X-射线荧光光谱分析技术的发展

归纳了X-射线荧光光谱分析技术发展的进程。从现代控制技术的改善、仪器检测性能的提高、元素检测范围的扩大等8方面阐述了波长色散X-射线荧光光谱技术的进展,还就能量色散X-射线荧光光谱仪的X射线管和探测器技术的快速发展及近10年来我国在X-射线荧光光谱分析方法方面的论文发表情况进行了总结,对近年来X-射线荧光光谱仪的发展趋势———手持式、偏振、微束分析等进行了评述,并对其技术的发展方向进行了展望。     

化学发光分析法(Ⅳ) 液相化学发光的测量仪器和技术

本文详细介绍了一般化学发光仪器的基本组成和作用,评价、比较了几种商品仪器的特点。对化学发光技术的最新进展,如化学发光光导纤维探头、定位化学发光探头与色谱联用,以及与微机相结合也作了介绍。     

第一届发光分析会议在西安召开

中国化学会第一届发光分析学术讨论会于1986年8月22日至26日在西安举行。来自高校、科研单位和仪器厂家的99名代表出席会议。会上交流论文52篇,其中大会报告有:“近年来荧光分析在某些方面的进展”(陈国珍教授);“分析化学中的荧光反应”(慈云祥教授);“磷光分析法的发展及应用”(许金钧付教授):“荧光和化学发光光导纤维化学传感器”(章竹君教授);“液相化学发光分析及其应用”(吕九如讲师);“发光免疫分析法在医学上的应用及进展”(蒋滋慧副研究员)。会议期间展出了江苏电分析仪器厂生产的8510型多功能光导纤维光度计、微机控制的流动注射化学发光分析仪、化学发光免疫分析仪,西安无线电八厂生产的YHF-1型液相化学发光分析仪,厦门大学试产的YF-2型荧光分光光度计和HF-1型智能化学发光分析仪。这些仪器的研制为在我国     

四氯化硅中痕量杂质的气相色谱测定法

在长波长光通信研究中,光导纤维中含氢氧基量对光的衰耗有极为严重的影响。制作光纤的主要原料(四氯化硅)中含氢及含碳氢化合物是氢氧基形成的重要原因之一,这方面的研究已引起分析工作者的重视。实验方法与结果 1.仪器与试剂: (1)仪器:英国Pye Unicam204系列色谱仪。氢的测定:热导池检测器(室温),1米×3毫米5A分子筛(30—60目)柱,柱温室     

X—射线荧光光谱法分析保护渣中元素

保护渣元素的定量分析一般采用传统的湿法化学分析 ,化学分析虽然准确度好 ,但难以做到快速且劳动量大。利用 X-射线荧光光谱法分析保护渣中各元素含量是一种快速、准确的分析方法 ,在国外已得到广泛应用。本文从现场分析的实际出发 ,选择融样条件、最佳仪器参数 ,用基准物质合成标准样品 ,绘制标准工作曲线 ,曲线线性良好 ,用化学分析法对荧光分析值进行验证 ,结果符合化学允许差。1　试验部分1 .1　仪器设备、试剂及工作条件MXF2 1 0 0 - X-射线荧光光谱仪TR- AUTO- BEAD- 1 0 0 0 S/W熔融炉混合熔剂 :4g四硼酸钠 +4g四硼酸锂 +0 .…     

