PROGRAMME

Session 15(P) - Emerging Pollutans

Prof. Nikolaos Thomaidis, Dr Pablo Gago-Ferrero

Development and validation of a novel analytical protocol for the simultaneous determination of organic micropollutants in biota specimens by GC-APCI-QToF MS.

B Thursday 2 September 15:45 - 16:00

During the last decades, overwhelming evidence has shown that various xenobiotic compounds have been released into the environment, due to anthropogenic activities. The term “Persistent Organic Pollutants (POPs)” has been established for organic chemicals that are resistant to degradation, persistent, bioaccumulative and toxic chemicals (PBTs). These chemicals are transported at low concentrations by movement of fresh and marine waters and, as they are semi-volatile, they are also transferred over long distances in the atmosphere. The result is their widespread distribution across the globe. They encompass a wide variety of compounds, including pesticides (such as insecticides, acaricides and fungicides), industrial chemicals (such as polychlorinated biphenyls, PCBs, polybrominated diphenyl ethers, PBDEs and polychlorinated naphthalenes, PCNs) and unintentional by-products of industrial processes (such as polycyclic aromatic hydrocarbons, PAHs, dioxins and furans) (M.S. El-Shahawi et al., 2010). The term “Chemicals of Emerging Concern (CECs)” refers to chemicals, which are not subjected to marketing restrictions and regulatory monitoring programmes, but are candidates for future regulation, due to their frequent detection in environmental samples and their potential hazardous properties (Thomaidis et al, 2012; Gavrilescuet al, 2015; Dulio et al, 2018). In recent years, research efforts have been focused on the development of analytical methods for the determination of organic contaminants in environmental compartments, with a special interest in wildlife exposure to them, because of their bioaccumulative and biomagnificative properties (Roscales J.L. et al, 2017). Biota play a key role as integrated indicators in the environmental monitoring for a number of reasons, including their position at the food webs, the potential negative effects on human health through their consumption and the relative ease with which samples can be obtained, due to their prevalence (C. Cruzeiro et al., 2016, T. K. Parmar et al, 2016). In a few studies, xenobiotics have been determined by target analytical methodologies, which despite their high selectivity and sensitivity, using mainly selected reaction monitoring (SRM) mode of detection, are limited to cover only a relatively narrow range of chemical classes. On the other hand, High Resolution Mass Spectrometry (HRMS) techniques, given the high resolution capability (R=35,000) and mass accuracy in full scan mode, has enabled the simultaneous determination of hundreds of micropollutants and their transformation products, initiating a new trend in analytical data processing towards wide-scope target, suspect and non-target screening strategies (Picó et al, 2012; Du et al, 2017). To keep up with this evolution in analytical methodologies and in order to approach their multi-residue character, generic sample preparation protocols, offering rapid and reliable analysis are needed. However, the different classes and physicochemical properties of the analytes make the development of comprehensive methodologies that allow their extraction, purification and separation from complex biological matrices, difficult (C. Baduel et al., 2015). According to the literature, several studies reported the occurrence of volatile, thermally stable and non-polar organic contaminants in biota matrices, however these methods were mainly focused on the determination of compounds from selected chemical classes, including a limited number of analytes (Fidalgo-Used et al, 2007; Wang et al, 2007; Zhang et al, 2015) There are only few research groups that applied a multi-residue protocol using ASE as the extraction technique of choice, due to its unique advantages, of automation, speed and use of small amounts of solvents, with a simultaneous clean-up of the produced extracts (Fidalgo-Used et al, 2007; E. Björklund et al, 2006). Within this context, the aim of this study was the development, optimization and validation of a novel generic analytical protocol for the determination of organic micropollutants of a wide chemical domain in biota matrices by Gas Chromatography coupled with High Resolution Mass Spectrometry (GC-APCI-QToF MS). Furthermore, the performance and suitability of the developed method was demonstrated through its application in real biota samples. In particular, in the frame of this study, the effect of various crucial parameters during the sample preparation, such as the extraction solvent and temperature as well as the use of sorbents for further extract purification, were investigated. These parameters were optimized by evaluating method performance criteria such as LODs, recoveries and matrix effect for selected GC amenable compounds. For the optimization and validation, a dataset of representative compounds of NKUA target list, based on their different physicochemical properties, was selected. The developed methodology was applied in marine biota of the lower trophic levels (fish and mollusks), demonstrating the suitability of the proposed analytical protocol for the simultaneous determination of GC-amenable xenobiotics in biota specimens.