Isotopic biographies reveal horse rearing and trading networks in medieval London.

This paper reports a high-resolution isotopic study of medieval horse mobility, revealing their origins and in-life mobility both regionally and internationally. The animals were found in an unusual horse cemetery site found within the City of Westminster, London, England. Enamel strontium, oxygen, and carbon isotope analysis of 15 individuals provides information about likely place of birth, diet, and mobility during the first approximately 5 years of life. Results show that at least seven horses originated outside of Britain in relatively cold climates, potentially in Scandinavia or the Western Alps. Ancient DNA sexing data indicate no consistent sex-specific mobility patterning, although three of the five females came from exceptionally highly radiogenic regions. Another female with low mobility is suggested to be a sedentary broodmare. Our results provide direct and unprecedented evidence for a variety of horse movement and trading practices in the Middle Ages and highlight the importance of international trade in securing high-quality horses for medieval London elites.

The effect of matrix interferences on in situ boron isotope analysis by laser ablation multi-collector inductively coupled plasma mass spectrometry.

RATIONALE: Boron isotope analysis of marine carbonates by laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) offers the potential for rapid sample throughput, and the means to examine micron-scale variations in the δ11 B signatures of fossil skeletons and shells/tests of marine organisms. Existing studies demonstrate an acceptable level of reproducibility is achievable, but also typically show a level of accuracy outside the limits required by most applications. Here we investigate matrix interference effects as a cause of inaccuracy and imprecision. METHODS: Analyses were performed on a standard format Thermo Scientific Neptune Plus MC-ICP mass spectrometer coupled to a New Wave Research 193 nm ArF laser ablation system. The effects of matrix interference on δ11 B analysis were investigated through analyses of a set of reference materials with differing B/Ca ratios. Three approaches to correct for matrix-induced effects were trialled: (1) use of matrix-matched standards, (2) utilisation of the relationship between δ11 B inaccuracy and11 B/43 Ca, 11 B/40 ArCa4+ or 11 B/Cainterference from three reference materials with known δ11 B values and varying B/Ca ratios, and (3) direct characterisation of the (sloping) interference itself. RESULTS: Matrix interference from scattered Ca ions on 10 B can impede both the accuracy and the reproducibility of δ11 B analysis by LA-MC-ICP-MS. Based on analyses of two in-house reference materials, deep sea coral PS69/3181 and inorganic calcite UWC-1, we find approach 2, following the 11 B/Cainterference relationship, gives the best mean accuracies (within 0.4‰ of solution values) and external reproducibilities (± 0.5‰ 2 SD for PS69/3181). This approach has been applied to analyses of an annual growth cycle of a Siderastrea siderea coral and eight Cibicidoides wuellerstorfi benthic foraminifera. Both coral and foraminifera data match solution MC-ICP-MS analyses within reported uncertainties. CONCLUSIONS: LA-MC-ICP-MS can produce accurate and precise δ11 B data to a 0.5‰ (2σ) level on <0.3 ng B after correction for Ca interference effects.

Determination of precise ¹³5Cs/¹³7Cs ratio in environmental samples using sector field inductively coupled plasma mass spectrometry.

Recent advances in sector field inductively coupled plasma mass spectrometry (ICP-SFMS) have led to significant sensitivity enhancements that expand the range of radionuclides measurable by ICP-MS. The increasing capability and performance of modern ICP-MS now allows analysis of medium-lived radionuclides previously undertaken using radiometric methods. A new generation ICP-SFMS was configured to achieve sensitivities up to 80,000 counts per second for a 1 ng/L (133)Cs solution, providing a detection limit of 1 pg/L. To extend this approach to environmental samples it has been necessary to develop an effective chemical separation scheme using ultrapure reagents. A procedure incorporating digestion, chemical separation and quantification by ICP-SFMS is presented for detection of the significant fission product radionuclides of cesium ((135)Cs and (137)Cs) at concentrations found in environmental and low level nuclear waste samples. This in turn enables measurement of the (135)Cs/(137)Cs ratio, which varies with the source of nuclear contamination, and can therefore provide a powerful dating and forensic tool compared to radiometric detection of (137)Cs alone. A detection limit in sediment samples of 0.05 ng/kg has been achieved for (135)Cs and (137)Cs, corresponding to 2.0 × 10(-3) and 160 mBq/kg, respectively. The critical issue is ensuring removal of barium to eliminate isobaric interferences arising from (135)Ba and (137)Ba. The ability to reliably measure (135)Cs/(137)Cs using a high specification laboratory ICP-SFMS now enables characterization of waste materials destined for nuclear waste repositories as well as extending options in environmental geochemical and nuclear forensics studies.

Analysis methods and reference concentrations of 12 minor and trace elements in fish blood plasma.

A comprehensive review of the analytical literature revealed substantial under-representation of trace element concentrations in fish blood, particularly for marine species. We describe a simple dilution procedure to measure Li, Mg, K, Ca, Mn, Cu, Zn, Se, Rb, Sr, Ba and Pb concentrations in low volumes of blood plasma of adult plaice (Pleuronectes platessa) using high resolution-inductively coupled plasma-mass spectrometry (HR-ICP-MS). Captive male and female plaice (n = 18) were serially sampled for one year and samples collected outside of the spawning season (n = 157) used to estimate reference ranges for this species. Method accuracy was deemed satisfactory, based on its application to the analysis of a certified reference material. Precision was generally <3%, with the most conservative measure of precision being ≤10% for all elements except Pb (∼20%). This is the first study to analyse fish blood plasma by ICP-MS and includes some of the first reference ranges for trace element concentrations in fish blood.