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1

Quantitative structure-retention relationship (QSRR) models for predicting the GC retention times of essential oil components

Pourbasheer E, Riahi S., Ganjali M. R., Norouzi P.

Acta Chromatographica

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2010

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Vol. 22, no. 3

357--373

EN

Multiple linear regression (MLR) and partial least squares (PLS) analysis have been used to model gas chromatographic retention times ( t R ) of 77 components of the essential oil of Ottonia martiana . The genetic algorithm (GA) was used to select the variables that resulted in the best-fitting models. Appropriate models with low standard errors and high correlation coefficients were obtained. MLR and PLS analysis were performed to derive the best quantitative structure-retention relationship (QSRR) models. The predictive quality of the QSRR models was tested for an external prediction set of 15 compounds, randomly chosen from the 77 compounds. Surprisingly, the results were of approximately the same quality for MLR and PLS modeling [squared regression coefficients ( R 2) of 0.964 and 0.968, respectively].

2

Rapid chemometric method for simultaneous determination of imipramine and clomipramine in serum

Riahi S., Bagherzadeh K., Akbari-Adergani B., Ganjali M. R., Norouzi P.

Chemia Analityczna

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2009

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Vol. 54, No. 6

1405-1421

EN

A numerical method has been developed and validated for the simultaneous determination of two tricyclic antidepressants (Imipramine (IMP) and Clomipramine (CLP)) in pure and serum samples. The spectrophotometric data were processed using the partial least squares multivariate calibration method and the genetic algorithm (GA). An orthogonal array data set consisting of absorption spectra in the 200-400 nm range obtained from the calibration set of mixtures containing the compounds and was used for the model construction. The predictive ability of the built model was then assessed applying a dataset obtained from solutions of pure substance where the percentage recovery was found to be 100.64 and 99.56, for IMP and CLP, respectively. Furthermore, the method was applied to real samples by spiking the binary standard solutions to the serum samples and analyzing the corresponding UV spectra by the GA-PLS method. High performance liquid chromatography was applied to validate the proposed method and a comparison between the obtained results revealed a satisfactory agreement between the HPLC and GA-PLS results.

PL

Opracowano i zwalidowano numeryczną metodę jednoczesnego oznaczania dwóch tricyk-licznych środków antydepresyjnych: imipraminy (IMP) i klomipraminy (CLP) w czystych próbkach i w surowicy. Wykorzystano w tym celu dane spektrometryczne i kalibrację opartą na metodzie cząstkowych najmniejszych kwadratów z użyciem genetycznego algorytmu (GA-PLS). Do konstrukcji modelu stworzono ortogonalny zbiór danych spektralnych z obszaru 200-400 nm z próbek kalibracyjnych zawierających oznaczane związki. Wcześniej upewniono się, badając widma czystych roztworów, że procentowy odzysk IMP i CLP wynosi odpowiednio - 100,64 i 99,56%. Opracowaną metodę zastosowano do rzeczywistych próbek po dodaniu do nich znanych ilości standardowych roztworów mieszanin. Metodę walidowano porównując otrzymane wyniki z wynikami wysokosprawnej chromatografii cieczowej. Zgodność była zadowalająca.

3

Solid Phase Extraction for Evaluation of Occupational Exposure to Pb (II) Using XAD-4 Sorbent Prior to Atomic Absorption Spectroscopy

Shahtaheri S. J., Khadem M., Golbabaei F., Rahimi-Froushan A., Ganjali M. R., Norouzi P.

International Journal of Occupational Safety and Ergonomics

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2007

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Vol. 13, No. 2

137--145

EN

Lead is an important constituent widely used in different industrial processes. For evaluation of workers’ exposure to trace toxic metal of Pb (II), solid-phase extraction (SPE) was optimized. SPE using mini columns filled with XAD-4 resin was developed with regard to sample pH, ligand concentration, loading flow rate, elution solvent, sample volume, elution volume, the amount of resins, and sample matrix interferences. Lead ions were retained on a solid sorbent and then eluted, followed by a simple determination of analytes with flame atomic absorption spectrometery. The obtained recoveries of metal ions were greater than 92%. This method was validated with 3 different pools of spiked urine samples; it showed a good reproducibility over 6 consecutive days as well as 6 within-day experiments. This optimized method can be considered successful in simplifying sample preparation for a trace residue analysis of lead in different matrices when evaluating occupational and environmental exposures is required.

