海洋微藻产生的不同粒级溶解有机物质的三维荧光光谱

通过过滤(0.7μm)和切向超滤(100kDa、10kDa、1kDa)技术将实验室内培养的赤潮异弯藻和中肋骨条藻藻液分离成100kDa-0.7μm、10～100kDa、1～10kDa的胶体浓缩液和＜1kDa的超滤液,利用激发-发射矩阵荧光光谱技术测定了不同粒级溶液中有机物的荧光性质,分析了三维荧光光谱图中的荧光峰位置、数量及荧光强度的变化情况.结果表明,两种微藻产生的类腐殖质荧光物质主要是＜1kDa的小分子物质.赤潮异湾藻产生的类蛋白荧光物质中,15%是100kDa-0.7μm的大胶体,8%是10～100kDa的中胶体,而大部分是＜1kDa的小分子物质.赤潮异弯藻各级超滤截留液的类蛋白荧光峰的发射波长与过滤液相比,发生蓝移,而超滤液的则发生红移,表明赤潮异湾藻产生的类蛋白荧光物质随着粒径的增大极性减弱.     

组合MBR系统处理北运河河水的三维荧光分析

在采用三维荧光技术分析组合MBR工程系统处理北运河受污染河水过程中溶解性有机物(DOM)变化的基础上,结合膜组件运行及污染状况、系统对DOC、UVA的去除效果,进行系统对溶解性有机物的去除研究.结果表明,受污染河水DOM中主要的荧光物质有芳香族蛋白质(荧光峰A和B)及类腐殖酸(荧光峰C),其中,A峰与B峰的中心位置分别位于240/380 nm及230/340 nm;经系统处理后,荧光峰的强度降低了21%～59.8%,同时部分芳香族蛋白质的结构也发生了变化.此外,经A段、O段、和膜过滤后的COD、DOC、UVA等值均呈现逐步降低的趋势,且膜的截留作用贡献相对较大.     

基于高光谱反射率的藻类水体基线荧光峰高度与叶绿素a浓度关系研究

采用现场实测和室内培养两种方式测定了甲藻、赤潮异弯藻、叉角藻赤潮和新月菱形藻、海洋蓝绿藻、叉鞭金藻、塔胞藻、扁藻和小球藻等非赤潮藻类光谱曲线。采用度量太阳激发的叶绿素荧光峰高度的基线荧光高度法 ,建立了不同藻类基线荧光高度与叶绿素浓度的关系。基线荧光高度法所用的 3个荧光高度波段分别为 6 6 5nm、6 80nm和86 5nm。在采用线性方程对不同藻类水体基线荧光高度与叶绿素浓度进行回归分析时 ,不同藻类产生了明显不同的结果。其中赤潮异弯藻、海洋蓝绿藻和甲藻为负相关 ,其余为正相关。在正相关的藻类中 ,小球藻最低 ,为 0 .4 6 92。结果偏差主要来自于两个方面 :一是藻类荧光峰位置变化影响 ;二是浮游植物红光和近红外波段高反射率的影响     

元充填碧玺的鉴别特征

碧玺作为一种中高档彩色宝石常常进行充填处理来掩盖裂隙,通过常规宝石学测试、红外吸收光谱和X射线荧光光谱对市场上购买的9粒充填碧玺和2粒天然碧玺进行相关检测。结果表明,充填物质为胶类有机物及含Pb和Bi的玻璃,可以通过折射率值的差异鉴别充填碧玺。胶类有机物充填的碧玺在红外光谱2871cm-1、2961cm-1、和3060cm-1位置有吸收,而Pb和Bi玻璃充填的碧玺在X射线荧光光谱中有Pb和Bi的吸收峰。     

浮游植物活体三维荧光光谱特征提取

测量了6种东海常见的浮游植物在两个温度(20℃,15℃)、三个光照(7000Lux,4100Lux,1100Lux)下的不同生长期的三维激发／发射荧光光谱,研究了光谱特征提取方法。对去除散射干扰后的三维光谱进行了奇异值分解,得到的相应于激发光谱的第一主成分具有区分藻种的能力,可作为三维光谱的特征光谱。分析结果表明,实验条件下,等鞭金藻(Isochrysis galbana)、岛国大扁藻(Platymonas helgolanidica)和中肋骨条藻(Skeletonema costatuma)的特征光谱相似度高,塔玛亚历山大藻(Alexandrium tamarense)、东海原甲藻(Prorocentrum dentatum)和尖刺拟菱形藻(Pseudo—nitzschia pungens)光谱相似度稍差。     

