H) Food research

1. U isotope ratios in food

The purpose of the work is to adjust and validate existing methodology for determination of U isotope ratios by multicollector inductively coupled plasma mass spectrometry for food samples. In the next step, student will perform screening study to evaluate usability as U isotope ratios as a tracer in food-related studies.

Mentors: dr. Marko Štrok (marko.strok@ijs.si), Leja Rovan (leja.rovan@ijs.si)

2. The change in the isotopic composition of aromatic volatile organic compounds during storage

The work includes the analysis of stable isotopes of aromatic compounds including the preparation of samples. The master will include analysis of aroma compounds of natural and synthetic origin and evaluation of the changes in the isotopic composition during the storage.

Mentors: dr. Nives Ogrinc (nives.ogrinc@ijs.si), Doris Potočnik (doris.potocnik@ijs.si)

3. Lipids and their use to detect the organic remains in prehistorical vessels

The topic includes the determination of lipids in prehistoric vessels that helps to determine the use and purpose of the vessel in the past. The work includes sample preparation and analysis and identification of organic components on GC-MSD. This topic would be appropriate only for master's degree work performed in July and August 2020.

Mentors: dr. Nives Ogrinc (nives.ogrinc@ijs.si), Doris Potočnik (doris.potocnik@ijs.si)

4. Linking Soil, Plant, and Honey Composition To Assess the Geographical Origin of Montenegrian Honey by Multielemental and Strontium Isotopic Analyses

Honey is a natural product with health benefits and its consumption has increased in recent years. All the properties of honey, including nourishing and healing effects, result from its unique chemical composition and a specific processing subjected by bees to the collected forage sources. The composition and concentration of elements in honey is correlated with the elemental composition of soil and botanical origin of nectar and pollen. The environmental pollution should also be considered as an additional source of potentially toxic elements in honey, namely Cd, Cr, Cu, Fe, Ni, Pb and Zn. These elements may condemn the quality and safety of honey, and exhibit a potential hazard to human health.

For the student's master's thesis, the elemental composition in the isotopic ratio ⁸⁷Sr/⁸⁶Sr will be determined in honey in a plant samples from Montenegro in Slovenia. The main objective of the thesis is to develop a reliable methodology for honey fingerprint determination.

Mentor: dr. Tea Zuliani (tea.zuliani@ijs.si)

5. Arsenic and its compounds in foods for babies and young children

Due to the toxicity of inorganic arsenic, its amount is regulated in some food products. The EU allows between 200 - 300 µg/kg As in rice, which usually contains more inorganic arsenic than other foods. Rice for infants and young children may contain even less arsenic (100 µg/kg). Other cereals also have the potential to absorb arsenic from the soil, but this is usually lower due to the method of cultivation. In this part, we intend to evaluate the content of inorganic arsenic and some organic compounds (monomethylarsonic and dimethylarsinic acid) in cereal-based food products for young children. The work will include the collection and preparation of samples, microwave digestion, and the determination of total arsenic in the decomposed samples. For arsenic speciation (determination of arsenic compounds), the arsenic compounds will be extracted into the appropriate solvents, separated by liquid chromatography and determined by atomic fluorescence spectrometry. This work will enable the evaluation of the health risk of young children potentially exposed to arsenic in cereals.

Mentor: dr. Zdenka Šlejkovec (zdenka.slejkovec@ijs.si)