Application of solid-phase microextraction for the determination of pyrethroid residues in vegetable samples by GC-MS.
A solid-phase microextraction (SPME) method has been developed for the determination of 7 pyrethroid insecticides (bifenthrin, lambda-cyhalothrin, permethrin, cyfluthrin, cypermethrin, fenvalerate, and tau-fluvalinate) in water, vegetable (tomato), and fruit (strawberry) samples, based on direct immersion mode and subsequent desorption into the injection port of a GC/MS. The SPME procedure showed linear behavior in the range tested (0.5-50 microg L(-1) in water and 0.01-0.1 mg kg(-1) in tomato) with r(2) values ranging between 0.97 and 0.99. For water samples limits of detection ranged between 0.1 and 2 microg L(-1 )with relative standard deviations lower than 20%. Detection limits for tomato samples were between 0.003 and 0.025 mg kg(-1) with relative standard deviations around 25%. Finally, the SPME procedure has been applied to vegetable (tomato) and fruit (strawberry) samples obtained from an experimental plot treated with lambda-cyhalothrin, and in both cases the analyte was detected and quantified using a calibration curve prepared using blank matrix. SPME has been shown to be a simple extraction technique which has a number of advantages such as solvent-free extraction, simplicity, and compatibility with chromatographic analytical systems. Difficulties with the correct quantification in a complex matrix are also discussed.
Analytical Chemistry, Experimental Sciences Dept., University Jaume I, P.O. Box 8029 AP, 12080, Castellón, Spain. beltranj@exp.uji.es
J
J
Beltran
A
A
Peruga
E
E
Pitarch
F J
FJ
López
F
F
Hernández
D005504:Food Analysis / Q000379:methods*; D005638:Fruit / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D007306:Insecticides / Q000302:isolation & purification*; D010573:Pesticide Residues / Q000302:isolation & purification*; D011722:Pyrethrins / Q000302:isolation & purification*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014675:Vegetables / Q000737:chemistry*
D007306:Insecticides; D010573:Pesticide Residues; D011722:Pyrethrins