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Abstract
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For the first time, combination of liquid–liquid extraction and dispersive liquid–liquid
microextraction (LLE-DLLME) is reported in this study. The method is efficient and was
applied to the analysis of pyrethroid pesticides (fenpropathrin, sumithrin, cyhalothrin,
permethrin, and deltamethrin) in fruit juices and fresh grape using gas chromatographic
techniques with flame ionization detection system and mass spectrometric
detection system. Five milliliter n-hexane was used for the traditional liquid–liquid
extraction of target analytes from 50mL aqueous samples. After manual shaking, the
supernatant phase (n-hexane) was transferred into a test tube to which 0.75mL
dimethylformamide (DMF) was added then and the tube was shaken manually. After
centrifugation, 0.6mL of DMF was removed and used in a following DLLME procedure
in which the extraction solvent was 20 mL of 1,1,2-trichloroethane. Extraction with
the optimized conditions resulted in linear analytical signals within the range
0.5–1200 mg L 1 and the limits of detection and quantification were in the ranges of
0.1–15 and 0.4–50mg L 1, respectively. The method also showed high enrichment
factors (2570–6835) and relatively good extraction recoveries (26–68%). Finally, the
method was successfully applied to determination of analytes in tap water, strawberry
juice, apricot juice, and fresh grape.
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