New extraction protocols for the determination of endocrine disrupting compounds in samples of environmental and agri-food interest

  1. Javier González Sálamo
Supervised by:
  1. Miguel Ángel Rodríguez Delgado Director
  2. Javier Hernández Borges Director

Defence university: Universidad de La Laguna

Year of defence: 2019

Department:
  1. Química

Type: Thesis

Abstract

Humans are highly exposed to endocrine disrupting compounds (EDCs) due to the multiple contamination sources and accessible routes to the organism, including oral consumption, skin contact, inhalation, etc. It has been demonstrated that these compounds are responsible for several health disorders and diseases related with the endocrine system which also include some types of cancer. Among the wide variety of EDCs currently known, those with oestrogenic activity have arisen great interest in the scientific community. Among the existing EDCs, the presence of natural oestrogens, which are steroid hormones produced by mammalians, should be highlighted, since they are involved in very important processes, being responsible for the development of female secondary sex characters, among other functions. Besides, there is also a wide variety of other natural as well as synthetic EDCs that can interact with the oestrogenic receptors by mimicking the activity of oestrogens when such compounds reach the organism. In this sense, some of them are used as growth promoters of livestock and in veterinary treatments, which constitutes the main source of their presence in the environment and in food of animal origin (i.e. meat, milk and dairy products). Furthermore, the so-called mycoestrogens and phytoestrogens also constitute an important source of contamination especially for humans. With respect to phthalic acid esters (PAEs), which also have endocrine disrupting activity, their use as plasticisers in industrial applications stands out from any other. While it is true that plastics are polymers of high molecular weight which do not normally constitute a risk for humans, these additives are not chemically bonded to them and show a great tendency to migrate to the surrounding environment. This fact, together with the notably increase of plastics production during the last decades, which has brought with it a great plastic waste generation and accumulation both in terrestrial and aquatic environments as a result of their improper management, have widely distributed them up to the point that they have been found in environmental waters, food, soils and even in the atmosphere, constituting a really serious risk for humans. The uncountable sources of contamination to which humans are exposed and the low concentrations at which these EDCs can produce such serious effects on health, make necessary the development of new effective and sensitive analytical methodologies to allow their determination at the low levels at which they appear in environmental and food matrices. In this sense, the use of new sorbents and miniaturised techniques which allow a high extraction efficiency, selectivity and sensitivity, with low consumption of reagents and organic solvents, have become important alternatives to address their analysis. Thus, in this PhD Thesis, new effective and sensitive analytical methodologies have been developed for the determination of a wide group of EDCs (natural, synthetic and myco-oestrogens as well as PAEs) in matrices of environmental and agri-food interest. Selective extraction techniques such as hollow-fibre liquid-phase microextraction, solid-phase extraction using molecularly imprinted polymers, and magnetic and non-magnetic micro-dispersive solid-phase extraction using different nanomaterials as sorbents (polydopamine magnetic nanoparticles, carbon nanotubes and metal-organic frameworks), have been applied to achieve this goal. All these procedures have been combined with high-performance liquid chromatography and gas chromatography mass spectrometry for the suitable separation and determination of the target analytes.