The 797 VA Computrace from Metrohm can monitor heavy metal traces using the anodic stripping voltammetry (ASV) method.
The US ASTM D 4806 and the European EN 15376 both restrict the amount of copper in fuel ethanol to 10ug/l.
Anodic stripping voltammetry (ASV) is a determination method that allows the quantification of Cu(II) without any sample pre-treatment.
The presence of heavy metal traces in car fuels adversely affects engine performance.
Copper, for example, is a very active catalyst for the low-temperature oxidation of hydrocarbons.
Consequently, copper concentrations above 12ug/kg in commercial gasoline are expected to promote the deterioration of olefins and the formation of gum.
ASV is a sensitive and selective electro-analytical technique comprising two steps.
First, metal ions are electro-deposited on the mercury electrode, which is held at a suitable potential.
Then, the (amalgamated) metal deposits are anodically stripped from the mercury electrode by scanning the potential.
The ASV is performed using the hanging mercury drop electrode (HMDE) and the Metrohm 797 VA Computrace for trace analysis.
The HMDE is used with a platinum auxiliary electrode and an Ag/AgCI reference electrode using saturated lithium chloride in ethanol as the inner electrolyte.
The concentration of the copper in the samples is quantified by standard addition.
