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E vs. SSCE Figure 3. (A) Cyclic voltammogram of 48., mM ferrocene in 0.5 M TBAP/acetonitrile at a 1 p m total tip, 27-A platinum disk electrode at a scan rate of 50 mV/s. (B) Blank at a scan rate 100 mV/s.
200 8, are lower than theoretically predicted. They proposed that the diffusion coefficient of the electroactive species near the electrode may be lower than that in the bulk solution. Since the bulk value of the diffusion coefficient was used to estimate the electrode radius, it is likely that the true radius is actually larger. However, we believe the estimation to be good within a factor of 2 or 3. This represents the smallest platinum disk electrode ever reported and illustrates the capability of the method presented. Third, the success to attempts ratio of constructing electrodes whose total outer diameter is less than 10 pm has been about 42%.
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RECEIVED for review November 10, 1989. Accepted January 3, 1990. This work was generously funded by the National Science Foundation. H.D.A. is a recipient of a Presidential Young Investigator Award (1984-1989) and an A. P. Sloan Fellow (1987-1991). B.D.P. acknowledges support as a Shell Doctoral Fellow (1989-1990).
C ORRECTI0N
Random-Walk Theory of Nonequilibrium Plate Height in Micellar Electrokinetic Capillary Chromatography Joe M. Davis (Anal. Chem. 1989, 61, 2455-2461). On page 2458, second column, line 44, the text should read as follows: Quantity t o / & for the nucleic acids was equated to 0.47, the ratio of the elution times of the void peak and the final peak.
