Determination of naptalam and its metabolite in foods, as 1-naphthylamine, using liquid chromatography with oxidative electrochemical detection.
A new method is described for the determination of the herbicide naptalam and its metabolite 1-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 1-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 1-naphthylamine. Aliquots of the distillate were injected onto a reverse-phase PRP-1 LC column for separation of 1-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 14C-radiolabeled naptalam and radioassay by liquid scintillation spectrometry of the 14C-1-naphthylamine released.
Health and Welfare Canada, Food Research Division, Ottawa, Ontario.
B L
BL
Worobey
J B
JB
Shields
D015057:1-Naphthylamine / Q000032:analysis*; D002853:Chromatography, Liquid; D004563:Electrochemistry; D005504:Food Analysis; D005638:Fruit / Q000032:analysis; D006540:Herbicides / Q000032:analysis*; D007202:Indicators and Reagents; D009281:Naphthalenes / Q000032:analysis*; D010084:Oxidation-Reduction; D010797:Phthalimides / Q000032:analysis*
D006540:Herbicides; D007202:Indicators and Reagents; D009281:Naphthalenes; D010797:Phthalimides; C002687:alpha-naphthylphthalamic acid; D015057:1-Naphthylamine