Time-of-flight secondary ion mass spectrometry analysis of hair from archaeological remains

Hair from four individuals excavated from burial sites in Pacatnamu, Peru from the Moche (450-800 AD) and Lambayeque (900-1100 AD) periods was sectioned longitudinally and analysed with time-of-flight secondary ion mass spectrometry (ToF-SIMS). An attempt was made to distinguish biogenic and diagenetic contributions to the elemental concentrations in the hair samples. Significant contamination was observed to have penetrated the hair samples from the burial environment. Results from the analyses indicate that the burial environment plays an important role in the postmortem variation in elemental content of hair samples. Various elements demonstrated an ability to permeate through the hair matrix over time. In addition, NaCl and what are believed to be aluminosilicates and mineral sulphates, were observed to have accumulated on the surface of the samples. Degradation of the samples was also suspected due to the presence of molecular fragments, possibly resulting from oxidation of the keratin proteins. The results should assist in the identification of reliable elemental signals in the analysis of ancient hair samples and promote caution when considering elements that are abundant in the burial environment.     

Tetramethylammonium hydroxide thermochemolysis for the analysis of cellulose and free carbohydrates in a peat bog

We have compared TMAH thermochemolysis with the classical method using acid hydrolysis for carbohydrates analysis in a peat core. Even if TMAH thermochemolysis does not analyse hemicellulosic carbohydrates and discriminate each individual carbohydrate sensu stricto, it allows the analysis of a cellulose pool hidden to acid hydrolysis and the specific analysis of free and terminal carbohydrates. Simple direct comparisons of thermochemolysis data with data generated from acid hydrolysis cannot be done because of the different mechanisms involved in each process. TMAH thermochemolysis must be viewed and used as a pertinent and complementary method for the analysis of carbohydrates protected and trapped by the organic matter in complex environmental systems.     

Gas chromatographic, mass spectrometric and stable carbon isotopic investigations of organic residues of plant oils and animal fats employed as illuminants in archaeological lamps from Egypt

Man's use of illuminants in lamps or as torches to extend the working day and range of environments accessible to him would have been a major technological advance in human civilisation. The most obvious evidence for this in the archaeological record comes from pottery and stone vessels showing sooting due to the use of a wick in conjunction with a lipid-based fuel or illuminant. A wide range of potential fuels would have been exploited depending upon availability and burning requirements. Reported herein are the results of chemical investigations of a number of lamps recovered from excavations of the site of Qasr Ibrim, Egypt. Gas chromatographic, mass spectrometric and stable carbon isotopic analyses of both free (solvent extractable) and 'bound'(released from solvent extracted pottery by base treatment) lipids have revealed a wide range of saturated fatty acids, hydroxy fatty acids and alpha, omega-dicarboxylic acids. Examination of the distributions of compounds and comparisons with the fatty acid compositions of modern plant oils have allowed a range of fats and oils to be recognised. Specific illuminants identified include Brassicaceae (Cruciferae) seed oil (most likely radish oil, Raphanus sativus), castor oil (from Ricinus communis), animal fat, with less diagnostic distributions and delta(13)C values being consistent with low stearic acid plant oils, such as linseed (Linum usitatissimum) or sesame (Sesamum indicum) oils. The identifications of the various oils and fats are supported by parallel investigations of illuminant residues produced by burning various oils in replica pottery lamps. The findings are entirely consistent with the classical writers including Strabo, Pliny and Theophrastrus.     

Mineralised organic remains from cesspits at the Roman town of Silchester: processes and preservation

Mineralised organic remains (including apple pips and cereal grains) collected during the ongoing excavations of Insula IX at the Roman town of Silchester, Hampshire have been analysed by a combination of SEM-EDX, powder XRD and IR spectroscopy. The experiments included mapping experiments using spatially resolved versions of each technique. IR and powder XRD mapping have been carried out utilising the synchrotron source at The Daresbury Laboratory on stations 11.1 and 9.6. It is concluded that these samples are preserved by rapid mineralisation in the carbonate-substituted calcium phosphate mineral, dahllite. The rapid mineralisation leads to excellent preservation of the samples and a small crystal size. The value of IR spectroscopy in studying materials like this where the crystal size is small is demonstrated. A comparison is made between the excellent preservation seen in this context and the much poorer preservation of mineralised remains seen in Context 5276 or Cesspit 5251. Comments on the possible mechanism of mineralisation of these samples are made.     

