Abstract
A new method is described for the determination of the herbicide naptalam and its metabolite l-naphthylamine in several foods. The method is sensitive, selective, and extremely rapid compared with previously reported methods. Liquid chromatography with electrochemical detection (LC/ECD) is used to determine l-naphthylamine produced from the metabolism or base hydrolysis of naptalam in asparagus, peaches, and cranberries. These foods were spiked with naptalam at 0.05 and 0.11 ppm and hydrolyzed with 30% NaOH with concomitant distillation of l-naphthylamine. Aliquots of the distillate were injected onto a reverse-phase PRP-1 LC column for separation of l-naphthylamine from coextractives near the solvent front and detection at an applied potential of +0.83 V using an amperometric electrochemical detector in the oxidation mode. Recoveries ranged from 89% ± 2% to 97% ± 8% for all foods at both spiking levels. Accuracy of these recoveries was confirmed by use of "C-radioIabeled naptalam and radioassay by liquid scintillation spectrometry of the "C-l-naphthylamine released.