FLUORESCENCE AND METALLIC VALENCY STATES .I. DETERMINATION OF SILVER WITH OXINE-5-SULPHONIC ACID

Small amounts (0.1-10 μg) of silver can be determined by measurement of the fluorescent intensity (at 485 nm) obtained on addition of persulphate to aqueous solutions (pH 1.5-3.5) containing silver(I) and oxine-5-sulphonic acid. Fluorescence intensity is linear from 12.5 p.p.b. to 5 p.p.m. and most metal ions do not interfere; 1 p.p.m. of copper, mercury or palladium, causes fluorescence quenching whilst similar amounts of zirconium and hainium form strongly fluorescent chelates and cause high results. The reaction involves formation of silver(III) which then reacts with the oxine-5-sulphonic acid to give the fluorescent product. © 1969.