Wyniki wyszukiwania - BazTech

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.