Thermal chemiluminescence of fibrous proteins

Thermal chemiluminescence (TCL) from the fibrous proteins wool and feather keratin, silk fibroin and Type I collagen is reported for the first time. The proteins all emit TCL when heated in the atmosphere of O₂ or N₂ in the range 40-220 °C. Plotting non-isothermal CL data in O₂ in Arrhenius format showed an increase in the activation energy at temperatures in the range 129-161 °C for each protein. This may indicate that a different free radical oxidation process operates when the mobility of the amorphous phase of the protein is increased above its T_g. Wool, silk and collagen exhibited a luminescence peak at 130 °C (with feather keratin at 145 °C) during non-isothermal CL experiments in N₂, similar to that observed in many synthetic polymers and characteristic of polymer hydroperoxides.     

The effect of dyes on photo-induced chemiluminescence emission from polymers

Weak photo-induced chemiluminescence (PICL) emission is observed when polymers are exposed to UVA or visible light. The presence of dyes can either increase PICL intensity via Type I photosensitisation which generates polymer free radicals, or reduce it via photo-protection. PICL studies on the eight Blue Wool Standards (BWSs) that are used commercially as lightfastness standards show higher PICL intensity from the least photostable BWSs that use triphenylmethane dyes and lower intensity from more photostable BWSs using UVA and visible wavelengths. The relative PICL intensities do not correlate in a stepwise manner with lightfastness ratings of the BWSs. However dye/polymer combinations that emit high levels of PICL relative to the undyed material are unlikely to have acceptable lightfastness. The xanthene dyes fluorescein and eosin Y are more strongly photosensitising than triphenylmethane dyes on wool and both produce higher PICL emission than undyed wool when irradiated with visible light.     

Thermal oxidation of nonstabilized and stabilized polymers and chemiluminescence

The chemiluminescence under isothermal and nonisothermal conditions accompanying the oxidation of some polymers (polyolefins, polyamides, and polysaccharides) has been examined from the viewpoint of its relationship with the rate of oxidation. The chemical structure of a given type of polymer plays a decisive role in the resulting shape of the chemiluminescence curves. In the presence of an antioxidant, the inhibition periods of oxidation are shifted to longer times and/or higher temperatures. This shift is directly proportional to the type and concentration of stabilizer. Attention has also been paid to the impact of the average molar mass on the oxidizability of the macromolecular material. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 648–660, 2004     

Selective chemiluminescence method for monitoring of vitamin K homologues in rheumatoid arthritis patients

Vitamin K is a fat-soluble vitamin involved in blood coagulation and bone metabolism. The detection and monitoring of vitamin K homologues in rheumatoid arthritis (RA) patients is a challenging problem due to the smaller concentrations of vitamin K and the presence of several interfering medications. Therefore, this study aimed to develop a new highly sensitive and selective chemiluminescence (CL) method designated to quantify vitamin K homologues in plasma of RA patients including phylloquinone (PK, vitamin K₁), menaquinone-4 (MK-4, vitamin K₂) and menaquinone-7 (MK-7, vitamin K₂). The method was based on the unique photochemical properties of vitamin K homologues that were exploited for selective luminol CL reaction. The correlation coefficients of 0.998 or more were obtained in the concentration ranges of 0.1-100 ng mL⁻¹ vitamin K homologues. The detection limits were 0.03-0.1 ng mL⁻¹ in human plasma for vitamin K homologues. The developed HPLC-CL system was successfully applied for selective determination of vitamin K homologues in plasma of RA patients. The developed method may provide a useful tool for monitoring vitamin K homologues in different clinical studies such as RA, osteoporosis and hepatocellular carcinoma in which vitamin K is intervented.     

Photo-induced Birefringence of Azo-dye Based on Three-dimensional Opal Photonic Crystals

A series of three-dimensional opal photonic crystals based on the polymer was synthesized and applied in the field of photo-induced birefringence. The data show that the photo-induced birefringence(PIB) of pure Sudan III film could be enhanced by increasing the thickness of azo films. When Sudan III was distributed on the three-dimensional opal photonic crystals, the photo-induced birefringence process could be modulated. In addition, the data also exhibit that the PIB processes with different pumping polarization directions are sensitive to the role of photonic crystals. The results could be beneficial to further understanding the photo-induced birefringence and utilizing the photonic crystals.     

