Flow injection biamperometric determination of metronidazole with on-line photodegradation Original Research Article

The determination of metronidazole is performed in a flow injection assembly, provided with a 40 W low pressure mercury lamp and a home-made biamperometric flow-cell furnished with two platinum electrodes polarized at 100 mV. The sample solution after being irradiated is inserted into a pure water stream. It then merges with an in situ mixed solution containing potassium iodide in sulphuric acid. The calibration graph was linear over the range 0.2–8.0 mg l−1 metronidazole; the 3σ limit of detection was 0.008 mg l−1; the relative standard deviation was 0.6% (for 4 mg l−1 n = 13) and the sample throughput 50 h−1. The influence of foreign compounds is slight and the method is applied for the determination of metronidazole in pharmaceutical and galenic formulations.