Agriculture Reference
In-Depth Information
characteristic also allows the performance of retrospective analysis, which means that
there is always the possibility of looking for the presence of any compound at any time
from stored full acquisition data without reinjecting the sample. Thus, it can improve
long-term high throughput because it eliminates the need for new runs (e.g.,
reinjection of the sample) and, therefore, saves time.
Taking into account all these advantages, multiresidue screening of VD residues in
food samples by UHPLC
HRMS has been developed in the past years using several
analyzers such as TOF and Orbitrap. Tables 6.1 and 6.2 show some screening
methods developed for VDs in food samples by UHPLC
-
-
HRMS.
MS was
developed by Stolker et al. [97]. This approach used full scan accurate mass
screening, enabling the analysis of 101 VDs and metabolites in raw milk samples
in
One of the
first multiscreening methods based on UHPLC
-
TOF
-
10min. The satisfactory quantitative results obtained during validation showed
the feasibility of the system for quanti
<
cation (Table 6.1). Moreover, mass accuracy
was a valuable tool to differentiate between positive and negative samples. Follow-
ing this approach, two years later, the same group reported another UHPLC
-
TOF
-
MS multiresidue and multimatrix screening and quanti
cation method for the same
analytes in eggs,
fish, and meat (Table 6.1) [73]. This last study was developed using
a Bruker micrOTOF system, whereas in the previous study, they used a Waters LCT
Premier TOF
MS was used, the authors found that
for
>
80% of the compounds, the mass accuracy was within the 10 ppm acceptability
limit and most of the compounds that did not comply eluted in the region where most
of the matrix compounds eluted [97]. In this study they found an average mass
measurement error of 3 ppm (median 2.5 ppm) with little difference between the
three matrices. While for
-
MS. When LCT Premier TOF
-
98% of the studied compounds the mass accuracy was
below the 10 ppm limit, individual analyte measurement exceptions up to 20 ppm
were encountered. These latest results were comparable to or better than the linearity
determined for the same compounds in a milk matrix using a Waters
>
-
Micromass
LCT Premier TOF
c extraction windows. The results obtained
in the validation of the proposed method showed that this method provided
satisfactory performance characteristics for
-
MS and drug-speci
90% of the compounds in meat, for
>
80% of the compounds in
fish, and for
70% of the compounds in eggs, clearly
>
>
showing the in
uence of the matrix on method performance. Considering that some
differences between matrices and concentrations were observed, the authors con-
cluded that the TOF
MS itself was not able to distinguish between unlimited
numbers of compounds in any matrix. In the case of simple matrices, such as
milk or meat, the instrument appeared to be less limited in terms of matrix effects, but
for more complicated matrices such as
-
fish and eggs, more complicated sample
preparation techniques seemed to be required. Additionally, in this study an
alternative validation procedure requiring a lower number of samples to be analyzed
was suggested and tested for the screening method. Repeatability, reproducibility,
and CC
shandslightlydifferentforeggs.The
results showed that the high number of samples required in the 2002/657/EC [16] for
the determination of specificity (
n
=
20), detection capability (
n
=
20), can be
reduced by about 50% using a different strategy.
β
results were similar for meat and