用稳定自由基聚合及光引发聚合制备嵌段共聚物

介绍了稳定自由基聚合的反应原理、引发剂设计，以及用稳定自由基聚合制备嵌段共聚物的几种方法：连续加料法、双官能团引发剂法和一步法。对于光引发聚合的原理及硫自由基的稳定性对聚合反应的影响也进行了讨论。     

Highly sensitive electrogenerated chemiluminescence biosensor in profiling protein kinase activity and inhibition using a multifunctional nanoprobe

We presented a novel electrogenerated chemiluminescence (ECL) biosensor for monitoring the activity and inhibition of protein kinases based on signal amplification using enzyme-functionalized Au NPs nanoprobe. In this design, the biotin-DNA labeled glucose oxidase/Au NPs (GOx/Au NPs/DNA-biotin) nanoprobes, prepared by conjugating Au NPs with biotin-DNA and GOx, were bound to the biotinylated anti-phosphoserine labeled phosphorylated peptide modified electrode surface through a biotin−avidin interaction. The GOx assembled on the nanoprobe can catalyze glucose to generate H₂O₂ in the presence of O₂ while the ECL reaction occurred in the luminol ECL biosensor. At a higher concentration of kinase, there are more nanoprobes on the electrode, which gives a higher amount of GOx at the electrode interface and thus higher electrocatalytic efficiency to the luminol ECL reaction. Therefore, the activity of protein kinases can be monitored by ECL with high sensitivity. Protein kinase A (PKA), an important enzyme in regulation of glycogen, sugar, and lipid metabolism in the human body, was used as a model to confirm the present proof-of-concept strategy. The as-proposed biosensor presents high sensitivity, low detection limit of 0.013 U mL⁻¹, wide linear range (from 0.02 to 40 U mL⁻¹), and excellent stability. Moreover, this biosensor can also be used for quantitative analysis of kinase inhibition. On the basis of the inhibitor concentration dependent ECL signal, the half-maximal inhibition value IC₅₀ of ellagic acid, a typical PKA inhibitor, was estimated, which is in agreement with those obtained using the conventional kinase assay. The simple and sensitive biosensor is promising in developing a high-through assay of in vitro kinase activity and inhibitor screening for clinic diagnostic and drug development.     

Photo-induced Alignment Behavior of Azobenzene-containing Polymer Films with Different Cross-linking Degree

Three series of amorphous copolymers containing azobenzene groups with various substituents and certain amounts of crosslinkable acrylic groups were prepared. The cross-linked polymer films were obtained by thermal polymerization of the acrylic groups in the copolymers, during which, by controlling the time of cross-linking reaction, the films can be made with different cross-linking degree (from 0 to 32%, which was monitored by FT-IR spectra measurement). Photo-induced alignment process of the films was performed under irradiation with linearly polarized light at 442 nm, and the effect of cross-linking degree on the photo-induced alignment rate was investigated. The dynamics of the photo-induced alignment was analyzed with biexponential curve fitting. The photo-induced alignment rate and the maximum transmittance of the films decreased because of the cross-linking. Furthermore, for the cross-linked samples, it was found that their saturated value of transmittances keep constant after repeated "writing" and "erasing" cycles. The findings reveal that the cross-linking of the film can effectively restrain the phototactic mass transport of azopolymer during irradiation by polarized light. The relationship between the cross-linking degree and the photo-induced alignment behavior of azopolymer is discussed in detail.     

TiO2光致双亲性与水性油墨转印的研究

研究了TiO2薄膜作为一种新型印刷材料的浸润性与光照时间和光照强度的关系以及光照时间对水性油墨在薄膜表面吸附的影响,实现了水性油墨由TiO2薄膜向纸张的多次转移.     

Optical coherence tomography image analysis of polymer surface layers in sound-absorbing fibrous composite materials

The material surface layer affecting sound absorption was identified by optical coherence tomography (OCT) image analysis. To characterise this layer, a special algorithm was developed to distinguish the polymer surface layer in thermoplastic composite materials, define its structure and thickness, and specify differences in these properties. The composite materials were obtained by thermal pressing of multilayer systems comprising viscose/polylactide and polylactide nonwoven fabrics, yielding thin polymer surface layers on the order of several hundred micrometres. The results of the measured sound absorption coefficient were analysed together with the OCT results. The use of OCT for the study of materials with specific acoustic characteristics was successfully demonstrated.     

复合物Mg+-S2(CH3)2的光诱导反应

研究了230~440 nm波段复合物Mg+-S2(CH3)2的单光子光诱导反应. 复合物光诱导产物的质谱揭示, 存在着非反应猝灭产物Mg+和反应产物Mg+SCH3. 复合物的光解离光谱由三个对应于离子Mg+(32P←32S)跃迁的宽谱峰构成. 用量化计算中的CIS方法所得的吸收谱理论值与实验值吻合较好.     

荧光素蒽醌甲酯分子内光诱导电子转移及电荷分离态的检测

合成了以荧光素为光敏剂的电子给体-受体二元化合物荧光素蒽醌甲酯(FL-AQ),用吸收光谱、荧光光谱、荧光寿命研究了该化合物在乙醇溶液中的光物理性质,并首次用纳秒级瞬态吸收光谱检测了此化合物分子内光诱导电子转移所形成的电荷分离态.在溶液中激发FL,电子可从FL有效地转移到AQ,其速率常数为3.95×10⁹s^-1,效率为95%.但由于电荷分离态寿命较短,瞬态吸收信号弱,若在此溶液中加入二氧化钛(TiO₂)纳米胶体,使FL-AQ吸附在胶体上,电荷分离态信号明显增强.480nm处FL^+·的寿命为11.1μs;560nm处AQ^-·的寿命为8.93μs.     

