Development and applications of fe(ii) and fe(iii)- selective potentiometric sensors

Iron is an important mineral for many living organisms and is present in places such as oceans, surface water and acid mine drainage. It is important for human health and environment to determine iron concentration. Total dissolved iron is typically analyzed by techniques such as inductively coupled plasma mass spectrometry or colorimetrically. However, these methods are time consuming, require expensive stationary instrumentation, sample pretreatment, specialists to operate and are not capable of direct determination of the Fe2+ concentration. Therefore, there is a significant need for mobile low-cost devices that can provide accurate and rapid assessment of dissolved iron. In this thesis, it was aimed to develop an effective and economic direct detection method for iron(II) and iron(III) ions especially in environmental samples. In recent methods, iron(III) ions are detected, then iron(II) ions are oxidized to iron(III) ions. After that, iron(III) ions are detected again and total iron is obtained or vice versa. Here, all solid state technology based miniaturized polyvinyl chloride(PVC) membrane iron(II) and iron(III)-selective potentiometric sensors were developed. While 2-Cyanomethyl N-Methyl-N-phenyl dithiocarbamate was used as the ionophore for fabrication of Fe(II)-selective sensor, morin-Fe+2 Schiff-base complex was used for fabrication of Fe(III)-selective sensor. Then, the potentiometric characteristics of the developed sensors have been investigated such as pH, selectivity, time response, detection limit, sensitivity. The sensors displayed high selectivity to iron ions and had short response time. Also, the sensors were applied environmental samples and the results compared with reference methods. The development of these Fe(II) and Fe(III)-selective sensors will allow for rapid inexpensive in-situ analyses of iron in complex environmental field samples.