Palladium determination using flow-through spectrophotometric sensing phase

The paper presents the application of a newly synthesised indicator (i.e. 2,2-bis-[3-(2-thiazolylazo)-4-4-hydroxyphenyl-propane], TAPHP) for selective detection of palladium. The indicator was immobilised on silica beads in order to increase the active surface of the layer interacting with a sample. A special flow cell was designed in a transilluminance configuration, in which the optical path length in the order of 5 mm was achieved. Multimode optical fibres were used to guide the light from the light source (a white LED) to the cell and from the cell to the detector (a miniature spectrometer). The work of the spectrometer was governed by software developed under LabVIEW environment. It was found that the indicator is selective to palladium since there were no observable changes in the signal caused by platinum, ruthenium ions. However, pH of the sample should be kept constant (pH 2). In other cases, the influence of metal cations occurs.