محبوبه شیرانی

a new method was developed for the simul-taneous determination of deltamethrin and permethrin in water samples with homogeneous liquid–liquid microex-traction via flotation assistance and gas chromatography– flame ionization detection. a special extraction cell was designed to facilitate collection of the low density solvent extracts. The sample solution was added into the extraction cell, which contained an appropriate mixture of n-hexane (as an extraction solvent) and acetone (as a homogeneous solvent). air flotation allowed the extraction solvent to be collected from the top of the solution. Under the optimum conditions, good linearity was observed in the range of 1.0–200 μg l−1 with a correlation coefficient (r2 ) greater than 0.9980 for both of the analytes. The limits of detection were 0.2 and 0.3 μg l−1 for deltamethrin and permethrin, respectively (S/n = 3). The developed method was suc-cessfully applied to determine the two pesticides in three different water samples.