阻抑荧光猝灭法测定环境水样中痕量砷

在H2SO4介质中,KIO4氧化吖啶黄,使体系褪色并伴随荧光猝灭,痕量的As(Ⅲ)能显著阻抑此反应,据此建立了一种新的荧光法测定痕量As(Ⅲ)。本文对该体系的实验条件进行了详细研究。在最佳条件下,方法的线性范围为5.0～400μg/L,检出限为2.4μg/L。方法已用于环境水样中痕量As(Ⅲ)的测定,加标回收率为94.2%～102.6%。     

四溴荧光素荧光猝灭法测定司帕沙星

基于司帕沙星能够猝灭四溴荧光素的荧光且荧光猝灭程度与司帕沙星的量成正比,建立了一种测定微量司帕沙星的方法。在pH3．5的Clark—Lubs缓冲溶液中,四溴荧光素激发波长λex=485nm、发射波长λem=545nm,司帕沙星的质量浓度在0～2．0mg／L范围内符合比耳定律,方法检出限为42．7μg/L。已用于片剂及胶囊中司帕沙星的测定。6次平行测定回收率为93．8％～104．3％,相对标准偏差为1．1％～2．8％。     

荧光淬灭法测定食品中的硼砂残留量

基于硼砂对姜黄素的荧光强度有显著的淬灭作用,建立了一种简单、快速、灵敏的测定食品中硼砂的新方法,选择了最佳实验条件,并将此方法用于面条、茶叶和腐竹中硼砂的测定,平均回收率为99.2%,相对标准偏差为1%。     

荧光熄灭法测定微量氟的研究和应用

在环境监测中微量F~-的分析受到很大的重视.过去采用了分光光度法、离子选择电极法和荧光光度法,前两种方法选择性好,但灵敏度略低;荧光光度法灵敏度较高,可直接测定简单样品中的微量氟.在测定氟的荧光方法中,均是采用荧光熄灭法.此法的特点是灵敏度高,但操作繁琐,很少用于实际样品分析.我们研究了氟的几个新体系,从中筛选出灵敏度高、操作简便的锆-8-羟基喹啉-5-磺酸体系.在水溶液中测定,1μg F~-使体系荧光强度下降68％,与文献报道的体系相比是较高的.本法灵敏度为0.002μgF~-/mL,是测定氟的最灵敏方法之一.     

Determination of proteins by fluorescence quenching of Magdala Red

Magdala Red (MR) binding to protein causes a decrease in the fluorescence intensity of MR at 556 nm. Based on this, a new quantitative determination method for proteins is developed. The linear range of this assay is 0.1-4.0 microg ml(-1) of Bovine Serum albumin (BSA). The measurements can be made easily on a common fluorimeter. The reaction between MR and proteins is completed in 1 min, and the fluorescence intensity is stable for at least 2 h. There is little or no interference from amino acids and most metal ions. The proposed method has been applied to the determination of protein in milk powder and soybean milk powder and the results are in agreement with the results by the other methods.     

四氧杂四烯衍生物荧光熄灭法测定微量草酸

基于草酸对荧光试剂 2 ,2 ,7,7,1 2 ,1 2 ,1 7,1 7 八甲基 2 1 ,2 2 ,2 3,2 4 四氧杂四烯镁 (MgTOE)的荧光熄灭 ,建立了测定微量草酸的荧光分析方法。在pH4.0NaAc HAc缓冲体系中 ,测定的最大激发波长和发射波长分别为 2 4 5nm和2 98nm ,测定草酸浓度的线性范围为 6.1× 1 0 - 6mol/L～ 8.2× 1 0 - 4 mol/L ,检出限为 8 2× 1 0 - 7mol/L。该法已用于人体尿液及菠菜中草酸的含量分析     

左氧氟沙星-CdS-BSA体系荧光猝灭法测定左氧氟沙星

以六偏磷酸钠为稳定荆,巯基乙酸为修饰剂,水相合成了具有优异光学性质的CdS量子点.利用左氧氟沙星对CdS与牛血清白蛋白复合物的荧光有明显的猝灭作用,在536nm测定其荧光强度.结果表明,体系荧光猝灭程度与左氧氟沙星的浓度在0.2～20μg/mL范围内呈良好的线性关系,r=0.9994,检出限为0.0289μg/mL.方法已用于盐酸左氧氟沙星片剂和胶囊的测定,并与药典方法一致.     

