Two-step microextraction combined with high performance liquid chromatographic analysis of pyrethroids in water and vegetable samples.
Dispersive liquid microextraction (DLME) combined with dispersive µ-solid phase extraction (D-µ-SPE) has been developed as a new approach for the extraction of four pyrethroids (tetramethrin, fenpropathrin, deltamethrin and permethrin) prior to the analysis by high performance liquid chromatography (HPLC) with UV detection. 1-Octanol was used as the extraction solvent in DLME. Magnetic nanoparticles (Fe3O4) functionalized with 3-aminopropyl triethoxysilane (APTS) were used as the dispersive in DLME and as the adsorbent in D-µ-SPE. The extracted pyrethroids were separated within 30 min using isocratic elution with acetonitrile:water (72:28). The factors affecting the extraction efficiency were investigated. Under the optimum conditions, the enrichment factors were in the range of 51-108. Linearity was obtained in the range 0.5-400 ng mL(-1) (tetramethrin) and 5-400 ng mL(-1) (fenpropathrin, deltamethrin and permethrin) with the correlation coefficients (R(2)) greater than 0.995. Detection limits were 0.05-2 ng mL(-1) (water samples) and 0.02-2.0 ng g(-1) (vegetable samples). The relative standard deviations of peak area varied from 1.8 to 2.5% (n=10). The extraction recoveries of the four pyrethroids in field water and vegetable samples were 91.7-104.5%. The proposed method has high potential for use as a sensitive method for determination of pyrethroid residues in water and vegetable samples.
Materials Chemistry Research Unit, Department of Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.
Siriboon
S
Mukdasai
Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.
Chunpen
C
Thomas
Materials Chemistry Research Unit, Department of Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand. Electronic address: supalax@kku.ac.th.
Supalax
S
Srijaranai
D002851:Chromatography, High Pressure Liquid / Q000379:methods; D007306:Insecticides / Q000032:analysis*; D057230:Limit of Detection; D009570:Nitriles / Q000032:analysis; D026023:Permethrin / Q000032:analysis; D011722:Pyrethrins / Q000032:analysis*; D052617:Solid Phase Microextraction / Q000379:methods*; D014675:Vegetables / Q000737:chemistry*; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*
D007306:Insecticides; D009570:Nitriles; D011722:Pyrethrins; D014874:Water Pollutants, Chemical; D014867:Water; C017180:decamethrin; D026023:Permethrin; C044267:fenpropathrin; C009424:tetramethrin
Dispersive liquid microextraction; Dispersive µ-solid phase extraction; High performance liquid chromatography; Magnetic nanoparticles; Pyrethroids