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Validation of a kinetic model for the biocatalytic synthesis of fluorinated azidoalcohol in different reactor modes
No full textU ovom radu provedena je validacija, odnosno provjera valjanosti matematičkog modela biokatalitičke sinteze (R)–2–azido–1-[4-(trifluorometil) fenil] etanola u reakciji otvaranja prstena rac-2-[4-(trifluorometil) fenil] oksirana uz azidne ione. Kao biokatalizator korištena je varijanta enzima halogenhidrin-dehalogenaze (HHDH) W249P. Također, ispitana je i operacijska stabilnost enzima, kao i njegova stabilnost prilikom inkubacije s racemičnom smjesom epoksida, odnosno azidom. Brzina reakcije opisana je dvosupstratnom Michaelis-Menteničinom kinetikom s inhibicijom supstratom (R)-2-[4-(trifluorometil) fenil] oksiranom, kompetitivnom inhibicijom (S)-2-[4-(trifluorometil) fenil] oksiranom, rac-2-[4-(trifluorometil) fenil]-1,2-etandiolom i DMSO te inhibicijom produktom (R)-2-azido-1-[4-(trifluorometil) fenil] etanolom. Eksperimentalno je utvrđeno da model dobro opisuje eksperimentalne podatke.In this research validation of mathematical model of biocatalytic synthesis (R)-2-azido-1-[4-(trifluoromethyl)phenyl]ethanol through rac-2-[4-(trifluoromethyl)phenyl]oxirane ringopening mediated by azide ions was carried out. The W249P variant of halohydrin dehalogenase (HHDH) enzyme was used as a biocatalyst. Also, the operational stability of enzyme, and its stability during incubation with rac-epoxide and sodium azide were evaluated. The reaction rate was described by double-substrate Michaelis-Menten kinetics with substrate (R)-2-[4-(trifluoromethyl)phenyl]oxirane inhibition, competitive inhibition by (S)-2-[4-(trifluoromethyl)phenyl]oxirane, rac-2-[4(trifluoromethyl)phenyl]-1,2-ethanediol and DMSO, and product inhibition by (R)-2-azido-1-[4-(trifluoromethyl)phenyl]ethanol. The mathematical model described the experimental data well
Use of ferrofluids in the removal of microplastics from waters
No full textU posljednje je vrijeme pojava mikroplastičnih čestica pod sve većim povećalom javnosti. Mikroplastika se nikada neće u potpunosti razgraditi, a negativno utječe na okoliš, ljudsko zdravlje te zdravlje drugih živih bića. Naime probavni sustav organizma ne može probaviti mikroplastiku što predstavlja rizik za ekosustav. Mikroplastika na sebe može vezati kemikalije iz okoliša, kao i bakterije i mikrobe koji potom mogu stvoriti biofilm. Upravo bi se zbog toga problem mikroplastike trebao ozbiljno shvatiti jer dođe li mikroplastika do ljudskog organizma ondje može otpustiti toksične spojeve kao i mikrobe koji su u njoj vezani, oštećujući time i ljudsko zdravlje. Kako bi se mikroplastika uklonila postoji nekoliko rješenja od kojih je u ovom radu predstavljena ekstrakcija mikroplastike ferofluidima. Ferofluidi predstavljaju vrlo snažnu magnetizirajuću tekućinu sastavljenu od tekućeg medija koji sadrži čvrste magnetske čestice vrlo male veličine, koloidno raspršene u tekućini nosača. Uklanjanje mikroplastike ferofluidima vrlo je efikasno jer se čak i najmanje čestice mikroplastike mogu vezati na ferofluid te se potom pomoću magneta mogu odstraniti. U ovom je radu korišten ferofluid na bazi sintetskog ulja te šest otopina mikroplastičnih čestica (polistirena (PS) i polivinil klorida (PVC)) u rasponu veličine od nešto manje od 300 μm do 500 μm. Dokazano je da je tehnika uklanjanja mikroplastike ferofluidom učinkovita i brza. Čestice polistirena imale su općenito bolju učinkovitost uklanjanja od čestica polivil klorida. Također je ustvrđeno da se veće čestice od 355-500 μm bolje ekstrahiraju od manjih čestica manje od 300 μm.Recently, the appearance of microplastic particles has come under increasing public scrutiny. Microplastics cannot be completely decomposed, and they have a negative impact on the environment, human health, and the health of other living beings. Namely, the digestive system of the organism cannot digest microplastics, which represents a health risk for the ecosystem. Microplastics can bind chemicals from the environment, as well as bacteria and microbes that then create a biofilm. It is precisely for this reason that the problem of microplastics should be taken seriously, because if microplastics reach the human body, they can release toxic compounds as well as the microbes bound in it, damaging human health. In order to remove microplastics, there are several solutions, of which the extraction of microplastics