2240
ANALYTICAL CHEMISTRY, VOL. 52, NO. 13, NOVEMBER 1980
data. The precise effect of the unit is seen in Figure 3. The first plateau, with the unit disabled, shows the effects of diffusion in the positive slope of 0.015 pH units/min. The second plateau, with the unit enabled, it virtually horizontal with a positive slope of less than 0.002 pH units/min. These data are taken from a titration of tartaric acid, 0.002 M, with 1.010 M potassium hydroxide.
0 002 pH unitr/mln
~
LITERATURE C I T E D (1) Leggett, D. J. Anal. Chem. 1978, 50, 718-722. (2) Guevremont, R.; Rabenstein, D. L. Can. J. Chem. 1979, 57, 466-471. (3) Lancaster, D. “CMOS Cookbook”; H. W. Sarns 8 Co.: Indianapolis, IN, 1979; p 31.
0
2
4
6
8
Time ( m i n l
Figure 3. Electrode response with (lower plateau) and without (upper plateau) titrant delivery tip in solution.
RECEIVED for review June 16,1980. Accepted August 18,1980.
can be gathered from weakly buffered regions and there are no discernible diffusion effects to be seen when processing the
Financial support for this work was provided by The Robert A. Welch Foundation (Grant E-755) and is gratefully acknowledged.
CORRECTION Pseudopolarographic Determination of Metal Complex Stability Constants i n Dilute Solution by Rapid S c a n Anodic S t r i p p i n g Voltammetry In this article by Steven D. Brown and Bruce R. Kowalski (Anal. Chem. 1979,51, 2133-2139) the term kf, in eq 5 and 8 should read k f h . Equation 10 should read
The last term in eq 11 should read t/21. The last line of eq 1 2 should be
ML,-,”+
+L
ML,”+
In the experimental section (p 2135, right-hand column), the sentence “The cell (27) was cleaned thoroughly with 5 N citric acid...” should read “The cell (27) was cleaned thoroughly with 5 N nitric acid...”.
