Simultaneous Determination of Fluorescein, Rhodamine 6G and Rhodamine B in Turbid Solution by Polarization Variable-Angle Synchronous Fluorescence Spectrometry

Polarization variable-angle synchronous fluorescence spectrometry was proposed to determine samples in turbid solution. A mixture of fluorescein, rhodamine 6G and rhodamine B was used to evaluate the technique. The background caused by scattering light was decreased remarkably. The limits of detection were 0.6 ng/ml for fluorescein, 2.3 ng/ml for rhodamine 6G and 4.1 ng/ml for rhodamine B, respectively.

A Spectrometric Setup for Synchronous Total Internal Reflection Fluorescence Measurement at the Solid/Liquid Interface

A spectrometric setup to perform total internal reflection fluorescence (TIRF) and synchronous TIRF measurements at solid/liquid interfaces is presented. The combination of TIRF and synchronous fluorescence was proposed to analyze simultaneously different components at interfaces. The TIRF excitation, emission and synchronous spectra of a watersoluble porphyrin were obtained from water/glass interface using this setup without the existence of a surfactant.

Synchronous Detection of DNA/RNA of Four Shrimp Viruses by Real-time Fluorescence Quantitative RT-PCR

[ Objective] This study aimed to establish a simultaneous detection method of shrimp viruses by real-time fluorescence quantitative RT-PCR, to improve the efficiency of inspection and quarantine. [ Method] A novel real-time fluorescence quantitative RT-PCR assay was established and optimized for simultaneously detecting DNA/RNA of four shrimp viruses （WSSV, IHHNV, TSV and YHV ）. [ Result] The optimized real-time fluorescence quantitative RT-PCR system gener- ated typical amplification curves with high amplification efficiencies （E = 1.06, 1.07, 0.92 and 0.92, respectively）, good hnear relationship （ r = 1 ）, uniform repeatability （ standard deviation = 0.05 - 0.46 ; variation coefficient = 0.26% - 1.62% ） and high sensitivity, exhibiting no significant differences compared with re- al-time fluorescence quantitative PCR （average error of Ct value = 0.04 -0.40; T = 0.53 -2.50; P 〉 0.05 ）. The total detection time was about 1 h. [ Conclusion] The optimized real-time fluorescence quantitative RT-PCR system can be used for rapid detection of WSSV, IHHNV, TSV and YHV.

Fast Evaluation Peanut Oil Quality by Synchronous Fluorescence Spectroscopy and Statistical Analysis

Peanut oil oxidation was to monitor and quantify combining synchronous fluorescence spectroscopy and chemometrics. Peanut oil was subjected to an accelerated oxidation testing. The spectral and related chemical indicators were caught during oxidation induce testing. Fluorescence spectra were gained for each sample with simultaneous excitation from 200 to 800 nm and the offsets (Δλ) of 10 to 180 nm during the oxidation process. The results showed the induce period (IP) of the peanut oil was 16.45 h. Parallel factor analysis (PARAFAC) was performed to select the best Δλ interval of 70 nm, which spectral data was the most suitable for interval partial least square (iPLS) and synergy interval PLS (siPLS) modeling and forecast. The study presented all interval selection methods had the better results than the global spectrum modelling. iPLS reached the best into 10 intervals with a ratio of prediction to deviation (RPD) of 2.10. siPLS that separated the whole spectrum into 15 intervals and combined the third intervals (282 to 320 nm, 362 to 400 nm, and 761 to 800 nm) had a ratio of RPD of 2.26. The results showed the optimal siPLS model performed a little better than iPLS. The established model lying on interval selection could improve the prediction accuracy. It could provide a quick, accurate method to monitor oil oxidation process.

Investigation of binding behaviour of procainamide hydrochloride with human serum albumin using synchronous,3D fluorescence and circular dichroism

Interaction of procainamide hydrochloride（PAH） with human serum albumin（HSA） is of great significance in understanding the pharmacokinetic and pharmacodynamic mechanisms of the drug. Multi-spectroscopic techniques were used to investigate the binding mode of PAH to HSA and results revealed the presence of static type of quenching mechanism. The number of binding sites, binding constants and thermodynamic parameters were calculated. The results showed a spontaneous binding of PAH to HSA and hydrophobic interactions played a major role. In addition, the distance between PAH and the Trp–214 was estimated employing the F？rster＇s theory. Site marker competitive experiments indicated that the binding of PAH to HSA primarily took place in subdomain IIA（Sudlow＇s site I）. The influence of interference of some common metal ions on the binding of PAH to HSA was studied. Synchronous fluorescence spectra（SFS）, 3D fluorescence spectra and circular dichroism（CD） results indicated the conformational changes in the structure of HSA.

