胃蛋白酶对CdTe纳米粒子的表面修饰及分析应用

以巯基乙酸为稳定剂和表面修饰剂, 在有机相中合成了平均粒径为3 nm左右的CdTe纳米粒子, 用胃蛋白酶改变纳米粒子的表面修饰状态并研究其系列特性. CdTe纳米粒子在320 nm处有强的紫外吸收, 在524.8 nm处有荧光发射. 经胃蛋白酶对其表面修饰后, 紫外吸收峰位不变, 但吸光强度升高, 荧光峰位蓝移至467.2 nm, 荧光强度降低. 温度、pH值及离子强度均对表面修饰产生影响. 在最佳实验条件下, 胃蛋白酶质量浓度在4—40 mg/L范围内与荧光降低值之间呈线性关系, 检测限(3σ)为0.28 mg/L(n=10), 该方法已被用于人体胃液胃蛋白酶的测定.     

CdSe量子点的合成及标记胃蛋白酶的研究

以硒粉及镉盐为反应前体,通过固相/液相沉淀反应及室温乙二胺溶剂体系两种方法合成了平均粒径为8～10nm的CdSe量子点,以巯基乙酸修饰量子点使之可溶,并标记胃蛋白酶。CdSe量子点在350和380nm附近有明显尖锐的紫外吸收,有481.6nm的荧光带边发射,标记胃蛋白酶后,紫外吸收峰位不变而吸光度增强,荧光峰位蓝移至467.2nm,荧光强度降低。在最佳实验条件下,胃蛋白酶浓度在5～50mg/L范围内与荧光降低值之间呈线性关系;检出限(3σ)为0.36mg/L(n=10),方法已用于人体胃液胃蛋白酶的测定。     

玛卡荧光碳点的合成及用于苦味酸的荧光检测

以玛卡为碳源,采用水热法制备荧光碳点。碳点水溶液在激发波长为315 nm时,最大荧光发射波长为425 nm。在玛卡荧光碳点的磷酸盐缓冲液(0.2 mol/L,pH 5.8)中,加入苦味酸,其荧光被猝灭,基于此建立了以玛卡荧光碳点为荧光探针测定苦味酸的方法。本方法检测苦味酸的线性范围为0.4~80 mmol/L,相关系数为0.9978,检出限为110 nmol/L(S/N=3),本方法线性范围宽、灵敏度高、响应快(2 min内),选择性和抗干扰能力良好。用于实际水样中苦味酸的检测,加标回收率为92.0%~110.0%,结果令人满意。     

诺氟沙星荧光光度法测定微量Al(Ⅲ)

铝对荧光试剂诺氟沙星有强的荧光增强作用,据此建立了测定微量铝的荧光分析方法。选择最大激发与发射波长分别为278 nm和441 nm,在pH 4.10的HAc-NaAc介质中,诺氟沙星的荧光强度变化与Al(Ⅲ)浓度呈良好的线性关系,线性范围为7.00×10-6~1.00×10-3mol/L,检出限为2.00×10-8mol/L,常见的共存离子不干扰测定。本方法已用于实际样品中Al(Ⅲ)的测定。     

酶荧光毛细管分析法测定微量血清中乳酸脱氢酶活性

基于丙酮酸/还原型辅酶I/乳酸脱氢酶(LDH)/乳酸/氧化型辅酶I荧光猝灭体系和荧光毛细管分析技术,建立了可用于微量样品中LDH酶活性测定的方法。优化的测定条件为:激发及发射波长分别为350和460nm;测定温度为25℃;酸度为pH 6.5;NADH浓度为300μmol/L;丙酮酸浓度为1.2mmol/L。本方法的测定范围为50～1500IU/L,检出限为30IU/L,相对标准偏差2.1%～2.2%(n=10),回收率在96.4%～105%范围内。本方法操作简单,每次测定仅需样品2.0μL、试剂18.0μL,分析速度约为30样/h,利用本方法测定了微量血清中LDH的活性。     

高效液相色谱法测定美白面膜中7种荧光增白剂

建立了同时测定美白面膜中7种荧光增白剂的高效液相色谱-荧光检测(HPLC-FLD)法。样品经乙腈超声提取后,经Eclipse XDB-C18色谱柱分离,以甲醇-25mmol/L乙酸铵溶液为流动相,梯度洗脱,在激发波长365nm、发射波长430nm进行测定。结果表明,FWA 85和FWA 71以及其他5种荧光增白剂分别在5~35mg/L和0.025~4mg/L的浓度范围内呈良好的线性关系,线性相关系数大于0.991;方法的检出限(S/N=3)为0.00071~0.18mg/L,定量限(S/N=10)为0.12~12.24μg/g。3种不同添加水平下的样品加标平均回收率为93.62%~115.87%,相对标准偏差为0.43%~5.40%。该方法简便、灵敏、准确,可用于美白面膜中7种目标荧光增白剂的同时测定。     

