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Differential pulse cathodic stripping voltammetry (DPCSV) was used to determine ultra trace platinum in gasoline after Wickbold combustion and subsequent UV digestion. A commercially available Wickbold combustion apparatus was slightly modified and used to mineralize the gasoline samples. Because a sufficiently high chloride concentration is necessary to avoid Pt losses, the chloride concentration in the condensate was increased by adding HCl vapor to the oxygen stream. The sample solution obtained from the Wickbold combustion still contained some organic compounds which were eliminated using an UV digestion (T > 90 °C, t > 90 min) prior to the electrochemical determination. The recovery was > 87% Platinum concentrations in the order of 5 pg g−1 were found in the analyzed gasoline samples (unleaded Normal, Super and Super Plus). Inductively coupled plasma mass spectrometry was used for comparative measurements.

By introducing the exhaust gas converters in automobiles (in 1975 in the USA and in Germany in 1984) the emission of combustion based pollutants (e.g., NOx, HCH) and of lead have been significantly reduced. But materials used in the catalysts (initially mainly Pt, later in various ratios also other Platinum Group Metals (PGM) such as Pd and/or Rh and nowadays often only Pd and some transition metals as promotors) are increasingly being introduced into the environment. Many efforts have been made to study the influence of the trace metals in the environment. At first it was necessary to develop powerful analytical techniques to determine precisely high concentrations in polluted samples as well as ‘natural’ background concentrations at much lower levels. Table 2 and 3 presents an overview of concentration ranges of Pt and Rh found in various materials in the last years.