Radial Electrochemical Flow Cell for On‐Line Coupling with Mass Spectrometry: Theory and Electrooxidation of Dimethylaminomethyl Ferrocene

Abstract

A new, radial, miniature, three-electrode flow cell is introduced. The cell×s configuration is most suitable for on-line electrochemistry ± mass spectrometry since it is characterized by low resistive losses, high conversion efficiency, and isolation of the counter electrode reaction by-products from the product stream reaching the MS. A mathematical model describing convection diffusion in the radial cell is developed. Cell×s performance can be predicted over a wide parametric range by a simple mathematical expression which converges to the Levich equation under low conversion conditions. The performance of the cell is demonstrated by studies of dimethylaminomethyl ferrocene (DMAMF) oxidation which is a simple single electron charge transfer reaction and allows validation of the mathematical model. The theoretical predictions of the model were in agreement with the results of on-line electrochemistry ± mass spectrometry studies of DMAMF.

On-line electrochemical–mass spectrometry study of the mechanism of oxidation of N,N-dimethyl-p-phenylenediamine in aqueous electrolytes

“…A table of 50 pairs of coefficients C k and k was given in [10]. The first 5 pairs of C 2 k and k are given in Table 1.…”

“…The degree of DPD conversion to quinonediimine in the radial flow cell at potentials of a current plateau can be calculated using the following expression [10]:…”

“…This characteristic response time depends on the electrolyte flow rate and the volume of the transfer line. It was determined separately by imposition of potential steps during MS measurements [9,10]. Mass spectra were acquired in the m/z range 50-500.…”

“…On-line electrochemistry/mass spectrometry (EC/MS) is a relatively new tool in the study of electrochemical transformations of organic substances, though the method has been successfully used for identification of products and intermediates which were produced in electrochemical transformations [1][2][3][4][5][6][7][8][9][10][11][12][13].…”

“…The radial, low volume (0.1 lL), electrochemical flow cell has been described in detail elsewhere [10]. The cell enables controlled potential operation.…”