Agriculture Reference
In-Depth Information
6.4 FOOD CONTROL APPLICATIONS
This section focuses on the description of relevant analytical methods reported in the
literature for the detection of VDs in a variety of food samples employing HRMS
analyzers. These analytical methods have been divided according to their objectives
into two groups: screening and quantitative/con
rmation methods. Additionally,
three tables summarizing these methods are also included.
6.4.1 Screening Applications
In screening methods, several modalities can be applied, basically targeted and
nontargeted screening, including in this last group the posttargeted and unknown
analyses, where there is no previous information or restriction on the compounds to be
sought in the sample.
In the development of screening methods, at least two relevant issues must be
considered for their successful implementation:
first, the preparation of the sample
(which is not the aim of this chapter and can be found elsewhere) [94], and, second,
the detection technique. The
first challenge can be overcome by developing/applying
generic extraction procedures that are able to cover a wide range of compounds
showing different chemical properties, such as dilute-and-shoot [95] and QuEChERS
approaches [44]. In the
first example, although extraction time is longer than 1 h,
several samples can be extracted in parallel, allowing simultaneous determination
of several families of compounds and increasing sample throughput. An obvious
advantage is the use of a single extraction procedure for different groups of
compounds, which are usually named as
methods, a step forward in
multiresidue methods. The reduction in the number of methods to be applied in a
single sample clearly bene
“
multiclass
”
ts sample throughput. On the other hand, the QuEChERS
approach allows the extraction of
cient
sample preparation approaches must be combined with determination techniques,
which can provide a response for all compounds at their required target limits with
high speci
20 VDs in
10min. Subsequently, ef
>
<
city and selectivity.
Multiresidue screening methods are generally developed for rapidly assessing the
presence/absence of contaminants in a complex sample, and currently they have been
developed most in the area of pesticide and VD residue analyses. For instance,
200
>
compounds can be analyzed in
250 compounds in 31 min [95], and
150 compounds in 9min [57] in one single run. Methods developed for multi-
component screening should be able to detect as many pollutants as possible in a
single run. In recent years, there have been important improvements in this
20 min [96],
<
>
field. First,
the possibility of replacing conventional HPLC with UHPLC was evaluated to
improve throughput. Second, the availability of HRMS instruments represented a
promising alternative to LRMS screening (i.e., by QqQ) for two main characteristics:
(i) accurate mass measurements and (ii) full scan acquisition of all ions generated in
the ionization source. Therefore, the selectivity needed for screening methods is
obtained from extracted ion chromatograms (XICs) of the accurate mass of the ions of
interest using
filters based on narrow mass windows (e.g., 20mDa, 10 ppm, etc.). This