铽-环丙沙星-SDS敏化荧光猝灭法检测雷公藤红素

在pH=9.26的氨-氯化铵缓冲溶液中,铽Ⅲ与环丙沙星反应形成络合物,而后加入十二烷基硫酸钠(SDS)形成了三元体系,其最佳激发、发射波长分别为λex= 330nm、λem=545 nm.在该反应体系中加入适量雷公藤红素溶液,铽Ⅲ与环丙沙星络合物的激发、发射波长位置不变,但荧光强度有规律下降.利用这一现象,建立了测定雷...     

Determination of antimony(III) in environmental water samples in microemulsion system by the fluorescence quenching method

A novel highly sensitive and selective fluorescent reagent, 2,6,7-trihydroxy-9-(3,5-dibromo-4-hydroxyphenyl)fluorone (DBH-PF) has been studied for the spectrofluorimetic determination of antimony(III) in cetyltrimethylammonium bromide (CTMAB) microemulsion media. DBH-PF reacts with antimony(III) forming a complex with 1:2 (metal to ligand) antimony-DBH-PF in the system of HAc-NaAc buffer solution at pH 5.33. The maximum excitation and emission wavelengths are at 522 and 556 nm, respectively. The linear range of the method is 0.05 approximately 1.50 mug 10 ml(-1) and the detection limit is 0.015 mug 10 ml(-1). Foreign ions are eliminated by preconcentration and separation with sulfhydryl dextrose gel (SDG) at pH 1.0. The proposed method has been applied to the determination of antimony(III) in industrial waste water samples with satisfactory results.     

亚甲基蓝荧光猝灭法测定抗坏血酸

在稀H2SO4介质中,抗坏血酸与亚甲基蓝发生反应,使其荧光猝灭,建立了荧光光度法测定痕量抗坏血酸的新方法,用正交法确定最佳测定条件。方法的激发波长为660 nm,发射波长为694 nm,在最佳条件下该法测定抗坏血酸的线性范围为0.1~40 mg/L,检出限为0.23 mg/L。方法可用于药品、饮料、果蔬中抗坏血酸的测定。     

Estimation of the molecular volumes of the reaction products between beta-lactam antibiotics and aminoglycoside antibiotics, and those of the degradation products of beta-lactam antibiotics by isotachophoresis

The correlative equations between the molecular volume and the qualitative indication (hR) for beta-lactam antibiotics, the reaction products between beta-lactam antibiotics and kanamycin, and the degradation products of beta-lactam antibiotics were hR = 0.32 + 0.080 VA2/3//Z/(N = 15, r = 0.972 for penicillins) and hR = 0.04 + 0.072 VA2/3//Z/(N = 12, r = 0.987 for cephems). Where VA is van der Waals volume (A3/molecule), hR is the relative step height in the isotachopherogram, and Z is the electric change, respectively. According to these equations, the molecular volumes of the reaction products between beta-lactam antibiotics and the other aminoglycoside antibiotics, and those of the degradation products of beta-lactam antibiotics can be estimated from the value of hR. Also according to the step height in the isotachopherogram, the reaction products or the degradation products may be estimated directly when the electric charge is known. It was confirmed that a molecule of aminoglycoside antibiotics reacted with a molecule of beta-lactam antibiotics. Therefore, the inactivation of aminoglycoside antibiotics is much greater than for beta-lactam antibiotics when the clinical doses of these antibiotic combinations are used.     

分子荧光法测定水中的微量铁

基于Fe（Ⅱ）与邻菲口罗啉生成络合物使其荧光猝灭的特性,讨论了在室温下,pH 5.5的乙酸-乙酸铵的缓冲介质中,以λex=270 nm为激发波长,于eλm=365 nm波长处测定该络合物荧光强度。结果表明Fe（Ⅱ）质量浓度在0.8-120.0 ng/mL范围内与络合物的荧光强度具有良好的线性关系,相关系数0.9994,检出限0.50 ng/mL。对60 ng/mL的Fe RSD（n=9）为2.8%。Fe的回收率为98.03%-102.9%。方法已用于水中微量铁的测定。     

Determination of dopamine in injections and urine by an enzyme-catalyzed fluorescence quenching method.

