The University of Almeria: Who we are and what do we do?

The lab in the sun of southern Spain

The University of Almeria (UAL) in southern Spain was founded in 1993, and offers a wide range of undergraduate, masters and PhD programs to more than 12,000 students. The University hosts more than 140 research groups from different areas, including agriculture, chemistry, health science, social sciences and human studies, amongst others. For more than 20 years, the University has also played an essential role in the control of pesticide residues in the agricultural crops grown in the region. The group led by Prof. Dr Amadeo Rodríguez Fernández-Alba has long experience in the analysis of pesticides and other environmental contaminants in different matrices, and is accredited as the  European Union Reference Laboratory for Pesticide Residues in Fruits and Vegetables.

Innovation is a key point of the university

This group has four separate laboratories within UAL and currently consists of 17 researchers with different training and specialities. Some take an active part in INSIGNIA-EU, performing different tasks within the UAL roles in the project. Examples of these include the development, preparation and shipment of the APIStrips, as well as their analysis by chromatographic techniques. Other samples from the citizen scientist beekeepers are also analysed by this group including pollen, honey bees, air filters and plastic strips. The analyses of these samples include pesticides, polycyclic aromatic hydrocarbons (PAHs), volatile compounds (VOCs), particulate matter (PM) and microplastics. Apart from the PM and the microplastics, the methodology for the analysis of these different contaminants is similar, as it is all based on the same procedure and quality control principles.

The keypoint of INSIGNIA-EU

What are exactly these contaminants and why are they important? Pesticides, PAHs and VOCs are all chemical contaminants; individual molecules that are present in the environment. Conversely, microplastics and particulate matter both consist of macroscopic (but very small) solid fragments of a different nature (for example, polymers from plastic materials or dust). The first group ‒ chemical contaminants are described here.

Chemical contaminants

Most people know about the existence and use of pesticides, and therefore their presence in both food and the environment. However, the PAHs and VOCs are less well known and are (wrongly) perceived to in general have a lower impact on society. PAHs are organic molecules that can be formed during industrial processes of our everyday life and even by natural events, as they are mainly linked to combustion. Cars, cigarettes, fires and, of course, factories, are all sources of PAHs. The constant exposure to these substances has been proved to be related to various health issues, so it is essential to monitor their presence in the environment. Similarly, VOCs are organic compounds that are released into the environment from a variety of different sources and have a direct impact on both global warming and human health.

The APIStrip – a keypoint of INSIGNIA-EU

The INSIGNIA-EU approach consists of analysing these chemical contaminants in both APIStrips and honey bee samples, in order to identify the most suitable approach for their evaluation in the environment. Close to 500 different chemical residues are covered in the scopes of the analytical methods from the two laboratories in INSIGNIA-EU (UAL and Benaki Phytopathological Institute in Greece). There are three main steps to follow during the analysis of any of these substances:

1.       Extraction of the contaminants (and other components) from the samples.

2.       Separation of the contaminants from the other sample components.

3.       Identification of the contaminants present and their concentration.

In the lab

The first step involves the transition from a solid sample (for example an APIStrip or a honey bee) to a liquid extract in solvent. Usually, the solid samples are immersed in an organic solvent, which will trap all the contaminants. For pesticides, the solvent acetonitrile will dissolve most residues expected, whereas hexane is the most suitable solvent for PAHs and VOCs. However, other sample components (such as fats or proteins) are also dissolved in the organic solvents, so we still need to separate the contaminants of interest.

The separation of the contaminants from the sample components (and also from other contaminants) is performed during the second step, with the use of chromatographic techniques. A chromatographic technique (mainly gas chromatography or liquid chromatography) allows us to separate the molecules of one sample. The sample is injected into the chromatograph, and the individual components are then separated throughout a thin column. Imagine a mixed group of bees gathered at the entrance of a tube, which is filled with different flowers. The bees will go through the tube, stopping from time to time to take the nectar and pollen they need. Nurse bees are expected to reach the end of the tube quicker, as they are not used to collecting pollen and probably they will stop less frequently; meanwhile, drones will most likely spend a lot of time visiting the flowers and it will take them more time to reach the end of the tube, so the different groups of bees will become separated. The same principle applies to chromatography: some molecules will go through the column very quickly, whereas others (depending on their properties) will be retained for longer.

For the second step, a mass spectrometer is attached at the end of the chromatographic column. Mass spectrometers allow us to identify the molecules that leave the column, and they can also calculate the amount of each molecule. However, they need to analyse each one individually, which explains the fact that mass spectrometry is often linked to chromatography. Identifying the structure of a molecule is a very complicated task, therefore mass spectrometers are expensive and complex instruments (and usually take up a lot of space in the analytical laboratories). It is ironic how we need to use such big instruments to detect some of the smallest things you can imagine!

This year’s task

During the first year of INSIGNIA-EU, the team at the University of Almeria will analyse by chromatographic and mass spectrometry techniques a total of 120 APIStrips and 240 honey bee samples from three different countries (Denmark, Austria and Greece). The main objective will be to compare the results obtained with these biotic and abiotic samples and evaluate which technique should be employed next year (2023) for the large-scale monitoring program throughout the European Union. For the PAH and VOC comparison, a different sampler will also be considered; the silicone wristbands that are being analysed at the Benaki Hpytopathological Institute.

María Murcia Morales