Session 6

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Various natural substances are too complex analytes even for recent highly efficient analytical methods. One research approach is to characterize and analyze such complex systems is based on operational definition. Operationally defined analytes isolated from complex matrices resulted in development of novel combined multidimensional methods based on liquid chromatography separation with potential extension to combinations with electroseparation methods (ESM) and multi-detection (UV-VIS spectrophotometry, spectrofluorimetry, electroanalytical detection) and mass spectrometry (MS). Liquid chromatography working under extreme separation conditions (pH, ionic strength, temperature, additives, solvents etc.) as first dimension separation method is investigated. Usually, tough separation conditions are not directly compatible with the other methods in second separation dimension – some modes of HPLC, capillary isotachophoresis (ITP), capillary zone electrophoresis (CZE) (with various detection principles) and MS.

Systematic study of orthogonality of novel combined techniques for characterization of operationally defined humic substances (HS) and/or lignin was done. Compatibility of used extreme extractive isolation and separation conditions in HPLC (ion exchange, reversed phase, size-exclusion) with common conditions of various end techniques was tested. The approach is valuable for solution of HS interferences elimination in soil samples containing pesticides. Comprehensive techniques of multidimensional liquid chromatography (under the conditions of extreme pH, I, temperature, large-volume injection, solid sample injection etc.) combined off-line or on-line with the other separation or identification methods are discussed. Application of methods combining extreme separation conditions in HPLC (pH within the range 0-2 or alternatively 10-14, ionic strength above 0.1 mol/l, temperature well above 40°C, non-common mobile phase solvents dimethylformamide) and normal separation conditions in ESM and MS in the field of environmental analysis, analysis of degradation products of soil humic substances.

Acknowledgements
The research was supported by the grant of projects APVV-17-0318, APVV-0462-20.

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The city of Kalush, located in Western Ukraine, was a major center of the chemical industry in the former Soviet Union. In particular, at the production association "Chlorvinyl" were produced perchloroethylene, carbon tetrachloride by direct chlorination of hydrocarbons. Hexachlorobenzene was formed as a by-product of this synthesis, the content of which in production waste was over 90%. According to the Stockholm Convention, this compound belongs to the persistent organic pollutants, and waste with hexachlorobenzene - to the first class of danger. As there were no such waste disposal plants in the Soviet Union at that time, it was decided to bury of hexachlorobenzene waste at a landfill near the city of Kalush. The waste was placed in iron barrels with a capacity of 200 liters and buried in the trench. As of 2001, there were 11,352.5 tons of hexachlorobenzene wastes at the landfill. Over time, the barrels corroded and hexachlorobenzene migrated into soils, groundwater and surface water. This posed a great danger to the health of the population of Kalush and other settlements located nearby. In view of this, it was decided to remove waste from the landfill.

During the work on the removal of waste, the placement of waste and the state of contamination of soils, groundwater and surface water were monitored. Sampling was performed both from the surface and from wells located on the landfill. It was found by gas chromatography that the concentrations of hexachlorobenzene in the soil exceeded the maximum allowable concentrations by hundreds of thousands of times. Soil contamination reached a depth of 12 m and the maximum levels of contamination were at a depth of 2-3 meters, where waste barrels were placed. Significant exceeding of the maximum allowable concentrations of hexachlorobenzene was observed in groundwater and surface water in the area of the landfill. A map of waste location was compiled and used for their removal.

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Pharmaceuticals are used in human and veterinary practice and are so-called emerging contaminants. Their occurrence in the environment is still not law regulated, while certain number of published articles record their negative impact on human health. From the literature overview, pharmaceuticals were determined in different environment samples, but little bit less in here examined sediment. Sediment acts like a potential receiver for many hazardous substances including pharmaceuticals who can be easily emitted to drinking water reservoirs depending on the sediment characteristics [1]. In this work pharmaceuticals who belong to different structure groups were determined in sediment sample and following five extractions were developed and optimized: extraction by agitation (EA), ultrasound solvent extraction (USE), microwave assisted extraction (MAE), matrix solid phase dispersion (MSPD) and pressurized solvent extraction (PSE). Chosen pharmaceuticals were tylosine as macrolide antibiotic, albendazole, febantel and levamisole as antihelmintics, lidocaine and procaine as anesthetics and hydrocortisone and dexamethasone as glucocorticoids. Pharmaceutical concentrations extracted from sediment sample were determined by high performance liquid chromatography using diode array detector. After chromatographic analysis, all methods were validated and the following optimal parameters were determined for each extraction method: sediment mass, solvent, contact time between sediment and solvent, extraction duration, agitation frequency and extraction temperature (EA); solvent, extraction duration, power and temperature of ultrasonic bath (USE); solvent, extraction duration, temperature, solvent volume (MAE); sorbent, solvent, solvent volume, sediment/sorbent mass ratio (MSPD); solvent (PLE) [2].

