Journal of the Iranian Chemical Research
Volume:5 Issue: 1, Winter 2012

An analytical methodology based on spectrophotometric and partial least squares (PLS) algorithm for the simultaneous determination of ampicillin and penicillin in human plasma was developed and validated. The multivariate model was developed as a binary calibration model and it was built and validated with an independent set of synthesis and real samples in presence of matrix. It is shown how a developed technique for signal filtering, orthogonal signal correction (OSC), can be applied in multivariate calibration to enhance predictive power. The experimental calibration matrix was constructed with 25 samples. The concentration ranges considered were 1.0-40.0 and 0.5-20.0 μg mL-1 for ampicillin and penicillin, respectively. This procedure allows the simultaneous determination of ampicillin and penicillin in synthetic and human plasma good reliability of the determination was proved. The results obtained by the OSC-PLS and HPLC were statistically compared. Very similar values were found by two methods. No time consuming pretreatment was needed and this method also provides rapid, accurate and economical analysis of these drugs.

Cerium and nitrogen co-doped TiO2 nanocrystals were synthesized by a simple sol-gel process, using tetrabutyl titanate as the raw materials with (NH4)2Ce(SO4)3 and urea as ion donors. The co-doped TiO2 nanoparticles were characterized by X-ray diffraction and transmission electro microscopy. The photodegradation of glyphosate has been investigated in aqueous suspensions of doped TiO2 under visible irradiation. The results exhibit a higher thermal stability of anatase than pure TiO2.The uniform test results show the optimal conditions: nCe/nTi nN/nTi and calcining temperature was 0.08,0.01 and 800􀀀. The highest degradation rate for co-doped TiO2 show five times photocatalytic activity of Degussa P25.

The uses of MCM-41 as adsorbent have been studied as an alternative substitution of activated carbon for the removal dyes. This adsorbent was prepared at laboratory by authors. Adsorption of safranine on MCM-41 was studied to examine adsorption thermodynamics. In this study was investigated the effect of procces parameters like pH, initial dye concentration, temperature and adsorbent mass. MCM-41, as adsorbent, is characterized by high surface area and high pore volume to adsorbed dye very well. In this study, both Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. Langmuir model being has found to provide the best fit of experimental data. Results of thermodynamic evaluation indicated that adsorption reaction was spontaneous because Gibs energy was negative. This reaction was exothermic with negative enthalpy and reducing entropy.

Highly efficient method for the preparation of N-tert-butyl amides by reaction of nitriles with tertbutylacetate is described using boron trifluoride etherate in solvent free condition. Selective amidation of benzonitrile in the presence of acetonitrile was also achieved.

The coupling of tetrazotised 1,8-diaminonaphthalene with 1,3-dicarbonyl compounds [acetylacetone, methylacetoacetate and acetoacetanilide] yielded a new series of tetradentate ligand systems. Analytical, IR, 1H NMR and mass spectral data indicate that the compounds exist in the intramolecularly hydrogen bonded dihydrazone form. Dibasic tetradentate N2O2 coordination of these compounds in their [ML] complexes [M= Ni(II), Cu(II) and Zn(II)] has been established on the basis of analytical and spectral data. The Ni(II) and Zn(II) chelates are diamagnetic while Cu(II) complexes showed normal paramagnetic moment.

The way of making cross-linkable polyethylene through silane grafting has gained much attention in recent years because of its various advantages such as easy processing, low cost and capital investment and favorable properties in the processed materials. This work deals with silane grafting and moisture crosslinking of linear low density polyethylene (LLDPE). The grafting reaction was performed in an internal mixer using di-cumyl peroxide (DCP) as initiator and vinyl-trimethoxy silane (VTMOS) as grafting agent. Characterization and quantification of the grafting was performed by Fourier transform infrared (FTIR) spectroscopy. The cross-linking was done by subsequent immersion of grafted samples in hot water. The effect of silane and peroxide concentration was more considerable than time. The order of degradation temperature was: cross-linked LLDPE then grafted LLDPE and at last LLDPE.

A simple, inexpensive and one-step synthesis route of Ag-TiO2 nanoparticles by arc discharge method is reported. The resulting nanoparticles were characterized using X-ray diffraction and scanning electron microscopy. X-ray diffraction patterns demonstrate dominance of rutile to anatase phase in TiO2 and formation of silver metal on TiO2 after arc discharge process. Scanning electron microscopy images exhibit the increase of reduced nanoparticles in 5 minutes arc duration compared with 1 minute arc duration. Photodegradation of Methyl Orange as a standard pollutant shows that the presence of silver in TiO2 was found to enhance the photocatalytic activity. The high activity of silver doped TiO2 is due to the enhancement of electron–hole separation by the electron trapping of silver particles. Antibacterial activities of Ag-TiO2 nanoparticles were investigated at the presence of Escherichia coli bacteria.

The β-carboline derivatives are a large group of naturally-occurring and synthetic alkaloids which have a wide spectrum of biological and pharmaceutical properties. The newly developed procedure called VolSurf has been used to explore a significant correlation between the 3D molecular interaction fields (MIF) and physicochemical and pharmacokinetic properties of a set of 30 β-carboline compounds acting as antitumor agents. In general terms, VolSurf generates a limited set of quantitative numerical descriptors from MIFs by calculating the volume or the surface of the interaction contours. These descriptors that encode the information content from the chosen probes are simple to interpret from a chemistry point of view. The aim of this approach is to allow the analysis of a large number of quantitative descriptors by using chemometric tools such as partial least squares (PLS) and principle component analysis (PCA). The PLS model gave statistically significant results with R2 and Q2 values of 0.92 and 0.72, respectively. The ability of the model was validated by an external test set of 10 compounds, which gave R2 (pred) of 0.85. The VolSurf model developed here identifies hydrophobicity as the major physicochemical parameters responsible for the antitumor activity of the β-carboline derivatives towards HepG2 cell lines.