Boron (B) is a rare element on Earth crust with a natural abundance of 0.001%. However, boron content of water and soils may be significantly high in the regions with rich boron reserves. In addition, extensive use of agrochemicals in soils as well as various natural processes increases the boron concentration in water. Despite B is an essential element for all living creatures, it may pose risks at high level exposures. World Health Organization (WHO) has recommended a daily intake of 1 to 13 mg B for adults. Turkey has almost 70% of world boron reserves principally in four regions: K&uuml / tahya, Emet / Balikesir, Bigadi&ccedil / Eskisehir, Kirka and Bursa, Kemalpasa. The boron content of water in these regions may go up to significant levels. Therefore, it is important to determine B in drinking water from these regions. Electrothermal atomic absorption spectrometry (ETAAS) is a relatively sensitive technique for determination of boron. However, the technique suffers from formation of molecular boron compounds. Therefore, use of chemical modifiers and pyrolytically coated graphite tubes modified with refractory carbide forming elements (Ta, W, Zr, Pd, Ru, Os) were utilized to develop a reliable and sensitive method. Based on optimization studies, Tantalum (Ta) coated tube and co-injection of 5.0 &micro / L 0.01 mol/L Ca(NO3)2, 5.0 &micro / L 0.05 mol/L citric acid together with 15.0 &micro / L sample solution prepared in 1000 mg/L Mg(NO3)2 have been chosen as optimum conditions. Optimum temperatures for pyrolysis and atomization temperatures were determined as 1100 and 2700 &deg / C, respectively. Under these conditions, a detection limit of 0.088 mg/L and a characteristic mass of 186 pg for 15.0 &micro / L sample volume were obtained. The accuracy of the method was checked by EnviroMAT-Waste Water EU-L-1 CRM and NIST 1573a Tomato Leaves SRM analyses. Drinking water samples were collected from Balikesir, Bigadi&ccedil / and K&uuml / tahya, Emet and analyzed by the developed method. Samples were also analyzed by more sensitive techniques / ICP-OES and ICP-MS for a comparison study. The results are compatible with each other.

Measurement of monoterpenes including / alpha-pinene, camphene, beta-pinene, d-limonene, gamma-terpinene, linalool, 1-isopulegol, 1-borneol, dl-menthol, alpha-terpineol, dihydrocarveol, citronellol, pulegone, geraniol / and gas phase inorganic pollutants (O3 and NOx) were investigated on Uludag Mountain, which is the highest point in North-west Turkey. The sampling site (1645 m altitude) is surrounded by mainly Uludag fir, which is characteristic to Uludag, while altitudes lower than 1000 m were composed of mixed deciduous trees. Sampling apparatus and sampling strategy for collection of the studied terpenes on Uludag Mountain were developed. Breakthrough Volume experiments were performed for accurate sampling. Samples were collected in a field campaign performed during October 2002 by means of active sampling onto glass coated stainless steel tubes containing Tenax&amp / #61666 / TA (55 mg) and Carbopack&amp / #61652 / B (65 mg). The mass flow rate and duration of sampling were 30 mL/min and 4 hours. Short-Path-Thermal-Desorption/Gas Chromatography-Mass Spectrometer (SPTD/GC-MS) was used for the analysis of monoterpenes during 12-14 October 2002. The cryogenic preconcentration (-40oC) was maintained by liquid CO2. HP-1-MS capillary column provided good resolution of peaks, except for pulegone and citronellol at standard operation procedure. Internal standard calibration was applied by adding carefully measured spikes of fenchone to the samples and standards. The detection limits for each terpene were found to be at sub-ppbv level. Daily intermediate standard measurements and auto-tune provided checking the instrumental capabilities. Selected Ion Monitoring mode was used for analysis of the terpenes. For quantitation of the spectra at least one qualifier ion was expected to be within 80% correlation with target ion. Alpha-pinene, camphene, beta-pinene, and d-limonene were determined. The average concentrations of monoterpenes were found to be 0.385, 0.168, 0.111, and 0.204 ppbv respectively. Simultaneous measurements of O3, NOx, SO2, and meteorological parameters were also performed. The data resolution was 15 min for each pollutant. Ozone displayed strong diurnal variation (around 5-30 ppb), while NOx concentrations were almost constant around 15 ppb. During the sampling campaign terpenes showed similar behaviours with O3, but not with NOx. Terpenes had a direct relation with temperature and relative humidity.

Immobilization of fluorescent chemosensors and chromogenic reagents on solid supports for developing optical sensors result in improved analytical performance characteristics such as continuous read-out, increased sensitivity, lower reagent consumption and possibility of using the sensor in solvents where the free molecule displays low solubility. The aim of this study is to immobilize dansylaminophenyl boronic acid (DAPB acid) and diphenylcarbazide (DPC) into various solid supports for the determination of fructose and hexavalent chromium, respectively. DAPB acid reacts with diol containing molecules to produce electron transfer resulting fluorescence quenching. Whereas DPC reacts specifically with chromate to produce a magenta colored complex having absorption maximum at 540 nm. Utilizing sol-gel technology, inorganic polymer matrices which enabled to observe fluorescence and absorbance signal in VIS region has been constructed. Also methylmethacrylate (MMA) and methacrylic acid (MAA), which are known to give transparent organic co-polymers, are chosen as monomers in the synthesis of organic copolymer. Hydrogels such as polyvinyl alcohol and Ca-alginate gel have been utilized for their good optical characteristics in the working range. Several considerations in the construction of host matrix were taken into account, such as the porosity of the polymers, functionalization of the matrix and use of additives for increasing the affinity of the medium toward the dopant molecule and swelling properties of organic polymers. The performances of the immobilizations were evaluated in terms of the transmittance and leaching properties of the host matrix, optical properties of dopant and optical response characteristic of the dopant for the analyte. The sensor applications of the immobilized probe molecule DPC were investigated. Studies regarding the enhancement of the performance of the flow injection analysis method for fructose determination, previously carried out in our laboratory, based on the fluorescence quenching of DAPB acid probe in solution were stated.

There is an increase in bombing assaults in recent years in our country. Determining the explosive material used in these cases by the quick and correct analysis of the evidence obtained after the explosions, is an important starting point for the investigations which are done to reach the perpetrators. The forensic chemistry investigations have to be correct, exact and rapid in order to reach the right criminal. In this study, the Gas Chromatography-Mass Spectrometry (GC-MS) and Gas Chromatography-Thermal Energy Analyser (GC-TEA) methods which are being used for the determination of the explosive materials&rsquo / residues used in bombing attacks are optimized with the standard solutions of 2,4,6-Trinitrotoluene (TNT) and 1,3,5-trinitro-1,3,5-triazocyclohexane (RDX) and standard mixture solution. The two methods were compared by analysing the postexplosion soil samples. Also an efficient and applicable sample preparation procedure was developed. The results showed that both methods are efficient and sensitive for the postexplosion investigations. It is seen that GC-TEA has lower detection limit and simple chromatograms due to its selectivity against only nitro group containing explosives. However it is concluded that there is a need for a reliable and sensitive method like GC-MS which provides identification and library search, for the determination of the organic components which can not be identified with GC-TEA

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.

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.