with ferrofluids is presented in this paper. Ferrofluids represent a very strong magnetizing liquid composed of a liquid medium, containing solid magnetic particles of very small size, colloidally dispersed in a liquid carrier. The removal of microplastics with ferrofluids is very effective because even the smallest particles of microplastics can bind to the ferrofluid and be removed using a magnet. In this work, ferrofluid based on synthetic oil and six solutions of microplastic particles (polystyrene (PS) and polyvinyl chloride (PVC)) in the size range from slightly less than 300 μm to 500 μm were used. The microplastic removal technique with ferrofluid has been proven to be effective and fast. Polystyrene particles had generally better removal efficiency than polyvinyl chloride particles. It was also found that larger particles of 355-500 μm are easier to extracted than smaller particles of less than 300 μm
Corrosion risk in aged water mains
No full textKorozijski rizik u ostarjelim vodovodima procjenjuje se kako bi se identificirali mehanizmi, procjenila vjerojatnost, posljedice i ukupni rizik oštećenja sustava. Vodovodni su sustavi ključni u osiguravanju osnovnih ljudskih potreba, te stabilnog i sigurnog pristupa pitkoj vodi. Međutim ostarjela vodovodna infrastruktura susreće se sa mnogim problemima, od kojih je glavni i najveći problem korozija. Postoje mnogi oblici korozije vodovodnih cijevi, svaki sa određenim karakteristikama koji se mogu naći na unutarnjoj ili vanjskoj strani cijevi. Ostarjeli vodovodni sustavi često su konstruirani od materijala i prema standardima koji većinom nisu usklađeni s današnjim zahtjevima i uvjetima okoline što dovodi do veće osjetljivosti na koroziju. Oštećujući vodovodnu infrastrukturu korozija uzrokuje mnoge kvarove ali i zdrastvene probleme kod ljudi. Otpadni metali iz ostarjelih cijevi često uzrokuju umor, glavobolje, mučnine te smanjene kognitivne sposobnosti. Zbog sporije obnove vodovodne infrastrukture Amerika se susreće sa problemom olova u vodi, što ponajviše utječe na zdravlje djece. Stare materijale kao što su lijevano željezo, pocinčani čelik i polibutilen zamijenili su moderniji i otporniji materijali poput bakra, PEX-a i PVC-a. Koristeći se različitim metodama zaštite cijevi od korozije povećava se otpornost na koroziju, a time i životni vijek vodovodnih sustava. Najprimjenjivanije metode zaštite su zaštitni premazi i katodna zaštita, iako ni jedna od metoda ne garantira stopostotnu zaštitu. Zamjena ostarjele vodovodne infrastrukture izvodi se najčešće metodom otvorenog rova, no razvojem novih tehnika omogućena je i zamjena tehnolgijom bez iskopa. Zahvaljujući novim metodama rješenja problema korozije u ostarjelim vodovodnim sustavima sve se više pažnje predaje što manjem oštećenju okoliša i životnog okruženja ljudi.Corrosion risk in aged water mains is assessed to identify mechanisms, assess probability, consequences and overall risk of system damage. Water systems are crucial in ensuring basic human needs and stable and safe access to drinking water. However, the aging water infrastructure faces many problems, the main and biggest of which is corrosion. There are many forms of water pipe corrosion, each with specific characteristics that can be found on the inside or outside of the pipe. Old plumbing systems are often constructed from materials and according to standards that are mostly not aligned with today's requirements and environmental conditions, which leads to greater susceptibility to corrosion. By damaging the water supply infrastructure, corrosion causes many malfunctions as well as health problems for people. Waste metals from aged pipes often cause fatigue, headaches, nausea and reduced cognitive abilities. Due to the slower restoration of the water infrastructure, Americal faces the problem of lead in water, which affects children's health the most. Old materials such as cast iron, galvanized steel and polybutylene have been replaced by more modern and resistant materials such as copper, PEX and PVC. By using different methods of protecting pipes from corrosion, resistance to corrosion increases, and increases the life span of plumbing systems. The most applicable protection methods are protective coatings and cathodic protection, although none of the methods guarantee 100% protection. The replacement of aging water infrastructure is most often carried out using the open trench method, but with the development of new techniques, it is also possible to replace it with technology without excavation. Thanks to new methods of solving the problem of corrosion in aging water systems, more and more attention is being paid to the least possible damage to the environment and people's living environment
