Remote electrochemical monitoring of trace silver

A novel electrochemical sensor for remote monitoring of trace silver is described. The probe relies on linear scan stripping voltammetry at a newly-designed carbon-fiber working electrode assembly, connected to a 50-ft. long shielded cable. High sensitivity and selectivity are achieved while the probe is fully submersed in unaltered river-, lake- or groundwater samples. The optimization of various parameters has resulted in low detection limits (e.g., 0.3 μg/1 with 10 min accumulation) and good precision (relative standard deviation (R.S.D.) = 8% for n = 18 at 3 μg/1 silver). The new probe can operate over a broad pH and ionic-strength ranges relevant to natural water matrices.