Iranian Journal of Analytical Chemistry
Volume:5 Issue: 2, Summer and Autumn 2018

A simple and efficient hollow fiber-based method, namely magnetic solvent bar liquid-phase microextraction (MSB-LPME) combined with gas chromatography-flame ionization detection (GC-FID) has been successfully developed for the sensitive determination of selected phthalate esters (PEs) in environmental water samples. The analytes were extracted from sample solution to the organic solvent immobilized in a fiber. Following the extraction, the analyte-adsorbed magnetic solvent bar can be easily isolated from the sample solution by a magnet which could greatly simplify the operation and also reduce the total pretreatment time. The bar was primarily eluted with methanol, evaporated to dryness while the residue was dissolved in toluene and finally injected into GC-FID. Begin with, effective parameters controlling the performance of the microextraction were evaluated and optimized. The values of the detection limit of the method were in the range of 0.02-0.09 µg L-1 and the RSD% values for the analysis of 25.0 g µL-1 of the analytes was below than 6.0% (n = 7). A worthy linearity (0.996 ≥ r2 ≥ 0.993) and a broad linear range (0.2-250 µg L-1) were achieved. The method was finally employed for the preconcentration and determination of the PEs in environmental water samples and satisfactory results were obtained.

The aim of this work was indirect determination of anti-cancer drug capecitabine using complexation with platinum (IV) and determination by graphite furnace atomic absorption spectroscopy (GFAAS). For this aim at first, the complex of platinum with capecitabine was performed and the ratio of drug to metal was evalutsd with several ways. In the all of these methods, the ligand to metal ratio of the Potassium hexachloroplatinate (IV) and capecitabine complex was found to be 2:1. The extraction process was carried out by the hollow fiber supported functionalized multiwalled carbon nanotubes/ polyurethane foam (fMWCNT/PUF) foam as the solid adsorbent in the solid phase microextraction mode. The amount of desorbed platinum ion has been indirectly used to measure the drug concentrations. Parameters affecting the hollow fiber-solid phase microextraction (HF-SPME) such as pH of the donor phase, donor phase volume, the sorbent type and desorption solvent were optimized. Calibration graph was plotted and a curve with a linear response range of the 3.32 to 98.17 µg mL -1 and a detection limit 0.38 µg mL -1 was obtained.

Two locally available, cost-effective, renewable biosorbents including the untreated straw of Smyrniopsis Aucheri and untreated leaf of Acer Negundo  were used for the removal of Methylene Blue dye. The influence of initial dye concentration on the dye removal was investigated. Isotherm and kinetics of the biosorption process were studied. The optimum pH was found to be 6 and 5 for Smyrniopsis Aucheri and Acer Negundo, respectively. The optimum biosorbent dosage was found to be 0.3 g for Smyrniopsis Aucheri and 0.5 g for Acer Negundo. The removal of Methylene Blue by Smyrniopsis Aucheri and Acer Negundo  occurred during 10 and 15 min, respectively. The quick biosorption using reasonably small amount of such natural and untreated materials is a big advantages of this work for wastewater treatment applications in an environmental friendly way. The Langmuir adsorption isotherm model, was found to be the best applicable one to fit the experimental data. The pseudo-second and pseudo-first order kinetic models were applied well to describe the kinetics of Smyrniopsis Aucheri and Acer Negundo biosorption, respectively.

A quantitative structure activity relationship analysis has been applied to a data set of 34 derivatives of 8-hydroxy-2-iminochromene with inhibitory activities for carbonyl reductase 1. Semi-empirical quantum chemical calculations at the AM1 level were used to find the geometry of the studied molecules. Whole numbers of descriptors were calculated with Dragon software, and a subset of calculated descriptors was selected from 407 Dragon descriptors with the multiple linear regression (MLR), partial least square and principal component analysis methods. Results displayed that the MLR method predicted of activity good enough. The best model of MLR, with seven descriptors was selected.  Also it indicates very good consistency towards data variations for the validation methods.  The predicted values of activities are in suitable agreement with the experimental results. The obtained results suggested that the PLS method could be more helpful to predict the biological activity of iminochromene derivatives. This study is be useful to predict the activity of other compounds in the same derivatives.

Biosorption of Cu(II) ions from aqueous solutions onto waste Tea and Coffee powder (WTCP) has been investigated in a batch biosorption process. The biosorption process was found to be dependent on pH of solution, initial metal ion concentration, biosorbent dose, and contact time. The experimental equilibrium biosorption data were analyzed by Langmuir, Freundlich, Temkin and Dubinin ̶ Radushkevic isotherms models. The Langmuir model gave a better fit than the other three models by higher correlation coefficient, R2. The maximum biosorption capacities calculated from the Langmuir isotherm model were 526 and 417 mg/g, for coffee and tea, respectively at optimum conditions. The kinetic studies indicated that the biosorption process of the metal ions followed well pseudo-second-order model. According to the biosorption capacity, waste coffee and tea powder considered as an effective, low cost, and environmentally friendly biosorbent for the removal of Cu (II) ions from aqueous solutions.

Amikacin (AM) belongs to the family of aminoglycoside antibiotics. It is a broad spectrum antibiotic, effective against both Gram-negative and Gram-positive bacterial infections. The chemical structure of AM consists of hydroxyl (OH), glucopyranosyl and amino (NH2) groups. However, the lack of chromophore in the AM structure made it difficult to detect it in the UV-visible region (200–800 nm). Therefore, derivatization of AM is carried out to introduce a chromophore in its structure which helps in its detection in the UV-visible region. Several methods have been developed and reported for the determination of AM in pharmaceutical and biological samples. These methods include chromatographic techniques such as thin layer chromatography (TLC), liquid chromatography (LC), hydrophilic interaction liquid chromatography (HILC), high performance liquid chromatography (HPLC), ultra-high performance liquid chromatography (UHPLC), ion chromatography (IC); spectrometry such as UV-visible spectrometry, spectrofluorimetry, nuclear magnetic resonance (NMR) spectrometry, mass spectrometry (MS); chemiluminescence; Rayleigh scattering method; electrochemical methods such as polarography, cyclic voltammetry, amperometry; immunoassay and microbial assay. This review highlights the application of these methods in the analysis of AM in pharmaceutical and biological samples.

Essential oil of bentazon- treated plants were extracted and herbicide content analyzed by electrochemical method. For this propose, carbon paste electrode was modified using ZnFe2O4 anchored on reduced graphene oxide which synthesized by solvothermal approach. The nature and morphology of nanoparticles were characterized using XRD, FT-IR and Fe- SEM image. Under optimal experimental condition, modified electrode produces powerful oxidation signal for bentazon at +0.95 V (vs. Ag/AgCl). The anodic current was increased linearly with bentazon concentration in the range of 0.1 -20.0 µmol L-1 with a detection limit of 0.07 µmol L-1. The practical usage of modified electrode was evaluated by electro analysis of extracted bentzon residues at three applied doses which revealed reasonable results.