A simple method to estimate relative stabilities of polyethers cationized by alkali metal ions

Dissociation of doubly cationized polyethers, namely [P + 2X]²⁺ into [P + X]⁺ and X⁺, where P = polyethylene glycol (PEG), polypropylene glycol (PPG) and polytetrahydrofuran (PTHF) and X = Na, K and Cs, was studied by means of energy‐dependent collision‐induced dissociation tandem mass spectrometry. It was observed that the collision voltage necessary to obtain 50% fragmentation (CV₅₀) determined for the doubly cationized polyethers of higher degree of polymerization varied linearly with the number of degrees of freedom (DOF) values. This observation allowed us to correlate these slopes with the corresponding relative gas‐phase dissociation energies for binding of alkali ions to polyethers. The relative dissociation energies determined from the corresponding slopes were found to decrease in the order Na⁺ > K⁺ > Cs⁺ for each polyether studied, and an order PPG ≈ PEG > PTHF can be established for each alkali metal ion. Copyright © 2011 John Wiley & Sons, Ltd.     

An efficient synthesis of ferrocenyl imidazo[1,2-a]pyridines

Abstract  

An efficient and simple synthesis of ferrocenyl 3-aminoimidazo[1,2-a]pyridines by the three-component reaction of ferrocenecarboxaldehyde, isocyanides, and 2-aminopyridines in the presence of a catalytic amount of InCl₃ in ethanol at room temperature is reported.     

Dispersive solid phase extraction of lead(II) using a silica nanoparticle-based ionic liquid ferrofluid

We demonstrate the application of an ionic liquid-based ferrofluid to the dispersive solid phase extraction of lead(II) using PAN as the chelator. The ionic liquid contains silica nanoparticles with a magnetic core as the dispersion medium, and its use results in improved stability of the colloidal dispersion and a complete extraction of lead(II) within a few seconds. In addition, there is no need for centrifugation. Specifically, the effect of different variables on the extraction of lead(II) was studied using an experimental design. Lead(II) was quantified by AAS. Under optimized conditions, the calibration graph for lead(II) is linear in the range from 5 to 372 μg L^?1, the relative standard deviation is 1.34 % (for n?=?7), the limit of detection is 1.66 μg L^?1, and the enrichment factor is 200. The maximum adsorption capacity of sorbent was calculated to be 10.7 mg g^?1, and adsorption follows a Langmuir isotherm. Figure

A schematic view of D-SPE experimental set up. We demonstrate the application of an ionic liquid-based ferrofluid to the dispersive solid phase extraction of lead(II) using PAN as the chelator. The ionic liquid contains silica nanoparticles with a magnetic core as the dispersion medium     

Cuminum cyminum fruits as source of luteolin- 7-O-glucoside,potent cytotoxic flavonoid against breast cancer cell lines

Abstract

Cuminum cyminum is famous for its spicy fruits used for culinary and therapeutic properties worldwide. Brine shrimp test was performed for detecting cytotoxic fractions and subfractions. Ethyl acetate (EA) and hexane (HE) fractions demonstrated LC₅₀ of 52.40 and 60.77 µg/ml against Artemia salina while other fractions showed no toxicity (LC₅₀> 500 µg/ml). Bioguided elucidation of EA and HE fractions were carried out and cytotoxicity of pure compounds were investigated against breast cancer cell lines (MCF-7 and MDA-MB-231) and normal cell line (NIH/3T3) by MTT assay. Four flavone structures as luteolin, apigenin, luteolin-7-O-glucoside and apigenin-7-O-glucoside from EA and cuminoid A from HE were purified and identified. Luteolin-7-O-glucoside demonstrated potent anticancer activities against MCF-7 cell line (IC₅₀ of 3.98 µg/ml) with selectivity index of 8.0. In conclusion, flavonoids especially luteolin-7-O-glucoside play a significant role in cytotoxic effect of C. cyminum fruits and can be introduced as candidate for chemopreventive and chemotherapeutic drugs.     

Zinc and copper oxide nanoparticles decrease synaptosomal glutamate uptake: an in vitro study

Nanoparticles (NPs) are considered as an important environmental risk factor for cognitive impairments and neurodegenerative disorders. Recent evidences have reported a glutamatergic system response against air-borne NPs. Zinc and copper oxides (ZnO and CuO) NPs are the most common metal oxide NPs in industries. The effects of these NPs on hippocampal voltage-dependent ion channels and spatial cognition have been previously studied. However, there is a lack of evidence regarding the effects of ZnO and CuO NPs on glutamatergic synapse neurotransmission in central nervous system. In the present study, the effects of ZnO and CuO NPs on glutamate (Glu) release and uptake have been investigated in isolated nerve terminals (synaptosomes). Our findings have shown that, even in high doses of ZnO and CuO NPs, no significant effect on Glu release is observed. However, a decrease has been observed in uptake of Glu. Hence, ZnO and CuO NPs can be considered as hazardous agents inducing neurodegenerative disorders through Glu excitotoxicity.     

Electrospray ionization tandem mass spectrometry of the star‐shaped propoxylated diethylenetriamine polyols

The collision‐induced dissociation of the protonated five‐arm star propoxylated diethylenetriamine polyols was studied under electrospray conditions. Two product ion series were detected because of the cleavage of the C? N bonds in the initiator moiety. No backbone fragmentation of the polyether chains was observed, which allowed to explore the initiation and side‐chain propagation process of the oligomers. On the basis of MS/MS spectra, it is probable that the rate of the initiation is larger than that of the chain propagation. The propylene oxide repeat units attach to the five arms with approximately the same probability. Furthermore, it was found that the collision energy necessary to obtain 50% fragmentation (CE₅₀) was linearly dependent on the molecular weight of the polyols. Copyright © 2015 John Wiley & Sons, Ltd.     

Application of magnetic graphene-based bucky gel as an efficient green sorbent for determination of mercury in fish and water samples

Research on Chemical Intermediates - In this article, a highly efficient method based on coupling magnetic solid-phase extraction and dispersive microsolid-phase extraction was proposed to...     

Supramolecular-based dispersive liquid-liquid microextraction: a novel sample preparation technique utilizes coacervates and reverse micelles

The present study reports a novel sample enrichment method termed supramolecular-based dispersive liquid-liquid microextraction (SM-DLLME). The SM solvent selected was made up of reversed micelles of decanoic acid dispersed in tetrahydrofuran (THF)-water. THF plays double role, not only acts as a disperser solvent but also causes self-assembly of decanoic acid. The contaminant used as a model was Malachite Green (MG). It was a cationic dye and was preconcentrated without any derivatization or ion-pair formation reaction. In SM-DLLME, the most important advantages of DLLME technique and preconcentration strategy based on the coacervation and reverse micelles have come together. Moreover, in this method, disadvantages of DLLME such as extraction capability of only hydrophobic analytes and hiring toxic and hazardous organic solvents as the extraction solvent and disadvantages of coacervation-based extraction method such as tedious, labor-intensive and time-consuming stirring procedure have been avoided. Several variables affecting the microextraction efficiency were investigated and optimized. Under the optimized conditions and preconcentration of only 5.00 mL of sample, the enhancement factor was 52, limit of detection (LOD) was 4 μg/L and relative standard deviations (RSDs) for 145 and 36 μg/L of MG in textile industry wastewater were 1.8 and 3.2%, respectively (n = 6).