title: Separation of benefin and trifluralin by gas chromatography using a liquid crystal column.
abstract: Benefin (N-[n-butyl]-N-ethyl-2,6-dinitro-alpha, alpha, alpha-trifluoro-p-toluidine) and trifluralin (2,6-dinitro-N,N-di-n-propyl-alpha, alpha, alpha-trifluoro-p-toluidine) (Figure 1) are isomeric preemergent herbicides (1,2). As they possess different activities, their use necessitates the development of a routine analytical method which differentiates between them. The separation of these isomers by gas-liquid chromatography (GLC) using conventional column packings has proved extremely difficult. Two partly successful separations have been previously reported to date. A partial separation was obtained using a Durapak-Carbowax 400/Poracil C column (3) and a complete separation using a column packed with a monomolecular layer of Carbowax 20M on Chromosorb W (4). Unfortunately, this latter column has a very limited life and the analysis time is 25 minutes. This paper reports a rapid and reproducible separation of benefin and trifluralin using a liquid crystal stationary phase.
mesh_terms: D002849:Chromatography, Gas / Q000379:methods*; D002853:Chromatography, Liquid; D006540:Herbicides / Q000032:analysis*; D007536:Isomerism; D008722:Methods; D014052:Toluidines / Q000032:analysis*; D014274:Trifluralin / Q000032:analysis*
chemical_list: D006540:Herbicides; D014052:Toluidines; C005947:benefin; D014274:Trifluralin