Preparation of ceramic monolithic catalyst supports based on ZrO2 using fused filament fabrication
No full textU ovom diplomskom radu pripremljeni su keramički monolitni nosači katalizatora na bazi cirkonijeva dioksida (ZrO2) primjenom tehnologije proizvodnje rastaljenim filamentom. Na dobivene nosače nanesene su katalitički aktivne komponente postupkom mokre impregnacije. Testiranje aktivnosti pripremljenih katalizatora provedeno je provedbom katalitičke oksidacije smjese aromatskih spojeva, odnosno smjese benzena, toluena, etilbenzena i o-ksilena (BTEX). Određena je učinkovitost pripremljenih monolitnih katalizatora za katalitičku oksidaciju BTEX-a s obzirom na kemijski sastav katalitički aktivne komponente (MnFeOx, MnCuOx i MnNiOx) te s obzirom na geometriju monolitnog nosača (ZDP, Z i M). Prije kinetičkih mjerenja ispitana je dimenzijska stabilnost 3D-ispisanih monolitnih nosača i mehanička stabilnost katalitičkog sloja te je provedena karakterizacija korištenog ZrO2 filamenta. Rendgenskom difrakcijskom analizom utvrđeno je da se keramička faza materijala sastoji od monoklinskog i tetragonskog ZrO2. Laserskom difrakcijskom analizom utvrđeno je da su u uzorku prisutne čestice dimenzija 71 - 3000 μm. Vrijednost medijana veličine čestica (d50) u populaciji iznosila je 540,10 μm, dominantna veličina keramičkih čestica u populaciji (dmode) iznosila je 562,34 μm, a Sauterov promjer (d3,2) čestica 886,25 μm. Simultanom TGA/DTA analizom ispitana su toplinska svojstva ZrO2 filamenta koji je poslužio za pripremu monolitnog nosača. Na temelju izmjerenog odstupanja karakterističnih dimenzija 3D-ispisanih monolitnih nosača od dimenzija predviđenih CAD modelom određen je dimenzijski korekcijski faktor koji je iznosio 1,18. Na temelju testova odstupanja mase 3D-ispisanih nosača utvrđena je jednolika raspodjela čestica keramike ispisanih nosača. Mehanička stabilnost katalitičkog sloja određena je testovima adhezije, odnosno izlaganjem katalizatora ultrazvuku radne frekvencije 37 kHz. Gubitak katalitičkog sloja uslijed djelovanja ultrazvučnih vibracija iznosio je od 0,016 % do 0,051 %, čime je dokazana izvrsna mehanička stabilnost pripremljenih katalitičkih slojeva. Rezultati ispitivanja učinkovitosti katalizatora za oksidaciju BTEX-a pokazali su da je 3D-ispisani model M koji je sadržavao MnFeOx kao katalitički aktivnu komponentu najuspješniji katalizator za oksidaciju BTEX spojeva. Navedeni katalizator omogućava katalitičku oksidaciju svih komponenata BTEX smjese već pri temperaturi od
177 °C.In this work, ceramic monolithic catalyst carriers based on zirconium dioxide (ZrO2) were prepared by fused filament fabrication. The active catalyst components were deposited on the obtained supports by the wet impregnation technique. The activity of the prepared catalysts was tested by carrying out the catalytic oxidation of a mixture of aromatic compounds, including benzene, toluene, ethylbenzene, and o-xylene (BTEX). The efficiency of the prepared monolithic catalysts used for the catalytic oxidation of BTEX was determined with respect to the chemical composition of the catalytically active component (MnFeOx, MnCuOx, and MnNiOx) and with respect to the geometry of the monolithic carrier (ZDP, Z, and M). Prior to the kinetic measurements, the dimensional stability of the 3D-printed monolithic carriers and the mechanical stability of the catalyst layer were investigated. Characterization of the ZrO2 filament used was performed too. X-ray diffraction analysis showed that the ceramic phase of the material consists of monoclinic and tetragonal ZrO2. The size of the ceramic particles was determined by laser diffraction analysis. The results of the analysis showed that the size of the ceramic particles ranged from 71 to 3000 μm. The median value of the particle size (d50) in the population was 540.10 μm. The predominant size of the ceramic particles in the population (dmode) was 562.34 μm, and the Sauter diameter (d3,2) of the particles was 886.25 μm. The thermal properties of the ZrO2 filament used to prepare monolithic carriers were investigated by simultaneous TGA/DTA analysis. The dimensional correction factor was determined by measuring the