Concentrations of 17 organochlorine and 14 organophosphorus pesticides were measured in 27 ground and 11 surface water samples collected from a heavily agricultural area, Kumluca, in spring and fall seasons of 2005. The samples were preconcentrated by Solid Phase Extraction. GC-ECD and GC-NPD systems were used for quantitative determination of organochlorine and organophosphorus pesticides respectively. The quality check/quality assurance tests were performed by the analysis of field and laboratory blanks, standard reference materials, spiked control and sample matrices, surrogate standards, sampling and analysis replicates. It is observed that, sample matrix lowers average percent recoveries from 89% to 76%. The uncertainties of measurements were calculated to determine major factors affecting the analysis results. It was observed that uncertainty arising from extraction procedure was generally the highest. The most commonly observed pesticide was endosulfan (70%) and chlorpyriphos (53%) for organophosphorus and organochlorine pesticides. The highest average concentration was observed for heptachlor (26 ng/L) and fenamiphos (184 ng/L). Generally pesticides were detected more often in surface waters, where the concentrations were also higher. The concentrations of organophosphorus pesticides in spring, and organochlorine pesticides in fall season were higher. The high occurrences and detection of degradation products of chlorinated pesticides clearly indicate their intense use before 1980s. It is shown that, in Kumluca environment, degradation of these pesticides mostly occurs in surface waters. It is observed that agricultural activities affect water quality in the region. The total concentration limit (500ng/L) was exceeded for 27% of surface and 14% of ground water samples, at least once in both seasons. The legal limit for a single pesticide (100ng/L) was exceeded by 32 % of surface, 24 % of ground water samples.

The aim of the thesis is to clarify the methodology of the original institutional economics and then to evaluate the current attempts to utilize critical realism as a superior methodology for it. After sketching the historical background of the discussions surrounding methodology of science and 19th century economic methodology, the thesis separately analyses the methodology of institutional economics and critical realist stance in the philosophy of science. A critical discussion of the subject matter reaches to the conclusion that critical realism does not offer a better methodology for institutional economics.

Flight simulators are widely used by the military, civil and commercial aviation. Visual cues are an essential part of helicopter flight. The required cues for hover are especially large due to closeness to the ground and small movements. In this thesis, density and height parameters of the 3D (Three Dimensional) objects in the scene are analyzed to find their effect on hovering and low altitude flight. An experiment is conducted using a PC-based flight simulator with three LCD monitors and flight control set. Ten professional military pilots participated in the experiment. v Results revealed that object density and object height are effective on the horizontal and vertical hovering performance. There is a peak point after which increasing the density does not improve the performance. In low altitude flight, altitude control is positively affected by smaller object height. However, pilots prefer the scenes composed of the high and mixture objects while hovering and flying at low altitude. Distance estimation is affected by the interaction of the object density and height.

Electrochemical hydride generation is an alternative technique to the chemical hydride generation by NaBH4 which is widely used for atomic spectrometric determination of volatile elements such as As, Bi, Ge, Pb, Sb, Se, Sn and Te. The aim of this research has been to develop an analytical technique at the level of ng/L for determination of antimony by using a simple and inexpensive AA spectrometer and the other parts that can be built in any laboratory. Carbon rod and platinum foil were used as cathode and anode materials, respectively, for the generation of antimony hydride. Argon was used as the carrier gas. Zr coated W-coil was used for on-line preconcentration of generated hydrides. A new apparatus independent from quartz T-tube atomizer was constructed and used to contain the atom trap. Zr coated W-trap was heated to the collection temperature for trapping the analyte species generated electrochemically. For the revolatilization of the trapped species, the trap was further heated to the revolatilization temperature. Revolatilized species were transported to a flame-heated quartz tube atomizer where the analytical signal was recorded. Duringcollection and revolatilization steps hydrogen gas was introduced into the system to prevent the oxidation of atom trap. The experimental operation conditions for electrochemical hydride generation and atom trapping were optimized. 3&amp / #963 / limit of detections were found to be 0.012 ng/mL and 0.41 ng/mL with and without using trap, respectively. The trap has provided 34 fold sensitivity improvement as compared with the electrochemical hydride generation alone. The interferences of some hydride forming elements and some transition metals on electrochemical hydride generation with and without employing the trap were investigated. Analysis of standard reference material was performed to check the accuracy of the proposed method.

