الفهرس 
General introductionOnly 14 pages are availabe for public view
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Abstract
Chapter one: This chapter includes a general introduction on potentiometry, the basic principles, theory, historical background, characteristics and classification of potentiometric as well as optical sensor. This chapter gives brief introduction about glass-ceramic and fabrication of reference electrodes, as well.
Chapter two: This chapter covers recycling of laboratory glass ware (Pyrex) through the preparation of a low thermal expansion and chemically durable borosilicate glass-ceramic (BsGC) using Kaolin and Pyrex. As well as preparation of nano-porous ceramic to avoid errors originated from screening effect of porous glass frit. Low thermal expansion and high chemical durability ceramics are advantageous in many applications such as lab supplies, corning ware, automobile components, and other low expansion products that are resistant to thermal shock. Kaolin and borosilicate were chosen for the preparation of glass-ceramic, because they have low thermal expansion and good chemical durability. BsGC was prepared by sintering borosilicate glass waste (e.g., Pyrex laboratory glassware, household glass) and kaolin at different temperatures (750-900 ° C). Water absorption method was used to measure the apparent porosity of the prepared composites. Surface morphology of the prepared BCGs was investigated using scanning electron microscopy (SEM). Phase composition of the prepared BGC samples was characterized sing X-ray diffraction technique (XRD). The XRD results showed that at sintering of 750 °C a monocrystalline quartz was only existing. By increasing sintering temperature up to 800°C the quartz phase decreased, while at 850 oC the quartz phase completely disappeared. The sintered BCG composites obtained exhibited low coefficients of thermal expansion in the range of 48 x 10-7 oC-1 and exhibited high chemical durability. Reference electrodes constructed with the developed nano-porous ceramic frits exhibited excellent performance characteristics in terms of flow rate (0.41 - 0.002 μL/h), potential drift (0.02 mV/hour), pH range (12-2), and impedance (680 Ώ). Reference electrodes prepared with nano-porous ceramic materials exhibited low potential drift, wide pH range, absence of screening effect. Moreover, decreasing the pore size of the ceramic frits from the micro range into nano range lowers the flow rate of the internal reference electrode solution, which prevents the contamination of test solutions.
Chapter three: This chapter includes characterization of potentiometric and optical sensors based on germanium (IV) octaethylporphyrin (Ge(IV)OEP). Polymeric membranes doped with Ge(IV)-OEP showed excellent potentiometric and optical selectivity toward fluoride compared to lipophilic anions such as thiocyanate and perchlorate. The potentiometric response of was enhanced by doping lipophilic anionic sites, which indicated that Ge(IV)-(OEP) ionophore worked via a potentiometric charged carrier mechanism. Potentiometric membranes composition formulated with 1 wt% Ge(IV)-OEP, 25 mol% anionic additive and PVC/DOS exhibited a limit of detection of 1.5x10-4 M. Optical sensor prepared using 1 wt%, Ge(IV)-OEP, 50 mol% anionic additive, and PVC/DOS showed a limit of detection down to 6x10-6 M. Both optical and potentiometric sensors have perfect selectivity over SCN-, ClO4-, Cl- and NO3- (Kpot<10-2.5 for the tested anions). However, such sensors show undesired response and recovery times. It is predicted that polymeric membrane formulated with Ge(IV)-OEP porphyrin electrodes can be further optimized and could be a competitor for that of the conventional LaF3 crystal-based fluoride electrode and offer the advantage of miniaturization, low cost of production, and mass fabrication.