紫外/可见光谱在有机光纤研制中的应用

有机光导纤维是近十几年来在新型光功能性高分子材料领域中的一支独秀.相对于玻璃光导纤维,有机光导纤维加工容易、口径大、轻而柔软、抗挠曲、抗冲击、耦合容易,更重要的因素是制作成本低和用途广泛.通常光导纤维是一种带包层的透明圆柱型的细丝.芯子的折射率高于包层并且是不变的,这种纤维称为突变型(SI)光纤.由于SI型光纤的带宽小,不能满足高信息量传输的需要,因而渐变型(GI)有机光纤得以发展.在这种光导纤维中,纤芯的折射率是呈抛物线型分布的,其轴心的折射率最大,折射率由纤维轴心沿径向到包层逐渐变小,在芯/包层界面处折射率无突变,光线在这种光纤的传播路径近似正弦波.沿正弦波处的折射率均小于轴心区的折射率.由于光速是反比于折射率的,因此当光沿着正弦途径传输时,其速度大于光沿着轴心传输的速度.于是,较长的光路被较大的光速所补偿,结果是光在正弦波处的传输时间与在轴心处的传输时间上没有大的区别,而脉冲加宽是正比于传输时间的差值,因此有望在GI型有机光纤中得到较小的脉冲加宽.GI型有机光纤的制备一般可在GI型有机预制棒的基础上通过熔融热拉技术拉制而成.因此,制备GI型有机预制棒及其折射率分布的检测成为关键步骤.折射率分布的测量方法有很多,如近场扫描法、折射近场法、切片干涉法等.本文首次介绍了将紫外/可见吸收光谱应用于预制棒折射率分布的定性测试上,得到了在预制棒芯区沿径向掺杂剂分子溴苯的吸收强度呈抛物线型分布.因测试折射率分布的其他方法较为繁杂以及受仪器的限制,所以利用紫外/可见吸收光谱这一非常普通的仪器来估计折射率分布的情况不失为一种简单易行的方法.     

纸带-光纤技术对硫化氢气体测量的初探

以研制的光导纤维反射分光光度计为仪器,建立了根据浸渍醋酸铅的纸带与硫化氢反应生成黑色硫化铅斑点而改变纸带相对反射率,达到对H2S测量的新方法。测量波长为450nm,测量H2S浓度范围为5×10-8mol/L～1.35×10-6mol/L。方法可用于测量废气中的硫化氢。     

光导纤维化学传感器

光导纤维化学传感器(Fiber Optic ChemicalSensors),又叫光极(Optrode),是八十年代出现的一种灵敏度高,可连续、自动、遥测的微量和痕量分析技术。经过短短几年,已在临床化学和环境监测中得到成功的应用。它是在光导纤维末端载一固定试剂相L,分析操作时将此端插入待测试液,由于试剂同分析组分M之间的相互作用,引起试剂相光学性质变化,通过光导     

聚偏氟乙烯膜光导纤维乙醇传感器的研制

聚偏氟乙烯膜光导纤维乙醇传感器的研制冯业铭１＊康琪２王永志１（１中国矿业大学煤综合利用系徐州２２１００８，２山东矿业学院济南分院化工系济南）关键词乙醇，传感器，聚偏氟乙烯膜，光导纤维１９９６－０３－１９收稿，１９９６－０７－２６修回光导纤维化学传感器...     

光纤动态过程实时监测系统的研制

一、引言光导纤维技术及其应用是当今发展十分迅速的一个研究领域。光导纤维作为一种传输光信号的工具,具有损耗低、抗干扰强、信息承载量大等优点。另外,光纤探头很容易实现微型化,加之其良好的柔软性能和机械性能,为实现原位检测、遥测以及过程控制提供了一种强有力的手段。近年来,大量基于不同机理的光纤传感器的涌现,展示了该技术在分析、检测     

IMMEDIATE PIGMENT DARKENING: VISUAL AND REFLECTANCE SPECTROPHOTOMETRIC ANALYSIS OF ACTION SPECTRUM

Immediate pigment darkening (IPD) occurs in human skin upon exposure to ultraviolet-A and visible radiation. The spectral changes that occur during IPD were measured with a rapid scanning reflectance spectrophotometer (RS) which employs optical fiber bundles for delivery and detection of light between 400 and 750 nm. The radiation dose dependence and wavelength dependence (334-549 nm irradiation) of IPD were studied by both the classical visual grading method and by spectrophotometric scoring using the RS system. The spectral changes that occur at long wavelengths with IPD mimic the natural absorption spectrum of melanin. Therefore, the IPD was scored in terms of the apparent change in melanin optical density, using the method Kollias and Baqer [Photochem. Photobiol. 43, 49-54 (1986)], based on reflectance in the 620-720 nm range. The nonlinearity of the visual grading method is demonstrated. The degree of IPD is first-order with respect to delivered dose and saturates after high doses. The maximum amount of IPD attained at saturation is greater for shorter wavelengths. Extrapolation of the reflectance data suggests the longest wavelength capable of eliciting IPD is about 470 nm.     

