Quantitation of mononitrotoluenes in aquatic environment using dispersive liquid-liquid microextraction followed by gas chromatography-flame ionization detection

A simple and efficient method (known as dispersive liquid-liquid microextraction (DLLME)) combined with gas chromatography-flame ionization detector (GC-FID) has been successfully developed for the extraction and determination of mononitrotoluenes (MNTs) in aquatic samples. The effects of parameters such as the nature and volume of the extracting and disperser solvents on the microextraction efficiency were also investigated. The volume of the extracting solvent (chlorobenzene) and that of the disperser solvent (acetonitrile) were obtained to be equal to 10.0 μL and 0.5 mL, respectively, in the optimal microextraction conditions established. Under the optimal conditions, the detection limit of the method was 0.5 μg L−1 and the relative standard deviations (RSDs%) for determination of the MNTs were in the range of 8.0-9.4. Linearity was found to be in the range of 1-1000 μg L−1; also, the pre-concentration factors were in the range of 351-357. Finally, the method was applied to determine the trace amounts of the MNTs in several real aquatic samples and satisfactory results were obtained.