2.4 QuEChERS (Quick, Easy, Cheap, Effective, Rugged,
Safe)
QuEChERS (acronym of quick, easy, cheap, effective, rugged, safe) extraction
technique, as its name tells, is known to be fast, easy, and cheap. It consists of two
consecutive steps, the extraction/partitioning step usually using acetonitrile as
extractant and salts for partitioning and a clean-up step using dispersive solidphase extraction (d-SPE). Additionally, QuEChERS is one of the widely known
green extraction methods. It requires small amount of low toxic, non-halogenated
solvents and reagents, as well as laboratory equipment and no external energy
supply. Furthermore, this method has also introduced the concept of d-SPE for
clean-up purposes. Also, the low cost and short time allow the extraction of a
reasonable number of samples. It was first introduced for the determination of
pesticides in vegetables [19]; later it was successfully employed for other compounds (e.g., pharmaceuticals, hormones, chlorinated compounds, etc.) in different
matrices (eggs, blood, earthworms, and environmental matrices) [20–24].
Nowadays, three main QuEChERS methods are officially known and widely
used. Briefly, the original method (OR) [19] is the first method developed by
Anastassiades and coworkers in 2003, who are known as the fathers of QuEChERS.
They employed acetonitrile as extractant and MgSO 4 + NaCl as partitioning salts.
Later in 2007, Lehotay and coworkers [25] introduced a modified QuEChERS, in
which they employed acidified acetonitrile with 1% acetic acid as extractant and the
acetate-buffered salts (MgSO 4 + CH 3 COONa) for partitioning; it is adopted as an
American official method (AOAC). Finally, Anastassiades and coworkers modified
their method in 2007 [26] to employ the citrate-buffered salts
(MgSO 4 + C 6 H 5 Na 3 O 7 •2H 2 O + Na 2 C 6 H 6 O 7 •1.5H 2 O) for partitioning, and it is
adopted as a standard method of the European Committee for Standardization
(CEN). Lastly, MgSO 4 + PSA (primary secondary amine) were used as d-SPE
salts in all three previously mentioned methods.
However, many authors have introduced own modifications according to their
needs, including the extractant and d-SPE salts. Details concerning extraction and
clean-up steps developed in the last couple decades are reported in Sects. 4 and 5 for
soil and crops, respectively. At last, several QuEChERS commercial kit versions are
now available and sold by many vendors, which played an important role in the
usage expansion and wide application of this method, since salts are already
precisely weighed and mixed, avoiding the extra effort and time loss for this step.
Thereupon, QuEChERS and modified QuEChERS methods have reached extraction yields for multiresidue analysis in the same order or even better than the three
previously reported techniques, without the need of the sophisticated expensive
equipment. However, to date and according to our literature survey, only 6 studies
have reported multiresidual extraction methods from soil using QuEChERS technique, whereas more than 30 studies are reported for crop extraction.
Development of Methods for the Determination of PhACs in Soil/Earthworm/Crop. . .
423
Safe)
QuEChERS (acronym of quick, easy, cheap, effective, rugged, safe) extraction
technique, as its name tells, is known to be fast, easy, and cheap. It consists of two
consecutive steps, the extraction/partitioning step usually using acetonitrile as
extractant and salts for partitioning and a clean-up step using dispersive solidphase extraction (d-SPE). Additionally, QuEChERS is one of the widely known
green extraction methods. It requires small amount of low toxic, non-halogenated
solvents and reagents, as well as laboratory equipment and no external energy
supply. Furthermore, this method has also introduced the concept of d-SPE for
clean-up purposes. Also, the low cost and short time allow the extraction of a
reasonable number of samples. It was first introduced for the determination of
pesticides in vegetables [19]; later it was successfully employed for other compounds (e.g., pharmaceuticals, hormones, chlorinated compounds, etc.) in different
matrices (eggs, blood, earthworms, and environmental matrices) [20–24].
Nowadays, three main QuEChERS methods are officially known and widely
used. Briefly, the original method (OR) [19] is the first method developed by
Anastassiades and coworkers in 2003, who are known as the fathers of QuEChERS.
They employed acetonitrile as extractant and MgSO 4 + NaCl as partitioning salts.
Later in 2007, Lehotay and coworkers [25] introduced a modified QuEChERS, in
which they employed acidified acetonitrile with 1% acetic acid as extractant and the
acetate-buffered salts (MgSO 4 + CH 3 COONa) for partitioning; it is adopted as an
American official method (AOAC). Finally, Anastassiades and coworkers modified
their method in 2007 [26] to employ the citrate-buffered salts
(MgSO 4 + C 6 H 5 Na 3 O 7 •2H 2 O + Na 2 C 6 H 6 O 7 •1.5H 2 O) for partitioning, and it is
adopted as a standard method of the European Committee for Standardization
(CEN). Lastly, MgSO 4 + PSA (primary secondary amine) were used as d-SPE
salts in all three previously mentioned methods.
However, many authors have introduced own modifications according to their
needs, including the extractant and d-SPE salts. Details concerning extraction and
clean-up steps developed in the last couple decades are reported in Sects. 4 and 5 for
soil and crops, respectively. At last, several QuEChERS commercial kit versions are
now available and sold by many vendors, which played an important role in the
usage expansion and wide application of this method, since salts are already
precisely weighed and mixed, avoiding the extra effort and time loss for this step.
Thereupon, QuEChERS and modified QuEChERS methods have reached extraction yields for multiresidue analysis in the same order or even better than the three
previously reported techniques, without the need of the sophisticated expensive
equipment. However, to date and according to our literature survey, only 6 studies
have reported multiresidual extraction methods from soil using QuEChERS technique, whereas more than 30 studies are reported for crop extraction.
Development of Methods for the Determination of PhACs in Soil/Earthworm/Crop. . .
423