Determination of microelements in crystal and liquid mineral fertilizers with ICP-AES

Namen diplomskega dela je bil določanje vsebnosti mikroelementov v kristalnih in tekočih mineralnih gnojilih z ICP-AES analizno metodo. V kristalnih gnojilih smo določali bor, baker, železo, mangan, molibden in cink. Pri tekočih gnojilih pa so nas zanimale vsebnosti bora, bakra, železa in cinka. Glede na dobljene rezultate smo ovrednotili primernost gnojila za tržišče na podlagi veljavne zakonodaje s tega področja za Slovenijo in ostale države EU, Hrvaško ter Srbijo. Najpomembnejši zakonski omejitvi sta maksimalno negativno odstopanje za posamezni mikroelement in minimalna vsebnost mikroelementa v mineralnem gnojilu. Mikroelemente smo določali na podlagi umeritvene krivulje, ki smo jo dobili z meritvami standardnih raztopin različnih koncentracij (v mg/L). Po tako pripravljeni umeritveni krivulji smo izmerili emisijske signale mikroelementov v vzorcih različnih tekočih in kristalnih mineralnih gnojil. Emisijske signale posameznih mikroelementov smo preko izračunov pretvorili v masni delež mikroelementa v gnojilu. V večini primerov tako tekočih kot tudi kristalnih gnojil vsaj eden od mikroelementov pade pod zakonsko določeno mejno vrednost. Pri kristalnih gnojilih povsem zadosti zakonu le eno gnojilo, pri tekočih gnojilih pa sta takšna primera dva.The purpose of the diploma thesis was to determine contents of microelements in crystal and liquid mineral fertilizers with the ICP-AES analytical method. In crystal fertilizers microelements such as boron, copper, iron, manganese, molybdenum and zinc were determined. In liquid fertilizers we were interested in contents of boron, copper, iron, and zinc. On the basis of the results we evaluated the suitability of fertilizers for target market in Slovenia and other countries of EU, Croatia and Serbia, in accordance with legislation. The most important law restrictions regarding mineral fertilizers are maximum negative deviation for each microelement and minimum content of microelement in mineral fertilizer. Microelements were determined by calibration curves, which were made using measurements of standard solutions with different concentrations. When such a calibration curve was constructed, we measured emission signals of microelements in different crystal and liquid fertilizer samples. Emission signals of specified microelements were transformed into mass fractions of each microelement in fertilizer. In most cases of both liquid and crystal mineral fertilizers at least one of the microelements drops below the legal limit. In the case of crystal fertilizers only one fertilizer completely suits the law guidelines while in liquid fertilizers there are two such cases