Platinum Metals Rev., 1989, 33, (4), 193
Palladium as an Aid in Trace Analysis of Food
Palladium has become established as one of the most widely applicable chemical modifiers in electrothermal atomic absorption spectrophotometry (ETAAS). Its applications have recently been extended to the determination of lead, cadmium and tin in food slurries.
In ETAAS a volume of sample is introduced into a small furnace—usually a graphite tube—and heated in stages to remove the solvent, decompose the sample matrix and finally produce a cloud of atoms in the central zone of the furnace. These atoms absorb light selectively, permitting the ultra-trace determination of metals. Chemical modifiers are added to the sample solution to avoid the loss of the elements of interest during the decomposition stage. Palladium appears to act by forming compounds, for example Pb3 Pd, which are more thermally stable than the base metal alone.
A recent report from the University of Strathclyde, Glasgow, describes the extension of this work to the determination of lead in slurries of freeze-dried foodstuffs (S. Lynch and D. Littlejohn, “Palladium as a Chemical Modifier for the Determination of Lead in Food Slurries by Electrothermal Atomisation Atomic Adsorption Spectrometry”, J. Anal. At. Spectrom., 1989, 4, (2), 157–161). Detection limits of 200 ng/g have been reported. Promising results have also been obtained for cadmium and tin. Palladium appears to have considerable potential in this area.