Study on fluorescence property of carvedilol and determination of carvedilol by fluorimetry

The property of carvedilol in acid-alkaline medium was studied by spectrofluorimetry. Effects of organic solvents on carvedilol fluorescence spectra were examined and the reason was discussed. A simple, rapid and high sensitive fluorimetric method for the determination of carvedilol in medicine is developed. The measurement of relative fluorescence intensity was carried out at 356 nm with excitation at 254 nm. Effects of pH, standing time and foreign ions on the determination of carvedilol have been examined. A linear relationship was obtained between the relative fluorescence intensity and concentration of carvedilol in the range of 0.50-270 ng ml(-1). The linear regression equation of the calibration graph is C = 0.000543F - 0.002 (C is concentration (microg ml(-1)) and F is relative fluorescence intensity in the equation), with a correlation coefficient of linear regression of 0.9998 and relative standard deviation of 2.31%. The detection limit of this method is 0.19 ng ml(-1), and recovery is from 98.70 to 102.1%. This method can be used for determination of carvedilol in tablet. The results obtained by this method agreed with those by the official method.     

Pefloxacin determination in urine by synchronous fluorimetry

The feasibility of using synchronous fluorescence spectra for the determination of fluoroquinolone antibiotics in biological liquids is demonstrated. Pefloxacin chelating with metal ions in a micellar medium increases the determination sensitivity.     

Trace zinc determination by synchronous derivative fluorimetry

A sensitive and selective synchronous-scanning derivative spectrofluorimetric determination of zinc based on the formation of a fluorescent chelate with 2-furaldehyde 2-pyridylhydrazone (FAPH) is described, and its analytical performance compared with that of the ordinary fluorimetric method. The detection limits lie in the ng ml range and the coefficient of variation is below 2% in both cases. The methods have been applied to the trace determination of zinc in pig liver tissue and environmental fume samples.     

Selective determination of gallium by flow injection fluorimetry

Gallium can be determined fluorunetrically, with linear response in the range 2.2 × 10^-5 M–1.08 × 10^-4 M, by means of chelate formation with lumogallion ; fluorescence is enhanced by mixing with a polyethylene glycol monolauryl ether solution. Up to 10-fold molar amounts of aluminum can be tolerated, because of the slow formation rate of the aluminum—lumogallion chelate.     

联苯双酯的荧光性质及其分析应用

研究联苯双酯的荧光性质,并建立用荧光光度法测定联苯双酯滴丸中联苯双酯含量的方法.样品用乙醇超声提取,过滤,取续滤液,在室温下用乙醇作溶剂直接测定荧光强度计算联苯双酯的含量,并用RP-HPLC测定的结果作对照.实验表明,联苯双酯有较强的荧光特性,最大激发波长和发射波长分别在282 nm和388 nm;质量浓度在0.24～3.4 mg/L范围内,荧光强度与浓度有良好的线性关系,检出限为(3σ/k) 0.010 mg/L,对2.4 mg/L的联苯双酯测定的相对标准偏差为1.1% (n=10).方法用于联苯双酯滴丸中联苯双酯含量的测定,相对标准偏差RSD (n=5)在0.83%～2.8%,与RP-HPLC测定结果相比,无论是精密度还是准确度不存在显著差异.方法已用于联苯双酯滴丸中联苯双酯含量的测定.     

Simultaneous determination of carvedilol and ampicillin sodium by synchronous fluorimetry

The carvedilol and ampicillin sodium were simultaneously determined by the synchronous fluorimetry. With excitation wavelength at 254 nm, the maximum emission wavelengths of carvedilol and ampicillin sodium were at 357 and 426 nm, respectively. Because the emission spectra of carvedilol and ampicillin sodium were overlapped partially, carvedilol and ampicillin sodium cannot be determined directly by normal fluorimetric method. However, the synchronous fluorimetry can be used for determining both drugs simultaneously without separation procedure. The (Delta)(lambda) = 80 nm was used. Iso-propanol was selected as sensing reagent. Effects of pH, organic solvents and foreign ions on the determination of both drugs were studied. The linear relationship was obtained between the relative fluorescence intensity and concentration of carvedilol and ampicillin sodium in the range of 0.005-0.1 and 5.0-70.0 microg ml(-1), respectively. The linear regression equation of calibration graph for carvedilol is C = 0.000151F - 0.00210, and for ampicillin sodium is C = 0.0770F - 2.62. The correlation coefficient of linear regression equation is 0.9995 for carvedilol and 0.9998 for ampicillin sodium, respectively. The detection limit is 1 ng ml(-1) for carvedilol and 1 microg ml(-1) for ampicillin sodium. The relative standard deviations of carvidelol and ampicillin sodium are 2.47 and 1.61%, respectively. The recovery is from 96.0 to 103.0% for carcvedilol and from 98.0 to 105.0% for ampicillin sodium. This method was rapid, simple and highly sensitive for the determination of carvedilol and ampicillin sodium without pre-separation. The results obtained by this method agreed with those by the official methods. This method can be used for the determination of carvedilol and ampicillin sodium in the medicine dosage.     

