Técnicas cromatográficas acopladas a espectrometría de masas de baja y alta resolución aplicadas al análisis de contaminantes orgánicos en seguridad alimentaria y control ambiental
2020
In general terms, this Thesis entitled “Chromatographic techniques coupled
to low and high resolution mass spectrometry applied to the analysis of organic
contaminants in food safety and environmental control”, has been focused on
the applicability of ultra-high liquid chromatography (UHPLC) and gas
chromatography (GC) using low resolution (LRMS) and high
resolution mass spectrometry (HRMS) analyzers for the analysis of
contaminants in food and environmental samples. With this purpose,
simple, reliable and rapid analytical methods using chromatographic
techniques coupled to LRMS have been developed, optimized and
validated for routine analysis. Likewise, a bibliographic review about
last tendencies in the analysis of contaminants by GC-HRMS in the
environmental field has been included.
Therefore, depending on the nature of analyzed matrix, this Thesis is
divided in two main sections for the determination of contaminants: i)
food safety, focused on the applicability of UHPLC coupled to MS in
tandem (MS/MS); and ii) environmental control, where GC-MS/MS
and GC-HRMS are applied.
In the first section of food safety, two analytical methods have been
developed for the determination of nitrofuran metabolites (broadspectrum antibacterial drugs) in seafood and residues of pesticides in
processed fruits by UHPLC-MS/MS. Extraction and clean-up (in the
case of nitrofurans) procedures, as well as instrumental conditions for
the chromatographic separation and detection of the analytes have been
optimized in both works. Besides, current legislation in Europe Union
(EU) was taken into account: the prohibition of nitrofurans in products
of aquaculture and the establishment of a minimum required performance limit of 1 µg/kg (MRPL), as well as existing strict
maximum limits of residues (MLRs) for pesticides in fresh fruits (MLRs
have not been specifically established for processed fruit). Additionally,
developed methods have been fully validated in terms of sensitivity,
selectivity, accuracy and robustness in order to verify its applicability
in routine analysis of samples and to ensure the reliability of results.
Finally, both methodologies have been applied to the analysis of real
food samples.
Therefore, studies which have been included in this first section are
listed below: Development and validation of an analytical method for the
simultaneous determination of 4 nitrofuran metabolites in seafood
by UHPLC-MS/MS. The extraction procedure was based on a
simultaneous acidic hydrolysis and derivatization followed by a
final step of clean-up by solid-phase extraction (SPE). The use of
the UHPLC technique allowed reducing the time consumed during
the chromatography analysis (5.5 min). It also increased the
sensitivity, with the objective of obtaining equal or lower
quantification limits (LOQs) than the MRPLs established by the
EU. The method was applied to real food samples, but nitrofurans
were not found. Development and validation of a reliable multiresidue analytical
method for the simultaneous determination of 250 pesticides in
processed fruit in a 16-min run by UHPLC-MS/MS. Extraction
was performed applying a modified QuEChERS (quick, easy,
cheap, effective, rugged and safe) method without any clean-up
step but including a dilution stage in order to obtain good peak
shapes and reducing matrix effects. Finally, the developed method
was applied to the routine analysis of 103 samples of different types of processed fruits (puree, concentrated puree, jam, pulp and fruit
in syrup), detecting the presence of several pesticides residues such
as fluopyram, spinosad or cyprodinil.
The second section of environmental control was focused on the study
of two families of ubiquitous and toxic contaminants (from industrial
and anthropogenic sources) in environmental samples: persistent
organic pollutants (POPs) and polycyclic aromatic hydrocarbons
(PAHs). In this context, published studies in this section are listed
below: Bibliographic review of analytical methodologies used between
2005 and 2013 for the determination of POPs in water and
sediments samples. This review includes extraction and cleaning
methods, as well as the “state of art” of GC and HRMS techniques
in this context. It also includes GC-HRMS applications and
quantification strategies of real samples. Development of a sensitive analytical method for the
determination of 12 PAHs (defined as priority pollutants by the
EU and the United States Environmental Protection Agency),
using GC-MS/MS. The main objective was achieving LOQs low
enough according to the requirements of current legislation. The
sample treatment was based on a SPE method. Additionally, the
method was validated to ensure the reliability of results in four
different types of water: seawater, drinking water, untreated inland
water and wastewater. And finally, it was applied to routine
analysis of aqueous samples, although PAHs above LOQs were not
detected.
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