紫外分光光度计反射光谱法研究

在紫外分光光度计上添置一个自制反射光谱法样品架，利用反射光谱附件进行各种固体粉末样品测定。将样品粉末置于不锈钢薄板的圆孔槽内，加盖一决石英片。将制得的样品架置于反射光谱光路中进行光谱测定。试验结果表明，该方法简便快速，并可回收测试样品，对于昂贵样品更为适宜。     

TIRF-based biosensor for sensitive detection of progesterone in milk based on ultra-sensitive progesterone detection in water

We report on recent advances of our immunoassay for the hormone progesterone in cows milk. Detection is based on total internal reflectance fluorescence (TIRF), the binding-inhibition assay with an immobilized progesterone derivative, and a commercially available monoclonal antibody to progesterone as biological recognition element. The fully automated River Analyzer (RIANA) biosensor for unattended, cost-effective, and continuous monitoring of environmental pollution therefore was adapted for sensitive determination of progesterone in milk. First, the sensitivity and robustness of the existing progesterone assay for water analysis were improved, resulting in a detection limit (LOD) of only 0.2 pg mL^–1 and a quantification limit (LOQ) of only 2.0 pg mL^–1. These extraordinary results are the lowest detection and quantification limits for progesterone determination using biosensors yet reported in the literature. Second, the accurate indicator of ovulation was calibrated and detected in three different types of milk (UHT milk, fresh milk, and raw milk). For commercial milk and randomly procured raw milk nominal levels of progesterone are typically in the range 5–15 ng mL^–1. Limits of detection (LOD) achieved for added progesterone (i.e. spiked samples) were between 45.5 and 56.1 pg mL^–1 depending on milk type. Having in mind the 1:10 dilution factor, these results are still a success. For the first time a commercially available antibody was incorporated into an immunoassay for progesterone detection in bovine milk, giving a detection limit below 1 ng mL^–1 for a fully automated biosensor. Thus the outstanding progress made with this biosensor in environmental monitoring and water analysis has now been successfully adapted to milk analysis for use in the field of reproduction management.Dedicated to the memory of Wilhelm Fresenius.     

稀土铕与2－［（取代苯胺基）羰基］苯甲酸配合物的研究

报道了配合物Ｅｕ（ＸｎＰ）３·３Ｈ２Ｏ［其中Ｘ＝Ｈ，２－Ｃｌ，３－ＯＨ，４－Ｂｒ，３－ＮＯ２，２－ＯＣＨ３，２－ＣＨ３，２，４－二氯；Ｐ＝２－（ＣＯＯ）Ｃ６Ｈ４ＣＯＮＨＣ６Ｈ５－ｎ－，ｎ＝１，２］的制备，并用元素分析，红外光谱，电子反射光谱，热重分析进行了表征。结果表明配位是通过羧酸基上氧原子和酰胺羰基氧原子进行的，含３分子水。通过电子反射光谱，对Ｎｅｐｈｅｌａｕｘｅｔｉｃ比率（Ｂ），平均共价参数（δ）和平均成键参数（ｂ１／２）进行了计算，对配合物的共价成键情况进行了讨论。     

Development of an optical fibre reflectance sensor for p-aminophenol detection based on immobilised bis-8-hydroxyquinoline

2,2′-(1,4-Phenylenedivinylene)bis-8-hydroxyquinoline (PBHQ), a highly sensitive reagent used for the colorimetric determination of p-aminophenol (PAP), was successfully immobilised on XAD-7 and coupled with optical fibres to investigate a sensor-based approach for determining p-aminophenol. The solid-state sensor is based on the reaction of PAP with PBHQ in presence of an oxidant to produce an indophenol dye. The reflectance measurements were carried out at a wavelength of 647 nm since it yielded the largest divergence different in reflectance spectra before and after reaction with the analyte. The linear dynamic range of PAP was found within the concentration range of 0.1-2.18 mg l⁻¹ with its LOD of 0.02 mg l⁻¹. The sensor response from different probes (n = 7) gave a R.S.D. of 4.4% at 1.09 mg l⁻¹ PAP concentration. The response time of the optical one-shot sensor was 5 min for a stable solution. As this PAP sensor is irreversible, a fresh sensor has to be used for each measurement. All the experimental parameters were optimized for the determination of PAP. Using the optical sensing probe, PAP in pharmaceutical wastewater and paracetamol was determined. The effect of potential interferences such as inorganic and organic compounds was also evaluated. Potential on-site determination of PAP with such sensors can indirectly aid detection of organo-phosphorus nerve agents and pesticides in the field by inhibition of acetylcholine esterase-catalyzed hydrolysis of p-aminophenyl acetate to p-aminophenol.     