基于高光谱反射率的藻类水体基线荧光峰高度与叶绿素α浓度关系研究

采用现场实测和室内培养两种方式测定了甲藻、赤潮异弯藻、叉角藻赤潮和新月菱形藻、海洋蓝绿藻、叉鞭金藻、塔胞藻、扁藻和小球藻等非赤潮藻类光谱曲线。采用度量太阳激发的叶绿素荧光峰高度的基线荧光高度法，建立了不同藻类基线荧光高度与叶绿素浓度的关系。基线荧光高度法所用的3个荧光高度波段分别为665nm、680nm和865nm。在采用线性方程对不同藻类水体基线荧光高度与叶绿素浓度进行回归分析时，不同藻类产生了明显不同的结果。其中赤潮异弯藻、海洋蓝绿藻和甲藻为负相关，其余为正相关。在正相关的藻类中，小球藻最低，为0．4692。结果偏差主要来自于两个方面：一是藻类荧光峰位置变化影响；二是浮游植物红光和近红外波段高反射率的影响。     

用溶胶—凝胶法研究Ormosils中C60掺杂及其Raman光谱和荧光光谱

利用溶胶－凝胶方法，研究了Ｃ６０在ＫＨ－５６０基Ｏｒｍｏｓｉｌｓ（Ｏｒｇａｎｉｃ Ｍｏｄｉｆｅｄ Ｓｉｌｉｃａｔｅｓ）中的掺杂过程，采用紫外激发的室温荧光光谱和Ｒａｍａｎ光谱分析研究Ｃ６０在有机改性硅酸盐材料中的结构状况，可能因为Ｃ６０受到环境的影响，两个Ｒａｍａｎ峰２７０和１４５９ｃｍ＾－１分裂成另外一些峰，与基质样品相比，Ｃ６０掺杂样品在２１９ｎｍ紫外波长激发的荧光光谱明显不同，发现有６２０，     

甲醇溶液的荧光光谱特性

应用SP-2558多功能光谱测量系统,由Xe灯通过激发光谱仪获得不同波长的紫外光,对不同浓度甲醇溶液在不同波长紫外光激励下产生荧光光谱的特性进行了实验研究。结果表明,甲醇溶液在波长220nm左右的紫外光激励下能产生较强的荧光。荧光峰是310nm至370nm范围的宽谱峰;荧光峰值波长在337nm附近,并随激励光波长增大而产生红移;在同一紫外光激励下,荧光强度随甲醇溶液浓度的增大发生先增强再减弱的变化。根据分子光谱理论,经分析提出,该荧光是由甲醇分子中-OH基团的孤对电子跃迁产生的,荧光光谱的上述特性由电子的跃迁情况决定。研究结果为甲醇作为常用溶剂和重要有机化工原料的应用、检测提供依据。     

烟碱类异黄酮的合成及其性能研究

用红外、核磁、质谱、元素分析仪表征所合成的两个烟碱类异黄酮;研究溶剂及浓度对其荧光光谱的影响,以及其抑茵性能.结果表明,其环己烷溶液荧光强度最大,浓度也有显著影响;且其对大肠杆菌、尤其是对金黄色葡萄球菌有较好的抑制作用.     

基于荧光机理的土壤农药浓度光纤检测系统

根据有机物分子受激发荧光的基本原理,分析了荧光法检测农药的可行性.基于光纤传感技术、荧光分析技术提出了一种能够检测土壤中有机农药浓度的光纤式荧光测量系统.系统以脉冲氙灯为激发光源,以特制的光纤式锥形探头探测荧光,以小型平场光谱仪实现荧光分光,以高速数据采集模块实现荧光信号的采集转换.该系统一次曝光即可获得农药的荧光光谱.利用该系统实现了不同浓度的西维因在土壤中荧光光谱实验,考察了系统的工作曲线和最低检测限.实验结果表明,系统能够获取分辨率较高的荧光光谱;在0.005 mg/kg~0.1 mg/kg范围内荧光强度和浓度基本呈线性关系;系统的最低检出限(LOD)可达0.005 mg/kg,相对标准偏差(RSD)≤3%.该系统能够满足土壤中农药浓度检测的需要.     

