对辣椒色素某些性能的测试

对辣椒色素某些性能的测试陈连文（河北经贸大学轻工系石家庄０５００６１）刘敬兰（河北师范大学实验中心石家庄０５００１６）关键词分离辣椒色素测定红辣椒属茄科，辣椒属（ＣａｐｓｉｃｕｍｆｒｕｔｅｓｃｅｎｓＬ．），我国各地均有栽培，品种多，资源丰富。内服有开...     

桑枝中桑色素的双安培法在线测定

桑色素是桑枝中的主要成分之一,属黄酮类化合物。该化合物是一种天然的生物活性物质,在自然界分布广泛,具有祛风湿、通血络、消浮肿和抗氧化等多种药理作用。同时,桑色素可与多种金属离子形成配合物作为配体进行分析。目前,有关桑色素的电化学行为及分析应用方法见报道的有高效     

食品中7种常见的非食用色素检测研究进展

食用色素可以明显的改善食品外观,激发食欲,在食品行业有着广泛的应用,但一些不法分子为了牟取暴利向食品中添加非食用色素来代替食用色素,但是非食用色素对人体存在致癌风险。食品中常见的非食用色素有以下7种：碱性嫩黄O、碱性橙II、酸性橙II、苏丹红、罗丹明B、美术绿和孔雀石绿,而目前对这7种非食用色素的检测还未全部建立国家标准。本文综述了近3年来食品行业中针对这7种非食用色素的各种检验方法,以期为食品安全监督监督检测机构提供参考。     

膜富集固相萃取-漫反射光谱法快速测定食品中柠檬黄北大核心CSCD

色素作为食品中常用的添加剂,近年来受到广泛关注。人工合成色素通常较天然色素色彩鲜艳、坚牢度大、稳定性强、价格低廉,所以有着广泛的应用[1]。柠檬黄是人工合成黄色素中具有代表性的一种,其为橙黄色均匀粉末,可溶于水,耐热性、耐光性等均好,被广泛用于饮料、固体食品中,但柠檬黄分子中含有苯环等结构,具有毒性,食品中最大使用量为100 mg·L-1[2]。因此,检测饮料中柠檬黄十分重要。     

聚合色素的研究 XI.蒽醌型聚酯色素的合成与可加工性

用熔融缩聚法合成蒽醌型聚酯色素，研究了色素用量、反应温度和反应时间等对反应的影响，对用所合成聚合色素着色的聚酯的可加工性能作了初步的研究。     

聚合色素的研究：（Ⅴ）PPP—MO在偶氮型可聚合色素单体中的应用

应用自洽场分子轨道理论对１２个可聚合色素单体的λｍａｘ进行了计算，并将其与实测值进行了比较，二者拟合程度较好。关于吡啶酮类色素的ＰＰＰ－ＭＯ的计算结果，理论上证明了吡啶酮型色素单体是以崇体结构存在。文中的参数选取及计算结果为今后偶氮型聚合色单体的分子设计奠定了基础。     

表面带负电荷氨基酸残基的突变对细胞色素bs与细胞色素c结合和识别的影响

利用核磁共振方法研究表面带不同负电荷氨基酸残基突变后的细胞色素b5与细胞色素c的结合与识别，结果表明，静电作用在细胞色素b5与细胞色素c的结合过程中有着重要的贡献，而且这些静电贡献在一定程度上具有 加性，E48的贡献略大于E44。同时还证明Brownian dyanmics simulations优化出的Glu48-Lys13,Clu56-Lys87,Asp60-Lys86和heme 6-propionate-Tml72（细胞色素b5的残基排在前面）的结合方式在溶液中的确存在，细胞色素b5突变体9E48，E56／A，D60／A）及[Cr(oxalate)3]^3－对细胞色素c的表面竞争实验表明，细胞色素c表面结合区SiteⅢ仍然同细胞色素b5突变体9E48，E56／A，D60／A）有结合作用，只是结合强度上相对于野生细胞色素b5同细胞色素c的结合有所降低，这表明除上述的Browni-an dynamics simulations模型外，尚有其它如Salemme模型等的结合方式，这也揭示出细胞色素b5和细胞色素c之间的结合是比较动态的。     

焦糖色素与食品安全

焦糖色素作为食品添加剂,广泛地使用在食品生产与加工中,从化学的角度分析生产焦糖色素时产生致癌物质4-甲基咪唑的可能途径,有助于人们丰富食品化学知识、增强食品安全意识。     

枸杞子中红色素的提取及稳定性

枸杞子中红色素的提取及稳定性伍明，王杰，闪春霞，任仲皎，宋锡瑾，詹国庆（中南民族学院化学系武汉４３００７４）关键词枸杞，色素，液泛提取法枸杞子为茄科枸杞属植物的果实，具有补肾养肝，润肺明目以及调节机体免疫力，抑制肿瘤生长和细胞突变，延缓衰老及抗脂肪肝...     

