荧光分光光度法测定环境水中痕量硫化物

在pH 9.10的氨性缓冲溶液中硫离子能导致荧光试剂水杨醛缩氨基硫脲荧光强度猝灭,荧光猝灭的程度随硫离子含量的增加而增大.其硫离子的质量浓度在20～440μg·L-1范围内与荧光强度的猝灭程度呈线性关系,方法的检出限(S/N=3)为6.7μg·L-1.据此建立了测定痕量硫化物的荧光猝灭分析方法.该方法操作简便、反应迅速、灵敏度高,可直接用于工业废水、自来水、井水中硫化物的测定.     

迷迭香酸的CdTe量子点荧光探针同步荧光法测定

基于迷迭香酸对CdTe量子点荧光的猝灭效应,建立了一种高灵敏度的测定微量迷迭香酸的同步荧光法.在pH 5.7的缓冲溶液中,当固定波长差为210 nm时,CdTe量子点的同步荧光最大发射波长位于320 nm.在最佳实验条件下,迷迭香酸质量浓度在0.36 ～11.52 mg·L-1(1.00×10-6 ～3.20×10-5 mol/L)范围与CdTe量子点的同步荧光强度存在良好的线性关系.其线性回归方程为I0F/IF=0.931 7+0.128 9 ρ(mg·L-1),相关系数r=0.998 2,检出限为0.16 mg·L-1.10次重复测定2.16 mg·L-1 的迷迭香酸,相对标准偏差为2.8%.同时对其同步荧光猝灭机理进行了探讨.     

荧光猝灭法测定壳聚糖含量

在pH 6.3的NaH2PO4-Na2HPO4缓冲溶液中,壳聚糖对荧光素的荧光强度具有明显的猝灭作用,且在一定浓度范围内,其猝灭程度与加入的壳聚糖浓度成线性关系,据此建立了一种新的测定壳聚糖含量的荧光猝灭分光光度法。该方法的回归方程为ΔF=64.02+42.28ρ(mg/L),R2=0.9942,线性范围为0.50~10.0 mg/L,检出限为0.27 mg/L。样品测定的RSD为4.5%(n=6),平均回收率为99.3%。采用该方法可测定复杂样品中的壳聚糖含量。     

能量转移荧光猝灭法测定加替沙星

在λ_(ex)/λ_(em)=470/566 nm、BR缓冲溶液(pH=5.72)、十二烷基苯磺酸钠介质中,吖啶橙(AO)与罗丹明6G(R6G)间能发生有效的能量转移,使R6G的荧光强度显著增强;加替沙星的加入,使R6G的荧光发生猝灭.应用AO-R6G能量转移荧光猝灭法测定加替沙星含量,提高了测定的灵敏度和选择性.加替沙星的浓度在0.6～9.0 μmol·L~(-1)范围内与R6G荧光猝灭程度呈线性关系;方法检出限为0.52 μmol·L~(-1);平行6次测定样品相对标准偏差为0.62%～0.84%;回收率为90.0%～105%.常见金属离子及药物敷料对测定无干扰,不经分离直接用于药物中加替沙星的测定.     

CdTe量子点荧光猝灭法测定培氟沙星

在水相中合成了巯基乙酸包被的CdTe量子点(CdTe ODs),培氟沙星(PEF)对该量子点的荧光具有显著的猝灭,基于该猝灭作用,实现了用CdTe ODs作为荧光探针对痕量PEF的定量检测.实验发现,在pH为9.5的B-R缓冲溶液中,当CdTeODs的浓度为2.0×10-4 mol/L时,PEF的浓度在6.40×10-5～1.28×10-3mg/mL范围与CdTe ODs的荧光猝灭强度呈良好的线性关系,相关系数r为0.9917,检出限(S/N=3)为1.30×10-5 mg/mL.用该方法对犬猫倍福康和注射用PEF的含量进行了测定,回收率为94.6％～106％.     

牛血红蛋白催化荧光猝灭法测定痕量甲巯咪唑

在NH3·H2O-NH4Cl缓冲溶液中,牛血红蛋白催化H202氧化L-酪氨酸产生荧光,甲巯咪唑对该荧光体系具有较强的猝灭作用.据此建立了酶催化荧光猝灭法测定痕量甲巯咪唑的方法.结果表明,甲巯咪唑含量在0.986～14.8 μg/L范围内与荧光强度变化值呈线性关系,其线性回归方程为△F405nm=50.923p+191....     