Potential impacts of nonalgal materials on water-leaving Sun induced chlorophyll fluorescence signals in coastal waters

It has been suggested that Sun induced chlorophyll fluorescence (SICF) signals could be used to estimate phytoplankton chlorophyll concentration and to investigate algal physiology from space. However, water-leaving SICF is also a product of the ambient light field. In coastal waters both algal and nonalgal materials affect the underwater light field. In this study we examine the independent impacts of varying loads of mineral suspended solids (MSS) and colored dissolved organic materials (CDOM) on water-leaving SICF signals using Hydrolight radiative transfer simulations. We show that SICF signals in coastal waters are strongly influenced by nonalgal materials. Increasing concentrations of CDOM and minerals can reduce the water-leaving SICF per unit chlorophyll by over 50% for the concentration ranges explored here (CDOM = 0 to 1 m(-1) at 440 nm, MSS=0 to 10 g m(-3)). The moderate-resolution imaging spectroradiometer (MODIS) fluorescence line height algorithm is shown to be relatively unaffected by increasing CDOM, but performance is significantly degraded by mineral concentrations greater than 5 g m(-3) owing to increased background radiance levels. The combination of these two effects means that caution is required for the interpretation of SICF signals from coastal waters.     

Fractionation of freshwater colloids and particles by SPLITT: analysis by electron microscopy and 3D excitation-emission matrix fluorescence

This paper reports the first application of a combined approach utilizing split-flow thin-cell (SPLITT) separation to size fractionate natural aquatic colloids and particles collected from freshwater samples. No sample preconcentration was performed although some samples were investigated after alteration of the ambient pH. The unfractionated and fractionated samples were analyzed by scanning electron microscopy (SEM), environmental SEM, and 3D excitation emission matrix fluorescence. Qualitative and quantitative results by microscopy indicated that SPLITT produces well-resolved fractionations at appropriate sizes but with some perturbation of the sample. In addition, tryptophan-like fluorescence was shown to be caused by different organic moieties compared with humic-like and fulvic-like fluorescence. Tryptophan-like fluorescence intensity is found mainly in the particulate material but is not pH dependent, while humic- and fulvic-like fluorescence intensities are dependent on pH but not on size. Fulvic-like fluorescence intensity normalized to absorbance, related to fluorescence efficiency and molar mass, varies with size.     

Validation of Terra-MODIS phytoplankton chlorophyll fluorescence line height. I. Initial airborne lidar results

The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Terra spacecraft contains spectral bands that allow retrieval of solar-induced phytoplankton chlorophyll fluorescence emission radiance. Concurrent airborne laser-induced (and water-Raman normalized) phytoplankton chlorophyll fluorescence data is used to successfully validate the MODIS chlorophyll fluorescence line height (FLH) retrievals within Gulf Stream, continental slope, shelf, and coastal waters of the Middle Atlantic Bight portion of the western North Atlantic Ocean for 11 March 2002. Over the entire approximately 480-km flight line a correlation coefficient of r2 = 0.85 results from regression of the airborne laser data against the MODIS FLH. It is also shown that the MODIS FLH product is not influenced by blue-absorbing chromophoric dissolved organic matter absorption. These regional results strongly suggest that the FLH methodology is equally valid within similar oceanic provinces of global oceans.     

纳米粉末ZrO2-CeO2-La2O3的XRF分析研究

本文用粉末压片法制样,ＸＲＦ分析纳米粉ＺｒＯ２－ＣｅＯ２－Ｌａ２Ｏ３中主,次量元素,研究了纳米粉中颗粒度效应对荧光强度的影响,随着粉碎时间的的延长和压力的增大,元素的荧光强度逐步上升,阳后达到一个坪区,在相同的压片条件下分析不同温度下煅烧的纳米粉,其荧光强度却没有明显的差别,因此,认为,纳米粉的团聚效应是影响元素荧光强度的主要因素。     

纳米粉末ZrO2-CeO2-La2O3的XRF分析研究

本文用粉末压片法制样,XRF分析纳米粉ZrO₂－CeO₂－La₂O₃中主、次量元素,研究了纳米粉中颗粒度效应对荧光强度的影响．随着粉碎时间的延长和压力的增大,元素的荧光强度逐步上升;最后达到一个坪区．在相同的压片条件下分析不同温度下煅烧的纳米粉,其荧光强度却没有明显的差别：因此认为,纳米粉的团聚效应是影响元素荧光强度的主要因素．     

