双原色发光比色氧传感器

简单、快速进行氧检测的方法一直是人们研究的热点.在众多检测氧的方法中,发光比色法由于简单和可直读的特性受到人们的广泛关注.本文将简单地介绍近几年国内外基于双原色发光比色氧传感器的研究进展,并展望其研究前景.     

State-of-the-art molecular imprinted colorimetric sensors and their on-site inspecting applications

Molecular imprinted colorimetric sensors can realize visual semi-quantitative analysis without the use of any equipment. With the advantages of low cost, fast response, ease of handling, and excellent recognition ability, the molecular imprinted colorimetric sensor shows great application potential in the field of sample rapid assay. Molecular imprinted colorimetric sensors can be prepared in various forms to meet the needs of different sample determination, such as film, hydrogel, strip, and adsorption coating. In this review, the preparation methods for various types of molecularly imprinted colorimetric sensors are systematically introduced. Their applications in the field of on-site biological sample detection, drug detection, disease treatment, chiral substance detection and separation, environmental analysis, and food safety detection are introduced. The limitations encountered in the practical application are presented, and the future development directions prospect.     

Synthesis of aza-crown ether-modified silver nanoparticles as colorimetric sensors for Ba2+

In this paper, we have demonstrated a facile strategy of preparing aza-crown ether (ACE)-modified silver nanoparticles (Ag NPs) by an efficient nano-conjugate technology named dithiocarbamate. This is the first report of using ACE to modify Ag NPs. ACE-modified Ag NPs have a good recognition of Ba²⁺, with the detection limit of 10^? 8 mol/l. It is reasonable to believe that Ba²⁺ induced the self-assembly of Ag NPs by the formation of the sandwich structure with ACE.

     

Highly selective silver nanoparticles based label free colorimetric sensor for nitrite anions

Highly selective label free colorimetric sensor based on AgNPs stabilized by phenolic chelating ligand, N,N′-bis(2-hydroxybenzyl)-1,2-diaminobenzene (1), for NO₂⁻ anions has been developed. Addition of NO₂⁻ showed selective decolourisation of brownish yellow colour of 1-AgNPs with the detection limit of 10⁻⁷ M. Absorption studies showed the complete disappearance of 1-AgNPs peak at 426 nm due to the conversion of AgNPs to silver ions. The presence silver ions were confirmed by white precipitates of AgCl formation with NaCl. The interference studies confirmed the high selectivity of NO₂⁻ sensing in presence of anions as well as cations by 1-AgNPs. A linear relationship was observed between the change of absorption and concentration of NO₂⁻. The present approach could be performed at room temperature and ambient conditions. The practical applications of 1-AgNPs for selective sensing of NO₂⁻ in different water samples such as ground, river, pond and tap water have also been demonstrated.     

Ammonia detection via integrated optical evanescent wave sensors

Detection of ammonia in the gas phase by means of integrated optical components, coated with sensitive films which reversibly change their spectral absorption with ammonia concentration, is demonstrated. The evanescent wave of the guided light continuously probes the absorbance of the sensor membrane at 633 nm. The output intensity is compared with that of a reference channel not influenced by the sensitive film. With Bromocresol Green and Bromophenol Blue in silicone as indicators, ammonia levels of less than 1 ppm are detectable, the dynamic range being from 1 to 200 ppm. The response depends on the relative humidity, and acidic gases including sulphur dioxide, carbon dioxide, and nitric oxides are found to reduce the relative signal change caused by ammonia, whilst in the absence of ammonia they remain inert. Aging of the film is observed within a few months after film preparation.     

Miniaturized measurement system for ammonia in air

The development of a miniaturized ammonia sensor made using microsystem technology is described. Gas is sampled in a sampler comprising two opposite channels separated by a gas permeable, water repellent polypropylene membrane. Subsequently, the acid sample solution is pumped into a selector where an alkaline solution is added to ionize all sampled ambient acid gasses, resulting in an enhanced selectivity. In the selector, the ammonia can diffuse through a second membrane into a purified water stream where an electrolyte conductivity sensor quantifies the resulting ammonium concentration. The realized system is shown to be selective enough not to be influenced by normal ambient carbon dioxide concentrations. Experiments with a gas flow of 3 ml/min, containing ammonia concentrations ranging from 9.8 to 0.3 ppm in a nitrogen carrier flow, into a 15 μl/min sample solution flow and finally into a 5 μl/min purified water stream have been carried out and show that the system is sensitive to ammonia concentration below 1 ppm.     

