The main standard method for gold karat determination is the cupellation method. However, this method is not sufficiently accurate to determine gold karat in the presence of insoluble Platinum–Group Metals (PGMs), such as Ir, Ru, and Rh. In this study, for the first time, a complementary method that can be used coupled with the reference cupellation method is presented for the high...

Titania of fine anatase nanoparticles (ST01) was modified successively with two components, i.e., a ruthenium(II) complex with phosphonic anchoring groups [Ru(bpy)2(4,4'-(CH2PO3H2)2bpy)](2+) bpy = 2,2'-bipyridine (Ru(II)CP) and gold nanoparticles (Au). Various compositions of two titania modifiers were investigated, i.e., Au, Au + Ru(II)CP, Au + 0.5Ru(II)CP, Ru(II)CP, 0.5Ru(II)CP and 0.25Ru(II)...

The scanning electrochemical microscope (SECM) is used to image the activity of enzymes immobilized on the surfaces of disk-shaped carbon-fiber electrodes. SECM was used to map the concentration of enzymatically produced hydroquinone or hydrogen peroxide at the surface of a 33-microm diameter disk-shaped carbon-fiber electrode modified by an immobilized glucose-oxidase layer. Sub-monolayer cove...

Modified colloids and flat surfaces occupy an important place in materials science research due to their widespread applications. Interest the development of modifiers that adhere strongly relates need for stability under ambient conditions many Diazonium salts have evolved as primary choice modification surfaces. The term diazonics has been introduced literature describe technology aryldiazoni...

We unveil experimental evidence that put into question the widely held notion concerning the impact of nanoparticles on the bioelectrocatalytic parameters of enzymatic electrodes. Comparative studies of the bioelectrocatalytic properties of fungal bilirubin oxidase from Myrothecium verrucaria adsorbed on gold electrodes, modified with gold nanoparticles of different diameters, clearly indicate ...

Abstract The wide application of gold nanoparticles has attracted much attention to the development research in nanoparticles. In this study, were prepared by chemical reduction method using potassium tetrachloroaurate as source and sodium borohydride reducer agent. formation was confirmed surface plasmon spectra ultraviolet-visible spectroscopy at wavelength 507 nm. capping process studied two...

Post-synthesis modification is a useful method for the functionalization of metal-organic frameworks (MOFs). A novel catalyst Au@MIL-101-ED-SA (ED = ethylenediamine, SA = salicylaldehyde), containing coexisting Au3+ ions and Au⁰ nanoparticles, was prepared successfully by post-synthesis modification with ethylenediamine, salicylaldehyde and gold. Gold nanoparticles supported on MIL-101 (Au@MIL-...

The Chah-Bagh gold occurrence is located in Muteh mining district, in the central part of the Sanandaj-Sirjan zone. Gold mineralization occurs in ductile to ductile-brittle shear zones and is comparable with orogenic gold deposits. Silicification and sulfidization are the most important hydrothermal alteration features in the inner parts of altered shear zones and coincide most closely with the...