Effect of surface type on stability of silver clusters upon laser desorption/ionization

The stabilities of silver clusters with organic and inorganic anions on carbon and metallic surfaces are compared. It was revealed that inorganic anions, primarily halides, stabilize the clusters more effectively than anions of amino acids do. A possible practical application of the cluster stabilization technique was demonstrated for investigation of surface morphology and determination of trace amounts of amino acids. The homogeneity of the morphology of Ad-0 and AMg-6 alloys on the distribution of cluster-forming compounds on the surface was investigated. It was shown that the distribution of silver chloride on the surface after exposure to an aggressive medium was less uniform than on a surface that was in an inert atmosphere. A method is proposed for identifying trace amounts of amino acids on the surfaces of these alloys with the use of a clustering salt of silver chloride, which causes ionization of the formation of the adduct of the amino acid with silver, as well as adducts of dimers and trimers of amino acids with alkali metals and salts that increase the reliability of determination. The sensitivity of determination of amino acids by this method increases up to ten times.