Agriculture Reference
In-Depth Information
applicability and achievements for VDs analysis. This fact allows that all the
information needed is acquired in the same run, and consequently, screening and
con
rmation/quanti
cation can be performed in one single analysis,
increasing
sample throughput.
In this section, the con
cation capabilities of HRMS systems
for the analyses of VDs are addressed. To this aim, a number of relevant studies are
discussed.
The
rmation and quanti
MS for quantitative analysis was developed by
Hernando et al. [62] for the simultaneous analysis of seven VDs in
first application of TOF
-
sh. For that
purpose, HPLC
-
TOF
-
MS with a resolution power of 9,500 FWHM was used. This
method achieved CC
α
and CC
β
values in the range of 103
-
218 and 107
-
234
μ
g/kg,
respectively, for substances with MRL values in the range of 100
g/kg, demon-
strating the feasibility of HRMS for quantitative approaches (Table 6.1). However,
sensitivity needed to be improved because for some analytes (e.g., malachite green and
leucomalachite green), CC
-
200
μ
were above the established MRLs.
Two subsequent works described methods for the quanti
α
and CC
β
cation of tetracyclines in
honey samples [67] and quinolones in pig liver samples [98], using TOF
-
MS. The
first [67] was based on the use of HPLC and two different online detectors, diode array
(DAD) and TOF
-
MS. In this work, the HPLC
-
TOF
-
MS method was validated in
terms of speci
city, linearity, sensitivity, precision, accuracy, recovery, and ion
suppression. Eventually, the proposed method allowed the detection of eight tetracy-
clines at concentrations between 0.05 and 0.76
μ
g/kg (Table 6.1), allowing their
quanti
5.3 ppm) even at a
low concentration. Additionally, the authors highlighted the ability of the TOF
cation with very low mass accuracy (less than or equal to
±
MS to
unambiguously identify these compounds because of the sensitivity, mass accuracy,
and true isotopic pattern provided by the TOF analyzer. In the second work [98], a
LC
-
MS method was developed for the determination and characterization of
quinolones regulated by the EU in pig liver samples below the MRLs. Satisfactory
quality parameters were established for the developed method according to the FDA
and European Community guidelines. The authors emphasized the improved selec-
tivity reached with this analyzer, especially for two quinolones, oxolinic acid and
-
TOF
-
flumequine, showing identical nominal mass ( m / z 262) and a common fragment ( m / z
244). However, they could be easily discriminated by the corresponding XICs of
accurate mass, m / z 262.0710 and 262.0874 for oxolinic acid and
flumequine,
respectively, setting a suitable extraction mass window. Apart from this, they showed
the ability of this analyzer to carry out the reliable identi
cation of fragments of
flumequine, generating characteristic fragments at m / z 244, 220, and 202. The m / z 244
was clearly due to the loss of H 2 O, whereas m / z 220 may have been due to the
fragmentation of the [M
H] + by loss of C 2 H 4 NorC 3 H 6 . In this way, the use of
accurate mass of each fragment and their errors allowed proposing structures for each
ion, and concluding that m / z 220 was due to [M
+
H
-
C 3 H 6 ] + and m / z 202 corre-
+
sponded to [M
C 3 H 6 ] + .
After these single-class multiresidue methods, other multiclass methods have been
reported. Villar-Pulido et al. [99] showed a quantitative determination method of 13
different VDs in shrimp using UHPLC
H
-
H 2 O
-
+
-
TOF
-
MS. The unambiguous identi
cation
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