Ultrasensitive electrochemiluminescence determination of trace Ag ions based on the signal amplification caused by its catalytic effect on Mn(II) oxidation using graphite catheter as electrode.

In this work, an ultrasensitive electrochemiluminescence (ECL) method was established for the detection of trace amount of Ag ions (Ag+). In sulfuric acid medium, Ag(II), the electro-oxidized product of Ag(I), oxidizes manganese ions (Mn2+) to produce permanganate (MnO4-) by using a pair of graphite catheters as electrodes. While permanganate and luminol can produce strong chemiluminescence, based on the catalytic effect of Ag(II) on Mn2+ oxidation, there is a good linear relationship between the concentration of Ag+ and luminescence intensity. Under optimized conditions, the linear range of this method for Ag+ is from 0.2 to 150 nM with a detection limit of 0.06 nM. The method was applied for determination of Ag+ in various water samples with satisfactory results.