The oxidation-reduction potential of aqueous soil solutions at the Mars Phoenix landing site

摘要: [1] Results from the Mars Phoenix mission Wet Chemistry Laboratory (WCL) are used to determine oxidation-reduction potential (Eh) of WCL Rosy Red sample soil solution. The measured Eh in aqueous test solution was 253 ± 6 mV at a pH 7.7 0.1. Measured changes correspond H+ activity, which is controlled mainly by headspace PCO2 and CO32−, HCO3−, CO2 concentrations. If 8 mbar water, rather than solution, would be ∼300 mV. results laboratory experiments using analog salt mixtures compatible with possible presence low levels (ppm) metal peroxides or other oxidants indicate that readily soluble ferrous iron below 1 ppm.