Agriculture Reference
In-Depth Information
methods (AOAC 991.39, AOCS Ce 1i-07, and the GOED voluntary monograph for
EPA and DHA) but also reduced analysts
'
time and solvent consumption.
1.2.2 QuEChERS
Anastassiades et al. developed an analytical methodology combining the extrac-
tion/isolation of pesticides from food matrices with extract cleanup [25]. The
traditional method was LLE followed by salting out of water and cartridge
cleaning up. Their new method used dispersive SPE sorbent (d-SPE) together
with salting out in a centrifugation tube, which simpli
es the whole procedure and
reduces solvent consumption and dilution error. They coined the acronym
QuEChERS for it. Since its inception, QuEChERS has been gaining signi
cant
popularity and has achieved of
cial method status from international organizations
(AOAC Of
cial Method 2007.01 and European Standard Method EN 15662) for
pesticide analysis.
Besides pesticide residue analysis in food samples, QuEChERS has also been used
for the analysis of other industrial chemicals or environmental pollutants such as
polycyclic aromatic hydrocarbons in
fish, veterinary drugs in animal tissue and
milk [26], and hormone esters in muscle tissues. QuEChERS and its variations have
also been used for the determination of xenobiotics, mycotoxins, veterinary drugs,
environmental or industrial contaminants, and nutraceutical products [27].
1.2.3 Swedish Extraction Technique (SweEt) and Other Fast Sample
Preparation Methods
The SweEt method [28] was developed by the Swedish National Food Agency. It is a
LLE technique that uses ethyl acetate to differentiate the polar impurities from less
polar residues of pesticides or other chemicals. Based on the SweEt method, food
samples are classi
ed into four categories: fruit and vegetable, cereals, animal origin
A, and animal origin B with high fat. For fruit, vegetable, cereals, or animal origin A
matrices, the sample cleanup is
ltration
-
centrifugation or centrifugation
-
ltration
prior to injection for GC
-
MS/MS or liquid chromatography coupled with tandem
mass spectrometry (LC
MS/MS) analysis. For animal origin B matrix, an additional
gel permeation chromatography (GPC) cleanup step to remove the coextracted fat
from the extracts and solvent exchange step is needed prior to GC
-
MS
injection. The method can cover multiresidues or single group of residue(s). The
method uses smaller volumes of solvent and provides extracts that are compatible
with GC or LC injection methods. It eliminates complicated cleanup steps (except
animal origin B samples with high fat) and introduces very low concentrations of
matrix components such as proteins and sugar. The method has been used to
determine pesticides in fruits, vegetables, cereals, and products of animal origin [28].
QuEChERS and SweEt are general methods for multipesticide residue screening.
Based on the same principles of LLE and SPE, many other methods were recently
developed for other analytes such as special groups of pesticide residues or veterinary
drugs.
-
MS or LC
-
