Isotope ratio mass spectrometer

Bone collagen stable isotope analyses were performed in duplicate on 0.5 mg collagen samples for δ¹³C and δ¹⁵N analyses and, where collagen yield allowed, 6.0 mg samples for δ³⁴S. For scales, duplicate analyses were performed on collagen from two separate scales per individual. For δ¹³C and δ¹⁵N analyses, samples were combusted in tin capsules in an Elementar vario MICRO cube elemental analyzer coupled to an Isoprime isotope ratio mass spectrometer in continuous flow mode. Carbon and nitrogen isotopic compositions were calibrated relative to VPDB and AIR using USGS40 and USGS41. For δ³⁴S analyses, samples were combusted in tin capsules with 1 mg of V₂O₅ in an Elementar vario MICRO cube elemental analyzer coupled to an Isoprime 100 isotope ratio mass spectrometer in continuous flow mode. Sulphur isotopic compositions were calibrated relative to VCDT using IAEA-S-1 and NBS-127.