Sulu Çözeltilerdeki N-Nitrozodifenilaminin Gama-Işınları İle Bozunması

Abstract

Nitrosoamines are not added to the compounds directly, their formation follows some consecutive reactions or chemical interactions. They can also be formed in living organisms as in vivo. Dimethylnitrosoamine (NDMA) is the first nitrosoamine compound known as cancirogenic and toxic. This compound is used as solvent in industry and can be also formed with the interaction of dimethylamine-nitrite. Amines are present in environment widely. Generally they are converted to nitrosoamines with nitrite by nitrosation. Nitrosoamines are polar compounds and generally their solubility in water is high. Their extraction to organic solvents is difficult because octanol/water partition coeficients are very low. These compounds can not be adsorbed on nonpolar surfaces significantly. Nitrosamines cannot be removed from water by aeration since their Henry constants are low. Nitrozamines are polar compounds and they do not bioflocculate but they resist on biodegradation. High hydrophility, low adsorptibility and high resistance of nitrosamines are important risks for ground water pollution. In addition to this, the most important risk for consumers is formation of NDMA and other nitrosoamines during disinfection of drinking water with disinfectants. Photolytic decomposition of

nitrosoamines is possible because their absorbance is strong at 225-250 nm wavelength. One of the main UV degradation product of NDMA is dimethylamine (DMA) can transfer the energy of UV selectively to certain chromophore groups so can not be decomposed and it is precursor of NDMA. It is important that NDMA or other nitrosoamines should not reform nitrosoamines after decomposition. It is not possible by photodegradation. Nitrosamines can be found in waste waters and drinking water because of industrial applications as well as during disinfection of supply water. Most of the nitrosamines were detected in water which are carcinogenic. In this study NNitrosodiphenylamine (NDPhA) is selected and its chromatographic separation from its intermediates after recovery from water was examined. Solid phase extraction (SPE) is a method of sample preparation that concentrates and purifies analytes from solution by sorption onto a disposable solid phase cartridge, followed by elution of the analyte with a solvent appropriate for instrumental analysis. In this study, the concentration process for aqueous solutions of NDPhA and the experimental conditions such as determination of experimental parameters and reproducibility after SPE were studied. The recovery of NDPhA were followed by using Dionex ICS 3000 system after SPE process by Thermo Dionex AT 280 with Thermo Scientific Solex C18 cartridge (1000 mg). Low concentration solutions of NDPhA were prepared and used for the autoconcentrator system which are carried out at different NDPhA concentrations in water, varying from 0.01 to 2 mg/L. To increase the yield of NDPhA extraction into the organic solvent, Carboxen 572 (Supelco, 20/45 mesh size), Alumina (BDH, for chromatographic adsorption analysis), Alumina (BDH, calcined) and Active Coal (Fluka, from peat, multi-purpose, steam activated and acid washed, powder) were used and used as filling materials. In this system, the aim was to determine the optimum experimental conditions, including filling material, volume of solvents, number of solvents, volume of the analyzed solution. NDPhA was eluted with methyl alcohol and analyzed by Dionex IC 3000 HPLC. The results are shown that the recovery yield was up to %97. Using C18 cartridge was found to be more efficent method to seperate NDPhA from aqueous solution. At this stage, treatment of nitrosoamines with gamma-irradiation and degradation products can be decomposed with nonselective high permeation of gamma rays and formation of nitrosoamines have been prevented. In this study, decomposition of N-nitrodiphenylamine with gamma-rays, detection of decomposition products and amount determination investigated, nitrosoamine initial concentrations in which gamma radiation dose have been realized to prevent reformation of nitrosoamine from decomposition products. The results of this study showed that gama irradiation alone can degrade the compound at 2.21 kGy. High pressure liquid chromatography (HPLC), ion chromatography (IC) and gas chromatography/mass spectrometry (GC/MS) methods for determination of Nnitrodiphenylamine (NDPhA) and its degredation products in aqueous system was studied. Our aim in this study is to protect human health from cancer and removal of nitrosoamines or decrease the amounts of nitrosoamines as minimum as possible in water sources.