4

Determination of propylthiouracil at a nanomolar level using Fast Fourier transformation continuous cyclic voltammetry under flow conditions

Norouzi P., Ganjali M. R., Sehat A. A., Mirahmadi S., Larijani B.

Chemia Analityczna

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2007

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Vol. 52, No. 3

399-410

EN

Asimple, fast, and economical Fast Foiirier Transformation Continuous Cyclic Voitammetric technique (FFTCV) for determinatipn of propylthiouracyl in pharmaceutical formulation under flow-injection conditions has been developed. The proposed method is also precise, accurate, sensitive, and selective. Potential waveform comprising consecutive potential steps for cleaning, accumulation, and redox reaction of the anaiyte was applied to Au disk micro-electrode. The effect of eluent's pH, accumulation potential, sweep rate, and accumulation time were considered. The method was linear in the analyte's concentration range of 20-3230 pg mL-1 (r = 0.998; detection and determination limits were 6 and 20 pg mL-1 respectively). The proposed method is advantageous to other methods with two respects: fast determination rate, and no requirement for oxygen removal from the solution.

PL

Opracowano pro sta, szybkąi tanią przepływowo-wstrzykowa^metodę oznaczania propylo-tiouracylu w preparatach farmaceutycznych. W metodzie zastosowano technikę wielokrotnej woltamperometrii i odszumianie woltamperogramów przy wykorzystaniu szybkiej transformacji Fouriera. Opracowana metoda jest również dokładna, precyzyjna, czulą i selektywna. Przebieg potencjału na elektrodzie ustalono tak, aby mogła być ona elektro-chemicznie oczyszczona przed zateżaniem i redukcją badanego związku. Zbadano wpływ pH eluenta, potencjału zateżania, szybkości zmiany potencjału i czasu zatężania. Sygnał by! liniowo zależny od stężenia analitu w przedziale 20-3230 pg mL-1(r = 0,998). Granice wykrywalności i oznaczalności określono odpowiednio, na 6 i 20 pg mL-1. Zaletami opracowanej metody, w porównaniu do innych metod, jest krótki czas oznaczania i brak potrzeby odtleniania roztworu.

5

Silver selective PVC-membrane sensors with and without graphite based on C-methycalix[4]resorcareneoctamethyl ester

Shamsipur M., Rouhani S., Mohajeri A., Ganjali M. R., Poursaberi T.

Chemia Analityczna

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2003

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Vol. 48, No. 6

947-958

EN

Novel polymeric membrane (PME) and coated graphite (CGE) silver-selective electrodes based on a calix[4]resorcareneoctamethyl ester has been prepared. The electrodes revealed Nemstian behaviour over a wide Ag+ion concentration range (1.0 x 10'5-1.0 * 10 ' mol L"' for PME and 1.0 * 1.0-10(-7) x 10(-1) mol L(-1) for CGE) with very low detection limits (4.7 x K)(-6) mol L(-1) for PME and 8.5 x 10(-8) mol L(-1) for CGE). They occurred to be very selective towards Ag+ even in the presence of other numerous cations. Their responses were independent of pH within the range of 4-9. The electrodes can be used for at least 3 months without any considerable potential deviations. They served as indicator electrodes in poten-tiometric titration of silver ion.

PL

Spreparowano nowe, selektywne w stosunku do srebra elektrody z polimerową membraną (PME) zawierające ester kaliks[4]rezorkarenooktametylowy. W jednym rozwiązaniu konstrukcyjnym matrycę PCV nakładano na grafit. Elektrody spełniają prawo Nersta w szerokim zakresie stężenia jonów Ag+(l,O x 10(-5)-l,0x 10(-1) 'mol L(-1) w przypadku PME i 1,0 x 10(-7)-1,0 x 10(-1) w przypadku CGE) przy bardzo niskiej granicy wykrywalności (4,7 x l 0(-6) mol L(-1) w przypadku PME oraz 8,5 x l 0(-8) mol L(-1) w przypadku CGE). Wykazują bardzo dobrą selektywność w stosunku do jonów srebra nawet w obecności wielu innych kationów. Ich odpowiedzi nie zależą od wartości pH w granicach 4-9. Elektrody mogą być używane co najmniej przez 3 miesiące bez widocznych zmian potencjału. Stosowano je jako wskaźnik w potencjometrycznym miareczkowaniu jonów srebra.

