Applied Biochemistry and Biotechnology - In this study, a homogenization-based extraction method was developed and was compared to five conventional methods of squalene extraction. Squalene... 相似文献
A promising electrochemical sensor based nickel‐carbon nanotube (Ni‐CNT) modified on glassy carbon (GC) electrode had been developed and the properties of the modified electrode were characterized by multispectroscopic analysis. The fabricated sensor (GC/Ni‐CNT) electrode was utilized to determine the catecholamines such as epinephrine and dopamine simultaneously. Differential pulse voltammetry and amperometry were used to verify the electrochemical behavior of the studied compounds. The GC/Ni‐CNT based amperometric sensor showed a wide linear range and low detection limit with high analytical sensitivity of 8.31 and 6.61 μA μM?1 for EP and DA, respectively which demonstrates better characteristics compared to other electrodes reported in the literature. Further, no significant change in amperometric current response was observed in presence of biological interference species such as glucose, cysteine, citric acid, uric acid and ascorbic acid in the detection of EP and DA. The utility of this GC/Ni‐CNT electrode was well established for the determination of EP and DA in human urine samples. 相似文献
We report a custom-geometry linear ion trap designed for fluorescence spectroscopy of gas-phase ions at ambient to cryogenic temperatures. Laser-induced fluorescence from trapped ions is collected from between the trapping rods, orthogonal to the excitation laser that runs along the axis of the linear ion trap. To increase optical access to the ion cloud, the diameter of the round trapping rods is 80% of the inscribed diameter, rather than the roughly 110% used to approximate purely quadrupolar electric fields. To encompass as much of the ion cloud as possible, the first collection optic has a 25.4 mm diameter and a numerical aperture of 0.6. The choice of geometry and collection optics yields 107 detected photons/s from trapped rhodamine 6G ions. The trap is coupled to a closed-cycle helium refrigerator, which in combination with two 50 Ohm heaters enables temperature control to below 25 K on the rod electrodes. The purpose of the instrument is to broaden the applicability of fluorescence spectroscopy of gas-phase ions to cases where photon emission is a minority relaxation pathway. Such studies are important to understand how the microenvironment of a chromophore influences excited state charge transfer processes.
A sensitive and rapid LC–MS/MS method was developed and validated for the simultaneous quantitation of five selective KCNQ channel openers, namely ICA-27243, ML-213, PF-05020182, SF-0034 and flupirtine in mice plasma as per regulatory guideline. The analytes and the internal standard (IS; flupirtine-d4) were extracted from 50 µL mice plasma by liquid–liquid extraction, followed by chromatographic separation using an Atlantis C18 column with an isocratic mobile phase comprising 0.2% formic acid: acetonitrile (20:80, v/v) at a flow rate of 0.6 mL min?1 within 2.5 min. Detection and quantitation was done by multiple reaction monitoring on a triple quadrupole mass spectrometer following the transitions: m/z 268.9 → 140.8, 258.1 → 95.1, 367.2 → 269.1, 322.2 → 248.2, 305.7 → 196.4 and 309.1 → 196.1 for ICA-27243, ML-213, PF-05020182, SF-0034, flupirtine and the IS, respectively, in the positive ionization mode. The calibration curves were linear from 1.00 to 2008 ng mL?1 for all the analytes with r2 ≥ 0.99. The intra- and inter-batch accuracy and precision (% CV) across quality controls varied from 90.0 to 113 and 2.64 to 13.0; 93.8 to 114 and 3.15 to 14.9%, respectively, for all the analytes. Analytes were found to be stable under different stability conditions. The method was applied to a pharmacokinetic study in mice. 相似文献
Ruthenium(II) complexes of the general formula [Ru(PPh3)2(L)(L)]ClO4 [L=2,2-bipyridine or 1,10-phenanthroline;L=2-hydroxy--4-X-phenylcinnamoylacetophenone] have been prepared by reacting L and L with Ru(PPh3)3Cl2 in CH2Cl2. The complexes are diamagnetic and absorb intensely in the visible region, owing to the MLCT transition. Hexacoordinated ruthenium(III) complexes, [RuCl2(PPh3)2(L)], have also been prepared by reacting Ru(PPh3)3Cl3 with -diketones. Solutions of ruthenium(III) complexes show rhombic e.s.r. spectra at 77 K, and distortion from the octahedral symmetry has been identified from the line spacings. The conjugation in diketones favours reversibility in RuII/III and RuIII/IV and stabilize ruthenium in different oxidation states owing to d–* interaction. Oxovanadyl(IV) complexes of the -diketones with a metal-to-ligand ratio of 1:2 and square pyramidal geometry were also prepared. The e.s.r spectra of these complexes show the presence of an unpaired electron in the dxy orbital and the hyperfine splitting constants are sensitive to solvent change. ¶ A new class of highly conjugated Schiff bases obtained from the above diketones and 2-aminothiophenol behave as dibasic, tridentate ligands in their copper(II) complexes. The subnormal magnetic moments and hyperfine splittings of these complexes are ascribed to an antiferromagnetic exchange interaction arising from dimerization. Cyclic voltammograms show that the electron transfer occurs in two steps corresponding to CuII–CuI and CuI–CuI redox states. 相似文献
Binding of fructose to the fructose imprinted polymer (MIP(Frc)) and pinacol imprinted polymer (control) were studied both in batch and a flow through mode. The influence of the cross-linkers ethylene glycol dimethacrylate (EDMA) and trimethylolpropane trimethacrylate (TRIM) on the binding characteristics was analysed. TRIM cross-linked MIPs showed a lower (unspecific) binding for the control polymer (pinacol imprinted) and higher binding of fructose as compared with the EDMA-MIPs. Furthermore interactions of a TRIM cross-linked molecularly imprinted polymer against fructose and its corresponding template were studied using a thermistor. Label-free detection of fructose was realised in the range of 0.5-10mM. The difference in enthalpy changes between specific binding of fructose to boronic acid moieties of the MIP and non-specific binding to the matrix leads to an 18-fold higher apparent imprinting factor than batch binding studies. Cross-reactivity studies using MIP sensor indicate that the interaction of fructose to MIP generates higher signal than disaccharides. The studies described in this paper demonstrate the potential of direct characterisation of molecular binding events. 相似文献
In this article, we describe the outcome of a mathematical collaboration between a university lecturer and an undergraduate student. The resulting investigation concerned a particular divisibility property of the Fibonacci numbers, and indeed it seems that a new result was found in this regard. An interesting point to be made here is that, although the mathematical content was relatively straightforward, this joint exploration did, in a very modest sense, mirror certain key aspects of the research process. 相似文献
A facile and convenient method for the synthesis of highly functionalized 2‐(substitutedbiphenyl) based benzimidazoles has been reported by the application of Suzuki‐Miyaura cross coupling reaction. 相似文献
A new, efficient, and highly diastereoselective synthesis of polycyclic indole derivatives through intramolecular imino Diels-Alder reaction of aminoanthraquinone with N-prenylated indole-2-carboxaldehydes in the presence of 20 mol % of triphenylphosphonium perchlorate (TPPP) is reported with extremely high cis selectivity in good yield. 相似文献