Razvoj i validacija metode za određivanje ukupnog dušika i fosfora ionskom kromatografijom

master's thesis

• Title (english): Development and validation of a method for determination of total nitrogen and total phosphorus by ion chromatography
• Author: Ivana Bošnjak
• Mentor: Lidija Furač (mentor)
• Committee member: Lidija Furač (predsjednik povjerenstva)
• Committee member: Matija Cvetnić (član povjerenstva)
• Committee member: Martina Miloloža (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2024-09-30, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry

Abstract

Pročišćavanje otpadnih voda ključno je za zaštitu vodenih ekosustava uklanjanjem štetnih tvari, uključujući višak dušika i fosfora. Dušik i fosfor su hranjive tvari koje u nekontroliranim uvjetima mogu dovesti do eutrofikacije, uzrokovajući cvjetanje algi i iscrpljivanje kisika u vodenim tijelima. Praćenje koncentracija dušika i fosfora u otpadnim vodama omogućuje optimizaciju procesa obrade, smanjujući operativne troškove. Učinkovito pročišćavanje otpadnih voda smanjuje rizik od onečišćenja hranjivim tvarima, što je glavni pokretač pogoršanja kvalitete vode u cijelom svijetu. Cilj ovog rada bio je razviti i validirati metodu za određivanje ukupnog dušika i fosfora ionskom kromatografijom (IC). Kao metoda za određivanje ukupnog dušika i fosfora korištena je alkalna persulfatna digestija. Alkalna digestija provedena je otopinama NaOH i K₂S₂O₈. Validacija je provedena procijenom parametara kao što su linearnost, granica detekcije, granica kvantifikacije i točnost te je proveden Grubbov test. Metoda nije zadovoljila kriterij linearnosti s koeficijentom determinacije manjim od 0,9900. Točnost metode je prikazana parametrom preciznosti injektiranja i preciznosti pripreme te je bila unutar granica 89 – 112% te je utvrđeno odsustvo sustavne pogreške. Preciznost se pokazala više zadovoljavajuća za primjenu kod određivanja fosfatnih iona nego nitratnih. Određene su i granice kvantifikacije i granice detekcije za oba spoja. Grubb-ov test za outlier detektirao je tri podatka kao outlier.

Abstract (english)

Wastewater treatment is essential to protect aquatic ecosystems by removing harmful substances, including excess nitrogen and phosphorus. Nitrogen and phosphorus are nutrients that, if left unchecked, can lead to eutrophication, causing algal blooms and oxygen depletion in water bodies. Monitoring of nitrogen and phosphorus concentrations in wastewater allows optimisation of the treatment process, reducing operational costs. Effective wastewater treatment reduces the risk of nutrient pollution, which is the main driver of water quality deterioration worldwide. The aim of this work was to develop and validate a method for the determination of total nitrogen and phosphorus by ion chromatography (IC). Alkaline persulfate digestion was used as a method for determining total nitrogen and phosphorus. Alkaline digestion was performed with NaOH and K₂S₂O₈ solutions. Validation was performed by evaluating parameters such as linearity, limit of detection, limit of quantification and accuracy and Grubb's test was performed. The method did not meet the linearity criterion with a coefficient of determination of less than 0.9900. The accuracy of the method was shown by the injection precision and preparation precision parameter and was within the limits of 89 – 112% and the absence of systematic error was determined. The precision proved to be more satisfactory for use in the determination of phosphate ions than nitrate ones. Both the limits of quantification and the limits of detection for both compounds were determined. Grubb's outlier test detected three pieces of data as outliers.

• Keywords: otpadne vode; dušik; fosfor; ionska kromatografija; validacija matode
• Keywords (english): wastewater; nitrogen; phosphorus; ion chromatography; method validation
• Language: croatian
• URN:NBN: urn:nbn:hr:149:487934
• Study programme: Title: Applied Chemistry - Graduate study; specializations in: Environmental chemistry and green technologies, Advanced materials and technologies, Applied organic chemistry; Course: Environmental chemistry and green technologies; Study programme type: university; Study level: graduate; Academic / professional title: sveučilišni/a magistar/magistra primijenjene kemije (sveučilišni/a magistar/magistra primijenjene kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Embargoed access; Embargo expiration date: 2034-09-01
• Created on: 2024-11-11 13:56:36