Razvoj spektroskopske metode za merjenje koncentracije vodikovega peroksida v plinski fazi

Modic, Adam (author), Kočar, Drago (mentor)

Metoda, ki sem jo preučeval v sklopu svoje diplomske naloge, temelji na ideji, da je možno koncentracijo vodikovega peroksida v plinski fazi določiti tako, da plinast vzorec uvajamo v raztopino kalijevega jodida. Pri tem v raztopini kot produkt reakcije med vodikovim peroksidom in jodidnim ionom nastane trijodidni ion, katerega koncentracijo je mogoče določiti spektrofotometrično z merjenjem absorbance. Za delovanje metode je torej ključna linearna zveza med koncentracijo plinastega vodikovega peroksida in izmerjeno absorbanco nastalega trijodidnega iona. V sklopu eksperimentalnega dela sem s pomočjo ustreznega laboratorijskega inventarja najprej sestavil sistem, ki je omogočil nastanek atmosfere plinastega vodikovega peroksida s konstantno koncentracijo in uvajanje slednje v raztopino kalijevega jodida. Preveril sem, kako na meritve vplivajo spremenljivke, kot sta čas prepihovanja in pretok nosilnega plina, ter poiskal optimalne pogoje za izvedbo meritev. Absolutne vrednosti koncentracij nastalega trijodidnega iona sem izračunal s pomočjo umeritve, ki sem jo izvedel z uporabo standardnih raztopin, pripravljenih iz elementarnega joda z znano maso. S poskusi sem potrdil, da je absorbanca prepihane raztopine res linearno odvisna od koncentracije vodikovega peroksida v plinski fazi. Preveril sem tudi, katere snovi bi se lahko uporabljale kot alternativni reagenti za bolj selektivno reakcijo z vodikovim peroksidom ter kako na rezultate metode vpliva sprememba nosilnega plina in prisotnost potencialnih interferenc.

• Language: Slovenian
• Keywords: vodikov peroksid, trijodidni ion, plinska faza, UV-VIS spektroskopija
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2023
• PID: 20.500.12556/RUL-149540
• COBISS.SI-ID: 163814659
• Publication date in RUL: 07.09.2023

Secondary language

• Language: English
• Title: Development of a spectroscopic method for the determination of gaseous hydrogen peroxide

Abstract

The topic of my bacehelor’s thesis is the development of a method for the determination of the concentration of hydrogen peroxide in the gas phase. This method is based on the reaction between molecules of hydrogen peroxide and iodide ion which takes place if gaseous hydrogen peroxide is bubbled into a solution of potassium iodide. The product of that reaction is triiodide ion, a species which absorbs electromagnetic waves in the region of ultraviolet and visible light. Therefore, for the method to work, linear dependence between the measured absorbance of triiodide ion and the concentration of gaseous hydrogen peroxide has to be proven. The development of a method began with the construction of a setup which enables the creation of a gas sample with constant concentration of gaseous hydrogen peroxide and the bubbling of that sample into the potassium iodide solution. The effect of various experimental variables, such as the duration of bubbling and the flow of the carrier gas, was analyzed and optimal conditions for making the experiment were chosen. The exact amount of the formed triiodide ion was determined by measuring the absorbance of standard triiodide solutions and constructing the calibration curves. My experimental results proved the linear dependence and consequently showed that the method is suitable for the determination of hydrogen peroxide in gas samples. In the final part of my laboratory work, alternative reagents which also react with hydrogen peroxide were tested in order to obtain higher selectivity, and the effect of potential interferences was examined.

• Keywords: hydrogen peroxide, triiodide, gaseous phase, UV-VIS spectroscopy