Quantitative determination of zinc in various household products

Na prehranskih dopolnilih ali izdelkih za osebno nego, ki vsebujejo cink, je zapisano, v kakšni obliki je prisoten. V nekaterih je zapisan tudi delež cinka. Pričujoča raziskava temelji na odkrivanju enostavne metode za kvantitativno določitev cinka v teh izdelkih. Analiziral sem kapsule, praške, šampon, kremo za dojenčke in masko za obraz. Dva izdelka se zaužijeta, trije pa so namenjeni zunanji uporabi. Izdelki se ločijo v obliki cinka, ki je v njih prisoten. Kapsule in maska za obraz vsebujeta cinkov glukonat, praški in krema za dojenčke vsebujejo cinkov oksid, šampon pa vsebuje cinkov pirition. Vsebnost cinka sem določeval z različnimi metodami: kompleksometrično titracijo z EDTA, metodo induktivno sklopljene plazme (ICP-MS), plamensko atomsko absorpcijsko spektrometrijo (AAS), termogravimetrično analizo (TG) in praškovno rentgensko difrakcijo (PXRD). Pedagoški del raziskave vključuje učno enoto, ki bi se lahko izvajala v osnovni šoli pri izbirnem predmetu Poskusi v kemiji. Učna enota vključuje predstavitev pomembnosti cinka v vsakdanjem življenju, samostojno kvalitativno določitev cinka z uporabo ditizonovega papirja ter interaktivno preverjanje znanja novo naučene snovi. S tem delom raziskave želim otrokom približati kemijo cinka, ki ni del učnega načrta za osnovno šolo, saj je preveč specifična.Each household product containing zinc has a declaration where it is written in which form zinc is present. In some products, the declaration states the exact amount of zinc. My research is based on the analysis of zinc in various household products. I analyzed capsules, powders, shampoo, baby cream and face mask. The chosen samples differ: two household products are intended for consumption and three are for dermal use. They also differ in the form of zinc that is present in them. The capsules and face mask contain zinc gluconate, powder and baby cream contain zinc oxide, and the shampoo contains zinc pyrithione. The zinc content was analyzed using various methods such as: compleximetric titration with EDTA, inductively coupled plasma with mass spectrometry (ICP-MS), flame atomic absorption spectrometry method (AAS), and thermogravimetric (TG) and PXRD solid residue analysis. The pedagogical part of the research includes a teaching unit that could be used in elementary schools in Experiments in chemistry which is an optional course. Teaching unit includes the presentation of the importance of zinc in everyday life, the qualitative determination of zinc by the dithizone paper method and interactive testing of the newly learned content. With this part of the research, I would like to acquaint children with the chemistry of zinc which is not part of the elementary school curriculum because it is too specific