In this study NO2 and O3 gases which are the secondary pollutants in ambient air were sampled with designed passive tubes. The collected samples were extracted for UV-VIS spectrometric analysis. NO2 gases were converted to NO2- ions by extracting with water and then this solution was colored with Saltzman reagent (5:1 sulfanilamide and N-(1 naphthly)-ethlyene-diamine dihydrochloride). Then the absorbance of the solution was measured at 537 nm. O3 was extracted with 3-metyl-2-benzothiazolinone hydrozone hydrochloride solution which gives yellow color after extraction. The absorbance of the solution was measured at 430 nm. Before starting the experiment, the exposure time was optimized. For this purpose, 15 days in winter and 65 days in summer samplings were conducted. For both NO2 and O3 it was decided that 7 days of sampling period was required as an optimum sampling time in order to reach maximum collection efficiency values for both pollutants. To determine the uptake rates of the passive tubes, NO2 was sampled in fifteen weeks and O3 was sampled in thirteen weeks. During each sampling period passive tubes were placed nearby the active air sampling stations of Refik Saydam Hygiene Center, Air Quality Control and Research Laboratory in Ulus and Ke&ccedil / i&ouml / ren. Then uptake rates of NO2 and O3 passive tubes were determined by comparing passive and active sampler data. The uptake rate was calculated for NO2 and O3 as 0.91 x 103 cm3 h-1 and 1.71 x 103, respectively. Since sampling was done in ambient air the effect of meteorological parameters should be determined. Each meteorological parameters, wind speed, wind direction, relative humidity, temperature, pressure and solar ration were correlated with uptake rates. It was found out that none of these parameters had a significant effect on NO2 passive tube uptake rate. However, O3 passive tubes were affected from temperature, solar radiation and relative humidity. Temperature and solar radiation showed positive correlation with uptake rate, on the contrary, relative humidity was inversely correlated with uptake rate. Finally the pollution map of Ankara was created by taking samples from forty points in the city.

Polypyrroles containing polyether pseudocages (PI, PII, PIII) have been synthesized via chemical oxidation of 1,5-bis(1,1-pyrrole)-3-oxabutane (MI), 1,8- bis(1,1-pyrrole)-3,6-dioxahexane (MII), and 1,11-bis(1,1-pyrrole)- 3,6,9-trioxaundecane (MIII) using anhydrous FeCl3 in CHCl3. Because as obtained polymer resins did not give any response toward any cations, they were reduced (undoped) using chemical reducing agents. Tetrabutylammonium hydroxide (TBAOH) was found to be more effective in undoping to obtain more reproducible and reusable polymer resins. It was investigated whether the undoped polymer resins were used for the extraction of rare earth metal ions from the aqueous medium. Among them, only PIII resin can extract La(III), Eu(III) and Yb(III) from their aqueous solutions and can be employed for the preconcentration of these metal ions. For batch extraction of La(III), Eu(III) and Yb(III) at neutral pH values, percent recoveries of 98.0, 90.7 and 87.3, respectively, has been obtained by using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) technique. The sorption capacity is found as 1.3 mg of La(III) per gram of PIII resin. The PIII resin could be reused at least five times without significant change in its sorption capacity. PIII has also been synthesized via electrochemical method to be used in the preparation of Surface Enhanced Raman Scattering (SERS) active substrate. PIII has been polymerized on Indium Tin Oxide (ITO) glass by using constant potential electrolysis. In an electrolyte solution containing 0.05M tetrabutylammonium perchlorate (TBAP), 1.2 V vs. Ag wire (oxidation potential of MIII) was applied for coating and then silver particles were deposited on the surface of PIII coated ITO electrode by reducing Ag(I) in monomer free electrolyte solution electrochemically. As an alternative, another SERS substrate was prepared electrochemically by depositing silver particles directly on ITO glass. The performances of prepared ITO-PIII-Ag and ITO-Ag SERS substrates were evaluated with dilute solutions of brilliant cresyl blue (BCB), crystal violet (CV), para amino benzoic acid (PABA), nicotine and nicotinic acid.

ABSTRACT DETERMINATION OF ARSENIC, SELENIUM AND CADMIUM IN SOME TURKISH SPICES BY INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY Senol, Feriye M.Sc., Department of Chemistry Supervisor: Prof. Dr. O. Yavuz Ataman July 2010, 106 Pages The major source of all the nutrient elements for human body is the daily diet which is affected by age, sex, and health status, geographic and climatic conditions. It is important to analyze food items in order to determine their elemental contents, estimate their dietary intakes and compare with recommended or tolerated intake values in order to limit or increase their consumption. Spices are taken from different parts of plants and widely used in cooking processes. They are convenient samples to investigate the distribution of elements among different parts of plants and to evaluate their daily intakes. Arsenic and selenium are both essential and toxic elements whereas cadmium is considered to be toxic to human health. The recommended dietary allowance (RDA) level of selenium ranges from 50 to 200 &mu / g/day. The RDA level of arsenic is set to be 100-200 &mu / g/day for adults to meet the requirements. The weekly tolerable intake of cadmium and arsenic are 7 and 15 &mu / g/kg, respectively whereas selenium is toxic when intake is greater than 750 &mu / g/day . In this study the analysis of a variety of Anatolian spices including daisy (Chamomillae Vulgaris), bay leaf (Folium Lauri), mint (Folium Menthane), rosehip (Rosae Caninae), sage (Folium Salviae Officinalis), thyme (Herba Thymi), cumin (Fructus Cummuni), sumac (Folium Rhois Coriariae), linden flower (Flos Tilliae) v and black pepper (Piper Nigrum) were performed and As, Cd and Se levels were determined by using inductively coupled plasma mass spectrometry (ICP-MS). The results obtained were evaluated together with the results of previous studies for determination of Na, K, Mg, Ca, Li, Zn, Fe, Cu, B, Hg, Pb and Mn by inductively coupled plasma optical emission spectrometry (ICPOES) and atomic absorption spectrometry (AAS). Samples were digested in microwave oven in optimized concentrations of HNO3 and H2O2. microwave temperature program was optimized to maximize digestion efficiency. Samples were analyzed by using direct calibration method for cadmium and standard addition method for arsenic and selenium considering the effect of HNO3 concentration on ICP-MS signals. The accuracy of the methods was checked by using Oyster Tissue 1566b SRM for cadmium and arsenic and BCR Human Hair, 397 SRM for selenium. The mean arsenic and selenium levels were found to be in the range of 100-500 &mu / g/ kg whereas cadmium levels were relatively lower falling in a range of 10-100 &mu / g/ kg with few exceptions. In order to investigate the effects of spectral and nonspectral interferences on arsenic signals interference studies were performed by using HCl, NaCl, NaNO3, CsCl, CsNO3, LiCl and LiNO3. Statistical evaluations were performed on data in order to detect on significant trends.