Synchronous fluorescence technique and its use in identification of polynuclear aromatic hydrocarbons in urine samples

The synchronous fluorescence spectroscopy of three polymiclear aromatic hydrocarbons was studied. It was shown that the specific Δλ of the spectra were 10nm for benzo(k) fluoranthene, 25 nm for benzo(a) pyrene, and 40 nm for pyrene. The peaks of the spectra were at 407, 404, and 373 nm for the three chemicals, respectively. Benzo(k) fluoranthene, benzo(a) pyrene, and pyrene in the urine samples from smokers were identified by high pressure liquid chromatography combined with the synchronous fluorescence spectroscopy.

THE RAPID DETERMINATION FOR BENZO(a)PYRENE WITH SYNCHRONOUS FLUORESCENCE SPECTROSCOPY SCANNING IN DEFINED RANGE OF DUAL—WAVELENGTHS

A rapid method of determination of BaP in various environmental samples,using synchronous fluorescence spectroscopy scanning in defined range of dual-wavelengths(SFDW)is described in this paper.

Characterization of Anabaena cylindrica Solution System Using Synchronous-Scan Fluorescence Spectroscopy

The characterization of the algae Anabaena cylindrical solution with Fe (III)was investigated using fluorescence emission and synchronous-scan spectroscopy. The ranges ofconcentrations of algae and Fe (III) in aqueous solutions were 5.0 X 10~7-2.5 X10^8 cell/L and 10-60mu mol/L, respectively. The effective characterization method used was synchronous-scanfluorescence spectroscopy (SFS). The wavelength difference (triangle open lambda) of 90 nm wasmaintained between excitation wavelength (lambda_(ex)) and emissionwavelength(lambda_(em)). The peakwas observed at about lambda_(ex) 236 nm / lambda_(em) 326 nm for synchronous-scan fluorescencespectroscopy. The fluorescence quenching in system of algae-Fe( III )-HA was studied usingsynchronous-scan spectroscopy forthe first time, Fe(III) was clearly the effective quencher. Therelationship between I_0/I (quenching efficiency) and c (concentration of Fe (III). added) was alinear correlation for the algae solution with Fe(III). Also, Aldrich humic acid (HA) was found tobe an effective quencher.

Adsorption Behavior of a Water-soluble Porphyrin at the Glass-water Interface as Studied by Synchronous Total Internal Reflection Fluorescence Spectroscopy

Total internal reflection fluorescence spectroscopy (TIRF) and synchronous scanning technique were combined to study the adsorption behavior of the meso-tetrakis (4-sulfonatophenyl) porphyrin (TPPS) at the glass-water interface without any surfactant. The pH dependence of synchronous fluorescence signal at the interface was analyzed. Both unprotonated (TPPS4-) and diprotonated (H2TPPS2-) forms of TPPS were observed at the interface. But the interface favored the adsorption of. The apparent estimated pKa2 value shifted from 5.00 in the bulk solution to 2.7 at the interface. STIRF provides a good technique to study multi-component systems at the interface.

Evaluation of Dissolved Organic Carbon Using Synchronized Fluorescence Emission Spectra and Unsupervised Method of Principal Component Analysis (PCA) and Independent Component Analysis (ICA)

Dissolved organic matter (DOM) can be originated from autochthonous or allochthonous sources, where allochthonous DOM can be from pedogenic sources (humic substances—HSs) or anthropogenicsources (wastewater). The analysis of fluorescence emission, excitation, synchronous or excitation-emission matrix (EEM) have been used to identify the main source or probable contribution of dissolved compounds, such as humic acids (HA), fulvic acids (FA) and dissolved organic carbon (DOC) from sewage, but does not quantify. Fluorescence emission is a powerful technique to detect and qualify organic dissolved compounds but fails in quantitative aspects. In this work, we propose an in situ method for direct determination of DOC using synchronous fluorescence spectra with independent component analysis (ICA). Well known standard solutions were used for method development and validation. In this work, we show that it is possible to predict the number of independent contributions using an unsupervised method based on iterative Principal Component Analysis and Independent Component Analysis (PCA-ICA) approach over combined matrix results. Within these results it’s also possible to see that with a very small amount of independent components it is possible to describe environmental samples of HA, FA and primary productivity (PP).

Study on Fluorescence Property of Sparfloxacin Derivatizing System and its Application

In acid medium, sparfloxacin is oxidized by nitrous acid, then reacts with hydrobromic acid to form a new fluorescence substance, which can emit the strong fluorescence. which is 151 fold more than that of sparfloxacin itself. By this, a new sensitive method for the determination of sparfloxacin in human urine by derivative-synchronous fluorescence is presented with good results.

