In this work, wet deposition samples were collected at Middle East Technical University campus, Ankara, between December 2000 and May 2002. Snow samples were collected from 50 grids in January, 2001 in Ankara to investigate dry deposition of PAHs. The collected samples were preconcentrated by Solid Phase Extraction and ultrasonic extraction tecniques. Extraction methodologies were improved prior to analysis of samples. Extracted samples were analyzed by Gas Chromotography-Mass Spectrometry for 14 Polycyclic Aromatic Hydrocarbons. Selected Ion Monitoring mode was used throughout the analysis. Phenanthrene, fluoranthene, pyrene and benzo (b+k) fluoranthene were found to be dominant PAHs in wet deposition samples. Seasonal variation of PAHs were observed having higher concentrations in winter period. Meterological parameters were also examined together with PAH concentrations. Contribution of PAHs coming from North East and South West direction were found to be dominant. Wet deposition fluxes were calculated and compared with other urban sites. Wet deposition fluxes are lower than industrial sites and comparable with urban sites in Europe. PAH ratios and factor analysis results demostrated combustion and traffic emissions are major sources of pollutants in the city. Dry deposition of PAHs were invesigated using snow as a natural collecting surface. Dry deposition fluxes calculated using snow surface are compareble with other similar sites. Dry deposition pollution maps of PAHs were drawn by MapInfo software and it was observed that the major pollution regions are the localities where low income families live and low quality coal used for heating purpose. Ratio calculations showed that the central parts of the city is mostly affected from traffic emissions while coal emissions are dominating at the other parts of the city. Factor analysis applied to data set and 6 factors distinquished as coal, soil, traffic, oil combustion, mixed combustion and road dust.

ABSTRACT ELECTROCHEMICAL HYDRIDE GENERATION AND ATOM TRAPPING ATOMIC ABSORPTION SPECTROMETRY FOR DETERMINATION OF ANTIMONY Menemenlioglu, ipek M.S., Department of Chemistry Supervisor: Prof. Dr. O. Yavuz Ataman June 2004, 82 pages Electrochemical hydride generation is a suitable alternative to common hydride generation by NaBH4 which is widely used for the detection of volatile elements such as As, Se, Sb, Sn, Bi, Ge, Te and Pb. In this study, a thin-layer flow through electrochemical cell was designed. Lead and platinum foils were employed as cathode and anode materials, respectively, for the generation of antimony hydride. Argon was used as the carrier gas. The inlet arm of the conventional quartz tube atomizer was used for on-line preconcentration of generated hydrides. A portion of the inlet arm was heated externally to the collection temperature for trapping the analyte species which were generated electrochemically. For the revolatilization of the trapped species, the trap was further heated to the revolatilization temperature and hydrogen gas was introduced into the system 10 seconds afterwards. The experimental operation conditions for electrochemical hydride generation which include the acidities and flow rates of catholyte and anolyte solutions, carrier gas flow rate and the applied electric current, were optimized. For trapping, collection and revolatilization temperatures and hydrogen flow rates were optimized. Analyses of standard reference materials were performed to check the accuracy of the proposed method. 3&amp / #963 / limit of detections were found as 1.03 ng ml-1 and 0.053 ng ml-1 with and without employing the trap, respectively. The trap has provided 20 fold sensitivity improvement.

Trace amounts of germanium is determined by flame atomic absorption spectrometry by utilizing the vaporization of germanium tetrachloride. Using a continuous flow reactor, sample solution is mixed with concentrated hydrochloric acid and heated to 80&ordm / C to form volatile germanium tetrachloride which can be subsequently sent to N2O-C2H2 flame AAS. The necessary conditions for the volatilization of germanium tetrachloride are investigated in detail and the applicability of the method for the determination of trace amounts of germanium in real samples and standard reference materials are presented. Detection limit of the method, based on 3s, was 0.034 ng mL-1 using a sample of 1 mL. The precision was 0.3 %, expressed as the relative standard deviation for a germanium concentration of 1 ng mL-1. Owing to the high selectivity of the proposed method, no interference effect was observed.

Lactic acid is a fermentation-derived organic acid used in a wide range of industries, such as food processing and pharmaceuticals. Its market is expected to expand due to the worldwide concern for the environment, as it is an essential feedstock for biodegradable polymers. However, fermentation product is a very dilute, multicomponent aqueous solution. Subsequent separation, purification and concentration of organic acids is difficult because of high affinity of the acids for water. Reactive extraction is a viable alternative to classical separation techniques. Amine extractants dissolved in organic diluents are suitable agents with reasonable ranges of viscosity and density of the solvent phase. The product is obtained in an organic phase after reactive extraction. The aim of this study is to obtain equilibrium data of back extraction of lactic acid into appropriate aqueous solutions from the organic phase. Aqueous solutions of NaCl, NaOH, Na2SO4, NaNO3 and Na2CO3 were examined as back extractant in various initial concentrations (0.005 &ndash / 3 M). The organic phase consists of tri-n-octylmethylammonium lactate (TOMA(La)) dissolved in either oleyl alcohol or octanol with initial concentrations between 0.1 and 0.3 M. According to results of the experiments, the level of back extraction generally increased with increasing initial salt concentration in aqueous phase and decreased with increasing initial TOMA(La) concentration in organic phase. For all salts investigated, considerable levels of back extraction were obtained. NaOH was considered as the most suitable back extractant among the salts investigated since it exhibits higher distribution coefficients, regenerates tri-n-octylmethylammonium hydroxide (TOMAOH) in the organic phase and has no adverse effect on fermentation medium when forward and backward extraction steps are coupled with the fermentation. The effect of diluent type of TOMA(La) was also investigated during the experiments and it was concluded that octanol is a better diluent since it gives higher equilibrium distribution coefficients in addition to its higher solvating power and lower viscosity. The present work is a part of a comprehensive research program aiming to collect data and develop knowledge for the design of an industrial reactive extraction process coupling forward and backward extraction of lactic acid in a single unit and integrating fermentation and product separation. The kinetic parameters should be obtained as the next step for the design of such a process.

