Preconcentration and determination of methyl methacrylate by dispersive liquid-liquid microextraction.

This article describes the preconcentration of methyl methacrylate in produced water by the dispersive liquid-liquid microextraction using extraction solvents lighter than water followed by gas chromatography. In the present experiments, 0.4 mL dispersive solvent (ethanol) containing 15.0 μL extraction solvent (toluene) was rapidly injected into the samples and followed by centrifuging and direct injection into the gas chromatograph equipped with flame ionization detector. The parameters affecting the extraction efficiency were evaluated and optimized including toluene (as extraction solvent), ethanol (as dispersive solvent), 15 μL and 0.4 mL (as the volume of extraction and dispersive solvents, respectively), pH 7, 20% ionic strength, and extraction's temperature and time of 20°C and 10 min, respectively. Under the optimum conditions, the figures of merits were determined to be LOD = 10 μg/L, dynamic range = 20-180 μg/L, RSD = 11% (n = 6). The maximum recovery under the optimized condition was determined to be 79.4%.