Simple Synchronous Fluorimetric Method for Determination of Benzo[a] pyrene in Airborne Particulates without a Pre-Separation Procedure

A sensitive analytical method, constant-energy synchronous fluorimetry, has been used to determine benzo[a]pyrene （BaP） selectively in airborne particulates （AP）. A constant-energy difference of 1 400 cm^-1 was selected for obtaining single spectral peak. The method could easily identify BaP in an 18-component polycylic aromatic hydrocarbons（PAHs） mixtures. Calibration plots in methanol solution and in sodium dodecylsulfate （SDS） micellar media show a good linearity （R〉0.999） in the BaP concentration range generally fotund in the environment. The method gives a detection limit of 0.40 nmol/L in SDS micellar medium and 1.34 nmol/L in methanol solution.

Investigation of Interaction of Some Chalcones and Cyclic Chalcone Analogues with Outer Mitochondrial Membrane by UV-VIS and Fluorescence Spectroscopy

Interaction of the synthetic chalcones (1b,1c) and their cyclic analogues (2b,2c) with bovine (BSA) and human serum albumin (HSA) as well as with rat liver mitochondria (RLM) was studied by fluorescence spectroscopy. The maxima of emission fluorescence spectra were changed only in the case of 2b and 2c during interaction with BSA, HSA as well as mitochondrial outer membrane showing a slight hypsochromic shift and decrease of fluorescence. Interaction of the methoxy-(1b,2b) and the dimethylamino-substituted (1c,2c) compounds with outer mitochondrial membrane were studied by fluorescence polarization. Fluorescence polarization of 1b in the presence of the two proteins and mitochondria was found to be unchanged. Under similar conditions (2b,1c,2c) showed continuously increasing fluorescence polarization signal during the 30 minute period of investigations. Since fluorescence polarization supposes that as a result of binding these substances to proteins and lipids. Compound 2c displayed a continuous increase of fluorescence polarization signal in the presence of proteins (BSA, HSA), yeast cytoplasm (YC) and mitochondria (YM and RLM). This compound displayed a significant cytotoxic effect. This pattern of interaction with proteins might be one of the contributing vectors of the observed cytotoxicity against several human carcinoma cell lines.

Qualitative Characterization and Differentiation of Digestates from Different Biowastes Using FTIR and Fluorescence Spectroscopies

Anaerobic digestion of biomasses originates different products, the most abundant of which are methane and carbon dioxide. During this process, a 60-70% organic matter reduction occurs and the final product, the digestate, is charac- terized by high biological stability and high contents of recalcitrant organic molecules and nutrients. In the present work digestates obtained by different mixture of biomasses in a full-scale co-digestion plant operating in Italy were characterized as whole samples without any pre-treatment or extraction by means of Fourier transform infrared spec- troscopy and fluorescence spectroscopy in the synchronous-scan mode and results were compared to those obtained on the single fresh substrates. Biomasses considered were: beef cattle slurry, maize or sorghum silage, agro-industrial residues, olive residues and olive mill wastewater. These substrates exhibited typical spectra related to their different chemical composition. Results obtained on digestates provided evidence of distinctive characteristic of the final product as a function of the different composition of the biomasses loaded into the digestion plant. We concluded that FTIR and fluorescence spectra of digestates produced in a real co-digestion plant “inherit” the main spectroscopic features of the organic wastes from which they are produced. Spectroscopic techniques used in this work succeeded in qualitatively characterizing and differentiating digestates obtained from biomasses of different chemical composition.

Effect of urea on synchronous fluorescence spectra and electrochemical behaviour of cytochrome

The changes of the synchronous fluorescence spectra and the electrochemical behaviour of cytochrome c with the urea concentration are studied. It has been found that with the increase of urea concentration, there occur sequentially the deaggregation of cytochrome c molecules, the increase of exposure extent of the heme group to the solvent, the disruption of Fe-S bond of the heme group and the change in the electrochemical behaviour of cytochrome c. It is suggested that the reason why the electrochemical reaction of cytochrome c is irreversible is that cytochrome c molecules exist in the concentrated solution as oligomers which are electrochemically inactive.