characteristic dimensions of the 3D-printed monolithic carriers against the dimensions predicted by the CAD model. The value of the dimensional correction factor was 1.18. Based on the measured mass deviation of the 3D-printed carriers, a uniform distribution of the ceramic particles in the printed carriers was observed. The mechanical stability of the catalytic layer was determined by adhesion tests. The catalyst was exposed to ultrasound at a frequency of 37 kHz. The loss of the catalytic layer due to the ultrasonic vibrations was from 0.016% to 0.051%, proving the excellent mechanical stability of the prepared catalytic layers. The results of the efficiency of the prepared monolithic catalysts used for the catalytic oxidation of BTEX showed that the 3D-printed model M, which contained MnFeOx as the catalytically active component, was the most successful catalyst for the oxidation of BTEX compounds. The mentioned catalyst enables catalytic oxidation of all components of the BTEX mixture at a temperature of 177 °C
Radioactive waste management
No full textRadioaktivni otpad primarno nastaje radom i razgradnjom nuklearnih elektrana i reaktora, proizvodnjom nuklearnog oružja i primjenom u medicini, industriji i istraživanju. Ovaj otpad obuhvaća različite oblike i materijale, od kojih svaki ima različita svojstva, razine radioaktivnosti i vremena poluraspada. Osnovna podjela radioaktivnog otpada s obzirom na radioaktivnost je na nisko, srednje i visoko radioaktivni otpad. Najveći izazov predstavljaju visoko radioaktivni otpad i istrošeno nuklearno gorivo zbog svoje visoke razine radioaktivnosti. Odgovorno gospodarenje radioaktivnim otpadom uključuje pažljivo rukovanje, skladištenje i odlaganje radioaktivnog materijala kako bi se zaštitilo ljudsko zdravlje i okoliš kako sada tako i u budućnosti.Radioactive waste is generated primarily during the operation and decommissioning of nuclear power plants and reactors, the manufacture of nuclear weapons, and other uses of radioactive materials in medicine, industry, and research. This waste includes various forms and materials, each with different properties, levels of radioactivity, and half-lives. The basic classification of radioactive waste is by radioactivity: low, medium, and high. The main challenge in managing high-level radioactive waste and spent fuel is its high radioactivity. Responsible handling of radioactive waste requires careful handling, storage and disposal of radioactive materials to protect human health and the environment now and in the future
Preparation and characterization of secondary amines for application in organic synthesis
No full textSinteza sekundarnih amina provedena je reakcijom reduktivnog aminiranja aldehida primarnim aminima uz prisutnost cinka u vodenom alkalnom mediju, čime je zadovoljen i pristup zelenoj kemiji. Ovisno o vrsti početnog aldehida uspješno su sintetizirani N-heksilbenzilamin, N-etilbenzilamin i N-benzil-1-(5-metiltiofen-2-il)metanamin na sobnoj temperaturi i temperaturi refluksa otapala, pri čemu se reakcija na povišenoj temperaturi pokazala uspješnijom. Sintetizirani spojevi potvrđeni su 1H NMR spetroskopijom.The synthesis of secondary amines was carried out by the reaction of reductive amination of aldehydes with primary amines in the presence of zinc in an aqueous alkaline medium, thus satisfying the green chemistry approach. Depending on the type of initial aldehyde, N-hexylbenzylamine, N-ethylbenzylamine and
N-benzyl-1-(5-methyltiophene-2-yl)methanamine were successfully synthesized at room temperature and solvent reflux temperature, whereby the reaction at elevated temperature proved to be more successful. The synthesized compounds were confirmed by 1H NMR spectroscopy
Synthesis of new 1,3-thiazolo-stilbenes as potential cholinesterase inhibitors and antioxidants
No full textU cilju daljnjeg napredovanja na području sinteze spojeva koji će imati inhibicijsko djelovanje prema enzimima kolinesterazama i antioksidacijsko djelovanje, sintetizirani su novi
1,3- tiazolo-stilbeni i tieno-stilbeni. Različito supstituirani produkti (2 – 8) dobiveni su Wittigovom reakcijom iz trifenilfosfonijeve soli i odgovarajućih aldehida. U sintezi su nastali cis- i transizomeri 1,3-tiazolo-stilbena i tieno-stilbena koji su razdvajani na čiste konfiguracijske izomere kolonskom i tankoslojnom kromatografijom. Svi sintetizirani spojevi u potpunosti su spektroskopski okarakterizirani u svrhu potvrde njihove strukture.