荧光猝灭法测定维生素C片和果汁饮料中抗坏血酸的含量

罗丹明B溶液在激发波长(λex)为365nm时,在发射波长(λem)580nm处有最大荧光发射强度。如向罗丹明B溶液中加入碘溶液(I3-),由于两者之间反应生成缔合物而使其荧光猝灭,但罗丹明B发射荧光的峰位未变。如在此猝灭反应之前加入一定量的抗坏血酸(AA),则上述猝灭作用由于I3^-被AA还原而失效,使荧光得以重现。进一步试验表明,在总体积为50mL中,1×10^-3 mol·L^-1碘溶液为2.0mL,1.0×10^-4 mmol·L^-1罗丹明B溶液为5.00mL,pH 4.7的乙酸-乙酸钠缓冲溶液为5.0mL,在常温下反应10min的条件下,抗坏血酸的浓度在40μmol·L^-1内与其对应的荧光强度之间呈线性关系(注:抗坏血酸反应在碘溶液及罗丹B溶液之前加入),其检出限(3s/k)为5.6×10^-9 mol·L^-1。根据以上事实,提出了应用上述荧光猝灭法间接测定维生素C片剂及注射液中抗坏血酸的含量。分析时取片剂样品5片,研磨混匀后称取25.0mg溶于水中,并定容至250.0mL,取1.00mL溶液按上述方法测定。注射液样品则取0.10mL,加水定容至250.0mL,取1.00mL溶液进行测定。在实际样品基础上进行加标回收试验,测得回收率为97.4%(片剂)和98.4%(注射液),测定值的相对标准偏差(n=6)依次为2.3%,1.7%。还应用此方法测定了3种果汁饮料,所测得结果与用碘量法校对的结果相符。     

光谱法研究硝基苯与牛血清蛋白的相互作用

本文应用荧光分析法研究了不同酸度、温度和反应时间条件下,硝基苯对牛血清蛋白(BSA)的荧光猝灭作用。实验结果表明在激发波长λex=280nm,发射波长λem=342nm,浓度为0.05 mol·L-1,pH=7.50的TrisHCl缓冲溶液中,猝灭效果最为明显。计算289,304和318 K温度下二者的结合常数分别为:1.25×104、1.00×104和0.833×104L·mol-1。通过Gibbs-Helmholtz方程对其相互作用的热力学参数进行计算(ΔH=-10.7 kJ·moL-1;ΔS=41.4 J·moL-1·K-1),表明二者之间是静电相互作用。实验结果表明,硝基苯对牛血清蛋白荧光猝灭方式为静态猝灭,最后使用紫外吸收光谱法对其作用机理进一步确认。     

氮掺杂碳量子点荧光猝灭法测定柠檬黄

以甘氨酸和乙二胺为前驱物,采用水热法一步合成了氮掺杂碳量子点(N-CQDs)。该量子点近乎球形,分散性好,稳定性高。在pH=5的B-R缓冲溶液中,柠檬黄对N-CQDs的荧光强度有明显猝灭作用,且其猝灭程度与柠檬黄浓度具有良好线性关系,基于此构建了荧光传感体系,建立了柠檬黄检测新方法。方法线性范围为0.16～20.0μmol·L~(-1),检出限为0.076μmol·L~(-1),应用于饮料和枸杞酒中柠檬黄的测定,加标回收率为92.3%～103.5%。光谱分析和荧光寿命测量结果表明柠檬黄对量子点的荧光猝灭为内滤效应和荧光共振能量转移协同作用的结果。     

共振光散射法测定丁胺卡那霉素

研究了以达旦黄（TY）作为共振光散射探针测定市售药品中丁胺卡那霉素（AMK）的测定方法．该方法基于在pH=5．5的Britton—Robinson缓冲溶液中,达旦黄和丁胺卡那霉素结合后有强烈的共振光散射作用．在λ=482nm处,共振光散射强度（△IRLS）最大且光散射的强度与AMK的浓度在0．4～2．4mg·L^-1范围内成正比（相关系数r=0．9986）,检出限为8．6×10^-3mg·L^-1．该方法简便、快速、灵敏,对1．0mg·L^-1的AMK溶液平行测定11次,RSD=2．57％．用于市售样品的分析测定,结果满意。     

岩白菜素与牛血清蛋白相互作用的荧光光谱研究

应用荧光光谱研究了岩白菜素与牛血清白蛋白(BSA)分子间的相互作用.结果表明,岩白菜素对BSA内源荧光的猝灭机制属于形成化合物所引起的静态猝灭,猝灭常数Ksv为1.905×104L.mol-1;岩白菜素与BSA反应的结合常数为2.083×104,结合位点数为1.由热力学参数确定了岩白菜素与牛血清白蛋白的结合作用主要为静电作用.实验还发现随着岩白菜素的加入,BSA的猝灭值与岩白菜素浓度在1.5×10-5~1.5×10-4mol.L-1的范围内呈良好的线性关系,检出限2.0×10-6mol.L-1,可用于岩白菜素的测定.     

