罗丹明B荧光猝灭法测定水中痕量亚氯酸根

在有KI存在的乙酸钠-HCl酸性缓冲溶液中,用520 nm光激发罗丹明B(RhB),在580 nm处有一个荧光峰。当有亚氯酸根(ClO-2)存在时,罗丹明B荧光峰发生猝灭。亚氯酸根浓度在0.021 8～0.51 μg·mL-1范围内与荧光猝灭强度成线性关系,据此建立了一个简便灵敏的亚氯酸根荧光分析新方法,用于测定合成水样中(ClO-₂)的分析,结果令人满意。     

多酚与蛋白质相互作用的荧光内滤效应校正方法的选择

用荧光猝灭法研究猝灭剂与荧光供体的相互作用时,内滤效应会使分析结果不准确,需加以校正,其中物理与化学方法存在操作复杂、耗资大等缺点,而数学方法简便快捷,较易推广使用。采用荧光光谱法分析酚类物质与蛋白质的相互作用时内滤效应明显,然而目前针对酚类物质与蛋白质作用的荧光校正,国内外鲜见报道。以柿单宁级分(PT40)、A型连接ECG二聚体和EGCG为多酚化合物的代表,以中华眼镜蛇磷脂酶A₂(PLA₂)为蛋白模型,比较了四种数学公式的校正结果,以经典Stern-Volmer回归方程的K值、线性相关性及截距为评价标准,优选一种适用于多酚物质与蛋白质作用的荧光校正方法,并以PT40-PLA₂为例,分析校正前后的差异。结果表明,用Gauthier等建立的数学公式进行校正后,K值有所降低,线性相关性变好且截距更接近于1,此外用该式对PT40-PLA₂体系进行荧光校正后PT40与PLA₂相互作用的结合常数仅为校正前的60%,且对两者相互作用力类型的判断更加准确,推断该式更适合于多酚与蛋白质作用的荧光内滤效应校正。     

A non-mixing technique for enhancement of the tuning range of Rhodamine 6G using Rhodamine B

An optical scheme for extension of spectral tuning range of Rhodamine 6G by Rhodamine B is reported. The dye solutions are kept separately in a specially designed coupled resonator. The tuning range of Rhodamine 6G dye laser is extended from 564–609 to 564–645 nm.     

Fluorescence of postgrafting Rhodamine B in the mesopores of rodlike SBA-15

Rhodamine B (Rh B) has been grafted into the channels of rod-like mesoporous silica SBA-15, which had been modified by organic silane with terminal amino group in CHCl₃ solvent. The investigations of UV-vis, photoluminescence, and FT-IR confirmed the existence of Rh B in the channels of RSBA-15 (rod-like SBA-15). The composites show strong fluorescence and obvious blue-shift at the yellow wave band compared with Rh B in CHCl₃.     

纳米银组装结构上罗丹明B的表面增强荧光效应

采用表面自组装技术,在玻璃表面构筑银纳米粒子的二维组装结构。银纳米粒子组装结构的表面等离子共振光谱中偶极子表面等离子体共振对组装结构更为敏感而表现出较大位移。组装银纳米粒子可极大增强罗丹明B的荧光。荧光的表面增强效应主要来自银纳米粒子对荧光分子所处区域的局部电磁场增强,银纳米粒子的表面分子修饰对其表面增强效应有较大的影响。     

新型罗丹明酰胺杯芳烃-Sb~(3+)配合物探针对钙离子的响应

合成了一种罗丹明B酰胺-氧杂杯芳烃衍生物1。在以Tris-HCl作为缓冲体系的乙腈溶液(pH7.0)中,化合物1本身无色且无荧光,加入Sb3+后,1的螺环结构打开,观察到显著的荧光增强和颜色变红。再加入Ca2+则导致1-Sb3+配合物的荧光猝灭及红色消失。在此条件下,其他共存离子没有明显响应。因此1-Sb3+配合物可作为检测Ca2+的超分子荧光和比色化学传感器。     

Decolourization of Rhodamine B: A swirling jet-induced cavitation combined with NaOCl

A hydrodynamic cavitation reactor (Ecowirl) based on swirling jet-induced cavitation has been used in order to allow the degradation of a waste dye aqueous solution (Rhodamine B, RhB). Cavitation generated by Ecowirl reactor was directly compared with cavitation generated by using multiple hole orifice plates. The effects of operating conditions and parameters such as pressure, pH of dye solution, initial concentration of RhB and geometry of the cavitating devices on the degradation rate of RhB were discussed. In similar operative conditions, higher extents of degradation (ED) were obtained using Ecowirl reactor rather than orifice plate. An increase in the ED from 8.6% to 14.7% was observed moving from hole orifice plates to Ecowirl reactor. Intensification in ED of RhB by using hydrodynamic cavitation in presence of NaOCl as additive has been studied. It was found that the decolourization was most efficient for the combination of hydrodynamic cavitation and chemical oxidation as compared to chemical oxidation and hydrodynamic cavitation alone. The value of ED of 83.4% was reached in 37 min using Ecowirl combined with NaOCl (4.0 mg L⁻¹) as compared to the 100 min needed by only mixing NaOCl at the same concentration. At last, the energetic consumptions of the cavitation devices have been evaluated. Increasing the ED and reducing the treatment time, Ecowirl reactor resulted to be more energy efficient as compared to hole orifice plates, Venturi and other swirling jet-induced cavitation devices, as reported in literature.     