Acknowledgments
This paper was prepared as part of the project Advanced Water Treatment Technologies for Microplastics Removal (IP-2019-04-9661, AdWaTMiR).

References
[1]  M. S. Díaz-Cruz, M. J. López de Alda, D. Barceló, TrAC 22 (2003) 340-551.
[2]  D. Drljača, D. Ašperger, M. Ferenčak, M. Gavranić, S. Babić, I. Mikac, M. Ahel, Chromatographia, 79 (2016) 209-223.

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Environmental monitoring of organic micropollutants (OMPs), even though based on advanced extraction and chromatographic analytical approaches, is indeed a rather laborious issue for several reasons. Among them, environmental analysis must address a wide range of matrices and is usually faced with the simultaneous analysis of a very large number of analytes, often characterized by different physicochemical properties. Furthermore, OMPs are often capable of exerting negative effects on the environment and humans, even if present at very low concentrations (i.e. ng/L and sub-ng/L levels), thus requiring highly sensitive analytical methods. The use of environmentally friendly analytical approaches is another important aspect that should not be overlooked, which involves the use of extraction solvents characterized by low or no toxicity and minimal sample handling. Last but not least, environmental monitoring requires a high number of data in order to allow a significant spatial-temporal evaluation, thus requesting methods characterized by a high throughput level, which is often obtained through method automation.
In this lecture, several examples of method optimization are illustrated, dealing with the increase of the overall analytical throughput. These case-studies focuses on the analysis of different classes of analytes of high environmental concern in various matrices, by means of the improvement of (i) the sample extraction and purification strategies [1], (ii) the chromatographic separations, and (iii) the instrumental detection, also using chemometrics tools [2,3]. Preliminary data regarding the unconventional extraction of emerging OMPs from solid samples are also given and discussed.

References
[1]  L. Ciofi, C. Ancillotti, U. Chiuminatto, D. Fibbi, B. Pasquini, M.C. Bruzzoniti, L. Rivoira, M. Del Bubba, Anal. Bioanal. Chem. 408 (2016) 3331-3347.
[2]  L. Ciofi, C. Ancillotti, U. Chiuminatto, D. Fibbi, L. Checchini, S. Orlandini, M. Del Bubba, J. Chromatogr. A 1362 (2014) 75-88.
[3]  L. Renai, C.V.A. Scordo, A. El Ghadraoui, S. Santana.Viera, J.J. Santana Rodriguez, S. Orlandini, S. Furlanetto, D. Fibbi, D. Lambropoulou, M. Del Bubba, J. Chromatogr. A 1649 (2021) 462225.

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For some time now, polar contaminants have been experiencing increased interest because they are not easily accessible with existing analytical methods such as GC or reversed-phase LC.
Polar pesticides, for example, cannot be included into the large panels for screening methods in Food Safety analysis.
Polar, mobile, and toxic (PMT) components have long been missed by regulatory agencies because their detection has been particularly difficult. In the drinking water sector, with the advent of suitable analytical methods, calls for guideline and limit values have now been growing louder since 2018.
In addition to ion chromatography/MS coupling and SFC-MS coupling, novel HILIC or mixed-mode separation phases for LC-MS/MS coupling have proven to be advantageous as suitable methods.
Examples are polar poly- and perfluorinated substances (PFAS) and precursors of nitrosamines.
Various suppliers have now successfully applied novel mixed-mode separation phases to the analysis of polar pesticides and polar, short-chain PFAS.
In this presentation, we want to show, how such a mixed-mode column can be applied in mini-screenings even for larger groups of similar components.
Up to 17 polar pesticides can be detected in one run, which has led to a method based on this column recently being included in the QuPPe document of the European Reference Laboratory for Single Residue Analysis.
In addition, we want to show, how new very short chain PFAS and novel polar substitutes like alcoholic Telomers can be analyzed together with legacy PFAS compounds in Environment and Food.