Novim 1,3-tiazolostilbenima određen je potencijal inhibicije acetil- i butirilkolinesteraze te je jednom kandidatu napravljeno i molekulsko pristajanje, kako bi se utvrdile nekovalentne interakcije koje stabiliziraju kompleks enzim-supstrat. Novim spojevima ispitivana je i potencijalna antioksidacijska aktivnost.With the goal of advancement in the field of synthesizing compounds that will have inhibitory effects on cholinesterase enzymes and antioxidant activities, new 1,3-thiazole-stilbenes and thieno-stilbenes have been synthesized. Various substituted products (2 – 8) were obtained through the Wittig reaction from triphenylphosphonium salts and corresponding aldehydes. During the synthesis, cis- and trans-isomers of 1,3-thiazole-stilbenes and thieno-stilbenes were formed and separated into pure configurational isomers using column and thin-layer chromatography. All synthesized compounds were fully spectroscopically characterized to confirm their structures. The new 1,3-thiazolo-stilbenes were determined for their potential to inhibit acetyl- and butyrylcholinesterase, and one of the candidate was subjected to a molecular fit in order to determine the non-covalent interactions that stabilize the
enzyme-substrate complex. Potential antioxidant activity was also tested with the new compounds
Preparation, characterization and testing of heterogeneous photocatalysts
No full textPodručje heterogene fotokatalize istražuje primjenu fotokatalizatora, često u obliku čvrstih materijala, kako bi se potaknule kemijske reakcije pod utjecajem svjetlosti. Cilj ovog preglednog rada bio je ocijeniti učinkovitost fotokatalizatora u razgradnji onečišćivala u vodi te pružiti bolji uvid u mehanizme reakcija i utjecaj različitih parametara na procese fotorazgradnje. Glavnina istraživanja proširen je na optimiranje procesa sinteze heterogenih fotokatalizatora, s posebnim naglaskom na primjene TiO2 fotokatalizatora vezanog na perlitnom nosaču. Kroz upotrebu različitih tehnika karakterizacije, istraživane su strukturne karakteristike fotokatalizatora, uključujući morfologiju, kristalnu strukturu te površinska i optička svojstva. Istraživanje značajno pridonosi produbljenom razumijevanju mehanizama fotokatalitičkih reakcija, pružajući smjernice za unapređenje učinkovitosti ovih procesa.In the field of heterogeneous photocatalysis, the use of photocatalysts, often in the form of solid materials, to initiate chemical reactions under the influence of light is being explored. The aim of this review was to evaluate the efficiency of photocatalysts in the degradation of pollutants in water and to provide a better understanding of the reaction mechanisms and the influence of different parameters on photocatalytic degradation processes. The main part of the research was extended to the optimization of the synthesis of heterogeneous photocatalysts, with a particular focus on the application of TiO2 photocatalysts immobilized on perlite supports. Through the use of various characterization techniques, the structural features of the photocatalysts have been investigated, including morphology, crystal structure, and surface and optical properties. This research contributes significantly to a deeper understanding of photocatalytic reaction mechanisms and provides insights to improve the efficiency of these processes
Testing of lithium titanate as electrode material for Li-ion batteries
No full textLitijev titanat ( Li4Ti5O12, LTO) smatra se obećavajućim anodnim materijalom za litij-ionske galvanske članke zbog strukturne i cikličke stabilnosti te male promjene u volumenu kristalne rešetke prilikom interkalacije/deinterkalacije litija. U ovome radu, izrađen je elektrodni anodni materijal u obliku dugmaste elektrode koristeći LTO, PVDF (vezivo) i acetilensko crnilo (vodljivi aditiv) u omjeru 8:1:1 uz otapalo N-metil-2-pirolidon. Provedena su elektrokemijska mjerenja cikličke voltametrije (CV) i kronopotenciometrije te je provedena karakterizacija uzorka LTO prije i poslije procesa pražnjenja pomoću Ramanove spektroskopije. Dobiveni ciklički voltamogram ukazuje na reverzibilnost reakcije prelaska litijevog titanata iz spinelne strukture u strukturu kamene soli tijekom interkalacije litijevih iona. Krivulje punjenja/pražnjenja, dobivene kao rezultat kronopotenciometrije, snimljene su pri C-stopama