Which of three voltammetric methods, when applied to a reversible electrode reaction, can best cope with double-layer capacitance and severe uncompensated resistance?

Jan C. Myland and Keith B. Oldham
 

The following measurements are those referred to in the original Analytical Chemistry article.
 

Sensitivity indices for all 540 trials
 

(Shaded areas within the tables indicate where that technique is the most robust of the three for that index.)
 

Linear-sweep voltammetry
 
t = 15 s t = 5 s t = 1 s
5 mM 1 mM 0.2 mM 5 mM 1 mM 0.2 mM 5 mM 1 mM 0.2 mM
1.5 k 0.098 0.018 0.0035 0.18 0.032 0.006 -0.48 0.073 0.012
5 k 0.40 0.063 0.01 0.79 0.11 0.020 2.1 0.29 0.040
15 k 1.6 0.21 0.04 3.0 0.41 0.063 6.3 1.1 0.13
50 k 5.8 0.94 0.13 9.3 1.8 0.24 1.8 3.8 0.46
200 k 20.1 4.46 0.70 33 6.8 1.3 68 13 0.79

Potential-step voltammetry
 
t = 15 s t = 5 s t = 1 s
5 mM 1 mM 0.2 mM 5 mM 1 mM 0.2 mM 5 mM 1 mM 0.2 mM
1.5 k -0.020 - - -0.013 -0.048 - -0.019 -0.027 -0.13
5 k -0.013 -0.03 1.2 -0.025 -0.019 -0.088 -0.21 -0.073 -0.74
15 k -0.05 -0.014 -0.05 -0.13 -0.045 -0.072 -5.0 -17 -37
50 k -0.26 -0.065 -0.09 -0.58 -4.8 -3.2 -36 39 -117
200 k -0.59 -5.4 -11 -2.2 -63 -199 -71 -63 200

Chronopotentiometry
 
t = 15 s t = 5 s t = 1 s
5 mM 1 mM 0.2 mM 5 mM 1 mM 0.2 mM 5 mM 1 mM 0.2 mM
1.5 k -0.0014 -0.18 -2.1 -0.016 -1.54 -10.2 -1.5 -24 -47
5 k -0.005 -0.59 -7 -0.053 -5.1 -33 -4.9 -66 27
15 k -0.014 -1.77 -21 -0.16 -15 -69 -15 -40 35
50 k -0.047 -5.9 -61 -0.53 -47 18 -46 54 272
200 k -0.19 -2.4 -20 -2.1 -63 37 -67 -29 284

Linear-scan voltammetry
 
t = 15 s t = 5 s t = 1 s
5 mM 1 mM 0.2 mM 5 mM 1 mM 0.2 mM 5 mM 1 mM 0.2 mM
1.5 k 0.0078 0.037 0.18 0.14 0.065 0.32 0.030 0.15 0.73
5 k 0.008 0.038 0.18 0.012 0.069 0.33 0.016 0.17 0.81
15 k 0.005 0.041 0.19 0.0052 0.070 0.35 0.0038 0.13 1.0
50 k 0.0015 0.033 0.21 0.0010 0.040 0.42 -0.0004 0.03 1.6
200 k 0.0008 0.009 0.21 -0.0003 0.0045 0.36 -0.0014 -0.00085 2.2

Potential-step voltammetry
 
t = 15 s t = 5 s t = 1 s
5 mM 1 mM 0.2 mM 5 mM 1 mM 0.2 mM 5 mM 1 mM 0.2 mM
1.5 k -0.0030 - - -0.0049 -0.020 - -0.0082 -0.057 -0.30
5 k -0.0025 -0.015 0.7 -0.003 -0.025 -0.13 0.032 0.18 0.18
15 k -0.001 -0.013 -0.08 0.0027 -0.0080 -0.10 0.045 3.7 7.6
50 k 0.004 0.003 -0.03 0.029 0.71 2.4 1.1 17 45
200 k 0.011 0.58 3.5 0.058 5.2 25 1.3 33 161