Study of geochemical aspects of the peat bog genesis in eutrophic marshes in West Siberia by neutron activation analysis

Siberian peat bog are the largest in the world. Collecting of data on contaminating elements in Siberian peat deposits is important because no quantitative information has been available till recently. As a rule, the distribution of the concentrations of elements over the vertical profile of the stratigraphic column is used to study the evolution of pollutants in the environment. Using neutron activation analysis the concentrations of nearly 33 elements in 23 layers of peat deposits were determined. The thickness of the deposit is 8.4 m. The results provide a possibility for studying the geochemical aspects of the peat bog genesis down to 10 000 years ago.     

Extraction of boron from GSJ rock reference samples and determination of their boron isotopic ratios

The extraction of boron from rocks by methyl borate distillation after alkali fushion was studied. Reproducible extraction was obtained when the ratio of the amounts of flux and rock was ?5:1. Isotope dilution experiments showed there was no appreciable boron isotope fractionation during the extraction under these conditions. ¹¹B/¹⁰B ratios for three standard rocks were 4.044–4.047.     

Stable hydrogen and oxygen isotope ratios of bottled waters of the world

Bottled and packaged waters are an increasingly significant component of the human diet. These products are regulated at the regional, national, and international levels, and determining the authenticity of marketing and labeling claims represents a challenge to regulatory agencies. Here, we present a dataset of stable isotope ratios for bottled waters sampled worldwide, and consider potential applications of such data for regulatory, forensic and geochemical standardization applications. The hydrogen and oxygen isotope ratios of 234 samples of bottled water range from -147 per thousand to +15 per thousand and from -19.1 per thousand to +3.0 per thousand, respectively. These values fall within and span most of the normal range for meteoric waters, indicating that these commercially available products represent a source of waters for use as laboratory working standards in applications requiring standardization over a large range of isotope ratios. The measured values of bottled water samples cluster along the global meteoric water line, suggesting that bottled water isotope ratios preserve information about the water sources from which they were derived. Using the dataset, we demonstrate how bottled water isotope ratios provide evidence for substantial evaporative enrichment of water sources prior to bottling and for the marketing of waters derived from mountain and lowland sources under the same name. Comparison of bottled water isotope ratios with natural environmental water isotope ratios demonstrates that on average the isotopic composition of bottled water tends to be similar to the composition of naturally available local water sources, suggesting that in many cases bottled water need not be considered as an isotopically distinct component of the human diet. Our findings suggest that stable isotope ratios of bottled water have the power to distinguish ultimate (e.g., recharge) and proximal (e.g., reservoir) sources of bottled water and constitute a potential tool for use in the regulatory monitoring of water products.     

Calculation methods for direct internal mass fractionation correction of spiked isotopic ratios from multi-collector mass spectrometric measurements

It is difficult to do internal mass fractionation corrections for isotope dilution analysis by thermal ionization mass spectrometry (TIMS) or multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS), especially for MC-ICP-MS. In this study, calculation methods for direct internal fractionation correction of spiked isotope analysis by TIMS or MC-ICP-MS cycle by cycle for elements having at least two internal reference isotopic ratios are presented. For TIMS, direct internal mass fractionation correction calculation methods, based on both power and exponential laws, are derived; whereas for MC-ICP-MS, due to larger mass fractionation effects, only exponential law is considered. These calculation strategies can be applied for both static and multi-dynamic measurements. For multi-dynamic measurements, the isotope fractionation effect, gain and cup efficiency effects of different collectors, as well as ion beam fluctuation effects are all simultaneously eliminated. The calculation methods were verified by Sr isotopic analyses of spiked NBS987 standard solutions by TIMS and Hf isotopic analyses of spiked geological reference materials by MC-ICP-MS. In addition, precise and accurate calibrations of isotopic ratios of the spikes, based on the calculation methods, are discussed.     

