| Eh
/ pE punch-in redox probes blue: SCHOTT with ring Pt-electrode red: INGOLD with cone-shaped Pt-electrode |
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| method Eh /pE | redox
potential is measured by punching electrodes into undisturbed sediment.
Raw readings (mV) on the pH-meter have to be corrected by the standard
potential of the reference system (usually Ag/AgCl in 3 M/L KCl) Eh (SHE) = Ehmeas.[mV] + 207 + 0.7*(25 - temp[°C] ). Measurement inside argon-flooded glove box yields reliable values for anoxic sediments. Make sure both electrode and diaphragm are covered with sediment. .If blocking of diaphragm by silver sulfide precipitates occurs double junction probes or Pt-electrodes with separate double-junction reference are preferred. |