花菁啶-3-葡萄糖甙的稳定性

蓝靛果可食用，是忍冬属植物，主要分布在长白山和大、小兴安岭地区。全果中花色甙(花菁啶-3-葡萄糖甙)的含量比较高，是理想的制取花色甙类天然色素的原料。其结构式为：     

食用天然色素密蒙黄稳定性分析研究

研究了食品中常见的几种金属离子Na^ 、Cu^2 、Al^3 、Fe^3 、Sn^2 和维生素C、苯甲酸等食品添加剂对食用天色色素密蒙黄稳定性的影响,并对色素的耐碱性和耐热性进行了探讨,结果表明其性能稳定。本研究为密蒙黄色素的开发应用提供了依据。     

Preparation of Cr-Doped YAlO_3 Red Ceramic Pigment and the Coloration Mechanism

The red ceramic pigment is widely used in industrial production, but the pigments with pure color and bright red performance are rare. Therefore, it is important to study and develop new red ceramic pigment with perfect color performance. This paper reports the preparation of Cr-doped YAlO_3 red ceramic pigment rendering by sol-gel method with high temperature resistance, good color and proposed color mechanism. The prepared samples were characterized by XRD, SEM, EDS and UV-vis, and the effects of Cr on the crystal structure, color rendering properties and color mechanism were discussed. The results showed that the optimum concentration of coloring agent(Cr) in Cr:YAlO_3 red ceramic pigment was 3 at.%. The main color mechanism was also discussed. Compared with the solid phase sintering and precipitation methods for the synthesis of red ceramic pigment, the sol-gel method possessed obvious advantages, such as perfect mixing of the raw materials, uniform dispersion of doping ions and the pure color.     

FTIR, magnetic, 1H NMR spectral and thermal studies of some chelates of caproic acid: inhibitory effect on different kinds of bacteria

A convenient method for the preparation of complexes of the Cr3+, Mn2+, Fe3+, Co2+, Ni2+, Zn2+, ZrO2+, UO2(2+), Zr4+ and Th4+ ions with caproic acid (Hcap) is reported and this has enabled 10 complexes of caproate anion to be formulated: [Cr(cap)3].5H2O, [Mn(cap)2(H2O)2], [Fe(cap)3].12H2O, [Co(cap)2(H2O)2].4H2O, [Ni(cap)2(H2O)2].3H2O, [Zn(cap)2], [ZrO(cap)2].3H2O, [UO2(cap)(NO3)], [Zr(cap)2(Cl)2] and [Th(cap)4]. These new complexes were synthesized and characterized by elemental analysis, molar conductivity, magnetic measurements, spectral methods (mid infrared, 1H NMR and UV-vis spectra) and simultaneous thermal analysis (TG and DTG) techniques. It has been found from the elemental analysis as well as thermal studies that the caproate ligand behaves as bidentate ligand and forming chelates with 1:1 (metal:ligand) stoichiometry for UO2(2+), 1:2 for (Mn2+, Co2+, Ni2+, Zn2+, ZrO2+ and Zr4+), 1:3 stoichiometry for (Cr3+ and Fe3+) and 1:4 for Th4+ caproate complexes, respectively, as bidentate chelating. The molar conductance measurements proved that the caproate complexes are non-electrolytes. The kinetic thermodynamic parameters such as: E*, DeltaH*, DeltaS* and DeltaG* are estimated from the DTG curves. The antibacterial activity of the caproic acid and their complexes was evaluated against some gram positive/negative bacteria.     