蒲公英中黄酮的响应面法优化提取和同步荧光法检测研究

本试验应用响应面法优化超声-微波协同萃取蒲公英中黄酮的提取工艺,并建立测定黄酮含量的同步荧光法。在单因素试验结果的基础上,以提取溶剂乙醇浓度、微波功率、萃取时间和料液比为自变量,提取液的荧光强度为响应值,设计4因素3水平响应面试验,优化蒲公英中黄酮的提取工艺;单因素试验确定同步荧光法的测定条件。结果表明:1)判定系数R^(2)=0.9648,说明模型与实际结果拟合程度好,所得模型能解释96.48%的响应值改变,校正判定系数(R_(Adj)^(2)=0.9295)与预测判定系数(R_(Pred)^(2)=0.8860)接近。2)响应面法优化超声-微波协同萃取技术提取蒲公英中的黄酮,其最佳提取条件为乙醇浓度50%,微波功率250 W,萃取时间30 min,料液比1∶30(g∶mL)。3)同步荧光法的最佳测定条件为波长差值(Δλ)=55 nm,Al(NO_(3))_(3)浓度0.2%,加入pH=6的醋酸-醋酸钠缓冲液1 mL,室温条件下反应50 min。在最佳测定条件下,测得蒲公英中黄酮的含量为3.52 mg/g。由此可见,响应面法优化提取工艺能较好地用于蒲公英中黄酮的提取,同步荧光法测定黄酮含量的方法干扰少、准确度高。

水相中溶解性有机物的浓度对荧蒽光降解的影响

本文以Suwannee River NOM(SRNOM)和Upper Mississippi River NOM(UMRNOM)两种溶解性有机物(DOM)为研究对象,利用500 W高压氙灯作为光源模拟太阳光,进行室内光解实验,考察了DOM的浓度对水相中荧蒽光降解的影响.研究结果表明,光降解是荧蒽的主要降解途径,荧蒽的光降解符合一级动力学方程.这两种DOM均促进了荧蒽的光降解,并且这两种DOM对荧蒽光降解的促进作用均随着溶解有机碳(DOC)浓度的升高而降低.在DOM存在的条件下,荧蒽的表观光降解速率常数(K)值与两种DOM的DOC(a_(280)和a_(350))均具有显著负相关性,而与E_(2)/E_(3)和荧光强度无显著性相关性.

基于导数-恒基体同步荧光的纺织品中萘胺同分异构体快速定量检测

2-萘胺是纺织品中禁用的一种致癌芳香胺,其与同分异构体1-萘胺(非禁用)的结构、性质相似,传统检测方法在检测纺织品实际样品时可能会造成阳性结果的误判,因此相关检测标准要求采用多种方法对阳性结果进行复查确认。目前常规的复查方法为气相色谱-质谱联用法和高效液相色谱法,存在操作复杂、耗时长等弊端,因此开发一种简单、快速的方法用于鉴别和定量纺织品中的致癌芳香胺及其异构体具有重要意义。导数-恒基体同步荧光法具有灵敏度高、选择性好、可消除背景干扰等特点,已广泛地应用于复杂基质中物质的测定。为了实现纺织品中1-萘胺(1-NA)和2-萘胺(2-NA)的快速鉴别定量,建立了一种导数-恒基体同步荧光分析法。研究确立了一条合适的恒基体同步荧光扫描路径,提高1-NA和2-NA的光谱分辨率;结合一阶导数技术消除背景干扰,得到1-NA和2-NA的净信号。以上两种技术的结合,能够保持较高的灵敏度和选择性,同时避免了耗时的物理分离过程且无需多次扫描。整个光谱的扫描过程可在2分钟内完成。实验结果表明,1-NA和2-NA的检出限分别为0.001 mg/L(相当于纺织品中的0.1 mg/kg)和0.006 mg/L(相当于纺织品中的0.6 mg/kg),远远低于国家标准中规定的限量(20 mg/kg);1-NA的加标回收率在89.1~122.1%之间,2-NA的加标回收率在88.5~111.0%之间,相对标准偏差均小于9.3%;将所提出的方法与HPLC法作统计比较,得到的测试结果之间无显著差异。因此,所提出的方法具有较高的选择性、灵敏度,能够准确、可靠地鉴别和定量2-NA及其同分异构体1-NA,可应用于纺织品中禁用芳香胺的实际检测。

柚皮素、柚皮苷与牛血清白蛋白相互作用的机理分析

采用荧光光谱法对柚皮素(naringenin,NG)、柚皮苷(柚皮素-7-新橙皮苷,naringin,NA)猝灭牛血清白蛋白(bovine serum albumin,BSA)荧光发射的机理进行了研究,并使用分子对接技术获得了NG,NA同BSA之间的结合模型。优化了水浴时间和溶液pH等实验条件,荧光测试结果显示NG,NA浓度与BSA的荧光发射强度呈负相关,并且NG猝灭BSA的程度强于NA。通过分析不同浓度NG,NA猝灭BSA的荧光发射可知,NG与NA猝灭BSA的机理都是静态猝灭,即与BSA形成1∶1型非共价复合物。同步荧光光谱实验结果表明,NG与NA对BSA的Trp残基的影响强于对Tyr残基的影响。分子对接结果表明,在BSA的Trp213残基附近存在一个疏水性口袋,NG可以进入其中并与BSA形成复合物,而NA则结合在BSA表面,无论NA还是NG都与BSA的多个氨基酸残基存在氢键或疏水作用。