A sensitive and specific LC–MS-MS method is described for the simultaneous quantification of risperidone and 9-hydroxyrisperidone in human plasma. After extraction with tert-butyl methyl ether, plasma samples were separated on an Atlantis HILIC Silica C18 column (4.6 × 150 mm, 5 μm)with a mobile phase of ammonium formate buffer (10 mM, pH 4.0)/acetonitrile (40/60, v/v). Detection was by MS-MS. The method was fully validated according to the accuracy profile theory. It is based on β-expectation tolerance interval for the total measurement error which includes trueness and intermediate precision. The measurement uncertainty derived from β-expectation tolerance interval was estimated at each of the validation standards. The linearity fitted well over the range of 0.11–26.75 ng mL−1 for risperidone with an LLOQ of 0.11 ng mL−1, and for 9-hydroxyrisperidone, at a range of 0.15–37.8 ng mL−1 with an LLOQ of 0.15 ng mL−1. The intra- and inter-batch precision of risperidone were <5.71 and 8.22%, respectively. For 9-hydroxyrisperidone, the data were 5.78 and 6.48%. The recoveries were 88.78% (risperidone) and 70.35% (9-hydroxyrisperidone). The developed method was applied to a pharmacokinetic study of risperidone.
Five new terpenoids, including four eudesmane‐type sesquiterpenoids, 1 – 4 , and one labdane‐type diterpenoid, 6 , together with ten known compounds, were isolated from the roots of Chloranthus spicatus. The structures and their relative configurations were mainly established by 1D‐ and 2D‐NMR spectra, and MS experiments. 相似文献
Three d10 tetranuclear complexes,Cd 4(1,8-nap) 4(2,2′-bipy) 4(H2O) 8·6H2O(1,8-nap=naphthalene-1,8-dicarboxylate and 2,2′bipy=2,2′-bipyridine)(1),Cd4(1,8-nap) 4(2,2′-bipy) 4(H2O) 8·6H2O(2) andZn4(1,8-nap) 4(2,2′-bipy) 4(H2O) 4·2H2O(3),have been synthesized under hydrothermal conditions and characterized by elemental analyses,IR and X-ray diffraction techniques. Complexes 1 and 2 are isomers showing one-dimensional ribbon-like structures connected by O-H···O hydrogen bonds,and the one-dimensional ribbons are ... 相似文献
Techniques that can effectively separate protein–peptide complexes from free peptides have shown great value in major histocompatibility complex (MHC)–peptide binding studies. However, most of the available techniques are limited to measuring the binding of a single peptide to an MHC molecule. As antigen presentation in vivo involves both endogenous ligands and exogenous antigens, the deconvolution of multiple binding events necessitates the implementation of a more powerful technique. Here we show that capillary electrophoresis coupled to fluorescence detection (CE–FL) can resolve multiple MHC–peptide binding events owing to its superior resolution and the ability to simultaneously monitor multiple emission channels. We utilized CE–FL to investigate competition and displacement of endogenous peptides by an immunogenic gluten peptide for binding to HLA-DQ2. Remarkably, this immunogenic peptide could displace CLIP peptides from the DQ2 binding site at neutral but not acidic pH. This unusual ability of the gluten peptide supports a direct loading mechanism of antigen presentation in extracellular environment, a property that could explain the antigenicity of dietary gluten in celiac disease. 相似文献
Hydrogen bonds exist in many polymer systems and play a large role in the physical and chemical properties. In this study, nylon-6, which consists of repeated amide groups and contains large number of hydrogen bonds, is chosen as an example. Meanwhile, the oxidized unzipped MWCNTs (μCNTs) with oxygenated species such as carboxyl and hydroxyl groups are used as mediator to regulate the crystallization process of nylon-6 thin films. In-site experimental techniques, including Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, and polarized optical microscopy were utilized to get more direct insights on the crystallization mechanism of nylon-6 and μCNTs systems. 相似文献
The increasing demand for high-performance rechargeable energy storage systems has stimulated the exploration of advanced electrode materials. MXenes are a class of two-dimensional (2D) inorganic transition metal carbides/nitrides, which are promising candidates in electrodes. The layered structure facilitates ion insertion/extraction, which offers promising electrochemical characteristics for electrochemical energy storage. However, the low capacity accompanied by sluggish electrochemical kinetics of electrodes as well as interlayer restacking and collapse significantly impede their practical applications. Recently, interlayer space engineering of MXenes by different chemical strategies have been widely investigated in designing functional materials for various applications. In this review, an overview of the most recent progress of 2D MXenes engineering by intercalation, surface modification as well as heterostructures design is provided. Moreover, some critical challenges in future research on MXene-based electrodes have been also proposed. 相似文献