In this work, dry deposition of metals is investigated in an urban area / city of Ankara using snow as a surrogate surface. Two sampling campaigns were conducted to determine dry deposited amount of 13 species namely / H+, Na, K, Al, Mg, Fe, V, Cd, Cr, Cu, Pb, Zn, Ni. First sampling was performed after a major snow fall in Ankara in January 2001, from 4 points according to a predetermined sampling procedure in order to assess background composition of snow. After 12 days, snow samples were collected from 54 points. All samples are filtered, digested and divided into two aliquots in order to investigate soluble and insoluble fractions separately. Temporal changes of snow showed that snow is a good surrogate surface for dry deposition of metals and provide multifunctional informative data. Pollution maps of the city are drawn using Mapinfo software to investigate spatial pollution distributions. Factor analysis are applied and five main factors for these elements are found, indicating three main sources as traffic, soil and combustion. Enrichment factor calculations showed that Ni, Ca, Pb, Zn, Ni, Cu and Cd are highly enriched pointing out the anthropogenic sources affecting the city atmosphere drastically.

In sugar industry, determination of invert sugars (fructose and glucose) provides information about the quality, process control and characteristics of the produced fructose and glucose syrups. Determination of invert sugar is also important for wine industries. In wine process, fructose and glucose are converted to ethanol by fermentation and the type of wine is designated by the amount of invert sugar remained. Fast and reliable invert sugar detection techniques are required to check the quality of wine throughout the fermentation process. Cathecholamines (eg. dopamine and epinephrine) are diol containing compounds which play important roles in higher animals&rsquo / physicomotor activities, learning, sleeping, memory and immune system. They also affect brain functions. Inbalances in dopamine level in brain result in a number of psychiatric disorders, particularly schizophrenia and Parkinson disease. Catecholamines are present in relatively high amounts in drugs. Many efforts have been made to develop analytical procedures for their rapid, simple and accurate determination. For these reasons, catecholamine quantification is important in the field of pharmacy and medicine. Boronic acids interact with 1,2 or 1,3-diol containing compounds, such as fructose, glucose and dopamine, rapidly and reversibly. Hence, boronic acids are used as the recognition moeity in the construction of photoinduced electron transfer (PET) fluorophores specific for saccharides and catecholamines. In this study, a flow injection analysis system has been developed for the rapid and selective recognition of fructose and glucose in wine and in commercial sugar syrups / dopamine and epinephrine in pharmaceutical injections by using dansylaminophenyl boronic acid (DAPB) which is a fluorescent PET molecule.

Narcotic and psychotropic substances are all chemicals that affect a person&rsquo / s mental activities, perceptual abilities, behavior and level of consciousness / they may cause physical and/or psychological dependence. For determination of narcotic and psychotropic substances, chromatographic techniques are usually preferred which are aimed to identify the target chemicals and require several extraction steps. In this study, an Infrared Spectrometric method has been developed for qualitative determination of most widely encountered substances (morphine, heroin, cocaine, MDMA (3,4-methylenedioxymethamhetamine) and amphetamine) and additives (caffeine, paracetamol and lactose). Standard reference materials and illicit samples have been analyzed in powdered form by using Fourier Transform Infrared-Attenuated Total Reflectance (FTIR-ATR) technique. In the first part, a spectral FTIR database was constituted from the standard references. Illicit samples containing drugs and additives in varying percentages were analyzed using the same method and their database forecast results were compared with results from Gas Chromatography and High Pressure Liquid Chromatography. In the second part of the study, the possibility of finding a similarity between two samples just by comparing their spectra was investigated. For this purpose, all illicit sample spectra were collected in a new database, and then randomly selected samples were searched using this database. Most of the search attempts resulted in a correct match. Consequently, it has been observed that FTIR-ATR can be used as a priory detection step for classification studies / moreover with this technique pre-determination of narcotic and psychotropic substances can be done simply and rapidly.

