Static SIMS Detection of Gold and Gold Cyanide Complexes on Carbon Using Crown Ether Enhancement

Determination of the nature of adsorbed gold cyanide species on activated carbon is difficult with presently available surface analysis techniques. Efforts toward the development of new, more specific analytical techniques are described in this paper. It is shown that static secondary ion mass spectrometiy can be used for the detection of gold on carbon surfaces and for the identification of cyanide species present The method described relies on two features: (1) the instrumentation employed utilizes pulsed secondary ion extraction, which mitigates the buildup of surface charge (a major problem in the bombardment of carbon) and permits the acquisition of the anion and cation spectra during the same analysis; (2) the surface of the carbon samples is doped with a crown ether, which results in the facile observation of AU(CN)₂^-, [M + crown]⁺ (where M is Na⁺ or K⁺), and in some cases Au^-. It is hypothesized that the crown ether facilitates the formation of gold cyanide ions by forming complexes with Na⁺ and K⁺ present on the surface of the charcoal, thereby loosening or freeing the Au(CN)₂^-.