6

Differential Pulse Polographic Study of mercury Complexes with Some Benzo-Substituted macrocyclic Diamides in Binary Nitromethane+Dimethylformamide Mixtures

Shamsipur M., Fakbari A. R., Sharghi H., Eshghi H., Ganjali M. R.

Polish Journal of Chemistry

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2002

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Vol. 76 / nr 12

1665-1671

EN

The complex formation of Hg2+ ion with five recently synthesized benzo-substituted macrocyclic diamides in binary nitromethane + dimethylformamide mixtures was studied by differential pulse polarography at 25_C. The stoichiometry and stability of the complexes were determined by monitoring the shift in the Hg2+ differential pulse peak potential against the macrocycles concentration. In all cases studied, it was found that the stability of the resulting 1:1 complex decreases drastically by increasing the amount of dimethylformamide in the binary mixtures. The observed stability order in a given solvent mixture is discussed in terms of the cavity size, structural flexibility and nature of the substituted on the macrocyclic diamide ring.

7

Solid phase extraction and flame atomic absorption determination of copper

Ganjali M. R., Ghasemi Z., Salvati-Niasari M., Babaei L. H-A.

Chemia Analityczna

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2002

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Vol. 47, No. 4

619-626

EN

The Cu(II) was separated by solid phase extraction on octadecyl-bonded silica membrane disks modified with N,N'-bis(salicylidene) ethylenediamine (SED) followed by elution and flame atomic absorption spectrometric detection and applied as a separation and detection method for copper(II) in water. Extraction efficiency and the influence of sample matrix, flow-rate, pH, and type and minimum amount of stripping acid were investigated. The maximum capacity of the membrane disks modified by 5 mg of SED was found to be 649š15 ug of copper. The limit of detection of proposed method is 0.04 ngmL(-1).

PL

Opracowano metodę wykrywania i oznaczania miedzi(II) w wodzie. Cu(II) wydzielano za pomocą ekstrakcji do fazy stałej na dysku C(18) modyfikowanym N,N'-bis(salicylideno)etyle-nodiaminą(SED), a następnie oznaczano metodą absorpcyjnej spektrometrii płomieniowej. Badano wpływ matrycy, pH oraz szybkość przepływu na wydajność ekstrakcji. Badano również wpływ rodzaju i ilości kwasu na proces wymywania miedzi z dysku. Maksymalna pojemność dysku modyfikowanego 5 mg SED wynosiła 649š 15 fig miedzi. Granica wykrywalności proponowanej metody wynosi 0.04 ng mL(-1).

8

Thermodynamic Study of Some Pyridinium Ion Derivatives with 18-Crown-6, Aza-18-crown-6 and 1,10-Diaza-18-crown-6 in Acetonitrile

Ganjali M. R., Khoshdan N., Hashemi O. R., Seiyed Sajjadi S. A.

Polish Journal of Chemistry

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2000

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Vol. 74, nr 10

1389-1398

EN

The complexation between the salts of protonated of pyridine, 2-methyl pyridine, 2,4-dimethyl pyridine and 2,4,6-trimethyl pyridine and macrocyclic ligands 18-crown-6, aza-18-crown-6 and 1,10-diaza-18-crown–6 have been studied conductometrically in acetonitrile at different temperature. Formation constants of the resulting 1:1 complexes were determined by the computer fitting of the molar conductance-mole ratio data. The stability of complexes decrease in the sequence: 1,10-diaza-18-crown-6 > aza-18- crown-6 > 18-crown-6. The enthalpy and entropy of complexation were determined from the temperature dependence of the formation constants. In all cases, the complexes were enthalpy stabilized, but entropy destabilized.