, (4) hydrogen/carbon ratios, (5) element ratio of nitrogen, oxygen, phosphor, and sulphur versus carbon, (6) element ratio probabilities and (7) presence of trimethylsilylated compounds. Formulas are ranked according to their isotopic patterns and subsequently constrained by presence in public chemical databases. The seven rules were developed on 68,237 existing molecular formulas and were validated in four experiments. First, 432,968 formulas covering five million PubChem database entries were checked for consistency. Only 0.6% of these compounds did not pass all rules. Next, the rules were shown to effectively reducing the complement all eight billion theoretically possible C, H, N, S, O, P-formulas up to 2000 Da to only 623 million most probable elemental compositions. Thirdly 6,000 pharmaceutical, toxic and natural compounds were selected from DrugBank, TSCA and DNP databases. The correct formulas were retrieved as top hit at 80–99% probability when assuming data acquisition with complete resolution of unique compounds and 5% absolute isotope ratio deviation and 3 ppm mass accuracy. Last, some exemplary compounds were analyzed by Fourier transform ion cyclotron resonance mass spectrometry and by gas chromatography-time of flight mass spectrometry. In each case, the correct formula was ranked as top hit when combining the seven rules with database queries. CONCLUSION: The seven rules enable an automatic exclusion of molecular formulas which are either wrong or which contain unlikely high or low number of elements. The correct molecular formula is assigned with a probability of 98% if the formula exists in a compound database. For truly novel compounds that are not present in databases, the correct formula is found in the first three hits with a probability of 65–81%. Corresponding software and supplemental data are available for downloads from the authors' website

Assessing human diet and movement in the Tongan maritime chiefdom using isotopic analyses.

The rise of stratified societies fundamentally influences the interactions between status, movement, and food. Using isotopic analyses, we assess differences in diet and mobility of individuals excavated from two burial mounds located at the `Atele burial site on Tongatapu, the main island of the Kingdom of Tonga (c. 500 - 150 BP). The first burial mound (To-At-1) was classified by some archaeologists as a commoner's mound while the second burial mound (To-At-2) was possibly used for interment of the chiefly class. In this study, stable isotope analyses of diet (δ13C, δ15N, and δ34S; n = 41) are used to asses paleodiet and 87Sr/86Sr ratios (n = 30) are analyzed to investigate individual mobility to test whether sex and social status affected these aspects of life. Our results show significant differences in diet between burial mounds and sexes. Those interred in To-At-2 displayed lower δ13C values, indicating they ate relatively more terrestrial plants (likely starchy vegetable staples) compared with To-At-1 individuals. Females displayed significantly lower δ15N values compared with males within the entire assemblage. No differences in δ34S values were observed between sexes or burial mound but it is possible that sea spray or volcanism may have affected these values. One individual displayed the strontium isotopic composition representative of a nonlocal immigrant (outside 2SD of the mean). This suggests the hegemonic control over interisland travel, may have prevented long-term access to the island by non-Tongans exemplifying the political and spiritual importance of the island of Tongatapu in the maritime chiefdom

Long-term monitoring of the ANTARES optical module efficiencies using K-40 decays in sea water

