magistrsko delo
Nika Verdelj (Avtor), Iztok Jože Košir (Mentor), Mitja Kolar (Komentor)

Povzetek

V sklopu magistrske naloge je bila razvita in validirana spektrofotometrična metoda za določanje bora v realnih vzorcih tal in rastlinskih tkiv. Bor je element, ki ga rastline za pravilno rast potrebujejo med 1 in 2 mg bora/kg zemlje, če pa je koncentracija bora previsoka, deluje toksično. Zato je točno in natančno določanje koncentracije bora v rastlinskih vzorcih in vzorcih tal zelo pomembno. Za določanje smo izbrali spektrofotometrično določanje z barvnim reagentom azometin – H. Metodi, ki se sicer uporabljata za določanje bora v realnih vzorcih tal in rastlinskih vzorcih smo validirali, ter ju primerjali z metodama, pri katerih smo spremenili način ekstrakcije bora iz vzorcev. Pri določanju bora v vzorcih tal smo vročo ekstrakcijo s CaCl2 primerjali s hladno ekstrakcijo s HCl. Pri določanju bora v rastlinskih vzorcih pa smo ekstrakcijo z žarenjem z raztopino HCl primerjali z ekstrakcijo s sušenjem z raztopino HNO3. Ker je v vzorcih tal in rastlinskih vzorcih prisotnih tudi veliko drugih ionov, smo preučili interference – vpliv posameznih ionov na rezultat določitve bora. Preverili smo tudi, kako dodatek tioglikolne kisline, ki zmanjšuje interference pri reakciji, vpliva na rezultate. Ugotovili smo, da je metoda za določanje bora v vzorcih tal bolj natančna in ponovljiva, kadar uporabimo hladno ekstrakcijo s HCl. Metoda za določanje bora v rastlinskih vzorcih pa je bolj natančna in ponovljiva, kadar uporabimo ekstrakcijo s sušenjem z raztopino HNO3. Vse metode so linearne v merilnem območju med 0,5 in 0,75 mg/L. Dodatek tioglikolne kisline ne zmanjšuje samo interferenc pri reakciji, ampak tudi zaznan bor v raztopini.

Ključne besede

spektrofotometrija;bor;validacija;tla;rastlinska tkiva;magistrske naloge;

Podatki

Jezik: Slovenski jezik
Leto izida:
Tipologija: 2.09 - Magistrsko delo
Organizacija: UM FKKT - Fakulteta za kemijo in kemijsko tehnologijo
Založnik: [N. Verdelj]
UDK: 543.422.3(043.2)
COBISS: 20356886 Povezava se bo odprla v novem oknu
Št. ogledov: 1574
Št. prenosov: 130
Ocena: 0 (0 glasov)
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Ostali podatki

Sekundarni jezik: Angleški jezik
Sekundarni naslov: Development and validation of spectrophotometric method for determination of boron in real samples of soil and plant tissues
Sekundarni povzetek: The master’s dissertation describes the validation of the spectrophotometric method for determining boron in real samples of soil and plant tissues. Boron is an element plants vitally need between 1 and 2 g/kg soil for proper growth, but if its concentration is too high, it has a toxic effect. Therefore it is very important to accurately determine boron concentrations in plant and soil samples. To determine levels of boron, spectrophotometric determination with the azomethine–H colour reagent was chosen. The two established methods for determining boron in real soil and plant samples were validated and compared to the two methods in which boron was extracted from samples in a different manner. When determining boron in soil samples, hot extraction with CaCl2 was compared to the cold extraction with HCl. In determining boron in plant samples, extraction by incinerating and heating with HCl solution was compared to extraction by drying with HNO3 solution. Because many other ions are present in soil and plant samples as well, we examined how the concentrations of these ions affect the results of boron determination. We looked into how the addition of thioglycolic acid, which reduces interferences during the reaction, affects the results. We have established that the method for determining boron in soil samples is more accurate and reproducible if cold extraction with HCl is used, while the method for determining boron in plant samples is more accurate and reproducible if extraction by drying with HNO3 solution is used. All methods are linear in measuring range between 0,05 and 0,75 mg/L Ading thioglycolic acid does not only reduce interferences during the reaction but also decreases the detected concentration of boron in the solution.
Sekundarne ključne besede: spectrophotometry;boron;validation;soil;plant tissues;
URN: URN:SI:UM:
Vrsta dela (COBISS): Magistrsko delo/naloga
Komentar na gradivo: Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Strani: IX, 49 f.
ID: 9165974