纳米银粒子对表面吸附罗丹明B的光谱学性质的影响及电解质效应研究

基于贵金属纳米粒子的局域场增强效应,利用透射电子显微镜、紫外-可见分光光度计和荧光分光光度计等分析手段研究了纳米银粒子对表面吸附罗丹明B的光谱学性质的影响以及罗丹明B-纳米银体系中加入电解质离子后,电解质离子与纳米银、染料分子间的相互关系和作用.研究结果表明,当罗丹明B溶液的浓度小于0.6 μmol·L－1时,微量纳米银可使其荧光强度略增加,继续增加纳米银浓度则造成荧光强度下降.当罗丹明B溶液的浓度高于0.6 μmol·L－1时,纳米银总是引起溶液的荧光强度下降.KNO3、KCl、Ca(NO3)2、MgCl2和CaCl2电解质可造成纳米银粒子不同程度的聚集和生长.引起的纳米银粒子的聚集程度关系为:CaCl2>MgCl2>KCl>Ca(NO3)2>KNO3.随着电解质加入量的增加,溶液的荧光强度先下降,而后又逐渐增强,直至达到定值.各电解质对罗丹明B-Ag溶液的荧光强度影响强弱关系为Ca(NO3)2>CaCl2>MgCl2>Cl>KNO3.     

光助Fenton氧化反应降解染料罗丹明B

研究了不同光源条件下光助Fenton反应催化氧化降解有机染料罗丹明B脱色情况及相关机理。内容包括 :不同光源、初始反应溶液酸度、反应时间、Fenton试剂浓度、初始染料溶液浓度等因素对光助Fen ton反应的影响 ,确定了方法的优化条件 ,并讨论了光助Fenton反应的反应机理。研究表明 :在 pH =3 5的条件下 ,4 5 0W高压汞灯照射以及较强太阳光照射的条件均可以明显加快Fenton法催化氧化降解罗丹明B溶液的过程 ,色度脱除率可达到 99%以上 ,COD也得到有效去除     

铂(Ⅳ)-钼酸盐-乙基罗丹明B离子缔合显色反应研究

本文研究了在聚乙烯醇（ＰＶＡ）存在下用钼酸盐与乙基罗丹明Ｂ（ＥＲＢ）形成离子缔合物，该缔合物的最大吸收位于５８０ｎｍ，摩尔吸光系数为１．１２×１０６Ｌ·ｍｏｌ－１·ｃｍ－１，服从比耳定律范围０—２．５μｇ／２５ｍＬ，缔合物至少稳定１周，考察了５０多种共存离子的影响，除生成杂多酸元素和Ａｕ（Ⅲ）、Ｏｓ（Ⅷ）、Ｐｄ（Ⅱ）、Ｉｒ（Ⅳ）外，大多数元素不干扰。测定铂的条件为：〔ＨＣｌＯ４〕＝１．２ｍｏｌ／Ｌ，〔ＭｏＯ４２－〕＝９．１×１０－４ｍｏｌ／Ｌ，〔ＥＲＢ〕＝３．２×１０－５ｍｏｌ／Ｌ，０．０８％ＰＶＡ。缔合物的摩尔比为Ｐｔ（Ⅳ）∶ＥＲＢ＝１∶２，本法已用于铂矿中铂的测定，结果满意。     

光助Fenton反应催化氧化降解罗丹明B表观动力学研究

Fenton反应作为处理难降解有机污染物有效的高级氧化技术之一,其氧化能力来自于在酸性条件下催化分解H₂O₂产生强氧化性(2.8 eV)的羟基自由基。而太阳光照下可促进羟基自由基的产生,从而提高Fenton反应氧化降解能力。文章在初始pH 3.5,太阳光直射的情况下研究了罗丹明B,Fe2+和H₂O₂等因素的初始浓度对光助Fenton反应降解罗丹明B速率的影响,采用求解拟合幂函数动力学方程获得了该反应体系的表观动力学方程。主要研究内容包括：罗丹明B溶液的紫外-可见光谱图;罗丹B溶液的浓度-吸光度工作曲线;不同初始罗丹明B浓度体系反应的分析;不同初始Fe2+浓度体系反应的分析;不同初始H₂O₂浓度体系反应的分析;表观动力学方程参数的计算。实验结果表明,该反应体系的动力学方程为：V=5×10-9P1.28F0.366E0.920,反应总级数为2.57。     

