Kinetic determination of ruthenium by on-line microwave flow injection analysis

A new rapid high sensitive and selective on-line: microwave flow injection method has been developed for the determination of micro-amounts of rutheni um, based on its catalytic effect on the oxidation of dibromocarboxyarsenaz o (DBM-AsA) by potassium periodide in acidic medium. The assay is performed in a microwave-induced flow injection analyzer by measuring the absorption of DBM-AsA at 538 nm spectrophotometrically. Microwave irradiation has bee n found efficient to supply enough energy for the reaction in a very short time and give a lower detection limit. Under the optimized experimental con ditions, ruthenium can be determined in the range 5 similar to 200 ng ml(-1 ) with the detection limit of 2.1 ng ml(-1) and the sampling frequency of 7 2 h(-1). The proposed method has been successfully applied to the determina tion of ruthenium in refined ore samples with the recovery of 93.0 similar to 99.9%.