双吲哚啉螺吡喃化合物的合成及其酸和金属离子致变色性能

设计、合成了一种新型双吲哚啉螺吡喃化合物1,用核磁、红外及质谱等技术手段表征了其结构。 利用紫外可见吸收光谱研究了化合物1的酸致变色和金属离子变色性能。 结果表明,化合物1能够在氢离子或金属离子的作用下发生可逆的开环与闭环反应。 当氢离子或金属离子加入到化合物1的异丙醇溶液中,溶液颜色从无色变为红色,同时产生460 nm新吸收峰。 进一步加入氢氧根离子或EDTA溶液后,溶液颜色变回无色,460 nm处的吸收峰又消失。 该化合物的酸和金属离子致变色性质在分子传感和离子识别等领域有潜在的应用价值。     

Novel small stable gold nanoparticles bearing fluorescent cysteine-coumarin probes as new metal-modulated chemosensors

Emissive molecular probes based on amino acid moieties are very appealing because of their application as new building blocks in peptide synthesis. Two new bioinspired coumarin probes (L1 and L2) were synthesized and fully characterized by elemental analysis, infrared, (1)H NMR, (13)C NMR, UV-vis absorption and emission spectroscopy, matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF-MS), lifetime measurements, and X-ray crystal diffraction. Their sensing ability toward alkaline earth, transition, and post-transition metal ions (Ca(2+), Zn(2+), Cd(2+), Cu(2+), Ni(2+), Hg(2+), Ag(+), and Al(3+)) and their acid-base behavior (H(+), OH(-)) were explored in absolute ethanol by absorption and fluorescence spectroscopy. Compound L1 shows a strong complexation constant with the soft metal ions Zn(2+), Cd(2+), and Ag(+). Compound L2 shows a high fluorescence quantum yield, and it could be used as a non-pH-dependent fluorescent biological probe. Very small gold nanoparticles (AuNPs) using compounds L1 and L2 as stabilizers were obtained by using a reductive method and were characterized by UV-vis, light scattering, and transmission electron microscopy (TEM). Dynamic light scattering and TEM studies show that the formation of small nanoparticles is around 4.27 ± 0.64 nm for L1 and around 2.69 ± 0.96 nm for L2. The new stable Cou@AuNPs behaved as supramolecular chemosensors, which have been selective for the heavy element Hg(2+), with a concomitant change of color from pink to dark red/brown and an increase of size up to 100-fold.     

Simultaneous ion chromatographic separation of anions and cations on poly(aspartic acid) functionalized silica

Poly(aspartic acid)-silica (PolyCAT A), originally designed for the cation-exchange chromatography of proteins, is proposed for the simultaneous ion chromatographic separation of inorganic anions and cations. This is possible owing to the zwitterion-exchange properties of this stationary phase, which are attributed to the presence of both protonated aminopropyl and dissociated carboxylic groups in poly(aspartic acid) attached to the silica. The retention of alkali metal (Li+, Na+, K+), alkaline earth metal (Mg2+, Ca2+), ammonium and inorganic anions (Cl-, H2PO4-, Br-, NO2-, I-, IO3-, NO3-, ClO4-, SCN-) was tested in aqueous solutions of sulfuric, perchloric, sulfosalicylic, citric, oxalic, maleic and aspartic acids with conductimetric detection. The effect of eluent pH, together with the concentration and characteristics of the eluting ions, were studied. Under optimum conditions (0.3 mmol dm(-3) H2SO4-0.2 mmol dm(-3) Li2SO4 eluent), the simultaneous separation of three anions (Cl-, H2PO4-, NO3-) and four cations (Na+, K+, Mg2+, Ca2+), on a PolyCAT A column (200 x 4.6 mm id, 5 microm film thickness) was achieved in 9 min.     

Effects of electron withdrawing and donating groups on the efficiency of tris(2,2'-bipyridyl)ruthenium(II)/tri-n-propylamine electrochemiluminescence

