Photo-induced chemiluminometric determination of Karbutilate in a continuous-flow Multicommutation assembly

The present paper deals with the chemiluminescent determination of the herbicide Karbutilate on the basis of its previous photodegradation by using a low-pressure Hg lamp as UV source in a continuous-flow Multicommutation assembly (a solenoid valves set). The pesticide solution was segmented by a solenoid valve and sequentially alternated with segments of the 0.001 mol l−1 of NaOH solution, the suitable media for the formation of photo-fragments; then it passes through the photo-reactor and was lead to the flow-cell after being divided in small segments which were sequentially alternated with the oxidizing system; 2 × 10−5 mol l−1 of potassium permanganate in 0.2% pyrophosphoric acid. The studied calibration range, from 0.1 μg l−1 to 65 mg l−1, resulted in a linear behaviour over the range 20 μg l−1-20 mg l−1 and fitting the linear equation: I = (1180 ± 30)C + (15 ± 5) with the correlation coefficient 0.9998. The limit of detection was 10 μg l−1 and the sample throughput 17 h−1. After testing the influence of a large series of potential interfering species, the method was applied to water and human urine samples.