indomethacin, ketoprofen, ketorolac, mefenamic acid, and methylprednisolone.
Finally, similar recovery yields were obtained by those two studies (88–113%
[102] and 70–120% [104]). On the contrary, this PSA effect was not observed
with Meng and coworkers [105] when it was added in a reasonable amount
(25 mg), and better recoveries (61.4–118.9%) and matrix effect (À40 to 54%)
were obtained using the combination 25 mg of PSA, 10 mg of C18, and 100 mg
of MgSO 4 . On the other hand, when the clean-up step was omitted, chromatograms
with less quality were obtained, due to the presence of a noisy baseline and
interfering peaks derived from co-extracted components [102]. However, no cleanup was employed by Bragança and coworkers (recoveries >80%) [101], and no
significant matrix effect was observed in their results. Finally, Salvia and coworkers
[106] tested the d-SPE using several sorbents: PSA, PSA + C18, Florisil, silica,
aluminum oxide, and SAX. However, great matrix effect was always obtained (>
80%), whereas satisfactory results were obtained using SPE cartridges (SAX and
Strata-X cartridges) which was adopted in their final method.
Finally, despite the advantages provided from the clean-up, some authors
believed that SPE step causes loss of analytes, so they omitted the clean-up step in
both soil and crop matrices [140, 153].
6.2 New Sorbents
Several sorbents have been introduced recently for a better clean-up step, among
them we list: Z-Sep, Z-Sep+, Z-Sep/C18, ChloroFiltr, CarbonX, Cleanert NANO,
Oasis PRiME, and finally EMR-Lipid.
Z-Sep and Z-Sep+ sorbents are based on zirconium dioxide (ZrO 2 ) and can
replace the use of PSA and C18. They were used to clean up extracts with high
amounts of fat for the analysis of pesticide residues [167, 168]. Z-Sep is
recommended for the clean-up of samples with hydrophobic analytes. Z-Sep+ is
used for samples containing greater than 15% fat, and finally Z-Sep/C18 is used for
samples containing less than 15% fat [167, 169]. Z-Sep/C18 was used for pharmaceutical analysis from fish samples [170].
ChloroFiltr, CarbonX, and Cleanert NANO are used to remove co-extracted
chlorophyll from plant matrices as for GCB (graphitized carbon black) [171–
173]. ChloroFiltr is a polymeric-based sorbent; it was used in combination with
MgSO 4 and PSA without scarifying the recovery of planar analytes
[171, 172]. CarbonX in a non-friable form of GCB, and similar to GCB, it reduces
the recoveries of planar analytes. It was effectively used in combination with
MgSO 4 , PSA, C18, and Z-Sep for the clean-up of pesticides and environmental
contaminants in shrimps [37]. However, CarbonX retain pesticides less strongly than
GCB, and it is easier to work with since it is available as filter-vial d-SPE [174] or
SPE minicartridges [173, 175]. Cleanert NANO is used to remove colorant and fatty
acids. It is composed of functionalized MWCNTs (multiwalled carbon nanotubes),
Development of Methods for the Determination of PhACs in Soil/Earthworm/Crop. . .
469
Finally, similar recovery yields were obtained by those two studies (88–113%
[102] and 70–120% [104]). On the contrary, this PSA effect was not observed
with Meng and coworkers [105] when it was added in a reasonable amount
(25 mg), and better recoveries (61.4–118.9%) and matrix effect (À40 to 54%)
were obtained using the combination 25 mg of PSA, 10 mg of C18, and 100 mg
of MgSO 4 . On the other hand, when the clean-up step was omitted, chromatograms
with less quality were obtained, due to the presence of a noisy baseline and
interfering peaks derived from co-extracted components [102]. However, no cleanup was employed by Bragança and coworkers (recoveries >80%) [101], and no
significant matrix effect was observed in their results. Finally, Salvia and coworkers
[106] tested the d-SPE using several sorbents: PSA, PSA + C18, Florisil, silica,
aluminum oxide, and SAX. However, great matrix effect was always obtained (>
80%), whereas satisfactory results were obtained using SPE cartridges (SAX and
Strata-X cartridges) which was adopted in their final method.
Finally, despite the advantages provided from the clean-up, some authors
believed that SPE step causes loss of analytes, so they omitted the clean-up step in
both soil and crop matrices [140, 153].
6.2 New Sorbents
Several sorbents have been introduced recently for a better clean-up step, among
them we list: Z-Sep, Z-Sep+, Z-Sep/C18, ChloroFiltr, CarbonX, Cleanert NANO,
Oasis PRiME, and finally EMR-Lipid.
Z-Sep and Z-Sep+ sorbents are based on zirconium dioxide (ZrO 2 ) and can
replace the use of PSA and C18. They were used to clean up extracts with high
amounts of fat for the analysis of pesticide residues [167, 168]. Z-Sep is
recommended for the clean-up of samples with hydrophobic analytes. Z-Sep+ is
used for samples containing greater than 15% fat, and finally Z-Sep/C18 is used for
samples containing less than 15% fat [167, 169]. Z-Sep/C18 was used for pharmaceutical analysis from fish samples [170].
ChloroFiltr, CarbonX, and Cleanert NANO are used to remove co-extracted
chlorophyll from plant matrices as for GCB (graphitized carbon black) [171–
173]. ChloroFiltr is a polymeric-based sorbent; it was used in combination with
MgSO 4 and PSA without scarifying the recovery of planar analytes
[171, 172]. CarbonX in a non-friable form of GCB, and similar to GCB, it reduces
the recoveries of planar analytes. It was effectively used in combination with
MgSO 4 , PSA, C18, and Z-Sep for the clean-up of pesticides and environmental
contaminants in shrimps [37]. However, CarbonX retain pesticides less strongly than
GCB, and it is easier to work with since it is available as filter-vial d-SPE [174] or
SPE minicartridges [173, 175]. Cleanert NANO is used to remove colorant and fatty
acids. It is composed of functionalized MWCNTs (multiwalled carbon nanotubes),
Development of Methods for the Determination of PhACs in Soil/Earthworm/Crop. . .
469