有机光纤研究进展

综述了近年来有机光纤(塑料光纤) 研究状况, 对有机光纤的分类及适用范围也给予了简单的说明。讨论了影响信号传输的因素和有机光纤光传输损耗的极限, 并对当前受到广泛重视的渐变型有机光纤的研究进展给予了特别的关注。     

Extracoordination sensitivity of tetraphenylporphyrin complexes to gaseous ammonia

The sensitivity of metal tetraphenylporphyrin complexes MTPP (M = Pt^II, Pt^IVCl₂, Re^IVO; TPP is tetraphenylporphyrin) to gaseous ammonia was studied. The gas sensitivity of MTPP is due to the heterogeneous catalytic oxidation of ammonia with the dioxygen ligands in the composition of MTPP. The influence of water vapor on the electrophysical properties of the surface layer of the complexes during adsorption of water and its participation in reactions of the coordinated ammonia and dioxygen were found. Empirical equations relating the conductivity of the MTPP surface layer to the content of water vapor and the concentration of gaseous ammonia were found.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2069–2074, October, 2004.     

Action of gaseous ammonia and water on neodymium diphthalocyanine

The method of flow injection into the gas flow with detection of current resistance of the film was used to investigate the action of ammonia and water vapor on neodymium diphthalocyanine film. The value and sign of the electrophysical response are reversible at 18–22°C. When the film contacts with vapor, the current is changed within a few seconds, whereas the relaxation to the initial value when vapor is removed occurs within tens of seconds. The response parameters are suitable for developing effective sensors based on resistant films. No optical changes in the absorption spectra of the films were observed in the 400–800 nm region under the action of ammonia and water vapor. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1446–1447, July, 1998.     

Novel fused-LEDs devices as optical sensors for colorimetric analysis

The development of a novel, low power optical sensing platform based on light emitting diodes (LEDs) is described. The sensor is constructed from a pair of LEDs fused together at an angle where one LED functions as the light source and the other LED is reverse biased to function as a light detector. Sensor function is based on the level of light received by the detector diode, which varies with the reflectance of the interface between the device and its environment, or the chemochromic membrane that covers the device. A simple microprocessor circuit is used to measure the time taken for the photon-induced current to discharge the detector LED from an initial 5 V (logic 1) to 1.7 V (logic zero). This sensing device has been successfully used for colour and colour-based pH measurements and offers extremely high sensitivity, enabling detection down to the sub micro molar level of dyes.     

A colorimetric and fluorometric fluoride sensor based on a BODIPY-phenol conjugate

A boradiazaindacenes (BODIPY)-phenol conjugate,1,can act as a colorimetric and fluorometric sensor for sensitive and se-lective measurement of F-over AcO-and H2PO-4 in CH3CN. Sensor 1 gives response to F-in a 1:1 ratio via the deprotonation of the phenolic OH proton,which results in color change from pale yellow to light green and quenching of bright green fluo-rescence.     

MOFs传感器在癌症及其生物标志物检测中的应用

癌症是世界上最致命的疾病之一,因此癌细胞的有效捕获和敏感检测对基础研究以及临床诊断和治疗都具有重要意义.基于金属有机骨架(MOFs)的催化活性和固有的发光性能等特点,MOFs已被成功地开发为传感平台实现对癌症及其标志物的检测.综述了基于MOFs的电化学、荧光、电化学发光、比色传感器在癌细胞及核酸、蛋白质等生物标志物检测...     

Novel aroylhydrazine-amide derivatives bearing pyridine core: synthesis,characterisations and selective colorimetric recognition properties

Four aroylhydrazine-amides receptors AR1-4 with a hydrazine spacer have been designed, synthesised and characterised as novel colorimetric chemosensors by typical spectroscopic techniques. The receptors AR1–3 exhibited certainly selectivity and sensitivity towards F^?  and AcO^? , forming 1:1 stoichiometry complex by hydrogen-bond interaction. Furthermore, AR4 has especially shown obvious colour change in the presence of these two important biologically anions.     