The effects of electron withdrawing and electron donating groups on the electrochemiluminescent (ECL) properties of tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)3(2+) where bpy = 2,2'-pyridine) are reported. The electrochemistry, photophysics and ECL of (bpy)2Ru(DC-bpy)2+, and (bpy)2Ru(DM-bpy)2+ (DC = 4,4'-dicarboxy-2,2'-bipyridine; DM = 4,4'-dimethyl-2,2'-bipyridine) have been studied relative to Ru(bpy)3(2+) in 50:50 (v/v) acetonitrile(CH3CN):H2O (0.1 M KH2PO4), and aqueous solutions. Furthermore, the effects of Triton X-100 (polyethylene glycol tert-octylphenyl ether) on the electrochemical, spectroscopic and ECL properties of these compounds are reported. The anodic oxidation of Ru(bpy)3(2+), (bpy)2Ru(DC-bpy)2+, and (bpy)2Ru(DM-bpy)2+ produces ECL in the presence of tri-n-propylamine (TPrA) in all solvent systems. ECL efficiencies (phi(ecl), photons produced per redox event) of 0.73 and 0.84 for (bpy)2Ru(DC-bpy)2+, and (bpy)2Ru(DM-bpy)2+ were obtained in aqueous buffered solution, using Ru(bpy)3(2+) as a relative standard (phi(ecl) = 1.0). Addition of 0.4 mM Triton X-100 results in a greater than 2-fold increase in ECL efficiences (i.e., 3.8, 2.4 and 2.3 for Ru(bpy)3(2+), (bpy)2Ru(DC-bpy)2+, and (bpy)2Ru(DM-bpy)2+, respectively) using aqueous Ru(bpy)3(2+) containing no surfactant as standard (phi(ecl) = 1.0). ECL efficiencies of 27.4, 16.5 and 26.1 were found in 50:50 (v/v) CH3CN:H2O (0.1 M KH2PO4) for Ru(bpy)3(2+), (bpy)2Ru(DC-bpy)2+, and (bpy)2Ru(DM-bpy)2+, respectively, using aqueous Ru(bpy)3(2+) containing no surfactant as standard (phi(ecl) = 1.0). Detailed studies support adsorption of surfactant on the electrode surface, thus facilitating TPrA and ruthenium oxidation.     

Ion-specific swelling of poly(styrene sulfonic acid) hydrogel

Poly(styrene sulfonic acid) (PSSA) hydrogel was prepared by radiation crosslinking using methyl N,N-bis-acrylamide as crosslinker. Effects of ion species and concentration on the swelling behavior of PSSA hydrogel were investigated in aqueous solution of selected anions (F-, Cl-, Br-, SCN-), cations (Li+, Na+, K+, Ca2+), and hydrophobic ions (tetramethylammonium cation TMA+, tetrabutylammonium cation TBA+, and dodecyltrimethylammonium cation TAB+). The deswelling extent of PSSA hydrogel follows anion Hofmeister series, i.e., SCN- < Br- < Cl- < F-, in solutions containing selected anions and K+ as counterion up to a concentration of 2 mol.L(-1). On the contrary, the deswelling extent of PSSA hydrogel in solutions containing selected cations and Cl- follows the sequence of Li+ < Na+ < K+ < Ca2+, which is the reverse of the Hofmeister series except Ca2+. We have discussed the effects of ions on the hydrogen bonding through SO3- and phenyl ring in salt solutions at low and high concentrations. Other interactions, such as the cation-pi and hydrophobic interactions, also contributed to the ion-specific swelling of PSSA hydrogel. The proposed mechanism was further elucidated by FTIR and NMR analysis. A very specific deswelling-reswelling phenomenon of PSSA hydrogel in KF solution has been observed and ascribed to the F- binding to phenyl ring through a specific interaction.     

A BODIPY-based colorimetric and fluorometric chemosensor for Hg(II) ions and its application to living cell imaging

A new monostyryl boron dipyrromethene derivative (MS1) appended with two triazole units indicates the presence of Hg(2+) among other metal ions with high selectivity by color change and red emission. Upon Hg(2+) binding, the absorption band of MS1 is blue-shifted by 29 nm due to the inhibition of the intramolecular charge transfer from the nitrogen to the BODIPY, resulting in a color change from blue to purple. Significant fluorescence enhancement is observed with MS1 in the presence of Hg(2+); the metal ions Ag(+), Ca(2+), Cd(2+), Co(2+), Cu(2+), Fe(2+), Fe(3+), K(+), Mg(2+), Mn(2+), Ni(2+), Pb(2+), and Zn(2+) cause only minor changes in the fluorescence of the system. The apparent association constant (K(a)) of Hg(2+) binding in MS1 is found to be 1.864 × 10(5) M(-1). In addition, fluorescence microscopy experiments show that MS1 can be used as a fluorescent probe for detecting Hg(2+) in living cells.