探针JDC-108测定生物样品中的蛋白质

在模拟人体生理条件下,基于JDC-108与人血清白蛋白(HSA)相互作用生成复合物,导致血清白蛋白的内源荧光产生特异性变化,而建立了以JDC-108为分子探针,用固定波长同步荧光光谱分析测定蛋白质的新方法。体系同步荧光光谱特征及强度受Δλ、反应介质、反应温度等因素的影响。在20℃、Tris-HCl缓冲液(pH=7.40)及离子强度为0.1 mol/L的NaCl溶液中,体系的Δλ为20 nm的同步荧光强度(ISF)与人血清白蛋白在2.0~497 mg/L的浓度范围内呈良好的线性关系;检出限为0.76 mg/L(n=11)。本实验对血清、尿样和唾液样品进行了测定,回收率在97.7%~103.4%之间。实验结果表明:本方法具有简单、快速、灵敏度较高、线性范围宽、精密度和回收率较好等优点,可直接用于生物样品中蛋白质总量的测定,结果令人满意。     

硫堇与DNA相互作用及DNA光散射/荧光比率测定方法

在pH4.56的BR缓冲溶液中,DNA能使硫堇的光散射增强,荧光发生猝灭。本实验基于硫堇的三维光谱讨论了其发光属性,并通过在普通荧光光度计上单次扫描同时获得的539nm处的光散射强度(I539)与630nm处的荧光强度(F630)之比,建立了测定痕量DNA的光散射/荧光比率法。当硫堇的浓度为1.0×10-4mol/L时,方法的线性范围为0.1~1.6mg/L,检测限为(3σ)为12.0μg/L。将所建立的方法用于DNA合成样品的测定,回收率为94.9%~107.0%,相对标准偏差小于3.0%。     

荧光光度法测定血清中碱性磷酸酶

合成了一种新的底物水杨酸磷酸酯 (SP),用于荧光光度法测定血清中碱性磷酸酶(ALP)活力.在37.0 ℃的Tris-HCl缓冲液(pH 9.0)条件下, 碱性磷酸酶作用于荧光底物SP,水解生成强荧光产物水杨酸(SA),生成的SA的量与参与反应的ALP 的活力成正比.据此建立了荧光光度法测定血清中碱性磷酸酶活力的新方法.测定碱性磷酸酶的线性范围是0.03～6.00 U/L,检测限为7.04 mU/L.本方法适用于血清中碱性磷酸酶的测定.测定结果与临床上常用的以对硝基苯磷酸酯为底物的分光光度法相比,无显著性差异.     

以Eu（Ⅲ）作荧光探针时间分辨荧光法测定吡哌酸

建立了一种以Eu(Ⅲ)作为荧光探针,时间分辨荧光法测定吡哌酸的新方法。吡哌酸和Eu(Ⅲ)配合后在受到紫外光激发时发生分子内能量转移,配合物发射铕离子的特征荧光。以荧光强度进行条件优化,结果表明,在pH 8.2的缓冲溶液中,加入适量阴离子表面活性剂十二烷基硫酸钠(SDS)后,体系荧光强度大大增强。方法的检出限(3σ)为2×10-8mol/L,测定精度RSD为0.62%(2×10-6mol/L,n=11)。吡哌酸溶液在5×10-8~5×10-6mol/L范围内线性关系良好。该方法可用于吡哌酸片剂及尿液中痕量吡哌酸的测定,药片测定结果与药典方法基本一致。     

荧光偏振发射平台法及其应用

本文从原理上叙述荧光偏振发射平台法,并用荧光单体-单体混合物及单体-聚合物体系进行验证试验。前者如荧光黄-罗丹明S(或四碘荧光素、或罗丹明B),后者如罗丹明6G-罗丹明6G聚合物体系,结果满意。     

乌拉地尔的荧光光谱研究及测定

建立了一种测定制剂中乌拉地尔的荧光分光光度法。用荧光分光光度法研究了不同溶剂和pH下乌拉地尔的荧光光谱性质。在pH5.0缓冲溶液中,在3.30×10-7～1.65×10-5mol/L浓度范围内,285nm紫外光的激发下,乌拉地尔在365nm处的荧光强度与浓度呈良好的线性关系。线性相关系数为0 9975,测定片剂和针剂的平均回收率分别为99.0%和99.8%,相对标准偏差小于3 0%。     

用于谷胱甘肽检测的新型罗丹明衍生物荧光探针EI北大核心CSCD

合成了一种反应型近红外荧光探针N-Rh-GSH,该探针以罗丹明衍生物为荧光母体,通过与谷胱甘肽(GSH)作用触发螺环的开关来实现信号的响应,其开环释放的荧光产物具有760 nm的近红外发射波长。细胞实验表明,该探针可实现对活细胞中GSH的成像。     