A study on the protection to relics and the related problems with diffuse reflectance spectroscopy

The application of diffuse reflectance spectroscopy to relic protection is studied by using a self-made fiber optics reflectance spectrophotometer. The major work done includes: (1) the composition of pigment on colored relics and its changes are identified; (2) the change on metal surface is monitored; (3) the reflectance spectrum characteristics of relic protection materials are studied. The results tell that diffuse reflectance spectroscopy is a new protection technique, characterized by its quickness and non-destructiveness to the relic.     

Fabrication and Characterization of Novel Salicylic Acid Sensors Using Different Reagents (Ferric and Copper)

Abstract

Fabrication of optical fiber salicylic acid (SA) sensors based on immobilization of ferric(III) nitrate and copper(II) acetate on Dowex‐50x8 is presented in this paper. The SA forms a stable purple complex with immobilized Fe³⁺ at pH 2.1 with a response time of 10 min while it forms a stable yellowish green complex with immobilized Cu²⁺ at pH 6.5 with a response time of 8 min. The reflectance spectra of the sensors were measured by using an optical fiber spectrophotometer. The results showed these SA sensors have maximum reflectance at 786 nm and 725 nm for SAFe complex and SACu complex, respectively. The useful dynamic response ranges are 0.02–0.50 g/L (SAFe) and 0.40–1.40 g/L (SACu). These complexes are stable for more than 24 hours. A good reproducibility (0.90%— SAFe; 0.86%— SACu) of measurement was obtained with these sensors.     

Non-invasive identification of surface materials on marble artifacts with fiber optic mid-FTIR reflectance spectroscopy

Research work using a compact and portable fiber optic mid-infrared reflectance spectrometer has been carried out to study surface materials on marble, first on laboratory reference models and then on historical objects. The laboratory research has shown that the complex optical reflectance phenomena of layered samples can be interpreted in terms of the nature of the compounds present (sulfates, oxalates, phosphates, resins, waxes and proteins were studied) even with a very low signal overlapping with the strong carbonate reflectance. The portable instrument was used for in situ examination of the surface condition of two Italian marble works of art: the Deposizione dalla Croce by Benedetto Antelami in the Parma cathedral and the David by Michelangelo in the Galleria dell’Accademia in Firenze.     

In vivo SPECTROPHOTOMETRIC EVALUATION OF NEOPLASTIC AND NON-NEOPLASTIC SKIN PIGMENTED LESIONS–I. REFLECTANCE MEASUREMENTS

Reflectance spectrophotometry from 400 to 800 nm on different cutaneous pigmented lesions, including primary and metastatic malignant melanoma, pigmented nevi, lentigo and seborrhoeic keratosis, has been performed by using an external integrating sphere coupled to a spectrophotometer. Measurements show that reflectance spectra of the different lesions manifest dissimilar patterns, particularly in the near IR region. Comparison of reflectance of nevi with that of malignant melanomas results in a highly significant difference (P less than 10(-6)) between the two samples. Though interpretation of the spectra remains difficult as a result of the complexity of the optical processes of scattering and absorption, our results suggest that a detailed analysis of the reflectance spectrum may give clinically useful information, and could be utilized as an aid in clinical diagnosis of cutaneous pigmented lesions, especially where malignant melanoma is concerned.     

Construction and Evaluation of a LEGO Spectrophotometer for Student Use

A simple visible-wavelength spectrophotometer has been constructed for educational purposes. The spectrophotometer contains simple, inexpensive components students can easily work with (small flashlight bulbs, batteries, etc.) and uses LEGO pieces for construction of the optical support elements. The spectrophotometer was designed to give students hands-on experience with typical spectrophotometer modules so that they may understand the important stages in the design of a scientific instrument. The spectrophotometer was characterized by examining an absorption spectrum and calibration curves of potassium permanganate.     

