Mustafa Saçmacı

Development of a new on-line system for the sequential speciation and determination of chromium species in various samples using a combination of chelating and ion exchange resins

A new on-line flow injection (FI) procedure for the sequential separation, preconcentration and speciation of Cr(III)/Cr(VI) species in different matrices is described based on the combining of solid phase extraction and flame atomic absorption spectrometry (FAAS). Poly 2-(5-methylisoxazol)methacrylamide-co-2-acrylamido-2-methyl-1-propanesulfonic acid-co-divinyl-benzene and Dowex 21K resins were used as chelating and ion-exchange materials for the separation/preconcentration of Cr(III) and Cr(VI) ions, respectively. Trace amounts of chromium retained on the resins were eluted sequentially with HNO3 and then introduced directly to the nebulizer-burner system of FAAS. The optimum conditions such as pH of the sample solution, amount of the resin, volume of the sample and interfering ions, which are effective on the quantitative recovery of the analytes, were investigated for sequential determination of Cr(III) and Cr(VI) ions. The preconcentration factors were found to be 48 and 30 for Cr(III) and Cr(VI), and the detection limits corresponding to three times the standard deviation of the blank (3s/b) were 0.05 and 0.3 µg L(-1), respectively. The method was verified by analyzing a certified reference material. The proposed method was applied to the determination based on the speciation of chromium in various real samples with satisfactory results.

A new chelating reagent and application for coprecipitation of some metals in food samples by FAAS

A new, simple and rapid coprecipitation method has been developed to separate and preconcentrate traces of Co(II), Cu(II), Fe(III), Pb(II) and Mn(II) in different samples prior to their determinations by flame atomic absorption spectrometry (FAAS). 2-[(E)-(8-hydroxy-2-methylquinolin-5-yl) diazenyl] benzoic acid (QAN) was firstly synthesized and characterized as a new chelating reagent for determination of some metals. IR spectra, (1)H-NMR spectrum and elemental analysis were evaluated for the characterization of the reagent. These metals were quantitatively recovered with Ni(II)/QAN precipitate in pH range of 8-10. Different factors such as sample volume, amount of QAN, and Ni(II) as carrier element, sample volume, and matrix effects for improving the quality of the preconcentration procedure were optimized. Under optimized experimentally established conditions, analytical detection limits were in the range of 0.03-0.83μgL(-1), while precision (RSD) was <3.5%, and enrichment factor was obtained as 100. The accuracy of the presented coprecipitation method was verified by the analysis of certified reference materials. The method was applied to the determination of the analytes in real samples such as food samples and make up products, and accuracy was found high (recoveries >95%).

Synthesis and Characterization of New Chelating Resin: Adsorption Study of Copper(II) and Chromium (III) Ions

Acrylamide based monomer, 5-methyl-2-thiozyl methacrylamide (MTMAAm) was synthesized by the reaction of 2-Amino-5-methyl thiazole with methacryloyl chloride in the presence of triethylamine(NR3) at 0–5°C. The monomer MTMAAm was characterized by FT-IR and 1H-and 13C-NMR spectral studies. A new chelating resin, poly(5-methyl-2-thiozyl methacrylamide-co-2-acrylamido-2-methyl-1-propanesulfonic acid-co-divinylbenzene) [MTMAAm/AMPS/DVB] was synthesized. This resin was characterized by FT-IR. In order to determine the adsorption behavior of chelating resin, the adsorption isotherm of Cr(III) and Cu(II) were studied. It was found that the adsorption isotherm of the ions fitted with Langmuir-type isotherms. From the Langmuir equation, the adsorption capacity of chelating resin for Cr(III) and Cu(II) was found to be 7.77 mg g− 1 and 4.27 mg g− 1, respectively. Binding equilibrium constant was calculated to be 0.155 L mg− 1 and 0.106 L mg− 1 for Cu(II) and Cr(III), respectively.

Selective back-extraction and preconcentration of zinc(II) from metal-1,3,5-triketone extracts prior to its determination by flame atomic absorption spectrometry

A simple back-extraction method was developed for the separation and preconcentration of trace levels of zinc from different matrices. Ethyl-2-(4-methoxybenzoyl)-3-(4-methoxyphenyl)-3-oxopropanoylcarbamate (EMPC) was used as a new complexing agent for the extraction of zinc(II) from the aqueous sample phase to the methyl isobutyl ketone (MIBK) phase as Zn(EMPC)2 complexes. The Zn(II) can be selectively stripped with 1 mL of 0.5 mol L−1 HCl from Mn+(EMPC)n complexes [Ag(I), Al(III), Cd(II), Cr(III), Cu(II), Fe(II), Fe(III), Mn(II), Ni(II), Pb(II) and Pd(II)] which dissolved in MIBK phase. Some experimental parameters, which are important for the whole extraction process, including pH, sample volume, shaking time, amount of the EMPC reagent, amount of MIBK, ionic strength, and type of back-extractant were investigated. The recovery for Zn(II) was greater than 95%. The detection limit of the method was found to be 0.2 µg L − 1 and the relative standard deviation as 6.4%. The concentrations of Zn(II) in the certified reference materials (LGC6019 river water and NIST-1547 peach leaves) by the presented method were in good agreement with the certified values. The proposed method was succesfully applied to the determination of zinc in some natural waters, rice, hair, soil, and tea samples.