DNA与苯胺红T的相互作用与荧光定量检测

荧光染料作为分子探针用于核酸的定量测定和构象分析一直备受关注 [1] .已有数十种荧光染料被应用[2 ,3 ] ,如溴化乙锭早期常用作 DNA探针[4 ,5] ,因其有很强的致癌性 ,目前已很少采用 ,而那些无毒性或含有可被衍生的活性基团的探针分子越来越受到青睐 [6～ 8] .苯胺红 T(ST)是一种阳离子型荧光染料 ,它既可很容易地与 DNA双螺旋结构发生插入作用 ,又可由带正电的吩嗪环与 DNA上带负电的磷酸基发生强烈的静电吸附作用 ,还可利用其氨基与 DNA或其它生物分子进行交联 .He等 [9] 曾研究了它与小牛胸腺 DNA之间的作用 ,得到的结合位点数…     

Photophysics of Indocarbocyanine Dyes in Organic Solvents

The absorption and fluorescence properties of a series of 18 indocarbocyanine dyes in organic solvents have been determined. The wavelengths of the absorption and fluorescence maxima, the fluorescence lifetimes and the fluorescence quantum yields relative to the benzo-15-crown-5-substituted phthalocyanine have been measured. The results are discussed in relation to the molecular structures or the dye studied.     

Selective Monitoring of Stern-Volmer Quenching of Chiral Molecules Via Fluorescence Detected Circular Dichroism

Abstract

The use of fluorescence detected circular dichroism (FDCD) for monitoring the quenching of chiral molecules is described. This technique combines the specificity for chiral centers of circular dichroism (CD), the sensitivity and selectivity of the fluorescence measurement with the additional chemical information provided by fluorescence quenching. Spectra are acquired using a multidimensional FDCD spectrometer which obtains a FDCD matrix of spectral data as a function of multiple excitation wavelengths (CD information) and multiple fluorescence emission wavelengths. This combination of FDCD and fluorescence quenching produces a very selective monitor for chiral fluorophores.     

Physico-chemical phenomena of double-layer spray and effect on enhancement and stabilization of fluorescence

Summary It was surprisingly found in TLC that double spraying of plates could enhance fluorescence of dansyl derivatives 200–360 fold after spraying with 20% triethanolamine in propane-2-of followed by 30% paraffin oil in hexane on a developed plate containing dansyl chloride derivatives. Visual detection limits as low as 1–6 pmole per spot even a month after spraying with a reproducibility of about 5–6% rsd were obtained. Spraying calibration graphs showed a dose-dependency of at least 1 pmole up to 1.5 nmole per spot. The stability of fluorescence of derivatives to light was increased and spectra of compounds acquired a hypochromic shift in which the color changed from yellow to blue. The graphical method employing the “organic concept” is introduced to explain this kind of synergistic effect of double spraying using different solvents.     

荧光各向异性法研究酸度对四磺基铝酞菁与牛血清白蛋白相互作用的影响

对酞菁类化合物与白蛋白相互作用的研究有助于了解其在血液中的存在形式,从而探索其光敏作用机制[1].荧光各向异性法是研究小分子与蛋白质相互作用的有力工具[2].本文将荧光各向异性的原理和方法应用于由光敏剂四磺基铝酞菁(AlS4Pc)与牛血清白蛋白(BSA)组成的体系,考察了AlS4Pc的荧光各向异性随酸度变化的规律.结果表明,BSA对AlS4Pc有较强的结合能力,提示血清白蛋白对酞菁类光敏剂可起到储存和转运的作用.1　实验部分1.1　试剂及仪器　四磺基铝酞菁的合成与纯化参照文献[3]方法进行.产物经聚酰胺层析、紫外可见吸收光谱、荧光光谱、红…     

A sensitive method for the detection of catecholamine based on fluorescence quenching of CdSe nanocrystals

A sensitive method for the detection of catecholamine based on the fluorescence quenching of CdSe nanocrystals was developed. The sodium citrate-protected CdSe nanocrystals were synthesized in water solution. The fluorescence quenching of CdSe nanocrystals by dopamine, uric acid, ascorbic acid and catechol was studied; the results showed that all of these four kinds of compounds could quench the fluorescence of nanocrystals, and the quenching constant was 6.3 × 10⁴, 2.57 × 10³, 2.14 × 10³ and 1.168 × 10³, respectively. The order of sensitivity for the biosensor was: dopamine > lactic acid > ascorbic acid > catechol. This method shows good selectivity for dopamine, the detection limit reaches 5.8 × 10⁻⁸ M.     

Luminescence-based methods for sensing and detection of explosives

The detection of explosives and related compounds is important in both forensic and environmental applications. Luminescence-based methods have been widely used for detecting explosives and their degradation products in complex matrices. Direct detection methods utilize the inherent fluorescence of explosive molecules or the luminescence generated from chemical reactions. Direct detection methods include high-energy excitation techniques such as gamma-ray and x-ray fluorescence, detection of decomposition products by fluorescence or chemiluminescence, and detection following reduction to amines or another reaction to produce fluorescent products from the explosive. Indirect detection methods utilize the interference caused by the presence of explosive compounds with traditional processes of fluorescence and fluorescence quenching. Indirect detection methods include quenching of solution-phase, immobilized, and solid-state fluorophores, displacement of fluorophores, fluorescence immunoassay, and reactions that produce fluorescent products other than the explosive. A comprehensive review of these methods is presented.