Non-target GC-TOF MS screening of organic contaminants in
environmental samples
R. Serrano1*, J. Nacher-Mestre1,T. Portolés1, J. C. Navarro2, I. Varó2, F. Amat2,
F. Hernández1
1Research
Institute for Pesticides and Water (IUPA). Avda Sos Baynat, s/n.
University Jaume I, 12071 Castellón, Spain
2Institute of Aquaculture of Torre la Sal (IATS-CSIC), 12595 Ribera de
Cabanes, Castellón, Spain
*Presenting author contact: serrano@uji.es
Hyphenation of gas chromatography (GC) with mass spectrometry(MS) is widely used
for determination of volatile and semi-volatile compounds of low-medium polarity in
aquatic ecosystems. Typically, environmental pollution has been monitored making use
of target analytical methods, focused on quantification of a limited number of analytes.
The development of modern high-resolution time-of-flight (TOF) analyzers opens new
perspectives to develop wide-scope screening methodologies, based on full-spectrum
acquisition techniques that combine high selectivity and sensitivity. GC coupled to TOF
MS is among the most powerful techniques for this purpose, due to its elevated mass
resolution that allows accurate mass measurements of the molecular ion (if present in
the EI spectrum) and its main fragmentions.
In this work, GC–TOF MS has been applied to characterize the organic pollution
pattern of marine waters, brines, salt and Artemia (crustacean Anostraca) samples
collected in a hyper-saline aquatic environment from the Spanish Mediterranean coast.
The sensitive and reliable qualitative analysis was favored as consequence of the
simple “universal” sample treatment developed, which allowed the pre-concentration of
analytes in the extract and collecting the widest range of analytes’ polarities. GC-TOF
MS screening has allowed the detection of contaminants present in the matrices in a
non-target way, i.e. without any kind of pre-selection of pollutants to be investigated.
After matching sample spectra with the EI GC-MS spectral library, the identity of
detected components was supported by the accurate mass measurements of the main
ions present in the spectrum, which were justified as possible fragments of the
identified compound (low mass errors observed) by using Mass Fragmenter software
as a tool.
Without using any list of compounds to be investigated, the application of this nontarget methodology has allowed the detection and tentative identification of several
contaminants of anthropogenic origin, belonging to quite different chemical groups,
even without reference standards being available. The unequivocal confirmation was
performed in a subsequent step after acquisition of reference standards and their
injection in the GC-TOF MS system. Organophosphorus pesticides, plasticizers,
organophosphate esters, pharmaceuticals and personal care products and other types
of emergent contaminants were the contaminants more frequently detected in brine
and salt samples. The antioxidant BHT and 2,6-diisopropylnaphthalene were among
the contaminants detected in Artemia samples.