Sequential Techniques

The Sequential Techniques function allows the user to set up a batch experiment with up to six individual experiments. The defined sequence of experiments can also be cycled, thereby allowing automated scan rate dependence and potential dependence studies. The Sequential Techniques is included as part of the Methods software package.

Techniques for the Sequential Techniques function can be defined in 2 ways. The individual experiments can be set up before opening the Sequential Techniques dialog box, or the experiments can be defined from within this dialog box. It should be noted that iR compensation cannot be set up from within the Sequential Techniques dialog box, and must be set up in the individual experiments, if required.

The Sequential Techniques dialog box is accessed using New in the Experiment menu. An example is shown in Fig1, with two experiments previously defined.

Sequential Techniques

Figure 1. Sequential Techniques dialog box.

  1. To define a new experiment, select the technique from the drop-down list, then click Add. The new experiment will be highlighted, and placed at the bottom of the list.
  2. To delete an experiment, highlight the approriate experiment, then click Delete.
  3. To change parameters for any of the experiments, highlight the approriate experiment, then click Parameters. Fill in the Change Parameters dialog box using the standard protocol.
  4. To change the order of the experiments, highlight the experiment to be moved, and use the up or down arrows on the right side of the list box as required.
  5. The default condition is that the data from each experiment is saved at the end of each experiment. Automatic data saving for the highlighted experiment can be switched on and off using the Save Data button.
  6. The following can be programmed to occur at the end of any experiment - (Timed) Event 1, Delay (up to 3600s), Purge on and Stir on (during the Delay time). Highlight the required experiment, and click the required functions (Fig2). For experiments with Sample Intervals greater than 1 sec (e.g., DC Potential Amperometry, Controlled Potential Electrolysis), the Delay after the experiment MUST be at least as long as the Sample Interval in order for Sequential Techniques to run.

    Post-experiment operations

    Figure 2. Post-experiment operations

  7. Multiple cycles of the defined sequence of experiments can be programmed by checking Continuous Run. The number of Total Runs (up to 9999) must then be defined. In addition, the Scan Rate (for CV and LSV experiments) and the applied potential (for constant potential experiments CPE and DCPA) can be incremented from one cycle to the next, allowing for scan rate dependence and potential dependence studies. Scan Rate can be varied in a 1, 2, 5 ratio (e.g., 10, 20, 50, 100, 200, 500, etc.) or as a user-defined increment (e.g., 50 mV/sec). The applied potential is varied using a user-defined increment (e.g., 50 mV).
  8. Once the sequence has been programmed, click Run to start the sequence. Sequential Techniques can be Saved and Loaded (however, Sequential Techniques Method files created with version 1.40 software cannot be loaded using later software versions, although the individual data files can still be loaded).

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