od 0,1, 0,6, 1,1 i 2,2 C. Kapacitet pražnjenja od 178 mA h g^-1 pri najmanjoj C-stopi (0,1 C) vrlo je blizak teorijskoj vrijednosti 175 mA h g^-1. Povećavanjem C-stope, odnosno jakosti struje u ciklusima punjenja/pražnjenja, smanjuje se kapacitet pražnjenja članka. Također se pri najmanjoj C-stopi uočava plato punjenja/pražnjenja na 1,57 V (punjenje) i 1,56 V (pražnjenje), a teorijska vrijednost potencijala fazne promjene LTO iznosi 1,55 V (prema Li+/Li). Provedbom Ramanove spektroskopije za LTO uzorak prije procesa pražnjenja dobivene su karakteristične vrpce na spektru koje odgovaraju spinelnoj strukturi s Fd3̅m prostornom grupom, a Ramanov spektar za uzorak LTO nakon procesa pražnjenja ukazuje na promjenu faze.Lithium titanate ( Li4Ti5O12, LTO) is considered a promising anode material for lithium-ion batteries due to its structural and cyclic stability, as well as minimal changes in crystal lattice volume during lithium intercalation/deintercalation. In this study, an electrode anode material in the form of a button cell electrode was made using LTO, PVDF (binder), and carbon black (to enhance conductivity) in an 8:1:1 ratio with N-methyl-2-pyrrolidone as the solvent. Electrochemical measurements, including cyclic voltammetry (CV) and chronopotentiometry, were conducted, and the LTO sample was characterized before and after the discharge process using Raman spectroscopy. The obtained cyclic voltammogram indicates the reversibilty of the lithium titanate transition from a spinel structure to a rock-salt structure during lithium ion intercalation. Charge/discharge curves, obtained as a result of chronopotentioemtry, were recorded at C-rates of 0,1, 0,6, 1,1 and 2,2 C. The discharge capacity of 178 mA h g^-1 at the lowest C-rate (0,1C) is very close to the theoretical values of 175 mA h g^-1. Increasing the C-rate, i.e., the current intensity during charge/discharge cycles, leads to a decrease in the cell's discharge capacity. Additionally, at the lowest C-rate, a charge/discharge plateau is observed at 1,57 V (charging) and 1,56 V (discharging), while the theoretical potential value for the phase change of LTO is 1,55 V (vs. Li+/Li).
By conducting Raman spectroscopy on the LTO sample before the discharge process, characteristic bands in the spectrum corresponding to a spinel structure with the Fd3̅m space group were obtained. However, the Raman spectrum of the LTO sample after the discharge process indicates a phase change
Validation of the spectrophotometric method for the determination of nitrite in water
No full textKoncentraciju nitrita u vodi za ljudsku potrošnju potrebno je neprestano pratiti zbog njihovog štetnog utjecaja na ljudsko zdravlje. Kako bi se utvrdilo da je metoda prikladna namijeni potrebno je provesti validaciju te metode. U ovom radu provedena je validacija spektrofotometrijske metode za određivanje nitrita u vodi, a ispitane izvedbene karakteristike su: selektivnost, linearnost, preciznost (ponovljivost i međupreciznost), istinitost, granica kvantifikacije i granica detekcije, radno područje i robusnost metode. Analiza je provedena sa standardnim otopinama nitrita u MilliQ i vodovodnoj vodi. Rezultati ispitivanja potvrđuju selektivnost, linearnost metode u određenom radnom području (0.01 – 1.00 mg/l NO2-), preciznost, istinitost te robusnost. Određene su granica kvantifikacije (0.01 mg/l NO2-) i granica detekcije (0.003 mg/l NO2-).The concentration of nitrites in water for human consumption should be constantly monitored due to their harmful impact on human health. In order to determine the suitability of the method for its intended purpose, the method should be validated. In this study, the validation of the spectrophotometric method for nitrate determination in water was carried out. The examined performance characteristics included: selectivity, linearity, precision (repeatability and intermediate precision), trueness, limit of quantification, limit of detection, working range, and robustness. The analysis was performed with nitrite standard solutions prepared in MilliQ and tap water. The test results confirm the method's selectivity, linearity within a certain working range (0.01 – 1.00 mg/l NO2-), precision, trueness, and robustness. The limit of quantification (0.01 mg/l NO2-) and limit of detection (0.003 mg/l NO2-) were determined