Sulu Çözeltilerdeki N-Nitrozodifenilaminin Gama-Işınları İle Bozunması
Özet
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.