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Description
The determination of pesticide residues in water requires efficient sample preparation procedures1 to ensure reliable analytical results. Therefore, the aim of this study was to evaluate the extraction efficiency of different organic solvents for the liquid–liquid extraction (LLE) of 2,4-dichlorophenoxyacetic acid (2,4-D), atrazine, malathion, fenitrothion and parathion from water samples.
Fortified distilled water samples containing selected pesticides were used as model samples. Three concentration levels were investigated for each pesticide, and for each concentration level, four samples (n = 4) were prepared. Liquid–liquid extraction was performed using dichloromethane, diethyl ether, petroleum benzine and a mixture of n-hexane and acetone (4:1, V/V). The extracts were analyzed by reversed-phase high-performance liquid chromatography (RP-HPLC) method and the extraction efficiency was evaluated through recovery values.
Among the investigated solvents, dichloromethane exhibited the highest overall extraction efficiency, providing recoveries between 96.09 % and 106.52 % for all analytes except malathion, for which a lower but still satisfactory recovery of 78.89 % was obtained. Diethyl ether also showed good performance, with recoveries ranging from 90.73 % to 106.99 %, except for malathion (71.95 %). Petroleum benzine proved unsuitable for the extraction of 2,4-D (only 5.24 % recovery), while recoveries for the remaining pesticides ranged from 57.27 % to 83.18 %. The n-hexane/acetone mixture (4:1, V/V) demonstrated high extraction efficiency for malathion, fenitrothion and parathion (96.59 % – 105.78 %), moderate efficiency for 2,4-D (84.17 %), and lower efficiency for atrazine (74.06 %).
The overall extraction efficiency decreased in the following order: dichloromethane > diethyl ether > n-hexane/acetone (4:1, V/V) > petroleum benzine. The obtained results indicate that dichloromethane is the most suitable extraction solvent for the investigated pesticides and provide a basis for future application of the proposed procedure to environmental, drinking and irrigation water analysis.