掺Fe~(3+) A-TiO_2的合成及其对酸性红B的光催化降解性能

以硫酸氧钛和FeCl_3·6H_2O为主要原料,采用水热法合成了掺Fe~(3+)的纯锐钛矿型A-TiO_2催化剂,其结构经FT-IR和X-射线衍射表征。以波长365nm紫外灯为光源,酸性红B为降解对象,研究了其光催化降解性能。实验结果表明:掺Fe~(3+)有利于提高TiO_2的催化性能,当掺Fe~(3+)量为0.2mol%时,A-TiO_2的光催化性能最强;当掺Fe~(3+)A-TiO_2投放量为400mg·L~(-1),于20℃降解时间40min,对10mg·L~(-1)酸性红B溶液(pH=5)的降解率最大(95.11%)。     

Determination of Parathion‐methyl in Vegetables by Fluorescent‐Labeled Molecular Imprinted Polymer

A novel sensor for the determination of parathion‐methyl based on couple grafting of functional molecular imprinted polymers (MIPs) was fabricated which is developed by anchoring the MIP layer on surfaces of silica particles embedded CdSe quantum dots by surface imprinting technology. The synthesized molecular imprinted silica nanospheres (CdSe@SiO₂@MIP) allow a high selectivity and sensitivity of parathion‐methyl via fluorescence intensity decreasing when the MIP material rebinding the parathion‐methyl molecule. Compared with the MIP fabricated in traditional method, the template of parathion‐methyl was easier to remove from the CdSe@SiO₂@MIP imprinted material. Under optimal conditions, the fluorescence intensity of parathion‐methyl at the imprinted sensor was detected by spectrofluorophotometer. The relative fluorescence intensity of CdSe@SiO₂@MIP decreased linearly with the increasing concentration of parathion‐methyl ranging from 0.013 mg·kg⁻¹ to 2.63 mg·kg⁻¹ with a detection limit (3δ) of 0.004 mg·kg⁻¹ (S/N=3), which is lower than the MIP in tradition. The imprinted film sensor was applied to detect parathion‐methyl in vegetable samples without the interference of other organophosphate pesticides and showed a prosperous application in the field of food safety.     

加替沙星-茜素红体系的紫外特性及加替沙星的测定

加替沙星与茜素红反应可形成配合物,使茜素红的紫外吸光度增强,且加替沙星浓度在0.20~110.00mg.L-1范围内与吸光度呈良好的线性关系,以此为基础,建立了测定加替沙星的新方法.将此方法用于片剂、粉针剂和尿液中加替沙星含量的测定,结果与文献报道的荧光法一致.     

Spectrofluorimetric Determination of Cu2＋ Using New Fluorogenic Reagent

A new synthesized fluorogenic reagent,8-[(2-pyridine)methylideneamino] quinoline (PMAQ), was utilized for spectrofluorimetric determination of Cu(II) at trace levels. PMAQ, a good fluorogenic reagent, though insoluble in water, but is soluble in ethanol and 20% ethanol-water. The excitation and the fluorescence wavelengths of PMAQ were 310 and 434 nm respectively. When the reagent was complexed with Cu(II), the fluorescence intensity decreased proportionally with the concentration of Cu(II) at pH 4.5 by a static quenching effect. The highest sensitivity to Cu^2＋ determination was shown to be at PMAQ concentration of 1.0×10^－5mol•L^－1. In order to enhance the quenching effect, the Cu(II)-PMAQ complex solution was kept at 22 ℃ for 20 min. Though the interferences by Co(II) and Fe(III) were very serious, they were however, completely eliminated by being masked with oxalate and ascorbate ions respectively. The linear dynamic range for Cu(II) determination was between 25—441 µg•L^－1 with the detection limit of 18 µg•L^－1 (RSD＝3.7%, n＝6). The proposed method was successfully applied to the determination of Cu(II) in real samples including human blood serum, commercial tea and wheat flour.     

