Chromium speciation analysis in wine and beer by high performance liquid chromatography - inductively coupled plasma mass spectrometry using enriched stable isotopes of 53 Cr(III) and 50 Cr(VI)

Vino in pivo sta priljubljeni pijači. Vsebujeta vodo, minerale, vitamine, elemente v sledovih in različne organske spojine, kot so organske kisline, polifenoli, aminokisline, polisaharidi in alkohol. Med elementi v sledovih se v obeh pijačah nahaja tudi krom (Cr). V okolju sta najbolj stabilni kemijski obliki trivalentni (Cr(III)) in šestvalentni (Cr(VI)) krom. Spojine Cr(VI) so za vse žive organizme zelo strupene in kancerogene, medtem ko so spojine trivalentnega kroma bistveno manj strupene in v nizkih koncentracijah esencialne za človeka. V znanstveni literaturi so v zadnjem obdobju objavili članke, ki poročajo o vsebnosti Cr(VI) v vinih in pivih. To bi pomenilo, da pitje teh pijač predstavlja dolgoročno kronično izpostavljenost velikega dela človeškega prebivalstva strupenemu Cr(VI). Polifenoli in ostale organske spojine, ki so v vinu in pivih so močni reducenti. Zaradi njih vina in piva, ne morejo vsebovati Cr(VI). Ugotovitve o navzočnosti Cr(VI) v vinih in pivih, so najverjetneje posledica napačno uporabljenih analiznih postopkov za določanje kemijskih zvrsti kroma (speciacije kroma). Zato smo v diplomski nalogi želeli potrditi hipotezo, da Cr(VI), v vinih in pivih, ne more obstajati. V ta namen smo analizirali vzorce vina in piva z zanesljivim postopkom speciacijske analize z anionsko-izmenjalno tekočinsko kromatografijo z visoko ločljivostjo (HPLC) v povezavi z masno spektrometrijo z induktivno sklopljeno plazmo (ICP-MS). Obnašanje Cr(III) in Cr(VI) v vzorcih vin in piv smo preučili z uporabo obogatenih stabilnih izotopov 53Cr(III) in 50Cr(VI). Kromatografsko ločbo smo spremljali z ICP-MS pri m/z 50, 52 in 53. V vzorcih vin in piv smo določili tudi celotne koncentracija kroma in nekaterih izbranih elementov. Rezultati kažejo, da vina in piva ne vsebujejo Cr(VI), ter da se je izotopsko označen 50Cr(VI), ki smo ga dodali v vino in pivo, zaradi prisotnosti antioksidantov in organske snovi v vzorcih, reduciral do 50Cr(III).Wine and beer are popular drinks. They contain water, minerals, vitamins, trace elements, and organic compounds, such as polyphenols, amino acids, sugars and alcohol. Among trace elements, chromium (Cr) is found in both beverages. In the environment, the most stable are trivalent (Cr(III)) and hexavalent (Cr(VI)) chromium chemical forms. Cr(VI) compounds are highly toxics for all living organisms, while Cr(III) compounds are far less toxic and, in trace concentrations, essential for humans. Recently, several papers have been published in the scientific literature on the presence of Cr(VI) in wine and beer samples. If Cr(VI) exists in these beverages, their consumption represents long-term chronic exposure to Cr(VI) and a health threat for a majority of the human population. Because of the presence of polyphenols and other organic compounds, which are strong reducents, Cr(VI) cannot exist in wine and beer. The findings on the presence of Cr(VI) in wines and beers are most likely erroneous due to the application of wrong analytical methodologies in the chromium speciation analysis. In the diploma thesis, we wanted to confirm the hypothesis that Cr(VI) cannot exist in wines and beers. For this purpose, we analysed wine and beer samples by applying reliable speciation analysis based on anion-exchange high performance liquid chromatography (HPLC) coupled to inductively coupled plasma mass spectrometry (ICP-MS). The behaviour of Cr(III) and Cr(VI) in wine and beer samples was followed by the use of enriched 53Cr(III) and 50Cr(VI) stable isotopic tracers. The chromatographic separation was monitored by ICP-MS at m/z 50, 52 and 53. In wine and beer samples, total chromium concentrations and concentrations of some selected elements were also determined. The results demonstrated that wines and beers do not contain Cr(VI). It was also showed that, due to the presence of antioxidants and organic matter, the added isotopically enriched 50Cr(VI) was in wines and beers reduced to 50Cr(III)