Sensitive and selective detection of glutathione based on anti-catalytical growth of gold nanoparticles colorimetric sensor

Gold nanoparticles (AuNps) are often employed in different detection paths based on the catalytic growth mechanism; AuNps could act as catalyst for the reduction of AuCl₄^? and result in the enlargement of the original AuNps. However, there are few probes based on the anti-catalytical growth of AuNps in previous studies. In this article, we proposed a simple colorimetric sensor for the detection of glutathione (GSH) based on the anti-catalytical growth of AuNps, the strong affinity of GSH make it readily combine with AuNps or metal ions (AuCl₄^?), and thus inhibit the catalytical growth of AuNps through the specific property of GSH. Therefore, the UV absorbance of detection system could be used to estimate the concentration of GSH, and the probe exhibits highly sensitive and selective detection of the concentration of GSH with a wide linear from 13 to 800 nM within 20 min. Meanwhile, a good linear relationship with correlation coefficient of R² = 0.9795 was obtained. It is believed that this research could broaden the choices of GSH detection methods.     

A novel anthracene-based fluorescent colorimetric sensor for the simple naked-eye diagnosis of methylmalonic aciduria

A novel molecular sensor using anthracene bearing two amidopyridines emits blue fluorescence in the presence of succinic acid and green fluorescence in the presence of malonic acid, and its fluorescence intensity increased upon binding. Using this molecular sensor, we succeeded in detecting the difference of one carbon atom between succinic acid and malonic acid with the naked-eye. Furthermore, when methylmalonic acid was dissolved in urine to provide a model system for methylmalonic aciduria, the fluorescence changed from blue to green, and methylmalonic acid was successfully detected with the naked-eye.     

Synthesis of polypyrrole films for the development of ammonia sensor

In the present investigation, we have synthesized a polypyrrole films by chemical polymerization technique for the development of ammonia sensor. The polypyrrole films were synthesized in an aqueous acidic medium on glass substrate with mild oxidation of ferric chloride at temperature 29°C. The concentrations (molar) of monomer (pyrrole), oxidant (ferric chloride), and dopant (polyvinyl sulfonate) have been optimized for the uniform and porous surface morphology of the synthesized polypyrrole film. The synthesized films were characterized by scanning electron microscopy, ultraviolet‐visible, and Fourier transforms infrared spectroscopy. Ammonia gas sensing behavior of polypyrrole films was studied by using indigenously developed gas sensing chamber. The synthesized polypyrrole film with optimized process parameters shows excellent and reproducible response to low concentration (100 ppm) of ammonia gas. Copyright © 2007 John Wiley & Sons, Ltd.     

含氟高分子材料在塑料光纤中的应用

近年来含氟高分子材料在塑料光纤中的应用使塑料光纤的各项性能得到了很大的改善.本文综述了当前含氟塑料光纤的研究进展,列举了几类已应用于塑料光纤的含氟高分子以及一些有良好应用前景的新型含氟高分子材料,简单介绍了几种制备塑料光纤的工艺方法.对氟塑料光纤今后的研究方向作了简要的讨论.     

A colorimetric formaldehyde assay

A room-temperature assay of formaldehyde is described. The assay uses few reagents and is colorimetric, read at a wavelength of 649 nm. Tryptophan and tryptamine were noted as interfering with the assay, probably by binding with the formaldehyde. High levels of sugar show smaller effects on final absorbance. Glyceraldehyde also reacts in the assay, but six other aldehyde compounds do not, although they do reduce the absorbance of added formaldehyde.     

Thermal decomposition of immobilized compounds for the generation of gaseous standard mixtures containing ammonia and amines

The thermal decomposition of phthalamic acid derivatives chemically bonded to the surface of silica gel was examined and utilized for the generation of single-component gaseous standard mixtures of ammonia, methylamine, diethylamine and triethylamine. The conditions of the thermal decomposition (temperature, time, diluent gas flow rate) were optimized to ensure complete liberation and rapid elution of the compounds from the bed of modified silica gel. The total amounts of these four compounds that can be released from unit mass of the modified silica gel are in the range of several mg.     

分光光度法测定化肥中有害成份硫氰酸盐

当SCN 浓度 >5mg/L时对植物尤其是农作物就会产生危害 ,因此 ,控制化肥中SCN- 限量十分必要。测定SCN- 的电位滴定法[2 ] 灵敏度高 ,线性范围宽 ,但样品中Cl- /SCN- >1比例 ,会严重干扰测定 ,必须分离。离子色谱、高效液相色谱大多是针对痕量SCN- ( <1mg/L)测定 ,很有效。化学滴定法要求SCN- > 1 % ,且Cl- 干扰也同样需加以考虑。对于SCN- <0 1mg/L ,甚至 μg/L级的测定 ,更多地用动力学光度法[3] ,但分析样品一定要基体少 (如水样 )。且该法对温度、放置时间要求极严格。本文利用Cu2 +、吡啶 (Py)、SCN- 在氯仿中形成稳定的…