Gold assay with Knudsen effusion mass spectrometry

Commercial 18 carat (ct) gold alloys along with pure coinage metals have been studied with Knudsen effusion mass spectrometry. Isotopic fractionation in vapour phase and the enthalpies of vaporization were estimated for Au, Ag and Cu samples. The assaying of the gold content was carried out by means of calibration with respect to standard reference alloys measured with energy dispersive X-ray spectroscopy. The accuracy of the gold determination resulted of about 1.5 wt.‰ in the ternary Au–Ag–Cu alloy.