Pérez-Ruiz T, Martínez-Lozano C, Tomás V, Fenoll J
Department of Analytical Chemistry, Faculty of Chemistry, University of Murcia, 30071 Murcia, Spain.
Analyst. 2000 Dec;125(12):2372-5. doi: 10.1039/b005987k.
A simple, sensitive, selective, fast and inexpensive assay for the determination of diquat is proposed. The method is based on the reduction of the herbicide to a strongly fluorescent monocation radical with sodium dithionite. The initial rate of this reaction is directly proportional to the diquat concentration. The stopped-flow mixing technique was used because the kinetic data can be obtained in only 7 s, meaning that the method can be automated. The calibration graph is linear over the range 5-500 ng ml-1 and the precision (RSD) is close to 1.2%. The applicability of the method was demonstrated by determining the herbicide in different kinds of samples.