磺胺多金属氧酸盐对人宫颈癌Hela细胞的抑制作用

对磺胺多金属氧酸盐（C6H9N2O2S）5HP2Mo18O62·15H2O（SPOM-1）,（C6H9N2O2S）H8P2Mo15V3O62·8H2O（SPOM-2）进行了体外毒性实验和抑制宫颈癌Hela细胞作用的研究．当SPOM浓度为50—100mg·L^-1时,对人胚胎成纤维细胞均无细胞毒性作用（P〉0．05）,TC50分别为459mg·L^-1、295mg·L^-1;抑制宫颈癌He—la细胞的EC50分别为88mg·L^-1、24mg·L^-1,治疗指数即分别为5．22,12．29．     

基于LaPO_4∶Ce,Tb-Au发光共振能量转移测定细胞色素C

以膦酰基羧酸共聚物为修饰剂,采用水热法制备了LaPO_4∶Ce,Tb发光纳米粒子,该粒子具有良好的水溶性和生物相容性。对合成的纳米粒子进行了发光光谱、X-射线衍射、透射电子显微镜和红外光谱表征。以制备的纳米粒子为能量供体,纳米金为能量受体,细胞色素C(Cyt C)为桥,构建了LaPO_4∶Ce,Tb-Au发光共振能量转移(LRET)体系,据此建立了测定Cyt C的新方法。实验结果表明,当Cyt C的浓度在0.333~21.0μg·mL~(-1)范围时,LRET体系发光猝灭程度与Cyt C浓度呈良好线性关系,检出限(S/N=3)为0.2μg·mL~(-1),相对标准偏差(RSD)为0.46%(c=10.0μg·mL~(-1),n=11)。该方法用于实际样品的测定,回收率范围为100%~101%。     

基于L-半胱氨酸修饰的锰掺杂ZnS量子点应用于叶酸测定

以L-半胱氨酸为表面修饰剂制备了稳定性和水溶性均优的ZnS∶Mn2+纳米晶,并应用于叶酸的检测。在pH 7.4的KH2PO4-Na2HPO4 缓冲溶液中,叶酸的加入使ZnS∶Mn2+体系的荧光发生猝灭,荧光强度的变化与叶酸浓度呈良好的线性关系,其线性范围为1.0×10-6~7.0×10-5 mol?L-1 （4.4×10-4~3.1×10-2 g?L-1）,方法检出限为9.6×10-7 mol?L-1 （4.2×10-4 g?L-1）。该方法用于叶酸片剂和健康人尿液中叶酸的测定,结果满意。采用荧光光谱、紫外可见吸收光谱及X-ray光谱等研究了ZnS∶Mn2+纳米晶及其水溶液的特性,通过热力学参数对叶酸测定的可能机理进行了探讨。     

A Novel Fluorescence Quenching Method for the Determination of Aloe Polysaccharide

Alizarin red (AR) can bind with aloe polysaccharide (APS) in doubly de‐ionized water to form a red complex resulting in fluorescence quenching of it. The maximum fluorescence quenching wavelength is 572 nm. The chromogenic reaction is rapid and the fluorescence intensity remains stable for at least 2 h at room temperature. The quenched fluorescence intensity (ΔF) is directly proportional to APS concentration. Based on this interaction, a sensitive and selective fluorophotometric method is proposed for the determination of APS. The optimal experiment conditions were established. The corresponding linear equation is (F=0.8807C+1.8132, R²=0.9999. The quantification and detection limits are 0.4752 and 0.1425 µg·mL^?1, respectively. The linear range is 0.444–16.65 µg·mL^?1 for APS and the mean recovery (100.2±2)%, RSD?3%. The effect of various substances on the determination of APS was also investigated in detail, and the results show that most of the studied coexistent substances can be tolerated in considerable amounts. The proposed method is sensitive, simple, fast and suitable for routine assay.     

Fluorescence quenching method for the determination of catechol with gold nanoparticles and tyrosinase hybrid system

<正>The determination method of catechol by fluorescence quenching was developed.The assay was based on the combination of the unique property of gold nanoparticles with tyrosinase enzymatic reaction.In the presence of tyrosinase,the fluorescence of gold nanoparticles was quenched by catechol which can be employed to detect catechol.Under the optimal conditions,a linear range 5.0×10~(-7)-1.0×10~(-3) mol L~(-1) and a detection limit 1.0×10~(-7) mol L~(-1) of catechol were obtained.o-Quinone intermediate produced from the enzymatic catalyzed oxidation of catechol was considered to play the main role in the fluorescence quenching.