Satellite retrieval of inherent optical properties by inversion of an oceanic radiance model: a preliminary algorithm

A previously published radiance model inversion theory has been field tested by using airborne water-leaving radiances to retrieve the chromophoric dissolved organic matter (CDOM) and detritus absorption coefficient, the phytoplankton absorption coefficient, and the total backscattering coefficient. The radiance model inversion theory was tested for potential satellite use by comparing two of the retrieved inherent optical properties with concurrent airborne laser-derived truth data. It was found that (1) matrix inversion of water-leaving radiances is well conditioned even in the presence of instrument-induced noise, (2) retrieved CDOM and detritus and phytoplankton absorption coefficients are both in reasonable agreement with absorption coefficients derived from airborne laser-induced fluorescence spectral emissions, (3) the total backscattering retrieval magnitude and variability are consistent with expected values for the Middle Atlantic Bight, and (4) the algorithm performs reasonably well in Sargasso Sea, Gulf Stream, slope, and shelf waters but is less consistent in coastal waters.     

Excitation-emission matrix fluorescence spectroscopy for natural organic matter characterization: a quantitative evaluation of calibration and spectral correction procedures

The influence of different data collection procedures and of wavelength-dependent instrumental biases on fluorescence excitation-emission matrix (EEM) spectral analysis of aqueous organic matter samples was investigated. Particular attention was given to fluorescence contours (spectral shape) and peak fluorescence intensities. Instrumental bias was evaluated by independently applying excitation and emission correction factors to the raw excitation and emission data, respectively. The peak fluorescence intensities of representative natural organic matter and tryptophan were significantly influenced by the application of excitation and emission spectral correction factors and by the manner in which the raw data was collected. Humification and fluorescence indices were also influenced by emission correction factors but were independent of reference (excitation) intensity normalization or correction. EEM surface contours were dependent on normalization of the fluorescence intensity to the reference intensity but were not influenced by either excitation or emission spectral correction factors. Authors should be explicit in how excitation and emission spectral correction procedures are implemented in their investigations, which will help to facilitate intra-laboratory comparisons and data sharing.     

Fluorescent nanocrystals as colloidal probes in complex fluids measured by fluorescence correlation spectroscopy

The diffusion properties of fluorescent colloidal CdSe and CdSe/ZnS nanocrystals (QDs) with different hydrophilic coatings were characterized in complex fluids such as actin solutions using fluorescence correlation spectroscopy (FCS). The hydrodynamic radii of the QDs were determined both in organic solvents and water. Attention was given to the potential artifacts arising from the fluorescence properties of the QDs. With increasing excitation intensities, the apparent particle concentration and diffusion times are overestimated if using a simple diffusion model. This can be explained by a numerical simulation. The diffusion behavior of QDs in actin networks of different concentrations was determined to demonstrate the potential use of nanocrystals as probes in soft biological matter. The decreasing diffusion coefficient of the nanocrystals with increasing actin concentration results in an intrinsic polymer viscosity of 0.12+/-0.02 ml mg(-1), in accordance with literature values.     

On-the-fly fluorescence lifetime detection of humic substances in capillary electrophoresis

On-the-fly fluorescence lifetime detection was investigated as a tool for studying humic substances in capillary zone electrophoresis (CZE). Humic substances are complex, heterogeneous mixtures of natural products that tend to migrate in a single, broad CZE peak. The intrinsic fluorescence lifetime of five humic substances from the International Humic Substances Society (IHSS) was monitored using excitation at 488 or 364 nm to produce intensity-lifetime electropherograms for each of the substances. Each frequency-domain lifetime measurement, collected at subsecond intervals during the CZE run, contains the equivalent of a complete decay profile. Lifetime analysis of each decay profile was used to construct a lifetime-resolved electropherogram for each lifetime component, from which the variation in relative intensity contributions of each lifetime across the broad CZE peak could be determined. Absorption spectra, fluorescence excitation-emission spectra, and lifetime profiles of batch solutions of the samples were determined as well. It was found that, whereas absorption and fluorescence spectral characteristics tended to discriminate between humic acids and fulvic acids, the batch solution lifetime profiles discriminated instead between samples from different sources, regardless of fraction. On-the-fly lifetime detection provided a more detailed view of the fluorescence decay of the samples, including greater resolution of lifetimes for two of the fulvic acids and greater discrimination among samples based on lifetime profiles across the CZE peaks.