An Oxysulfide Photocatalyst Evolving Hydrogen with an Apparent Quantum Efficiency of 30 % under Visible Light

Photocatalytic water splitting is a simple means of converting solar energy into storable hydrogen energy. Narrow-band gap oxysulfide photocatalysts have attracted much attention in this regard owing to the significant visible-light absorption and relatively high stability of these compounds. However, existing materials suffer from low efficiencies due to difficulties in synthesizing these oxysulfides with suitable degrees of crystallinity and particle sizes, and in constructing effective reaction sites. The present work demonstrates the production of a Gd₂Ti₂O₅S₂ (λ<650 nm) photocatalyst capable of efficiently driving photocatalytic reactions. Single-crystalline, plate-like Gd₂Ti₂O₅S₂ particles with atomically ordered surfaces were synthesized by flux and chemical etching methods. Ultrafine Pt-IrO₂ cocatalyst particles that promoted hydrogen (H₂) and oxygen (O₂) evolution reactions were subsequently loaded on the Gd₂Ti₂O₅S₂ while ensuring an intimate contact by employing a microwave-heating technique. The optimized Gd₂Ti₂O₅S₂ was found to evolve H₂ from an aqueous methanol solution with a remarkable apparent quantum efficiency of 30 % at 420 nm. This material was also stable during O₂ evolution in the presence of a sacrificial reagent. The results presented herein demonstrates a highly efficient narrow-band gap oxysulfide photocatalyst with potential applications in practical solar hydrogen production.     

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.     

Gonio-spectrophotometric analysis of white and chromatic reference materials

White and chromatic specimens, including barium sulfate plaque, Spectralon, Everwhite and BCRA tiles, which are used as reference materials, were measured by a gonio-spectrophotometer, and from the spectral directional reflectance factor for each geometric condition, colorimetric values were calculated. These specimens were also measured by a spectrophotometer having an integrating sphere, by specular component including and excluding conditions.

From the results of these measurements, at first, the uniformity of angular distribution of reflected light in a near normal direction, when specimens were illuminated from −45° direction, was examined. Then the spatial distribution of reflected light in a near specular direction for −45° incidence was examined. Specularly reflected components from some kinds of surfaces were spread over a considerably wide range from the regular direction.

Finally, luminous reflectance and chromaticity changes with geometric condition were examined, and colorimetric values under the usual geometric conditions, i.e. d/0, D/0, −45/0 and −7/45, were compared.     

利用紫外可见反射光谱鉴定血迹陈旧度

凶杀案的血迹陈旧度与案发时间有着必然联系,推断案发时间对于侦破案件具有重要意义,也是司法鉴定中的一个难题,建立一种快速确定出血时间的方法非常必要。使用UV-2450型紫外可见分光光度计,ISR-240A积分球附件,BaSO₄标准白板参比,测定16 ℃、湿度70%条件下血迹纱布、铝片、玻璃、保鲜膜的8 h内每间隔1 h的反射光谱,同样方法测定24 ℃、湿度70%条件下血迹纱布的反射光谱,利用SPSS软件处理,求出541和577 nm反射率比值（R₅₄₁/R₅₇₇）,进行直线拟合,建立线性回归方程,进行F检验。随着时间的增加,血迹在541和577 nm处的反射率增加,除了带血迹玻璃的R2为0.769外,其余R2均大于0.900,F均大于F_0.05（1,6）=5.59,线性回归模型有显著意义。利用紫外可见光谱仪积分球附件可以实现一定环境载体条件下8 h内血迹陈旧度推断,方法操作简单,不需要对检验对象进行任何处理,保证了其完整性,不影响对其进一步的个人信息等方面的检验,适合司法实践中的需求。     

山东省焦家式金矿区土壤重金属铬高光谱监测研究

矿区土壤环境问题日益突出,以山东省烟台市焦家式金矿区为典型区,系统采集了85个表层土壤样品进行野外光谱实测,其中35份用于重金属铬含量测定。利用光谱变换技术对原始光谱提取了一阶微分、二阶微分和去包络线三种光谱指标,采用偏最小二乘回归法建立光谱数据与铬含量间的定量关系,将最优预测模型应用于其余50个样本点铬浓度值的获取,最终通过克里金插值实现了对研究区土壤重金属铬的快速监测。结果表明,基于一阶微分数据模型预测精度最高,其次为二阶微分,原始光谱和去包络线数据。研究区铬的含量与金矿的分布情况密切相关,即金矿密集区域铬含量更高,这表明金矿开采对土壤中铬的含量与分布存在一定影响。