Zsuzsanna Czégény

Study on the leaching of phthalates from polyethylene terephthalate bottles into mineral water

Carbonated and non-carbonated mineral water samples bottled in 0.5-L, 1.5-L and 2.0-L polyethylene terephthalate (PET) containers belonging to three different water brands commercialized in Hungary were studied in order to determine their phthalate content by gas chromatography-mass spectrometry. Among the six investigated phthalates, diisobutyl phthalate, di-n-butyl-phthalate, benzyl-butyl phthalate and di(2-ethyl-hexyl) phthalate (DEHP) were determined in non-carbonated samples as follows: <3.0 ng L(-1)-0.2 μg L(-1), <6.6 ng L(-1)-0.8 μg L(-1), <6.0 ng L(-1)-0.1 μg L(-1) and <16.0 ng L(-1)-1.7 μg L(-1), respectively. Any of the above-mentioned phthalate esters could be detected in carbonated mineral water samples. DEHP was the most abundant phthalate in the investigated samples. It could be detected after 44 days of storage at 22 °C and its leaching was the most pronounced when samples were stored over 1200 days. Mineral water purchased in PET bottles of 0.5L had the highest phthalate concentrations compared to those obtained for waters of the identical brand bottled in 1.5-L or 2.0-L PET containers due to the higher surface/volume ratio. No clear trend could be established for phthalate leaching when water samples were kept at higher temperatures (max. 60 °C) showing improper storage conditions. Phthalate determination by pyrolysis-gas chromatography/mass spectrometric measurements in the plastic material as well as in the aqueous phase proved the importance of the quality of PET raw material used for the production of the pre-form (virgin vs. polymer containing recycled PET).

Pyrolysis GC/MS and IR spectroscopy in chitin analysis of molluscan shells.

Chitin is an insoluble component in the shells of several molluscan species. It is thought to play important roles, in biomineralization and shell structure. To date, however, reports are scarce and sometimes contradictory, and suffer from methodological problems. Only in a single cephalopod species has the chitin been identified as β-chitin. We present data on chitin occurrence in 22 species of shell-bearing Mollusca (Conchifera) and Polyplacophora, including the first evidence for scaphopods, based on pyrolysis gas chromatography, mass spectrometry (GC-MS), and infrared spectroscopy (IR). Pyrolysis GC-MS detected chitin in every tested member of the Conchifera. IR spectroscopy before and after chitinase treatment revealed at least three distinct patterns of peak changes. The contents of the insoluble shell organics included not only chitin and proteins, but also insoluble polysaccharides, e.g., glucan. We conclude that chitin was present in the last common ancestor of the Conchifera and that its abundance in the shell matrix depends on the differentiation of the shell.

Decomposition of Chlorobenzene by Thermal Plasma Processing

Decomposition of chlorobenzene as a model molecule of aromatic chlorinated compounds was studied in radiofrequency thermal plasma both in neutral and oxidative conditions. Optical emission spectroscopy was applied for the evaluation of the plasma excitation and molecular rotational-vibrational temperature. Atomic (C, H, O) and molecular (CH, OH, C2) radicals were identified, while the morphology of the formed soot was characterized by electron microscopy. Organic compounds adsorbed on the surface of the soot after plasma processing were comprised of various polycyclic aromatic hydrocarbons (PAH) and chlorinated PAH molecules. Their amount was greatly affected by experimental conditions, especially the oxygen content and plate power. The higher input power reduced the ring number of the PAH molecules. Addition of oxygen significantly reduced the amount of both PAHs chlorinated PAH molecules but enhanced the formation of polychlorinated benzene compounds.

Thermal Plasma Decomposition of Tetrachloroethylene

Tetrachloroethylene (C2Cl4) has been used widely as a solvent and dry cleaning agent, but was later specified as possible human carcinogen. As a result, its safe treatment became a priority. In this paper, we report on its decomposition in an atmospheric radiofrequency thermal plasma reactor. Main components of the exhaust gases were determined by Fourier transform infrared spectroscopy. We found that complete decomposition can be achieved in either oxidative or reductive conditions but not in neutral one. The solid soot product was characterised by transmission electron microscopy and specific surface area measurement. Organic compounds adsorbed on the surface of the soot were extracted by toluene and comprised, based on gas chromatography mass spectrometry, of various perchlorinated aliphatic (for example hexachlorocyclopentadiene) and aromatic compounds (like hexachlorobenzene, octachloronaphthalene or octachloroacenaphthylene). Several nitrogen containing molecules were also identified whose presence are rare during thermal plasma treatments. Further investigation of the extract by mass spectrometry revealed various higher molar mass chlorinated carbon clusters and two types of fullerenes (C60 and C70).