Simultaneous detection of sodium dithionite, sulphite and indigo at a wall-jet electrode

7 Simultaneous detection of sodium dithionite, sulphite and indigo at a wall-jet electrode 

In this section, the aim is to explain how the previously discussed results can be implemented in an industrially acceptable setup, taking into account parameters such as long-term stability, selectivity, reproducibility, simplicity and low cost. Therefore, it was the intention of the authors not to use the rotating-disc electrode, but rather to implement a so-called wall-jet electrode, which possesses similar characteristics but with a long-term stability, simplicity and cost effectiveness that are much more favourable than for a rotating-disc electrode. The setup of the wall-jet electrode is discussed in Chapter 1, pages 19-21. 

Prior to use for analytical purposes, the developed wall-jet electrode should first be characterised and calibrated. This is described here, where the wall-jet disc electrode is optimised by making use of a reversible, one-electron exchanging, redox system ([Fe(CN)6]47[Fe(CN ,]3 ) in order to obtain the most favourable conditions for the determination of sodium dithionite, sulphite and indigo. 

A second parameter that was varied is the flow rate of the solution. This was done in the same solution as was used in the previous section with the same nozzle and electrode.The NES gap was fixed at 2.14mm, the flow rate 

12 Current-potential curves of the reduction of 2.0x10 3mol I 1 

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