荧光分光光度法测定氨基糖苷类药物的研究

氨基糖苷类药物如庆大霉素、小诺霉素、阿米卡星、卡那霉素本身有微弱荧光,在与邻苯二甲醛、2-巯基乙醇、曲拉通X-100作用后生成一种具有强荧光的衍生物。此衍生物在硼酸氯化钾缓冲溶液中最大激发波长和发射波长分别为340 nm和440 nm,在4.0×10-7mol/L~4.0×10-6mol/L浓度范围内,4种药物衍生物的荧光强度与浓度呈现良好的线性关系。回归方程的相关系数均大于0.9990,标出度均小于0.04μg/mL对实际样品进行了测定。     

Direct determination of uranium in seawater by laser fluorimetry

A method for estimation of uranium in seawater by using steady state laser flourimetry is described. Uranium present in seawater, in concentration of approximately 3 ng ml⁻¹ was estimated without prior separation of matrix. Quenching effect of major ions (Cl⁻, Na⁺, SO₄⁻, Mg⁺, Ca⁺, K⁺, HCO₃⁻, Br⁻) present in seawater on fluorescence intensity of uranium was studied. The concentration of phosphoric acid required for maximum enhancement of fluorescence intensity was optimized and was found to be 5%. Similarly the volume of concentrated nitric acid required to eliminate the quenching effect of chloride and bromide completely from 5 ml of seawater were optimized and was found to be 3 ml. A simple equation was derived using steady state fluorescence correction method and was used for calculation of uranium concentration in seawater samples. The method has a precesion of 1% (1 s, n = 3). The values obtained from laser fluorimetry were validated by analyzing the same samples by linear sweep adsorptive stripping voltametry (LSASV) of the uranium-chloranilic acid (2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone) complex. Both the values are well in agreement.     

Direct determination of antibacterial norfloxacin in urine by isopotential fluorimetry

A novel and simple method is presented for the determination of norfloxacin in human urine by matrix isopotential synchronous fluorescence spectrometry (MISF). This method is useful for the determination of compounds in samples with unknown background fluorescence, such as norfloxacin in urine, without the need for tedious sample pre-treatment. The method was performed in ethanol-water medium (10% v/v), at an apparent pH of 4.8 provided by adding sodium acetate-acetic acid buffer solution. In the determination of norfloxacin in urine the fluorescent intensity varied linearly with its concentration from 20 to 200 ng/mL. An exhaustive statistical analysis has been developed to all calibration graphs, this treatment includes robust regression such as least median of squares, which also detects outliers and leverage points. The overall least-squares regression has been applied to find the more exact straight line that fits the experimental data. The error propagation has been considered to calculate the detection limit and the repeatability of the method. The method shows very low detection limits with acceptable recoveries and precisions. The applicability of the proposed method was illustrated in the determination of norfloxacin in human urine sample without sample pre-treatment.     

Laser fluorimetry of polynuclear aromatic hydrocarbons based on time-resolved fluorescence detection

Three polynuclear aromatic hydrocarbons are quantified from the pre-exponential factor of the fluorescence decay curve, instead of the integrated fluorescence intensity. The slopes of the calibration plots are independent of the oxygen concentration in the solvent as predicted. Deaeration of sample solutions gives lower detection limits (around 10^?10 M); the extent of improvement depends on the fluorescence lifetime.     

Direct determination of salicylamide in serum by matrix isopotential synchronous fluorimetry

A method for the determination of salicylamide at concentrations between 25 and 350 ng ml(-1) by use of matrix isopotential synchronous fluorescence spectrometry (MISF) in combination with derivative techniques is proposed. The method allows the determination of compounds in samples with unknown background fluorescence without the need for tedious pre-separation. Synchronous scans are performed along a trajectory that connects points of identical intensity in a three-dimensional fluorescence spectrum. The unknown analytical signal of the serum is suppressed from the MISF spectrum, by calculating its first derivative at lambda(exc)=324 nm and lambda(em)=392 nm. In order to ensure maximum sensitivity and adequate selectivity, the experimental variables affecting the fluorescence intensity of the salicylamide band at lambda(exc)=328 nm and lambda(em)=418 nm were studied. Based on the results, the determination was performed in an aqueous medium at pH 12 that was adjusted with a sodium phosphate/hydrogen phosphate buffer. Calibration graphs were subjected to a comprehensive statistical analysis. The error propagation has been considered in order to calculate the detection limit by the criterium of Clayton.     

