Amperometric and potentiometric determination of iodide using carbon electrodes modified with salophen complex

- Potentiometric and amperometric methods were compared for iodide analysis.
- The amperometric method is more appropriate to measure low iodide concentrations.
- CME (salophen complex) with Pt UME was compared against other electrodes.

A statistical treatment was carried out on electrochemical methods intended for iodide determination as a tracer in seawater reservoirs. Comparison was made for amperometric and potentiometric detection, including the use of a modified carbon electrode. The potentiometric method showed a good linear correlation coefficient (r = 0.9926) with a Nernstian behavior in a concentration range of 10− 5 to 1 mol L− 1 (1.3 mg L− 1 to 127 g L− 1) and a limit of detection of 1.3 mg L− 1 (10 μmol L− 1). The amperometric method showed a good linear correlation coefficient (r = 0.9988) with a linear response over a concentration range of 1 to 4 mg L− 1 (8 to 31.5 μmol L− 1) and a limit of detection of 0.5 mg L− 1 (4 μmol L− 1). The statistic treatment has shown that the potentiometric method is promising to measure the iodide concentration in samples with high iodide content and the amperometric method is appropriate to measure the iodide concentration in samples with low iodide content, for example, in the case of produced water from petroleum reservoirs. Moreover, the salophen modified electrode can be readily used for routine analysis in laboratory.

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