Application of modified carbon electrode for voltammetric determination of heavy metals in sweeteners : bachelor thesis

Do pojave teških metala u medu najčešće dolazi u rudarskim i industrijskim središtima i u blizini frekventnih prometnica, gdje se teški metali apsorbiraju u tlo, atmosferu i vodu te posljedično u biljke. Također, nedostatak pojedinog elementa u tlu, stijenama ili vodi imat će utjecaj na mineralni sastav biljke. Stoga, med može služiti kao izvrstan bioindikator onečišćenja okoliša teškim metalima te obzirom na sadržaj drugih elemenata biti pokazatelj zemljopisnog podrijetla meda. U ovom završnom radu određivane su koncentracije teških metala (Cu, Pb) u zaslađivačima (medu i šećeru) pomoću metode standardnog dodatka voltametrijskih mjerenja. U tu svrhu ispitivana je uporaba hidroksiapatita (HAp) kao modifikatora na elektrodi od staklastog ugljika (GC). Uz radnu HAp/GC elektrodu, korištene su referentna (Ag/AgCl) i protuelektroda (platinska pločica). Pomoću mjernih tehnika, cikličke i pravokutnovalne voltametrije, dobiveni su potrebni podaci koji su nam poslužili za određivanje metala. Metodom standardnog dodatka te primjenom pravokutnovalne voltametrije uz optimirane parametre mjerenja određivane su koncentracije bakra i olova u medu i šećeru. Dobivena koncentracija Pb u šećeru iznosila je 823,7 μg kg -1 , dok koncentracija dobivena za Cu također u šećeru je iznosila 693,7 μg kg -1 . Dobivena koncentracija za Pb u medu iznosila je 587,5 μg kg -1 , dok koncentracija dobivena za Cu iznosila je 2775 μg kg -1 .The most common occurrence of heavy metals in honey comes in mining and industrial centers and near frequent roads where heavy metals are absorbed into the soil, atmosphere and water and consequently into the plants. Also, the lack of an element in soil, rocks or water will have an impact on the mineral composition of the plant. Therefore, honey can serve as an excellent bioindicator of heavy metals contamination of the environment and considering the content of other elements to be an indication of the geographical origin of honey. In this final work, concentrations of heavy metals (Cu, Pb) in sweeteners (honey and sugar) were determined using the standard addition method and voltammetric measurements. For this purpose, the use of hydroxyapatite (HAp) as a modifier on glassy carbon electrodes (GC) was investigated. Along with the working Hap / GC electrode, we used reference (Ag / AgCl) and (platinum plate) counter electrodes. By using measurement techniques, cyclic and square wave voltammetry, we have come up with the necessary information that serves us to determine the metal. Also, by using standard addition method, and using square wave voltammetry with optimized measurement parameters, copper and lead were determined in honey and sugar. The obtained Pb concentration in sugar was 823.7 μg kg -1 , while the concentration obtained for Cu also in sugar was 693.7 μg kg -1 . The obtained concentration for Pb in honey was 587.5 μg kg -1 , while the concentration obtained for Cu was 2775 μg kg -1 .honey, sugar