引言

正分离性能优异的色谱技术是现代分离测定的重要手段,在食品、药品、医疗、化工、环境、生物技术等领域获得了广泛应用,尤其在食品领域,被称为食品安全检测的最佳利器。由于食品基质复杂、有害物种类繁多、含量范围宽泛等特征,加之有害物结构与形态变化多样、代谢情况复杂,为食品分析带来极大的挑战。近年来,随着色谱、质谱、化学计量学、材料学与生物技术等学科的不断交叉发展,新型分离技术及装置、新型固定相、新型富集净化材料、新型质谱联用技术等不断涌现,为色     

金属酞菁化合物在TiO2表面的分散研究

Dispersion of copper(Ⅱ) phthalocyanine (CuPc), copper(Ⅱ) phthalocyaninesulfonate (CuPcS) and cobalt(Ⅱ)phthalocyaninetetrasulfonate (CoPcTS) on the surface of titanium dioxide was investigated by XRD, XPS, FT-IR and UV-Vis techniques. Results show that interaction between CuPc and TiO2 was very weak and CuPc was difficult to disperse on the surface of the support. While partly sulfurized CuPcS could be dispersed on the surface of support through sulfo-groups and its dispersion capacity was determined to be 0.085 g CuPcS/g TiO2. Completely sulfurlzed CoPcTS could also be dispersed on the surface of TiO2 as a monolayer and its dispersion capacity was 0.12 g CoPcTS/g TiO2. Interactions of the sulfo-groups as well as the electrons of CoPcTS with the surface of TiO2 could be evidenced by FT-IR characterization. Therefore, it was suggested that CoPcTS molecules be adsorbed on the surface of TiO2 in a flat-lying mode while CuPcS in a slanting one. UV-Vis spectra show that the dispersed CuPcS and CoPcTS molecules exist in both forms of monomers and dimers.     

Synthesis of the Biomimetic Polymer： Aliphatic Diamine and RGDS Modified Poly（d,l-lactic acid）

A novel poly（d, /-lactic acid） （PDLLA） based biomimetic polymer was synthesized by grafting maleic anhydride, butanediamine and arg-gly-asp-ser （RGDS） peptides onto the backbone of PDLLA, aiming to overcome the acidity and auto-accelerating degradation of PDLLA during degradation and to improve its biospecificity and biocompatibility. The synthetic copolymer was characterized by FTIR, ^13C NMR and amino acid analyzer （AAA）.     

Structures, stabilities, and electronic and optical properties of c(58) fullerene isomers, ions, and metallofullerenes.

The 1205 classical isomers of fullerene C58, as well as one quasi-fullerene C58 isomer with a heptagonal ring (labeled as Cs:hept) have been investigated by the quantum chemical methods PM3, HCTH/3-21G, and B3LYP/6-31G(d). Isomer C3v:0001, which has the lowest number of adjacent pentagons, is predicted to be the most stable isomer, but the quasi-fullerene isomer Cs:hept is only 2.50 kcal mol-1 higher in energy. Systematic investigations of the electronic properties of C3v:0001 and Cs:hept find that the C3v:0001 isomer has high vertical electron affinity (3.19 eV). The nucleus-independent chemical shifts (NICS) value at the center of Cs:hept (-5.1 ppm) is more negative than that of C60 (-2.8 ppm). The NICS value at the center of the heptagonal ring in Cs:hept (-2.5 ppm) indicates weakly aromatic character. In contrast, the C58(6-) and C58(8-) ions of the C3v:0001 and Cs:hept geometries possess large aromatic character, with NICS values between -14.0 and -26.2 ppm. To clarify the thermodynamic stabilities of C58 isomers at different temperatures, the entropy contributions are taken into account on the basis of the Gibbs energy at the B3LYP/6-31G(d) level. The C3v:0001 isomer prevails in a wide range of temperatures, and the Cs:hept isomer is also an important component around 2800 K. The IR spectra of C58 isomers are simulated to facilitate experimental identification of different isomers. In addition, the electronic spectra and the second-order hyperpolarizabilities are predicted by ZINDO and the sum-over-states model. The static second-order hyperpolarizability of the C3v:0001 isomer is 96.5 % larger than that of C60, and its second-order hyperpolarizabilities at external field frequencies are at least nine times larger than those of C60.     

活性酚醛树脂中羟甲基含量的测定

本文提出一种酚醛树脂中羟甲基含量的化学分析法，分别以＾１３ＣＮＭＲ和化学分析法测定酚醛树脂的羟甲基含量。将两种测试结果与已知的投料量进行比较，证明所建立的化学分析法可行。     

Swelling kinetics and release characteristic of crosslinked chitosan: Polyether polymer network (semi-IPN) hydrogels

The aqueous swelling kinetics of a series of crosslinked chitosan (cr-CS) with glutaraldehyde (GA) interpenetrating polyether hydrogels have been studied as functions of pH, the N-deacetylation degree of chitosan, the amount of crosslinking agent, the electrolyte composition in solution, temperature, and gel composition. Based on these results, the swelling mechanism of the hydrogels was discussed. The release profiles of chlorhexidini acetas from the semi-IPN were also investigated. © 1994 John Wiley & Sons, Inc.     

RESEARCH ON CATALYSTS OF ANTI-CARBON DEPOSITION FOR CH_4 REFORMING WITH CO_2

IntroductionMethaneandcarbondioxidearetWomaincompositionsforthegreenhouseeffectandtheworldglobewanningll].ItisbeneficialtoourlivingenviroIUnenttocontrolthereleaseofthesetwogases.Theconversionofmethanetothecommonfeedstocksynthesisgas(carbonmonoxideandhydro…     

Simultaneous Determination of Oxytetra- cycline, Doxycycline, Tetracycline and Chlortetracycline in Tetracycline Antibiotics by High-Performance Liquid Chromatog- raphy with Fluorescence Detection

A simple, rapid and sensitive high-performance liquid chromatographic method with fluorescence detection for the simultaneous determination of oxytetracycline, doxycycline, tetracycline and chlortetracycline was developed, and successfully applied to the analysis of commercial tetracycline antibiotics. The separation was performed on a reverse-phase C₁₈ column with a gradient elution composed of methanol and sodium acetate buffer (containing disodium ethylenediaminetetraacetate and calcium chloride, pH 8.10) as the mobile phase, and fluorescence detection at 532 nm (excitation at 380 nm). The detection limits for oxytetracycline, doxycycline, tetracycline and chlortetracycline were 0.1, 0.5, 0.3 and 0.4 g L^–1, respectively. Data with respect to precision and accuracy were reported and discussed.     

固相热分解反应最可几机制的判断

固相热分解反应最可几机制的判断高永煜，邹文樵，冯仰婕（华东理工大学化学系上海２００２３７）关键词热分解，动力学方程，反应机制固相热分解反应机制的判断，是热分析动力学中令人感兴趣的领域。常用的方法是从含机制函数的非等温积分动力学方程出发，分别用Ｓｅｓｔ...     

DTA研究二水二草酸合铬酸钾的顺、反异构化

顺—反异构体的研究,在配合物化学中占有重要的地位。二水二草酸合铬酸钾这一配合物顺、反异构体的制备和异构化现象的研究已有报导,但多限于水溶液体系。也有关于该配合物热稳定性和热分解动力学研究的报导但对固相中该配合物异构体转变的研究尚未见报导。本文利用DTA方法,对二水二草酸合铬酸钾顺、反异构体的制备以及固相中异