Agriculture Reference
In-Depth Information
not as critical as for steroids in hair samples. UHPLC
-
TOF
-
MS allowed the detection
of all coccidiostats, whereas UHPLC
MS at a resolving power of
7,500 only missed the detection of amprolium at the lowest concentration (15
-
LTQ
-
Orbitrap
-
g/kg).
The successful detection of coccidiostats in feed extracts in contrast to the failure to
detect steroid esters in hair extracts at a mass resolving power of 7,500 was most likely
explained by the difference in the relative concentrations of compounds versus the
sample matrix. This indicated that a medium resolving power of 7,500
μ
-
10,000 was
suf
cient to prevent inaccurate mass assignment owing to matrix interferences,
although for complex matrices, higher resolution should be needed [90].
6.5 CONCLUSIONS AND FUTURE TRENDS
It has been shown throughout this chapter that in the past several years there has been
an increase in the number of studies reporting HRMS-based approaches for VDs
determination in food. The reported works derived from HRMS measurements are
still scarce, which re
ects the fact that HRMS has not yet been widely used in routine
residue analysis. This could be explained by the relatively recent availability of
modern HRMS instrumentations; the resistance to leave/change a successful, well-
established, and time-proven technology such as MS/MS (QqQ, IT, etc.); the lack of
speed; the dif
culty of the data processing software; and some hardware limitations of
HRMS instruments. However, taking into account the successful applications dis-
cussed in this chapter, it is expected that HRMS based on resolutions higher than
10,000 FWHM will be implemented and used together with LRMS techniques in the
field of VDs analysis in food in the near future. The latest generation of HRMS
instrumentation is capable of providing higher resolution, superior sensitivity, larger
dynamic ranges, and improved speed, and therefore a shift toward the application of
HRMS and away from LRMS has been observed. Nevertheless, their implementation
will be effectively accelerated as long as the available software improves signi
cantly.
Current limitations concerning processing speed, ease of use, con
rmation tools (e.g.,
utilization of exact masses and isotopic ratio), and
flexible report generation are
hindering their application in routine analysis.
Additionally, it is important to highlight the high-throughput abilities of HRMS
techniques. The use of full scan-based MS techniques simpli
ed method setup
because of the application and selection of generic acquisition parameters. The
use of this acquisition mode also implies monitoring of every analyte ionized in
the source, and therefore, there is no theoretical limit on the number of compounds per
method. This allows the development of multiclass methods with a high number of
monitored compounds, which also reduces the number of analyses per sample,
increasing sample throughput. Furthermore,
it
is possible to perform screening
and con
rmation processes in one single injection,
increasing again sample
throughput.
The first multicompound analyses employing HRMS, which allowed determina-
tion of over 100 compounds, consisted of a preliminary screening using the
LC
-
HRMS platform for initial qualitative identi
cation followed by a quantitative
