Voltammetric determination of trace platinum in gasoline after Wickbold combustion

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.