吸收谱交迭的双组分混合液的荧光谱校正研究

荧光内滤效应以及样品池中荧光物质对激发光的吸收分布会直接影响荧光谱的强度和谱形,共同制约荧光分析法的应用。使用吸收谱及荧光谱存在交迭的双组分混合溶液,研究一种新的基于物理吸收模型的校正方法,以校正荧光内滤效应及吸收分布对荧光强度的影响。对三聚噻吩和五聚噻吩混合液的光谱研究表明,使用所述校正方法可以达到较为理想的校正效果, 误差小于5%。     

A combined theoretical and experimental study of the ultrafast photophysics of Rhodamine B

The ultrafast dynamics of zwitterionic and cationic Rhodamine B in ethanol have been investigated using TDDFT calculations and ultrafast transient absorption spectroscopy. The calculations show that the zwitterionic form exhibits an electronically excited dark state which could potentially quench the initially photoexcited state, while in the case of cationic form the lowest excited lying dark state is outside the energy region of interest and cannot explain its quenching. Due to similarities in the relaxation dynamics of the two molecules, it is suggested that the electronically excited dark state may not play such an important role in the quenching process of this dye as previously proposed. Experimental evidence presented suggests that a quenching mechanism is active on the picosecond timescale for both forms of Rhodamine B.     

Combined effect of acoustic cavitation and pulsed discharge plasma on wastewater treatment efficiency in a circulating reactor: A case study of Rhodamine B

The present study investigates the wastewater treatment performance of an acoustic cavitation assisted plasma (ACAP) process in a circulating reactor using Rhodamine B (RhB) as a model water pollution. The concept of this process was proposed by the authors recently for a batch type rector. The measurements revealed that combining the ultrasound irradiation with pulsed discharge plasma allows the RhB degradation efficiency to be drastically increased as compared with the plasma-alone case. This effect is especially significant at higher values of solution electrical conductivity examined in a range of 20 ~ 400 μS/cm. Acidic conditions and larger flow rates of solution were found to be favorable for the degradation efficiency. The effect of flow rate was also analyzed through numerical simulation. The results indicated that the mass transfer of RhB to the plasma-cavitation zone is one of the controlling parameters influencing the degradation performance. Behavior of bubbles and pulse discharge frequency were examined using a high-speed video camera. Relatively large bubbles were found to favor the plasma pulse generation and propagation when move near the high-voltage electrode. On the whole, the results of this study suggest that the ACAP process has the potential to synergistically extend the application area of underwater plasma in both research and industry.     

Effect of Host Medium on the Fluorescence Emission Intensity of Rhodamine B in Liquid and Solid Phase

In this work, we study the effect of concentration, host medium, PH and phase states on the fluorescence emission from the laser dye Rhodamine B pumped by UV laser as exited source. The polymethylmethacrylate PMMA is used as a host medium in case of solid phase samples while, ethanol and Tetrahydrofuran (THF) are used in case of a liquid one. Laser Induced Fluorescence (LIF) technique was used to study the fluorescence properties of both cases of liquid and thin film solid-state samples. In addition, the Dual Thermal Lens (DTL) technique was used to study the quantum yield of these samples. The concentrations of Rhodamine B in ethanol as solvent between 2 × 10⁻² M and 5 × 10⁻⁶ M were studied. The maximum fluorescence emission is observed at concentration of Rhodamine B C = 3 × 10⁻⁴ M. Comparison studies were investigated for different host medium such as ethanol, THF, PMMA in liquid phase state and PMMA in solid phase state. The measurements revealed that, the behavior of both phases state was analogous. Rhodamine B/PMMA thin film sample by ratio of 4:1 and thickness 0.12 mm was found to have the best photostability sample with a quantum yield about ≈0.82.     

基于滤波函数的分立变形镜波前校正效果预估

采用变形镜影响函数对畸变波前的校正过程进行模拟,并利用超高斯滤波函数对模拟的校正效果进行拟合和统计,确定出变形镜交连值与滤波函数平滑因子的定量关系,进而建立和完善了基于滤波函数的分立变形镜波前校正预估模型。在此基础上,针对具有随机畸变波前的环状光束,对波前校正预估模型的有效性和适应性进行了验证和分析。在实际工作中,只要给定分立变形镜的驱动器间距和变形镜交连值,即可利用给出的超高斯滤波函数波前校正预估模型,从而简便而准确地预估变形镜对不同畸变波前的校正效果。     

Fluorescent Carbon Dot as Nanosensor for Sensitive and Selective Detection of Cefixime Based on Inner Filter Effect

