Kinetic-fluorimetric determination of ethylenethiourea by the stopped-flowtechnique

A simple, sensitive, and rapid kinetic-fluorimetric method based on the oxi dation of ethylenethionrea with cerium (IV) is proposed for the determinati on of ethylenethiourea. The rate of formation of fluorescent cerium (III) i s high, while the stopped flow mixing technique allows this initial rate to be easily measured and facilitates the automation of the method. The calib ration graph is linear over the range 0.1-2 mug mL(-1) and the precision (% RSD) is close to 1.1%. The usefulness of the method was tested for the det ermination of ethylenethiourea in water, milk, and fruit.