A novel method that makes use of a desolvation unit in combination with ICP-SFMS was developed for the direct and reliable determination of platinum at sub-ppb levels in environmental and biological samples, without the need for time-consuming pre-enrichment techniques. The determination of palladium has proven to be much more difficult than the determination of platinum; therefore the project was subsequently focused on platinum.
The new method was successfully applied to the determination of ultra trace levels of platinum in soil and a variety of plant-food samples from locations with high or low platinum burdens, i.e., frequency of traffic. In addition, Swiss lunch diets and urine samples were measured. The platinum concentration was considerably higher in food-plants and soil that were sampled in the proximity of well frequented highways. The highest value of about 230 ng/kg was found in green salad; however, a large platinum-fraction can be attributed to platinum (airborne) on the leaf surface. The platinum concentrations in the diets and urine samples were below the detection levels of 2 ng/kg and 0,5 ng/kg, respectively.
Moreover, the method permitted assessment of the anthropogenic platinum emission in peat-bog. The results revealed the time dependant evolution of the platinum emissions into the environment from analyzed peat cores dated back to 1944 by Pb-210. Samples collected adjacent to the well-frequented highway N 12 near Düdingen and from the remote area near St Moritz were compared. The level of platinum in the samples mirrored the introduction of the car catalysts and the respective traffic loads.
