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. Author manuscript; available in PMC: 2011 Mar 1.
Published in final edited form as: Anal Chem. 2010 Mar 1;82(5):1659–1668. doi: 10.1021/ac901066p

Table 1.

Shielding factors observed without (collectors off, 0c) and with (collectors on) redox cycling in the open and closed microchannel. For the calculation of Sf, the current at a single generator electrode (collectors off) was set to i1, and the current at x-shorted-generator electrodes with collectors on was set to ix.

Scan Rate/V/s
# gen./# coll. 0.001 0.010 0.050 0.100 0.500 1.000
Open 2g/0c 0.12 0.03 −0.01 0.00 −0.01 −0.01
3g/0c 0.20 0.01 −0.03 −0.04 −0.05 −0.04
7g/0c 0.37 0.27 0.20 0.19 0.18 0.18

2g/3c −0.10 −0.11 −0.02 0.00 0.00 0.00
3g/4c −0.15 −0.15 −0.06 −0.05 −0.04 −0.04
7g/7c 0.13 0.14 0.19 0.19 0.18 0.18

Closed 2g/0c 0.28 0.58 0.53 0.23 0.54 0.56
3g/0c 0.33 0.29 0.18 0.17 0.16 0.18
7g/0c 0.15 0.28 0.11 0.15 0.11 0.11

2g/3c −0.99 0.38 0.47 0.48 0.57 0.59
3g/4c −4.06 −0.19 0.17 0.18 0.17 0.19
7g/7c −3.13 −0.20 0.17 0.16 0.08 0.12

Negative values at intermediate and high scan rates, where diffusion layers have minimal overlap, indicate that the signal of the single electrode is less than the average signal of x electrodes, but are within error of the electrode-to-electrode signal reproducibility. Negative values at low scan rates (0.001 and 0.010 V/s) result from large ix values that reflect the amplified signal due to redox cycling.