were 95–114% (MLODs, 0.1 g/mL) [40]. Matrix solid-phase dispersion (MSPD)
extraction was performed for the determination of cypermethrin and deltamethrin in
porcine tissue [41]. Neutral alumina was used as MSPD dispersion adsorbent, and
diatomaceous earth was used as cleanup adsorbent, while n-hexane was the eluent
solvent (20 mL). For cypermethrin, the recoveries were 96–88%, 90–103%,
86–90%, and 98–94% at spiked levels of 0.5 μg/g and 0.2 μg/g for the liver, muscle,
heart, and kidney, respectively [41]. Closely, similar recoveries were found for
deltamethrin [41]. Tissue samples were also extracted by PFE with a Dionex ASE
200. Cleanup of extracts was accomplished using automated GP. The GPC column
was packed with 65 g Bio-Beads of 200–400 mesh size. The eluent was
dichloromethane at a flow rate of 5 mL/min. The sample was a 10 mL
dichloromethane extract [15]. Recoveries were 74–98% (MLODs, 1–3 ng/g)
[15]. The QuEChERS method was successfully applied for extraction of
cypermethrin and deltamethrin from fish product tissues (salmon, arctic char, trout,
mussels, oysters, shrimp, tilapia, and crab). Acetonitrile was the extraction solvent,
and MgSO4 and acetic acid and sodium acetate were added before centrifugation.
Recoveries were of 35–135% and MLODs of 0.3 ng/g [42]. A modified QuEChERS
approach was developed for fish sample by Jia et al. replacing the traditional
acetonitrile with isopropanol [43]. They found that isopropanol improved the extraction efficiency of the QuEChERS. For the pyrethroids in the protein-matrix samples,
the overall recoveries of 76–89% for the modified QuEChERS method are better
than those of 69–85% for the original QuEChERS method [43]. MLODs were of
0.008–0.014 μg/mL [43]. Pyrethroids were extracted from heparinized plasma by
SPE cartridges. Plasma samples were loaded on the cartridges, and these were
washed with 4 mL deionized water followed by 4 mL of 40% methanol in water
[44]. Elution was performed with 2 mL of toluene. Samples were reconstituted in
100 μL toluene, ready for GC analysis. Recoveries were of 37–84% and MLODs
were of 17–93 pg/mL [44].
2.5 Extraction from Food Samples
Dispersive liquid-liquid microextraction (DLLME) was developed for determination
of pyrethroids in fruit juice (apple, red grape, orange, kiwi, passion fruit, pomegranate, and guava juice) samples combined with high-performance liquid chromatography [47]. Methanol was used as dispersive solvent, while chloroform was used as
extraction solvent. Recoveries were of 84–94% and MLODs were of 2–5 μg/L
[47]. DLLME technique was also employed for the extraction of pyrethroids from
vegetable oil after a preliminary liquid-liquid extraction step. Initially, oil samples
were partitioned in a dimethylformamide (DMF)-hexane mixture, and then DMF
was removed and used as a disperser solvent in the following DLLME procedure in
which 1,1,2-trichloroethane was used as an extraction solvent [46]. Recoveries were
34
M. L. Feo
extraction was performed for the determination of cypermethrin and deltamethrin in
porcine tissue [41]. Neutral alumina was used as MSPD dispersion adsorbent, and
diatomaceous earth was used as cleanup adsorbent, while n-hexane was the eluent
solvent (20 mL). For cypermethrin, the recoveries were 96–88%, 90–103%,
86–90%, and 98–94% at spiked levels of 0.5 μg/g and 0.2 μg/g for the liver, muscle,
heart, and kidney, respectively [41]. Closely, similar recoveries were found for
deltamethrin [41]. Tissue samples were also extracted by PFE with a Dionex ASE
200. Cleanup of extracts was accomplished using automated GP. The GPC column
was packed with 65 g Bio-Beads of 200–400 mesh size. The eluent was
dichloromethane at a flow rate of 5 mL/min. The sample was a 10 mL
dichloromethane extract [15]. Recoveries were 74–98% (MLODs, 1–3 ng/g)
[15]. The QuEChERS method was successfully applied for extraction of
cypermethrin and deltamethrin from fish product tissues (salmon, arctic char, trout,
mussels, oysters, shrimp, tilapia, and crab). Acetonitrile was the extraction solvent,
and MgSO4 and acetic acid and sodium acetate were added before centrifugation.
Recoveries were of 35–135% and MLODs of 0.3 ng/g [42]. A modified QuEChERS
approach was developed for fish sample by Jia et al. replacing the traditional
acetonitrile with isopropanol [43]. They found that isopropanol improved the extraction efficiency of the QuEChERS. For the pyrethroids in the protein-matrix samples,
the overall recoveries of 76–89% for the modified QuEChERS method are better
than those of 69–85% for the original QuEChERS method [43]. MLODs were of
0.008–0.014 μg/mL [43]. Pyrethroids were extracted from heparinized plasma by
SPE cartridges. Plasma samples were loaded on the cartridges, and these were
washed with 4 mL deionized water followed by 4 mL of 40% methanol in water
[44]. Elution was performed with 2 mL of toluene. Samples were reconstituted in
100 μL toluene, ready for GC analysis. Recoveries were of 37–84% and MLODs
were of 17–93 pg/mL [44].
2.5 Extraction from Food Samples
Dispersive liquid-liquid microextraction (DLLME) was developed for determination
of pyrethroids in fruit juice (apple, red grape, orange, kiwi, passion fruit, pomegranate, and guava juice) samples combined with high-performance liquid chromatography [47]. Methanol was used as dispersive solvent, while chloroform was used as
extraction solvent. Recoveries were of 84–94% and MLODs were of 2–5 μg/L
[47]. DLLME technique was also employed for the extraction of pyrethroids from
vegetable oil after a preliminary liquid-liquid extraction step. Initially, oil samples
were partitioned in a dimethylformamide (DMF)-hexane mixture, and then DMF
was removed and used as a disperser solvent in the following DLLME procedure in
which 1,1,2-trichloroethane was used as an extraction solvent [46]. Recoveries were
34
M. L. Feo