动力学荧光猝灭法测定柠檬酸的研究

在稀H2SO4介质中,柠檬酸活化钒(Ⅴ)催化溴酸钾氧化吡口罗红Y的褪色反应,使其荧光猝灭,建立了动力学荧光猝灭法测定柠檬酸的新方法。反应在沸水浴中进行10min,测定柠檬酸的线性范围为0.1～4.0μg/mL,检出限为6.0×10-8g/L。本法用于饮料中柠檬酸的测定,并进行了加标回收试验,回收率在96%～103%之间。     

荧光猝灭法测定次黄嘌呤及机理研究

研究了次黄嘌呤猝灭伊文思蓝的荧光猝灭机理并根据次黄嘌呤对伊文思蓝荧光的猝灭作用建立了测定次黄嘌呤的新方法.线性回归方程为:ρ=6.292×103F-1-26.49,相关系数为0.9990,线性范围为0.20～20.0 μg/mL,检出限为0.14 μg/mL,相对标准偏差(RSD)为2.5%.求算了伊文思蓝与次黄嘌呤的形成常数K=2.63×102L/moL,实验了pH、放置时间、干扰离子等对测定的影响.     

Simultaneous determination of dissolved anthracene and pyrene in aqueous solution by synchronous fluorimetry

A synchronous fluorimetry for simultaneous determination of dissolved anthracene and pyrene in aqueous solution has been established. The linear ranges for determination of dissolved anthracene and pyrene were 1.00x10(-8) to 4.50x10(-7)molL(-1) and 5.00x10(-9) to 6.50x10(-7)molL(-1), and the limits of detection (LOD) for anthracene and pyrene were 2.23x10(-9) and 8.24x10(-10)molL(-1) with relative standard deviations (R.S.D.) of 2.90 and 2.34% (n=5), respectively. Satisfactory results were obtained when the established method was used to simultaneously determine anthracene and pyrene in spiked water samples.     

液膜分离富集二甲氧基羟基苯基荧光酮荧光猝灭法测定微量钼的研究

研究了在pH5．0～6．4的HAC-NaAC缓冲介质中和CTMAB存在下,Mo(Ⅳ)对二甲氧基羟基苯基荧光酮(DMH-PF)的荧光猝灭效应,建立了荧光猝灭法测定微量Mo(Ⅳ)的新体系,DMH-PF最大激发波长为λex=514nm、最大发射波长为λem=547nm,DMH-PF与Mo(Ⅵ）形成1：2配合物使荧光猝灭,荧光猝灭量与Mo(Ⅵ)在0～0．072mg／L范围内呈线性关系,方法的检出限为0．0022mg／L,体系稳定,灵敏度高,采用液膜分离富集钼,可应用于合金钢和石墨中微量钼的测定。     

荧光共振能量转移测定牛血清白蛋白的研究

随着生物分析技术进入了后基因组时代,生命科学领域里的研究课题不断深入,DNA、RNA、蛋白质和其他生物大分子的检测技术发展十分迅速,生命科学中单分子分析技术不断揭示出生命活动的客观规律.相关的新的分析方法和仪器不断取得进展,成为生命科学的前沿领域.     

荧光共振能量转移测定牛血清白蛋白的研究

随着生物分析技术进入了后基因组时代,生命科学领域里的研究课题不断深入,DNA、RNA、蛋白质和其他生物大分子的检测技术发展十分迅速,生命科学中单分子分析技术不断揭示出生命活动的客观规律.相关的新的分析方法和仪器不断取得进展,成为生命科学的前沿领域.     

利用荧光共振能量转移体系测定食品中NO2-的研究

在λcx/λem=450／580nm,0．1mol／L的HCl溶液中,番红花红T和吖啶橙能够发生有效的共振能量转移,使得番红花红T荧光增强,同时吖啶橙的荧光猝灭,而NO2^-的加入使得两者的荧光强度同时减弱。由此建立了一种新的测定痕量NO2^-的方法。结果表明,NO2^-在0．02～10μg／mL范围内与染料的荧光强度减弱程度呈良好的线性关系,方法检出限为1．73ng／mL;该法用于食品中NO2^-的测定,回收率为105．0％～112．4％。