1,10-邻菲(口罗)啉荧光光度法测定微量元素硒

研究了痕量元素硒的荧光强度测试新方法,进行了最佳条件实验.该法有良好的线性关系(r=0.9991),检测限是1.0×10-9mol·L-1,RSD(n=6)为0.47%,回收率在92.6%～106.9%之间.     

Simultaneous Determination of Magnolol and Honokiol by Synchronous Fluorescence Spectroscopy

MOL and HOL are the useful ingredients of Houpo that has been used in traditional Chinese medicine for the treatment of thrombotic stroke, typhoid fever, and headache. Therefore, it is necessary to determine theirs contents in pharmaceutical dosage. Up to…     

同步荧光法探究硝苯地平与胃蛋白酶荧光基团的作用机制

以同步荧光法研究了298,310,318 K下硝苯地平（NDP）与胃蛋白酶（PEP）的荧光基团酪氨酸残基（P-Tyr）、色氨酸残基（P-Trp）之间的相互作用。表明药物以动态猝灭的方式猝灭P-Tyr、P-Trp的荧光,结合位点数n为1,主要作用力是疏水作用。310 K时NDP与PEP氨基酸残基反应的荧光猝灭比率份数P-Trp 53.43%>P-Tyr 46.57%,结合位置更靠近P-Trp,NDP与蛋白结合率P-Tyr:69.43%~87.15%,P-Trp:73.64%~90.60%,分别建立了结合模型。且Hill系数n_H约为1,该结合与后继配体无协同作用。结合距离r都小于7 nm,则NDP与P-Tyr、P-Trp之间都存在非辐射能量转移。     

Time-Resolved Fluorescence Receptor Assay for Benzodiazepines

Abstract

A novel non-isotopic receptor binding technique for the detection of benzodiazepines is described. A benzodiazepine labeled with europium chelate was prepared and employed as a labeled ligand, and time-resolved measurements of the long lifetime fluorescence of europium chelate allowed avoidance of interference due to proteins in the receptor preparation. Experimental results demonstrate a sigmoid inhibition curve, with binding of the labeled ligand inhibited by comparable concentrations of the unlabeled drug. The proposed assay may provide a simple procedure for the measurement of benzodiazepines in biological systems and a useful tool in the screening of natural substances for new classes of benzodiazepine-like compounds.     

Preparation of Ion Exchange Films for Solid-Phase Spectrophotometry and Solid-Phase Fluorometry

ABSTRACT

Atomic spectroscopy has dominated the field of trace inorganic analysis because of its high sensitivity and selectivity. The advantages gained by the atomic spectroscopies come with the disadvantage of expensive and often complicated instrumentation. Solid-phase spectroscopy, in which the analyte is preconcentrated on a solid medium followed by conventional spectrophotometry or fluorometry, requires less expensive instrumentation and has considerable sensitivity and selectivity. The sensitivity gains come from preconcentration and the use of chromophore (or fluorophore) developers and the selectivity is. achieved by use of ion exchange conditions that favor the analyte in combination with speciative chromophores. Little work has been done to optimize the ion exchange medium (IEM) associated with these techniques. In this paper we present a method for making ion exchange polymer films which considerably simplify the solid-phase spectroscopic techniques. They are mechanically sturdy and optically transparent in the ultraviolet and visible portion of the spectrum, which makes them suitable for spectrophotometry and fluorometry.     

A Fluorometric Assay of L-Aspartate: 2-oxoglutarate Aminotransferase in Human Serum with N-(9-Acridinyl) maleimide

Abstract

A new assay of L-aspartate:2-oxoglutarate aminotransferase (EC 2, 6, 1, 1) (glutamic-oxaloacetic transaminase: GOT) is reported. Substrate L-aspartate was replaced with L-cysteine sulfinic acid (CSA) which yields sulfite and pyruvate. The enzyme activity was determined by measuring the sulfite with the aid of a fluorescent reagent, N-(9-acridinyl)maleimide (NAM). The method presents a extremely sensitive GOT assay in the range of 4 to 140 U/l using less than 10 μl of human serum.     

Comparative Study of Fluorometric and Electrochemical Detection of Catecholamine,Serotonin, and Metabolites in Rat Brain by High-Performance Liquid Chromatography

Abstract

A high-performance liquid chromatograph connected to a newly designed fluorometer was used for the simultaneous determination of norepinephrine, dopamine, serotonin, 3-methoxy-4-hydroxyphenylglycol (MHPG), homovanillic acid, and 5-hydroxyindoleacetic acid by measuring native fluorescence. These amines and metabolites extracted from the frontal cortex of a rat were purified by adsorption on alumina and an extraction with ethyl acetate and separated in the chromatograph with an ODS column. The detection limits ranged from 0.5 to 3 pmoles. Compared to the electrochemical (EC) detection at an electrode potential of 0.8 V, the sensitivity was almost the same or somewhat lower, but MHPG was highly fluorescent. In the fluorometry, large front peaks observed in the EC detection did not appear, and interfering peaks were not observed.     

Applications of Laser-Induced Fluorometry to the Analysis of Ultratrace Levels of Uranium in an Industrial Environment

Abstract

Laser-induced fluorometric analysis of ultratrace levels of uranium in industrial environmental samples is compared with commonly used spectroscopic techniques for uranium analysis.     

同步荧光法测定功能饮料中维生素B2和B6的研究

研究了测定功能饮料中维生素B2和B6的同步荧光分析法。确定了最佳实验条件:波长差Δλ为70 nm,扫描速度为150 nm/min,入射和出射狭缝宽度均为10 nm,测定波长:B2为448 nm,B6为323 nm。标准曲线在0.01~0.15μg/mL线性良好,维生素B6和B2的平均回收率分别为96.4%~98.5%和98.3%~100.0%。方法可用于功能饮料中维生素B2和B6的测定。     

A Subnanosecond Time-Resolved Fluorescence Lifetime Spectrometer Applying Laser Diodes

Summary.  Since the first application of laser diodes (LD) for the determination of fluorescence lifetimes in our group in 1995, great technical improvements have been made to increase the time resolution of the apparatus. Using the phase fluorometric method, measurements down to 100 ps are now possible. Values can be measured in steps of 10 ps with good reproducibility using a high-frequency signal generator and a GHz digital storage oscilloscope. No additional optical equipment is necessary for this new method. Following an easy calibration procedure, results are available within one minute without any adjustments. The components of the new apparatus including light source, sample chamber for standard fluorescence cuvettes, and detection unit are situated in a 12 × 13 × 9 cm setup. The apparatus was tested with different fluorophores, and the results correlate very well with known values in the range of 0.1 to 1000 ns. Received February 16, 2000. Accepted March 13, 2000