A new, sensitive method for determining dopamine has been established based on the principle of fluorescence quenching. A linear relationship is obtained between F(0)/F and the concentration of dopamine in the range of 0.80 -16.00 microg mL(-1). The detection limit was 0.23 microg mL(-1) and the relative stand deviation was 1.54%. The mechanism of the fluorescence quenching has been discussed. Effects of pH, foreign ions, and standing time on the determination of dopamine have been examined. This method is simple and can be used for the determination of dopamine in injections solution of dopamine. The results obtained by this method agreed with those obtained by the official method.     

Determination of lectin in very dilute solution with umbelliferyl sugars by fluorescence quenching

Umbelliferyl sugars have been used to determine the lectin concentration in very dilute solution by fluorescence quenching methods. The Stern-Volmer plot of fluorescence quenching after considering ground-state complexation is obeyed by several sugars. As little as 1 μg of lectin (in 10 μl) and 250 nM of umbelliferyl sugars can be determined. This method offers a simple, non-destructive and rapid method for the determination of lectin activity.     

Determination of environmentally important metal ions by fluorescence quenching in anionic micellar solution

This work describes the effect of a variety of metal ions as quenchers of the fluorescence of naphthalene, in aqueous micellar solutions of sodium dodecyl sulfate (SDS). The quenching by the metal ions can be adequately described by the Stern-Volmer equation and the best signal to noise ratios are obtained with low micellized detergent concentrations. Apparent Stern-Volmer constants decrease in the order: Fe3+ > Cu2+ > Pb2+ > Cr3+ > Ni2+ and directly reflect the relative sensitivity of the method for these ions. Detection limits (defined as three times the standard deviation of the blank for n= 10) for the fluorescence quenching of naphthalene by the metal ions in aqueous micellar SDS are in the range of 1.0 x 10(-6) to 1.0 x 10(-5) mol dm(-3). The proposed fluorescence quenching method shows good repeatibility for a variety of added quencher metal ions, indicating that anionic micelle-enhanced fluorescence quenching by metal ions constitutes an analytical method of rather general application.     

Determination of technetium based on quenching of the fluorescence of some organic compounds,with application to vegetation

Technetium is an effective quencher of the fluorescence produced by 2,5-diphenyloxazole (PPO), 1,4-bis(4-methyl-5-phenyl-2-oxazolyl)benzene (POPOP) and 2,2′-pyridil [1,2-dioxo-1,2-bis(2-pyridyl)ethane]. Spectrofluorimetric procedures for 0.01–12 μg Tc ml^?1 with PPO and 0.1–12 μg ml^?1 with 2,2′-pyridil, and a spectrophotometric method for 1–15 μg ml^?1 are described. The distribution of technetium in vegetation is measured by applying the PPO method.     

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....     

荧光反猝灭法测定药剂中卡托普利

建立荧光反猝灭法测定卡托普利(CAT)的体系.碘(I-3)与罗丹明B(RhB)缔合作用使罗丹明B荧光信号强度减弱直至荧光猝灭,而卡托普利可将I-3还原为I-,使体系荧光信号再现.在2～20μmol·L-1范围内荧光强度再现值ΔF与卡托普利浓度有线性关系:ΔF=-8.438+10.774c(r=0.9986),检出限为3...     

Determination of cerium in rare earth ores by fluorescence quenching of rhodamine 6G

A fluorescence quenching method has been developed to determine cerium with rhodamine 6G. The method is based on the oxidation of rhodamine 6G by cerium(IV) in sulfuric acid solution. The linear calibration range is 4.0 × 10^–7 -1.6 × 10^–6mol/L. The detection limit is 1.0 × 10^–7 mol/L. The relative standard deviation was 1.0% (n = 5). The method has been used to determine cerium in rare earth ores, with satisfactory results. The method offers the advantages of simplisity, sensitivity and selectivity.