[Problems in the determination of small ethylenethiourea residue concentrations in plant crops].

It has been shown by residue analysis for ethylene thiourea in plant crops using gel and high performance liquid chromatography that residues are considerably reduced when the samples are macerated for extraction, and the plant juices are liberated. Consequently, residue values which are too low are obtained. Therefore, it is recommended, that only surface rinsing should be used.