Table 1.

Relationship between detector performance and microelectrode diameter measured for CAT.

	5 μm Carbon Fiber Microelectrode	30 μm Carbon Fiber Microelectrode
Detection Volume (pL)	160	100
Peak Asymmetry (a)	1.04 ± 0.00211	1.03 ± 0.00428
Peak Efficiency (N)	38000 ± 300	38000 ± 300
Peak Area (pA*min)	50 ± 8	130 ± 10
S/N Ratio	400 ± 100	250 ± 50
Coulometric Efficiency	43 ± 8 %	78 ± 3 %
Detection Limits (nM)	230 ± 50	430 ± 80

Separations were performed in a 16 μm i.d. capillary with a 5-μm and a 30-μm diameter carbon fiber microelectrode. Detector volumes represent the total volume of the etched portion of the capillary less the volume displaced by the microelectrode. Peak asymmetries, obtained by measuring the front and back of the peak at 10 % of the peak height, are reported as the mean ± the standard error. Peak efficiencies are reported as the mean ± standard error from three separations, calculated using the peak widths at half-height. Peak areas and coulometric efficiencies are reported as the mean ± standard error from three separations. Concentration detection limits are reported as the mean ± standard error from three separations and were estimated using twice the signal-to-noise (S/N) ratio. Sample concentrations and buffer conditions as in Figure 2.