Optical properties of in vitro epidermis and their possible relationship with optical properties of in vivo skin.

Using a spectrophotometer with an internal integrating sphere, the absorption (mu a) and reduced scattering (mu s') coefficients of in vitro epidermis were evaluated from reflectance and transmittance measurements. mu a and mu s' varied from 24 to 0.2 cm-1, and from 32 to 21 cm-1 respectively, on passing from 400 to 800 nm. Moreover, using an external integrating sphere, the reflectance spectrum of in vivo skin was compared with the reflectance spectrum calculated with a Monte Carlo model, in which the mean values of mu a and mu s' and different anisotropy parameters were used as input data. In vivo results show that the principle of similarity is entirely valid for wavelengths greater than 600 nm and may be considered a good approximation in the 400-600 nm band, and suggest that optical characteristics of in vivo skin may be inferred from reflectance measurements.     

Serial filter method for fluorescence evaluation

A method has been developed to obtain the reflective spectral data, β_R(λ), for a fluorescent sample by making a simple modification to a conventional poly-chromatically illuminated spectrophotometer. To use this procedure, a series of sharp cut-off filters are inserted successively into the illumination beam of the instrument to obtain a number of spectral curves from which the complete reflectance curve is constructed piece-wise. The calculation of the complete reflectance curve is done wavelength-by-wavelength, starting at about 30 nm above the peak emission of the sample and proceeding toward the shortest wavelength cut-off filter, selecting the spectral data that are the lowest value. When the data from each filter are assembled, the long wavelength portion above the peak emission is made equal to the unmodified spectrum. Examples are given of the method of computation and comparison with bi-spectral data. The serial filter technique is equally applicable to instruments having either 45/0 or d/8 integrating sphere optical geometry.     

THE MEASUREMENT OF DIHEMATOPORPHYRIN ETHER CONCENTRATION IN TISSUE BY REFLECTANCE SPECTROPHOTOMETRY

The in vivo quantitation of local photosensitizer concentration is an important problem in photodynamic therapy because tumor response depends on this parameter. This paper describes a new method for measuring dihematoporphyrin ether (DHE) concentration by reflectance spectrophotometry—a technique which could be applied to other photosensitizers. The absorbance due to the 630 nm absorption peak of DHE was determined by obtaining diffuse reflectance spectra before and after the addition of DHE in the form of Photofrin II. Spectra were obtained by placing an optical fiber bundle source and single fiber detectors in contact with the tissue surface. The sensitivity of the technique was measured for three tissues in vitro with a range of optical properties as well as for Nutralipid—a liquid with a very high scattering to absorption ratio. The results were in qualitative agreement with the predictions of a diffusion model of light propagation although a systematic discrepancy was observed. The technique was also successfully demonstrated in vivo for VX-2 carcinomas implanted in rabbit ears by correlating simultaneous absorbance measurements with gamma counting of radiolabeled ^6-4Cu Photofrin II. Our results suggest that reflectance spectrophotometry may be a useful clinical and research tool for the in vivo quantitation of DHE and other photosensitizers.     

Infrared diffuse reflectance instrumentation and standards at NIST

A spectrophotometer system for spectral characterization of materials in the infrared has been built around a bench-top Fourier transform instrument. Its capabilities include the measurement of directional-hemispherical reflectance from 1 to 18 μm. The spectral reflectance measurement is performed with an integrating sphere with an incidence angle of 8°. Both relative and absolute measurements can be made. Several methods can be used to determine the absolute value of the directional-hemispherical reflectance of samples. The primary method used is independent of the integrating sphere theory and the requisite assumptions associated with its use. The calibration of a standard reference material (SRM) is described. This SRM has a reflectance value near 0.9 over the complete calibration range 2–18 μm. As part of the calibration procedure the spatial uniformity of the sphere throughput and the bi-directional reflectance distribution function (BRDF) of the SRM material are evaluated.