Flow injection biamperometric determination of chloramine-T in environmental, pharmaceutical and veterinary samples

[EN] A flow injection assembly for the determination of chloramine-T is proposed. The sample (213 mu l) is inserted into the carrier, de-ionized water flowing at 4.1 mi min(-1). This carrier merges with a mixture of potassium iodide and sulphuric acid, and the resulting solution flows to the flow cell through a reactor 66 cm long. The chloramine-T oxidises the iodide to tri-iodide. The resulting iodide/iodine ratio is biamperometrically tested. The calibration graph is linear up to 65 mu g ml(-1) chloramine-T; the limit of detection is 0.5 mu g ml(-1); the relative standard deviation (r.s.d) of the calibration slope is 2.8% for a series of eight independent calibrations. The r.s.d. of a series of 74 peaks for 40 mu g ml(-1) chloramine-T) is 0.8%, and the sample throughput 220 h(-1). Few foreign substances interfered. The method is applied to pharmaceutical, veterinary and waste water samples.