A new method for determining ultrasmall (nL) volumes by anodic stripping voltammetry has been proposed (W. R. Vandaveer and I. Fritsch, Anal. Chern., 2002,74,3575). In this method, a metal is exhaustively deposited from the small volume to be measured onto an electrode, from which it is later stripped. The solution volume V, is related to the total charge 𝒬 required to strip the metal by
where n is the number of moles of electrons per mole of analyte, F is the faraday, and C is the molar concentration of the metal ion before electrolysis.
(a) Beginning with Faraday's law (see Equation 22-8, derive the above equation for vs.
(b) In one experiment, the metal deposited was Ag(s) from a solution that was 8.00 mM in AgNO3 The solution was electrolyzed for 30 min at a potential of -0.700 V versus a gold top layer as a pseudoreference. A tubular nano band electrode was used. The silver was then anodically stripped off the electrode using a linear sweep rate of 0.10 V/s. The following table represents idealized anodic stripping results. By integration, determine. The total charge required to strip the silver from the tubular electrode. You can do a manual Simpson's rule integration or do the integration with Excel.49From the charge, determine the volume of the solution from which the silver was deposited.
(c) Suggest experiments to show whether all the Ag+ was reduced to Ag(s) in the deposition step.
(d) Would it matter if the droplet were not a hemisphere? Why or why not?
(e) Describe an alternative method against which you might test the proposed method.