Sampling, sample preparation and analysis methods based on supported liquid membranernatrazine and ametryn and phenoxyacid herbicides; 2,4-D. In SLM extraction, neutralrnherbicides could be extracted from a flowing aqueous solution to a stagnant acidicrnacceptor solution for the two weakly basic s-triazines and to stagnant basic acceptorrnsolution for the weakly acidic phenoxyacid herbicide. Specifically, a liquid membranerncontaining 0.1 mol/L sulphuric acid for the triazines and 0.1 mol/L sodium hydroxide forrnthe 2,4-D was suggested. The uncharged herbicide molecules from the flowing aqueousrndonor solution diffused through a liquid membrane impregnated in a porousrnpoly(tetrafluoroethylene) membrane, immobilized organic solvent, and then will berntrapped in a stagnant acceptor phase. The efficiency of the extraction process will bernfound to depend on the donor solution pH, the amount of the mobile carrier added to thernliquid membrane and the concentration of the counter ion in the acceptor solution. From detailed studies, the optimum values of these parameters for the efficient extraction of thernherbicides will be determined. The applicability of the method for (SLM) have beenrnproposed for selective extraction of two s-triazine herbicides, namely extraction of thesernselected herbicides at different stages of production of sugar will be also investigated byrnspiking analyte sample solutions in sugar-cane juice, syrups, and molasses and sugarrncrystal samples. The suggested method will be utilized for trace enrichment of thernanalytes from samples containing matrices of various types and concentrations. A 20rnminutes of sample enrichment at a flow rate of 1.0 mL/min, was suggested to determinernthe concentrations of atrazine, ametryn and 2,4-D in sugar samples at various stages ofrnproduction.