On-line determination of palladium by flame atomic absorption spectrometry coupled with a separation/preconcentration minicolumn containing a new sorbent

A method was developed for the on-line determination of palladium in complex matrices with flame atomic absorption spectrometry (FAAS) using Amberlite XAD-16 resin functionalized with 2-[2-(5-thiol-1,3,4-thiadiazolyl)]-azonaphthol (TTAN) reagent. Optimum experimental conditions such as pH of sample, type of eluent, amount of resin, volumes of sample and eluent solution, flow rates of sample and eluent, and effect of interfering ions were established. A 0.1 mol L−1 thiourea solution in 0.5 mol L−1 HCl was used as the eluent and subsequently transportation the analyte ions into the nebulizer–burner system for atomization. The synthesized chelating resin material showed excellent chemical and mechanical resistance, fast adsorption kinetics permitting the use of high sample flow rates without significant losses of retention efficiency. The detection limit of the method was 1.5 µg L−1 while the relative standard deviation (RSD%) was 2.4% at 0.1 mg L−1 Pd(II) level. The developed method was successfully applied to the determination of palladium in the catalytic converter and water samples.

Preparation and characterization of novel pyrrol-3-ones attached to α/β-amino acids, esters and amides

Summary.Various α/β amino acid derivatives 5 were attached to compounds 3 to yield 2,3-dihydro-1H-pyrrol-3-ones amino acids derivatives 6. This rare heterocyclic amino acid skeleton including the pyrrolo[1,2-b][1,3]oxazol moiety was also successfully prepared in the esteric form. The structure of the new compounds was characterized by spectroscopic methods.

Synthesis, characterization and vibrational spectra analysis of ethyl (2Z)-2-(2-amino-4-oxo-1,3-oxazol-5(4H)-ylidene)-3-oxo-3-phenylpropanoate.

In the present study, the experimental and theoretical vibrational spectra of ethyl (2Z)-2-(2-amino-4-oxo-1,3-oxazol-5(4H)-ylidene)-3-oxo-3-phenylpropanoate (AOX) were investigated. The experimental FT-IR (400-4000 cm(-1)) and Laser-Raman spectra (100-4000 cm(-1)) of the molecule in the solid phase were recorded. Theoretical vibrational frequencies and geometric parameters (bond lengths, bond angles and torsion angles) were calculated using ab initio Hartree Fock (HF), Density Functional Theory (B3LYP and B3PW91) methods with 6-311++G(d,p) basis set by Gaussian 03 program, for the first time. The computed values of frequencies are scaled using a suitable scale factor to yield good coherence with the observed values. The assignments of the vibrational frequencies were performed by potential energy distribution (PED) analysis by using VEDA 4 program. The theoretical optimized geometric parameters and vibrational frequencies were compared with the corresponding experimental X-ray diffraction data, and they were seen to be in a good agreement with each other. The hydrogen bonding geometry of the molecule was also simulated to evaluate the effect of intermolecular hydrogen bonding on the vibrational frequencies. Also, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies were found.

Grafting of glutathione to magnetic graphene oxide and application for the determination of As(III)/(V) in food samples via a zeta potential analyzer

A new selective method based on magnetic dispersive solid-phase extraction (MDSPE) and a zetasizer system is proposed for the determination of As(III)/As(V) species in some water and food samples. In the developed procedure, the crucial issue is that a novel adsorbent was synthesized and characterized by grafting L-glutathione (reduced) (GSH) onto a magnetic graphene oxide surface (GO/Fe3O4@GSH) and was also applied in quantitative adsorption of As(III)/As(V) ions. Moreover, GO/Fe3O4@GSH demonstrates selectivity towards As(III) in the presence of As(V). The best determination and speciation conditions were achieved by testing different nanocomposite quantities, the pH of the sample, type of desorption solution, sample and desorption solution volumes, and the effect of interfering ions. Due to features of the GO/Fe3O4@GSH nanocomposite such as a wrinkled structure and excellent dispersibility in water, GO/Fe3O4@GSH seems to be ideal for the fast and simple preconcentration/determination of As(III)/As(V) using methodology based on MDSPE and zetasizer measurement. As(III) was quantitatively recovered with the nanocomposite at concentrations between 0.5 and 1.5 mol L−1 of HNO3, while As(V) was not quantitatively recovered at any pH. The detection limit of the method was 0.1 μg L−1 while the relative standard deviation was 1.0% for 0.5 mg L−1 As(III). The developed method was applied successfully for the determination of As(III) in some water and tea samples, and standard reference material samples with satisfactory results. Moreover, GO/Fe3O4@GSH can be applied for arsenic speciation due to its selectivity towards arsenite.

Synthesis, structural and spectral studies of N-p-methylbenzyliden-N-phenyl-p,p′-dimethoxybenzoyl acetic acid hydrazide

Abstract The structure of the organic derivative of N-p-methylbenzyliden-N-phenyl-p,p′-dimethoxybenzoyl acetic acid hydrazide, [C32H28N2O5], has been determined by X-ray diffraction. The structure derived from the NMR spectroscopy, the IR spectra and elemental analysis is consistent with that of the X-ray diffraction. The compound crystalizes in the monoclinic system with space group P21/c, a = 16.234(1), b = 9.399(2), c = 19.389(1), β = 110.924(3)°, V = 2763.3(5) Å3 and Z = 4. In the crystal, there is one weak C—H…O type intermolecular hydrogen bond interaction.

Methyl (+/-)-1-ethyl-2-hydroxy-4-(4-methoxybenzoyl)-5-(4-methoxyphenyl)-3-oxo-2,3-dihydro-1H-pyrrole-2-acetate.

The title compound, C(24)H(25)NO(7), is a racemic mixture of 2,3-dihydro-1H-pyrrol-3-ones. It crystallizes in the triclinic system, space group P1, with Z = 2. The asymmetric unit contains two enantiomorphic molecules and the structure is stabilized by hydrogen-bond contacts.