Simultaneous determination of malachite green, gentian violet and their leuco-metabolites in aquatic products by high-performance liquid chromatography-linear ion trap mass spectrometry

A method has been developed for the simultaneous determination of malachite green, gentian violet and their leuco-metabolites in various aquatic products using isotope dilution liquid chromatography-linear ion trap mass spectrometry without post-column oxidation. Sample was extracted with McIlvaine buffer and acetonitrile, followed by partitioning with dichloromethane, purified on basic alumina and OASIS MCX SPE column, and finally analyzed by LC-ESI-MS/MS with the select reaction monitoring (SRM) mode. Decision limits (CCalpha, alpha=0.01) and detection capability (CCbeta, beta=0.05) of the method were in the range of 0.02-0.09 and 0.04-0.13microg/kg for MG, GV, LMG and LGV in grass carp, eel, salmon, shrimp and shellfish, respectively, recoveries of MG, GV, LMG and LGV at all fortification levels (0.25-10microg/kg) were from 80.8% to 115.7%, inter-day relative standard derivations were from 1.9% to 18.4%. This method appeared suitable for the control of MG, GV, LMG and LGV residues in aquatic products.     

Anion-directed assembly: Framework conversion in dimensionality and photoluminescence

Six novel Ni(II)-fluconazole complexes formulated as (C₁₃H₁₁N₆OF₂)₂Ni₂(NO₃)₂ (1), (C₁₃H₁₂N₆OF₂)₂Ni(NO₃)₂·H₂O (2), (C₁₃H₁₂N₆OF₂)Ni(SO₄)(DMF)₂(H₂O) (3), (C₁₃H₁₂N₆OF₂)₂Ni(H₂O)₂(SO₄)·4H₂O (4), (C₁₃H₁₂N₆OF₂)₂NiCl₂·2(CH₃OH) (5), (C₁₃H₁₂N₆OF₂)₄Ni₂ (MoO₄)₂·6H₂O (6) have been hydrothermally or solvothermally synthesized under similar conditions except different anions and solvents. They are structurally characterized by elemental analysis, IR, TG and single crystal X-ray diffraction. Complex 1 is a molecular binuclear nickel cluster. Complex 2 exhibits a one-dimensional (1D) chain linked by double-stranded fluconazole-bridge. Complex 3 shows a novel 1D chain linked by double-stranded fluconazole-bridge and double-stranded SO₄²⁻-bridge. Complex 4 shows a three-dimensional (3D) architecture and SO₄²⁻ anions occupy the cavity. Complex 5 exhibits a two-dimensional (2D) structure constructed by alternating left- and right-handed helices. Complex 6 exhibits a 3D architecture, in which the 2D layers are pillared by {MoO₄} tetrahedra. Complex 2 can be irreversibly converted to complex 1 in the presence of DMF (N,N′-dimethyllformamide). Complexes 1, 3 and 6 show antiferromagnetic interactions between the nickel (II) ions The photoluminescence properties of the six complexes indicated that the introduction of different anions can enhance or weaken the intra-ligand transitions of fluconazole.     

Recognition of alkyl ketone molecules based on thickness-shear-mode acoustic sensors with calixarene derivatives

The frequency response characteristics for twenty-two organic vapours by piezoelectric thickness-shear-mode (TSM) acoustic wave sensors coated with four supramolecule compounds—calixarenes have been investigated. Among them, 2,8,14,20-tetraethyl-4,6,10,12,16,18,22,24-octahydroxylcalix[4]arene (I) was the most efficient actively adsorptive material for host-guest recognizing alkyl ketone molecules such as 2-butanone and acetone. The supramolecule recognition mechanism has been discussed, that is based on the formation of C-H?π bond interaction between the methyl group of ketone molecule and the phenyl ring of the calixarene compound. The linear range of the TSM sensor upon exposure to 2-butanone vapour was 0-940.5 ppm with a detection limit of 2.67 ppm when the coating mass of the compound I was selected as 19 μg. The kinetics behaviours in the adsorption and desorption processes have been examined with polynomial curve fitting procedure. Furthermore, the proposed TSM sensor possessed good selectivity, reversibility, reproducibility and high stability. Compared with gas chromatography (GC) method, the proposed sensor can be used for on-line determination of 2-butanone vapour in air with a recovery of 94.8-106.5%, which was in consistent with those obtained by GC method.     

pH-controlled construction of chitosan/alginate multilayer film: characterization and application for antibody immobilization

In this work, a chitosan/alginate multilayer film was constructed via layer-by-layer self-assembly and studied by in situ surface plasmon resonance monitoring and contact angle measurements. The results demonstrate that the surface composition of the self-assembled multilayer film can be simply tailored through pH control during the assembly process. The biological property of the assembled film was further characterized via antigen-antibody interactions, showing that the loading capacity of the antibody on the multilayered film and the binding activity of the antigen to the immobilized antibody could be also well-tuned by pH control. This work can provide more scientific insight in the interaction between protein and polymer matrix and render a novel simple approach to build high-performance biointerfaces through pH control for potential applications of highly sensitive immunosensors.     

相干态直积空间中的置换算符

本文用相干态方法导出了相干态直积空间中的一类置换算符,给出了它们的正规序形式和显式形式,并讨论了置换算符的一些性质。     

单片微机系统时钟软件的一种实现方法

本文介绍一种用MCS—51汇编语言设计的单片微机系统时钟软件。该软件所需的中断服务时间短,因而不影响CPU进行其他实时性较高的处理工作,该软件还能提供时间显示功能,文中给出了相应的显示硬件结构。     

十水硫酸钠体系潜热蓄热材料的研究

本文研究了 十水硫酸钠 体系潜热蓄热及其熔冻行为,并对熔化热的测定技术及计 算 公式进行 了研 究.该 蓄热材料经 15。。次熔冻循环后,蓄热客量仍在 30 C al·g一`以上.     

峰宽法快速测定程序升温脱附活化能

TPD技术^[1]已成为研究固体表面性质的重要手段,本文在总结前人工作的基础上考察了TPD谱峰峰宽和相应参数与脱附活化能(E_d)之间的变化规律,证明用任意峰宽法或半峰宽法测定E_d值有很好的实用性,该法直接运用TPD谱图参数,无需另外作图,故十分快速、简便,与其它方法比较,结果吻合。     

宏观速度对电弧螺旋不稳定性影响的数值分析

采用抛物型电导率和与时间有关的线性微扰理论,给出了有宏观速度存在的热势分布(温度分布)、稳定性条件以及不稳定性增长率等定量结果。     

氯丙基键合硅胶固定相色谱性能与应用 I.二取代苯及前列腺素差向异构体的分离

研究了氯丙基键合硅胶固定相的高效液相色谱性能和在分离二取代苯异构体、前列腺素差向异构体方面的应用,探讨了流动相组成、性质、ｐＨ值等对溶质保留和分离的影响,讨论了溶质保留机理和最佳色谱分离条件。对上述异构体进行了良好的分离,而且分离速度比一般的反相色谱体系要好。