SIMULTANEOUS DETERMINATION OF LINURON AND TRIFLURALIN RESIDUES IN CARROTS AND THEIR PULP BY LIQUID-CHROMATOGRAPHY AND GAS-CHROMATOGRAPHY

A simple method is described for determining trifluralin and linuron i n carrots and their pulp. Samples are extracted with hexane-ethyl ethe r (1 + 1), cleaned up with a disposable Florisil cartridge, and eluted first with hexane-ethyl ether (99 + 1) (for trifluralin), and then wi th hexane-ethyl ether (3 + 7) (for linuron). Trifluralin is then analy zed by electron capture gas chromatography (GC/ECD), and linuron by GC /ECD and liquid chromatography with ultraviolet detection (LC/UV). Rec overies were determined by spiking untreated carrot and carrot pulp ho mogenates with trifluralin and linuron at 0.04, 0.16, and 0.32 mug/g. Six determinations were performed at each level for both compounds. GC /ECD average recoveries were 87.1% for trifluralin and 93.6% for linur on in carrots and 89.9% for trifluralin and 94.2% for linuron in carro t pulp. LC/UV recoveries for linuron were 91.5% for carrots and 92.8% for carrot pulp.