Here a simple and sensitive fluorescent assay for detecting Cefixime based on inner filter effect (IFE) has been proven, which is conceptually different from the previously reported CEF fluorescent assays. In this sensing platform, fluorescent carbon dots (CDs) were prepared by one-pot synthesis and was directly used as fluorophore in IFE. The method is based on the complexation reaction between cefixime and palladium ion in the presence of acidic buffer solution (pH 4). The Pd(II)-CEFcomplex was capable of functioning as a powerful absorber in IFE to influence the excitation of fluorophore (CDs). Production Pd(II)-CEFcomplex induced the absorption band transition from 310 to 400 nm, which resulted in the complementary overlap with the excitation spectra of CDs. Due to the competitive absorption, the excitation of CDs was significantly weakened, resulting in the quenching of CDs. The present IFE-based sensing strategy showed a good linear relationship from 0.2 × 10^?6 M to 8 × 10^?6 M (R² = 0.987) and provided an exciting detection limit of 0.5 × 10^?7 (3δ/slope). The proposed method has been successfully applied for the determination of cefixime in raw milk and human urine samples.     

基于石墨相氮化碳量子点直接荧光猝灭法检测碘离子的研究

石墨相氮化碳(g-C₃N₄)荧光纳米材料具有原料便宜、制备容易、荧光量子产率高、光学稳定性好、毒性低等优点,并且避免有机荧光染料复杂的合成步骤或者金属半导体量子点对环境潜在的危害,这些优点使得g-C₃N₄纳米材料成为新兴的荧光探针用于检测金属离子。最近,已有文献报道重金属汞离子能够高灵敏高选择性地猝灭g-C₃N₄量子点的荧光,加入碘离子能够提取被键合的汞离子形成碘化汞(HgI₂)进而恢复g-C₃N₄量子点的荧光,从而建立一种高灵敏检测碘离子的荧光传感器。然而,该方法依然需要重金属汞离子的参与,限制了该方法的推广应用。通过硝酸氧化块体g-C₃N₄并结合水热法处理制备了一种水溶性好、荧光强度高的g-C₃N₄量子点。该量子点的荧光发射波长位于368 nm,且其荧光发射波长不随激发波长的改变而改变,表明该量子点的尺寸比较均一。笔者发现碘离子在220 nm处有一个较强的吸收峰,与该量子点的激发光谱(中心波长245 nm)具有较大的重叠,从而产生内滤效应引起该量子点的荧光发生猝灭。利用这一性质,构建了一种选择性检测碘离子的新型荧光传感器。在最优检测条件下,g-C₃N₄量子点的荧光猝灭强度(ΔF)与碘离子浓度(X,μmol·L-1)在10～400 μmol·L-1之间具有良好的线性关系,线性方程为ΔF=0.325 79X+6.039 05(R2=0.999 5),检出限为5.0 μmol·L-1。通过“混合即检测”并且不需要借助与重金属离子的配位作用就能够检测碘离子,因此该方法具有快速、环保以及操作简便等优点。     

一种便携式快速等离激元增强拉曼光谱检测前处理仪的研制与在食品安全中的应用

便携式拉曼光谱仪在现场快速分析中往往由于现场样品比较复杂,需要处理后才能采用光谱仪进行测定,因此一定程度上限制它的使用。常规实验室前处理虽然行之有效,但是过程繁琐费时,不适合现场使用。本课题组开发了一种便携式快速PERS前处理仪器,具有便携、功耗低、操作简便,提取时间短以及重复性好等特点,能满足现场快速检测的前处理需求。该仪器由超声波提取单元、加热抽气挥发单元、尾气净化与吸收单元以及控制系统四个功能模块组成,并且设有LED控制面板和报警装置。整个工作流程主要包括超声提取、液液萃取和溶剂加热抽气挥发三个环节。以三种实际样品(辣椒粉、辣椒油、豆瓣酱)中的违禁添加剂罗丹明B检测为例,结果表明：与常规实验室前处理方法相比,两种前处理方法对于PERS谱图影响不大,但是检测时间缩短一半。另外,重复性实验检测结果的相对标准偏差(relative standard deviation, RSD)小于±5%。     

Photonics True-Time-Delay Unit for Phased-Array Antenna Using Multiwavelength Fiber Laser Based on a Sagnac Interferemetric Filter

A photonics true-time-delay system for phased array beamforming using a chirped grating-based time-delay element and a novel multiwavelength erbium-doped fiber ring laser source employing a Sagnac filtering mirror is proposed. The Sagnac filtering mirror consists of a polarization maintaining directional coupler and two pieces of polarization maintaining fibers. The lasing wavelength and number are determined by properly adjusting the polarization controller within the unidirectional ring cavity and are very stable. A chirped-grating-based true-time-delay system using the proposed laser source is constructed and demonstrated experimentally.