Reasons for the variability of isotopic ratios of stretching vibration frequencies of H-bonded complexes

The effect of random resonances and vibration anharmonicity on the isotopic ratios of frequencies for molecules containing hydrogen atoms has been studied. It was found that the anomalous frequency dependence of the v(XH)/v(XD) isotopic ratio of the stretching vibration frequencies observed for H-bonded systems can be explained in terms of the theory of harmonic vibrations of molecules. The substantial deviation of experimental v(XH)/v(XD) from the magnitude equal to the square root of the reciprocal ratio of adjusted masses results from random resonances between the stretching mode of the bridging proton and some other vibration of the system.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2090–2097, December, 1994.This work was carried out with the financial support of the Russian Foundation for Basic Research, Project No. 94-03-09340.     

226Ra and uranium isotopic ratios characterization into the Gran Sasso aquifer,Italy

Journal of Radioanalytical and Nuclear Chemistry - Groundwater samples, collected into the deep underground facilities of Gran Sasso National Laboratory of the National Institute of Nuclear Physics...     

Stable isotope ratios of carbon and hydrogen to distinguish olive oil from shark squalene‐squalane

Squalene and its hydrogenated derivate squalane are widely used in the pharmaceutical and cosmetic fields. The two compounds are mainly produced from the liver oil of deep sea sharks and from olive oil distillates. Squalene and squalane from shark cost less than the same compounds derived from olive oil, and the use of these shark‐derived compounds is unethical in cosmetic formulations. In this work we investigate whether ¹³C/¹²C and ²H/¹H ratios can distinguish olive oil from shark squalene/squalane and can detect the presence of shark derivates in olive oil based products. The ¹³C/¹²C ratios (expressed as δ¹³C values) of bulk samples and of pure compounds measured using isotope ratio mass spectrometry (IRMS) were significantly lower in authentic olive oil squalene/squalane (N: 13; ?28.4 ± 0.5‰; ?28.3 ± 0.8‰) than in shark squalene/squalane samples (N: 15; ?20.5 ± 0.7‰; ?20.4 ± 0.6‰). By defining δ¹³C threshold values of ?27.4‰ and ?26.6‰ for olive oil bulk and pure squalene/squalane, respectively, illegal addition of shark products can be identified starting from a minimum of 10%. ²H/¹H analysis is not useful for distinguishing the two different origins. δ¹³C analysis is proposed as a suitable tool for detecting the authenticity of commercial olive oil squalene and squalane samples, using IRMS interfaced to an elemental analyser if the purity is higher than 80% and IRMS interfaced to a gas chromatography/combustion system for samples with lower purity, including solutions of squalane extracted from cosmetic products. Copyright © 2010 John Wiley & Sons, Ltd.     

An approximate theory of the ozone isotopic effects: rate constant ratios and pressure dependence

The isotopic effects in ozone recombination reactions at low pressures are studied using an approximate theory which yields simple analytic expressions for the individual rate constant ratios, observed under "unscrambled" conditions. It is shown that the rate constant ratio between the two competing channels XYZ-->X+YZ and XYZ-->XY+Z is mainly determined by the difference of the zero-point energies of diatomic molecules YZ and XY and by the efficiency of the deactivation of the newly formed excited ozone molecules, whereas the mass-independent fractionation depends on a "nonstatistical" symmetry factor eta and the collisional deactivation efficiency. Formulas for the pressure effects on the enrichment and on the rate constant ratios are obtained, and the calculated results are compared with experiments and more exact calculations. In all cases, ratios of isotope rates and the pressure dependence of enrichments, the agreement is good. While the initial focus was on isotope effects in the formation of O(3), predictions are made for isotope effects on ratios of rate constants in other reactions such as O+CO-->CO(2), O+NO-->NO(2), and O+SO-->SO(2).