Photo-induced flow-injection determination of nitrate in water

A sensitive flow-injection method for the chemiluminescent determination of ultra-low concentration of nitrate in water is presented. Nitrate is on-line photolytically converted to peroxynitrite by absorption of UV light inside of 60 mm long quartz capillary (i.d. 530 µm, o.d. 720 µm). Peroxynitrite is subsequently determined by the chemiluminescent reaction with luminol. The detection limit of nitrate is 7 × 10^?10 M (S/N = 3). The linear range of the method is 2 × 10^?9–1 × 10^?5 M nitrate. The interference of nitrite is eliminated by its conversion to nitrogen after mixing of sample with a solution of sulfamidic acid. Other common anions do not interfere. The interference of cations is eliminated by passing the sample through a cation-exchange column. The FIA procedure allows analysing of 15 samples per hour. The method was applied to the determination of nitrate in various real water samples. The results are in good agreement with a reference ion chromatographic method.     

Electrogenerated chemiluminescence from thiol-capped CdTe quantum dots and its sensing application in aqueous solution

In this paper, the electrogenerated chemiluminescence (ECL) from thiol-capped CdTe quantum dots (QDs) was reported. The ECL emission was occurred at −1.1 V and reached a maximum value at −2.4 V when the potential was cycled between 0.0 and −2.5 V. The reduced species of CdTe QDs could react with the coreactants to produce the ECL emission. The CdTe QD concentration (6.64 × 10⁻⁷ mol L⁻¹) of ECL is lower than that (1.0 × 10⁻³ mol L⁻¹) of chemiluminescence (CL). Based on the enhancement of light emission from thiol-capped CdTe QDs by H₂O₂ in the negative electrode potential, a novel method for the determination of H₂O₂ was developed. The light intensity was linearly proportional to the concentration of H₂O₂ between 2.0 × 10⁻⁷ and 1.0 × 10⁻⁵ mol L⁻¹ with a detection limit of 6.0 × 10⁻⁸ mol L⁻¹. Compared with most of previous reports, the proposed method has higher sensitivity for the determination of H₂O₂. In addition, the ECL spectrum of thiol-capped CdTe QDs exhibited a peak at around 620 nm, which was substantially red shifted from the photoluminescence (PL) spectrum, suggesting the surface states play an important role in this ECL process.     

流动注射化学发光检测盐酸异丙嗪

在碱性介质中,盐酸异丙嗪对luminol-KMnO4发光体系有显著的增强作用.基于此增强作用,建立了一种FI-CL检测盐酸异丙嗪的新方法.在最优化的实验条件下,盐酸异丙嗪的ΔICL强度与其浓度在7.0×10-9~9.0×10-7 mol/L浓度范围内有较好的线性关系.线性方程为ΔICL=35.19+1.19×10-10 c,相关系数r=0.998 4,检出限为4.9×10-9 mol/L.对7.0×10-9 mol/L的盐酸氯丙嗪标准溶液进行11次平行测定,其RSD为2.4%.盐酸异丙嗪加标回收率在89.1%~96.1%之间.     

铽-妥舒沙星的敏化化学发光研究

镧系离子Tb3 能极大增强TSLX Ce(Ⅳ ) Na2 SO3 体系的化学发光强度 ,据此提出了妥舒沙星的敏化化学发光测定妥舒沙星 (TSLX)的新方法。在选定的最佳实验条件下 ,TSLX的浓度在 8.0× 1 0 -9～ 1 .0× 1 0 -5mol L-1 范围内与化学发光强度呈良好的线性关系 ,检出限为 5 .6× 1 0 -1 0 mol L ,对 1 .0× 1 0 -7mol L的TSLX标准溶液进行 1 1次平行测定 ,相对标准偏差为 1 .3 %。     

电化学发光法测定盐酸普鲁卡因

基于盐酸普鲁卡因对鲁米诺在中性介质中铂电极上电化学发光的催化增敏作用 ,建立了测定盐酸普鲁卡因电化学发光新方法。电化学发光强度与盐酸普鲁卡因质量浓度在 4 .0× 1 0 -7～6 .0× 1 0 -6g mL范围内有良好的线性关系 ,检测限为 2 .0× 1 0 -7g mL,相对标准偏差为 4 .4 %。该方法已用于针剂中盐酸普鲁卡因的测定     

流动注射化学发光法测定白藜芦醇苷

基于白藜芦醇苷对Luminol KIO4 H2O2体系化学发光的抑制作用,建立了一种快速测定白藜芦醇苷的流动注射化学发光分析法。测定白藜芦醇苷的线性范围为2.0×10-8～8.8×10-6mol L;检出限为6.7×10-9mol L;相对标准偏差为1.9%(c白藜芦醇苷=4.4×10-7mol L,n=11);采样频率为144次 h。该方法可用于葡萄酒和中药虎杖中白藜芦醇苷的测定。