Knowledge about selenium content of foods containing selenium species is very important in terms of both nutrition and toxicity. Bioavailability of selenium species for human body is different from each other. Hence, speciation of selenium is more important than total selenium determination. In the selenium speciation study, chicken breast samples, selenium supplement tablets and egg samples were analyzed for their selenium contents. In chicken breast study, chickens were randomly categorized into three groups including the control group (25 chickens), inorganic selenium fed group (25 chickens) and organic selenium fed group (25 chickens). After the optimization of all the analytical parameters used throughout the study, selenomethionine, selenocystine, Se(IV) and Se(VI) were determined using Cation Exchange-HPLC-ICP-MS system. In selenium supplement tablet study, anion and cation exchange chromatographies were used to determine selenium species. Arsenic is known as toxic element, and toxicity of inorganic arsenic species, As(III) and As(V), is much higher than organic arsenic species like arsenobetaine and arsenosugars. Hence, speciation of arsenic species in any matrix related with human health is very important. In the arsenic speciation study, Cation Exchange-HPLC-ICP-MS and Cation Exchange-HPLC-ES-MS systems were used to determine arsenobetaine content of DORM-2, DORM-3 and DOLT-4 as CRMs. All of the parameters in extraction, separation and detection steps were optimized. Standard addition method was applied to samples to eliminate or minimize the matrix interference. Thiols play an important role in metabolism and cellular homeostasis. Hence, determination of thiol compounds in biological matrices has been of interest by scientists. In the thiol study, Reverse Phase-HPLC-ICP-MS and Reverse Phase-HPLC-ES-MS systems were used for the separation and detection of thiols. For the thiol determination, thiols containing &ndash / S-S- bond were reduced using dithiothreitol (DTT). Reduction efficiencies for species of interest were found to be around 100%. Reduced and free thiols were derivatized before introduction on the column by p-hydroxymercuribenzoate (PHMB) and then separated from each other by using a C8 column. In the real sample measurement, yeast samples were analyzed using HPLC-ES-MS system.

Approaches on transfer of technology to developing countries within the development discourse are discussed in historical perspective and determinants of disembodied technology transfer of Turkish manufacturing industries are analyzed via enterprise-level data and microeconometric methods. While firm size, general skill level, export behaviour, capital intensity have significant effect of technology transfer decision of the firm, foreign ownership does not. Sectoral characteristics&rsquo / effects are also statistically significant.

Antimony is a toxic element which is mostly found in two oxidation states (III and V) in environmental, biological and geological samples. Antimony may form various inorganic and organic compounds that exhibit differences in analytical behavior, toxicity and mobility / inorganic compounds of antimony are more toxic than organic forms and toxicity of Sb(III) has been shown to be 10 times higher than that of Sb(V). Therefore selective determination of Sb(III) and Sb(V) is required in environmental and biological samples. Hydride generation atomic absorption spectrometry is a sensitive, fast and economical technique for the determination of antimony at trace level. A possible non-chromatographic method for antimony speciation is hydride generation atomic absorption spectrometry that is based on the relatively slow kinetics of hydride formation from Sb(V). In this study, continuous flow hydride generation method for the determination of antimony was developed and hydride generation conditions were optimized. Analyte solution was prepared in 0.050 mol/L HCl and 1.2% (w/v) NaBH4 stabilized in 0.30% (w/v) NaOH was used as a reductant solution. Inorganic antimony speciation conditions were determined by continuous flow HGAAS system. For the pre-reduction of Sb(V) to Sb(III), 8.0% (w/v) potassium iodide (KI) and 0.10% (w/v) ascorbic acid were used. Further speciation study was also carried out using Ir coated W-coil Atom Trap Hydride Generation Atomic Absorption Spectrometry. Tungsten coil atom trap was used to enhance the sensitivity. Tungsten coil surface was treated with Ir and totally 250 &amp / #956 / g 1000 mg/L Ir stock solution was used for coating of tungsten coil. LOD and LOQ values were calculated as 152 pg/mL and 508 pg/mL according to 120 seconds trapping. 128 and 37 fold enhancement were obtained for 120 seconds collection with respect to W-coil-ETAAS and ETAAS, respectively.