Artículos de revistas
Multi-electrode detection in voltammetry - Part 3. Effects of array configuration Hadamard multiplexed voltammetric technique
Registro en:
Analyst. Royal Soc Chemistry, v. 124, n. 11, n. 1657, n. 1660, 1999.
0003-2654
WOS:000083557100021
10.1039/a904670d
Autor
Freire, RS
Rohwedder, JJR
Pasquini, C
Institución
Resumen
The effect of the number of electrodes and their relative distribution on the gain of the signal-to-noise ratio (SNR) in a multiplexed voltammetric measurement was evaluated. A voltammetric multi-channel instrument was constructed capable of operating with up to 63 ultramicroelectrodes (mercury coated copper discs , diameter 55 mu m). The gain in the SNR was investigated as a function of the number of electrodes (15, 31 and 63) in the array. For each array a design matrix was employed for the multiplexed measurements. The results show that the detection limit for Pb(II) can be improved 5.1-fold by employing 63 electrodes. The overlapping effect of diffusion layers was also evaluated and the results allow the conclusion that, for multiplexed readings obtained at 100 per second, and when the distance between adjacent electrodes is less than 20 times their diameter, the radial component is disturbed, causing a reduction in the faradaic current. On the other hand, by keeping the distance greater than this limit, the multiplex gain can be fully achieved with a substantial reduction in data acquisition time. 124 11 1657 1660