[EN] Cherenkov light induced by radioactive decay products is one of the major sources of background light for deep-sea neutrino telescopes such as ANTARES. These decays are at the same time a powerful calibration source. Using data collected by the ANTARES neutrino telescope from mid 2008 to 2017, the time evolution of the photon detection ef¿ciency of optical modules is studied. A modest loss of only 20% in 9 years is observed. The relative time calibration between adjacent modules is derived as well.Albert, A.; Andre, M.; Anghinolfi, M.; Anton, G.; Ardid Ramírez, M.; Aubert, J.; Aublin, J.... (2018). Long-term monitoring of the ANTARES optical module efficiencies using K-40 decays in sea water. The European Physical Journal C. 78(8):1-8. https://doi.org/10.1140/epjc/s10052-018-6132-2S18788M. Ageron et al., ANTARES: The first undersea neutrino telescope. Nuclear Instruments and Methods in Physics Research A 656, 11–38 (2011)A. Albert et al., First all-flavor neutrino pointlike source search with the ANTARES neutrino telescope. Physical Review D 96, 082001 (2017)A. Albert et al., All-flavor Search for a Diffuse Flux of Cosmic Neutrinos with Nine Years of ANTARES Data. The Astrophysical Journal Letters 853, L7 (2018)B.P. Abbott et al., Multi-messenger Observations of a Binary Neutron Star Merger. The Astrophysical Journal Letters 848, L12 (2017)S. Adrián-Martínez et al., Measurement of atmospheric neutrino oscillations with the ANTARES neutrino telescope. Physics Letters B 714, 224–230 (2012)A. Albert et al., Search for relativistic magnetic monopoles with five years of the ANTARES detector data. Journal of High Energy Physics 7, 54 (2017)S. Adrián-Martínez et al., Limits on dark matter annihilation in the sun using the ANTARES neutrino telescope. Physics Letters B 759, 69–74 (2016)A. Albert et al., Results from the search for dark matter in the Milky Way with 9 years of data of the ANTARES neutrino telescope. Physics Letters B 769, 249–254 (2017)M.G. Aartsen et al., The IceCube Neutrino Observatory: instrumentation and online systems. Journal of Instrumentation 12, P03012 (2017)K. Abe et al., Calibration of the Super-Kamiokande detector. Nuclear Instruments and Methods in Physics Research A 737, 253–272 (2014)P. Amram et al., The ANTARES optical module. Nuclear Instruments and Methods in Physics Research A 484, 369–383 (2002)S. Adrián-Martínez et al., The positioning system of the ANTARES Neutrino Telescope. Journal of Instrumentation 7, T08002 (2012)J.A. Aguilar et al., Performance of the front-end electronics of the ANTARES neutrino telescope. Nuclear Instruments and Methods in Physics Research A 622, 59–73 (2010)J.A. Aguilar et al., The data acquisition system for the ANTARES neutrino telescope. Nuclear Instruments and Methods in Physics Research A 570, 107–116 (2007)J.A. Aguilar et al., Measurement of the atmospheric muon flux with a 4 GeV threshold in the ANTARES neutrino telescope. Astroparticle Physics 33, 86–90 (2010)J.A. Aguilar et al., Transmission of light in deep sea water at the site of the ANTARES neutrino telescope. Astroparticle Physics 23, 131–155 (2005)S. Kim et al., PubChem Substance and Compound databases. Nucleic Acids Research 44, 1202–13 (2016)G. Audi et al., The NUBASE evaluation of nuclear and decay properties. Nuclear Physics A 729, 3–128 (2003)J. Floor Anthoni. The chemical composition of seawater. http://www.seafriends.org.nz/oceano/seawater.htmJ.R. De Laeter et al., Atomic Weights of the Elements: Review 2000 (IUPAC Technical Report). Pure Applied Chemistry 75, 683–800 (2003)P. Amram et al., Background light in potential sites for the ANTARES undersea neutrino telescope. Astroparticle Physics 13, 127–136 (2000)C. Tamburini et al., Deep-sea bioluminescence blooms after dense water formation at the ocean surface. PLOS ONE, 8(7), (2013)J.A. Aguilar et al., Time calibration of the ANTARES neutrino telescope. Astroparticle Physics 34, 539–549 (2011)M. Ageron et al., The ANTARES optical beacon system. Nuclear Instruments and Methods in Physics Research A 578, 498–509 (2007)S. Adrián-Martínez et al., Time calibration with atmospheric muon tracks in the ANTARES neutrino telescope. Astroparticle Physics 78, 43–51 (2016)S. Adrián-Martínez et al., Letter of Intent for KM3NeT 2.0. Journal of Physics G. Nuclear Physics 43(8), 084001 (2016