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master's thesis
Određivanje limunske kiseline u voćnim sokovima primjenom tekućinske kromatografije visoke djelotvornosti
Zagreb: University of Zagreb, Faculty of Pharmacy and Biochemistry, 2019. urn:nbn:hr:163:753330
Ljepović, Maja
University of Zagreb
Faculty of Pharmacy and Biochemistry
Department of analytical chemistry

Institutional repository: Repository of Faculty of Pharmacy and Biochemistry University of Zagreb

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Ljepović, M. (2019). Određivanje limunske kiseline u voćnim sokovima primjenom tekućinske kromatografije visoke djelotvornosti (Master's thesis). Zagreb: University of Zagreb, Faculty of Pharmacy and Biochemistry. Retrieved from https://urn.nsk.hr/urn:nbn:hr:163:753330

Ljepović, Maja. "Određivanje limunske kiseline u voćnim sokovima primjenom tekućinske kromatografije visoke djelotvornosti." Master's thesis, University of Zagreb, Faculty of Pharmacy and Biochemistry, 2019. https://urn.nsk.hr/urn:nbn:hr:163:753330

Ljepović, Maja. "Određivanje limunske kiseline u voćnim sokovima primjenom tekućinske kromatografije visoke djelotvornosti." Master's thesis, University of Zagreb, Faculty of Pharmacy and Biochemistry, 2019. https://urn.nsk.hr/urn:nbn:hr:163:753330

Ljepović, M. (2019). 'Određivanje limunske kiseline u voćnim sokovima primjenom tekućinske kromatografije visoke djelotvornosti', Master's thesis, University of Zagreb, Faculty of Pharmacy and Biochemistry, accessed 03 April 2025, https://urn.nsk.hr/urn:nbn:hr:163:753330

Ljepović M. Određivanje limunske kiseline u voćnim sokovima primjenom tekućinske kromatografije visoke djelotvornosti [Master's thesis]. Zagreb: University of Zagreb, Faculty of Pharmacy and Biochemistry; 2019 [cited 2025 April 03] Available at: https://urn.nsk.hr/urn:nbn:hr:163:753330

M. Ljepović, "Određivanje limunske kiseline u voćnim sokovima primjenom tekućinske kromatografije visoke djelotvornosti", Master's thesis, University of Zagreb, Faculty of Pharmacy and Biochemistry, Zagreb, 2019. Available at: https://urn.nsk.hr/urn:nbn:hr:163:753330

Metadata
TitleOdređivanje limunske kiseline u voćnim sokovima primjenom tekućinske kromatografije visoke djelotvornosti
Title (english)Determination of citric acid in fruit juices using high performance liquid chromatography
AuthorMaja Ljepović
MentorSuzana Inić (mentor)
Committee memberSuzana Inić (predsjednik povjerenstva)
Committee memberJasna Jablan (član povjerenstva)
Committee memberAna-Marija Domijan (član povjerenstva)
GranterUniversity of Zagreb
Faculty of Pharmacy and Biochemistry
(Department of analytical chemistry)
Zagreb
Defense date and country2019-09-25, Croatia
Scientific / art field,
discipline and subdiscipline		BIOMEDICINE AND HEALTHCARE
Pharmacy
Pharmacy
Abstract
Limunska kiselina se u farmaceutskoj i prehrambenoj industriji koristi kao antioksidans i regulator kiselosti, a u većim koncentracijama može biti štetna za ljudsko zdravlje. U ovom diplomskom radu određena je koncentracija limunske kiseline u uzorcima prirodnih i komercijalo dostupnih voćnih sokova. Za određivanje limunske kiseline korištena je tekućinska kromatografija visoke djelotvornosti (HPLC, Knauer, Berlin, Njemačka) s UV/Vis detektorom, uz kolonu obrnute faze ( LiChrospher RP-18,... More 125 x 4,6 mm, 5 μm Merck, Darmstadt, Njemačka). Mobilna faza je bila 50 mM fosfatni pufer (pH = 2,8) s protokom 0,5 mL/min, a valna duljina detektora bila je podešena na 214 nm. Metoda je ispitana standardnim otopinama limunske kiseline u koncentracijskom rasponu od 0,1 do 1,0 g/L. U ispitivanom području metoda je bila linearna (koeficijent korelacije, R2 = 0,9999). Ponovljivost metode, izražena kao relativna standardna devijacija (RSD) bila je ispod 2,5%, a srednja preciznost izražena kao relativna standardna devijacija (RSD) iznosila je manje od 3%. Granica dokazivanja bila je 0,01 g/L, a granica određivanja 0,03 g/L što pokazuje da je metoda osjetljiva za određivanje koncentracije limunske kiseline u voćnim sokovima.. Koncentracija limunske kiseline u šest komercijalno pribavljenih voćnih sokova bila je u rasponu od 1,42 g/L (uzorak 1) do 4,42 g/L (uzorak 4). Izmjerene koncentracije u devet uzoraka prirodnih voćnih sokova iznosile su od 0 g/L (uzorak 1, 2, 4 i 5) do 7,66 g/L (uzorak 6). Iz dobivenih rezultata može se zaključiti da je HPLC metoda brza, pouzdana i precizna za određivanje koncentracije limunske kiseline u uzorcima voćnih sokova. Budući da je u sedam uzoraka, koncentracija limunske kiseline prelazila propisima dozvoljenu vrijednost, važno je pratiti njenu koncentraciju u svim prehrambenim proizvodima. Less
Abstract (english)
Citric acid is used in the pharmaceutical and food industries as an antioxidant and acid regulator, but at the higher concentrations can be harmful to human health. The concentration of citric acid in samples of natural and commercially available fruit juices is determined in this thesis. High performance liquid chromatography (HPLC, Knauer, Berlin, Germany) with UV / Vis detector together with a reversed phase column (LiChrospher RP-18, 125 x 4.6 mm, 5 μm Merck, Darmstadt, Germany) was... More used for the determination of citric acid. The mobile phase was 50 mM phosphate buffer (pH = 2.8) with a flow rate of 0.5 mL/min, and the detector wavelength was adjusted to 214 nm. The method was tested with standard citric acid solutions in a concentration range of 0.1 to 1.0 g/L. In the study area, the method was linear (correlation coefficient, R2 = 0.9999). The repeatability of the method, expressed as relative standard deviation (RSD) was below 2.5%, and the intermediate precision expressed as relative standard deviation (RSD) was less than 3%.The limit of detection was 0.01 g/L and the limit of quantification was 0.03 g/L indicating that the method is sensitive to the determination of citric acid concentration in fruit juices. The citric acid concentration in the six commercially obtained fruit juices ranged from 1.42 g/L (sample 1) to 4.42 g/L (sample 4). The measured concentrations in nine samples of natural fruit juices ranged from 0 g/L (sample 1, 2, 4 and 5) to 7.66 g/L (sample 6). From the obtained results, it can be concluded that the HPLC method is fast, reliable and accurate for the determination of citric acid concentration in fruit juice samples. Considering that the concentration of citric acid in seven samples exceeded the regulatory limit, it is important to monitor its concentration in all food products. Less
Keywords
Keywords (english)
Languagecroatian
URN:NBNurn:nbn:hr:163:753330
Study programmeTitle: Pharmacy
Study programme type: university
Study level: integrated undergraduate and graduate
Academic / professional title: magistar/magistra farmacije (magistar/magistra farmacije)
Type of resourceText
File originBorn digital
Access conditionsOpen access
Terms of useLicence In copyright icon
Created on2021-04-22 13:27:48
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