ABSTRACT PRECONCENTRATION OF SOME PRECIOUS METALS USING DEBT IMPREGNATED RESIN Refiker, H&uuml / rm&uuml / s M. Sc., Department of Chemistry Supervisor: Prof. Dr. R. Sezer Ayg&uuml / n Co-supervisor: Assoc. Prof. Dr. Melek Merdivan August 2005, 107 pages In this thesis, trace amounts of gold and silver have been determined by flame absorption spectrometry (FAAS) after preconcentration by N,N-diethyl-N&#039 / -benzoylthiourea (DEBT) impregnated resin (Amberlite XAD-16). In the first part of the thesis, sorption behaviours of gold and silver with DEBT impregnated resin under optimized conditions / stirring time, pH, desorption of metals and metal ion capacities of the resin have been studied in batch process. Metal ion capacity of resin is calculated as 0.17 mmol/g resin and 0.104 mmol/g resin for silver and for gold, respectively. In the second part of the thesis, preconcentration of gold and silver was tried by DEBT impregnated resin using column process under optimized conditions / pH, flow rate and volume of sample solution, nature of eluent, flow rate and volume of eluent However, due to partial leaching of DEBT by time, no satisfactory and reproducible results could be obtained. In the final part of the study, metal chelates prepared in aqueous solutions were passed through the column under optimized conditions and satisfactory sorption-desorption and selective preconcentration could be achieved. Under optimized conditions, silver and gold ions at the concentrations of 0.05 &amp / #61549 / g/mL and 0.015 &amp / #61549 / g/mL with preconcentration factors of 7.7 and 6.7, respectively could be determined by FAAS. The proposed method is highly selective without the need for any interference elimination process. Keywords: Precious metals, Solid-phase extraction, DEBT, Amberlite XAD-16

Increasing concern about the pollution of environment by inorganic and organic chemicals arising from naturally occurring ecological events and industrial processes has created a need for the search of new techniques in the removal of these contaminants. One of the natural material that can be used in such processes is clay. Clay minerals have large surface areas and high cation exchange capacities which enables them to be modified by cationic surfactants. The material prepared, often called as &amp / #8216 / organoclay&amp / #8217 / , can be used to remove hydrophobic organic and anionic contaminants from polluted water. Among the anionic contaminants, oxyanions such as nitrate, chromate are detrimental to human life and environment even at &micro / g/L- mg/L levels. Application of organoclays for their removal from polluted water appears as one of the practical and rather cheap solution. In this study, a local clay from Ankara-Kalecik (Han&ccedil / ili Bentonite) was modified by hexadecyltrimethylammonium bromide (HDTMA-Br) to a level of twice of its cation exchange capacity. This process alters the negatively charged surface of the clay into a positively charged one, providing sites for the removal of anionic contaminants. In this study, the degree of HDTMA+ uptake by the clay within a period of eight hours is found to be 97% of the initial amount added. In desorption studies it was revealed that only about 1% of the sorbed HTDMA+ was leached in a seven days of water-organoclay interaction revealing a rather stable organoclay structure in aqeous media. Sorption experiments with nitrate, borate, and chromate solutions were performed in order to determine the anion sorption capacity of the organoclays prepared. It turns out that while untreated clay has insignificant capacity, the modified clay can remove considerable amount of nitrate and chromate ions from aqeous solutions. While the nitrate sorption was increased about eleven fold, change in chromate sorption was reached to a level of twenty fold compared to that of the untreated clay. Sorption data for nitrate and chromate are both well described by the Langmuir isotherms. No significant change was observed in case of borate-organoclay interaction. Desorption of nitrate and chromate ions from organoclay surface were also investigated. Sorption of these oxyanions were found to be almost irreversible in aqeous media. The results imply that a properly prepared organoclay can be used for the removal of oxyanions, such as nitrate and chromate from polluted water systems.

ABSTRACT EVALUATION OF METAL CONCENTRATIONS IN GROUNDWATER NEARBY SOMA COAL FIRED POWER PLANT Giuma Sasi M.S., Department of Chmistry Supervisor: Prof. Dr. Semra G. Tuncel December 2005, 95 Pages In this work, metal pollution in groundwater near by Soma coal-fired power plant was invistigated. Coal combustion results in huge amounts of bottom ash from which metals can originate and migrate to groundwater and pollute it. Forty groundwater samples were collected from water wells in an area near by the power plant to determine 14 metals namely / Na, Ca, K, Mg, Al, Ba, Fe, Zn, Cu, Pb, Cr, Cd, Ni and V. Samples were collected in polyethylene bottles, the pH of the water was measured. Then, the samples were acidified and stored to be analyzed. FAAS, FAES, GFAAS and ICP-AES were used to determine the elements. The results were compared with the WHO, the Turkish and EC guidelines for drinking water quality. Fe concentrations in 12 wells were higher the three guidelines. Zn concentrations in 5 wells were higher than the EC guidelines, but not higher than the Turkish guidelines. Pb concentrations was less than all guilelines but it was relatively high in 8 wells. The other anthropogenic elements were lower than all guidelines but these metals tend to accumulate and they will exceed the guildlines overtime. Enrichment factor calculations showed that the anthropogenic elements were enriched in the regions close to the ash piles pointing out that the ash piles are the main source of these elements. Factor analysis was applied and four main factors of the determined metals were found indicating that the power plant and the ash piles are the main source for the anthropogenic elements.