Chronopotentiometry
 
t = 15 s t = 5 s t = 1 s
5 mM 1 mM 0.2 mM 5 mM 1 mM 0.2 mM 5 mM 1 mM 0.2 mM
1.5 k 0.014 2.7 54 0.071 9.1 101 1.4 38 123
5 k 0.014 2.7 56 0.071 9.1 101 1.4 38 123
15 k 0.014 2.7 55 0.071 9.1 101 1.4 38 123
50 k 0.014 2.7 52 0.071 9.1 101 1.4 38 262
200 k 0.014 2.7 54 0.071 9.1 101 1.4 38 262

Linear-scan voltammetry
 
t = 15 s t = 5 s t = 1 s
5 mM 1 mM 0.2 mM 5 mM 1 mM 0.2 mM 5 mM 1 mM 0.2 mM
1.5 k -0.25 -0.054 -0.015 -0.42 -0.099 -0.034 -0.91 -0.26 -0.14
5 k -0.77 -0.18 -0.05 -1.3 -0.32 -0.11 -2.6 -0.79 -0.44
15 k -2.0 -0.51 -0.15 -3.3 -0.88 -0.32 -9.2 -2.0 -1.2
50 k -6.8 -1.5 -0.46 -14 -2.5 -0.96 -37 -7.5 -3.8
200 k -35 -5.9 -1.6 -66 -13 -3.2 -160 -37 -19

Potential-step voltammetry
 
t = 15 s t = 5 s t = 1 s
5 mM 1 mM 0.2 mM 5 mM 1 mM 0.2 mM 5 mM 1 mM 0.2 mM
1.5 k -9.4 - - -12 896 - -14 -14.7 -19
5 k -13 -7.6 - -15 -12 -9.5 -21 -146 -150
15 k -17 -13 -11 -22 -17 -70 -63 -698 -1200
50 k -32 -17 -55 -50 -106 -950 -267 2114 29000
200 k -106 -67 -805 -188 -490 -6000 -827 -791 112000

Chronopotentiometry
 
t = 15 s t = 5 s t = 1 s
5 mM 1 mM 0.2 mM 5 mM 1 mM 0.2 mM 5 mM 1 mM 0.2 mM
1.5 k -0.77 -0.92 -10.4 -1.4 -7.1 -55 -9.3 -116 -351
5 k -2.6 -3.1 -35 -4.6 -24 -178 -31 -343 -1600
15 k -7.7 -9.2 -104 -14 -71 -222 -93 -329 -3500
50 k -26 -31 -316 -46 -230 251 -301 2301 5200
200 k -102 -122 -196 -186 -440 -6400 -809 -401 71000

Linear-scan voltammetry
 
t = 15 s t = 5 s t = 1 s
5 mM 1 mM 0.2 mM 5 mM 1 mM 0.2 mM 5 mM 1 mM 0.2 mM
1.5 k 0.01 0.61 3.2 0.16 1.03 5.5 0.26 2.1 12.1
5 k 0.072 0.55 3.1 0.091 0.89 5.3 0.11 1.6 12
15 k 0.035 0.44 3.0 0.039 0.63 5.0 0.050 0.93 11
50 k 0.015 0.24 2.6 0.019 0.28 4.1 0.035 0.35 11
200 k 0.009 0.08 1.6 0.014 0.11 2.3 0.030 0.21 11

Potential-step voltammetry
 
t = 15 s t = 5 s t = 1 s
5 mM 1 mM 0.2 mM 5 mM 1 mM 0.2 mM 5 mM 1 mM 0.2 mM
1.5 k 0.20 - - 0.18 536 - 0.35 3.6 17
5 k 0.067 1.74 - 0.10 1.3 19 0.70 43 43
15 k 0.043 0.55 5.2 0.090 2.1 38 2.7 119 2100
50 k 0.044 0.73 24 0.17 14 481 4.8 137 2000
200 k 0.061 4.5 195 0.27 29 576 5.7 169 1600

Chronopotentiometry
 
t = 15 s t = 5 s t = 1 s
5 mM 1 mM 0.2 mM 5 mM 1 mM 0.2 mM 5 mM 1 mM 0.2 mM
1.5 k 0.070 11.6 270 0.32 41 567 6.0 182 990
5 k 0.069 11.6 77 0.32 41 567 6.0 182 990
15 k 0.069 11.6 272 0.32 41 567 6.0 182 990
50 k 0.069 11.6 272 0.32 41 567 6.0 182 1700
200 k 0.069 11.6 270 0.32 41 567 6.0 187 1700

 

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Last modified: 25 May 2000