Multipass cuvettes for spectrofluorimetry

Multiple-pass cuvettes which provides a 6-12-fold increase in the sensitivity of spectrofluorimetric measurements are described. With these cuvettes, radiation losses by reflection and polarization are greatly decreased. The cuvettes can be placed directly into most commercial spectrofluorimeters. In the mirror cuvette, the exciting radiation is reflected by an aluminium or silver layer applied to the outer walls of the cuvette. In the cuvette based on total internal reflection, exciting radiation is reflected at the quartz/air boundaries of two attached prisms. Fluorescence spectra of rhodamine-B (1×10^?8 M) in ethanol illustrate the enhancement obtained and the improved accuracy of measurements of fluorescent lifetimes.     

Determination of magnesium by spectrofluorimetry and synchronous scanning first and second derivative spectrofluorimetry with 2-quinizarinsulphonate

Summary Determination of Magnesium by Spectrofluorimetry and Synchronous Scanning First and Second Derivative Spectrofluorimetry with 2-Quinizarinsulpbonate An analytical method has been developed for the fluorimetric determination of microgram amounts of magnesium in solution. The method is based on the reaction of magnesium with 2-quinizarinsulphonate. Synchronous scanned first and second derivative fluorimetry has been employed to increase the sensitivity of the method. The influence of reaction variables as well as instrumental parameters and the composition of the complex is discussed. The interference of various foreign cations and anions has also been examined and in some cases eliminated or reduced by addition of cyanide.     

Constant-wavelength synchronous spectrofluorimetry for determination of riboflavin in anchovies

Constant-wavelength synchronous spectrofluorimetry was used for the analysis of riboflavin in anchovies. Synchronous fluorescence spectra were recorded between 300 and 600 nm at a scan rate of 240 nm min^–1 and with excitation and emission slit-widths both set to 5 nm. The excitation-emission wavelength difference was 65 nm. The fluorescence was measured by peak-area base between 430–509 nm. Recovery was higher than 90.8%.     

Constant-wavelength synchronous spectrofluorimetry for determination of riboflavin in anchovies

Constant-wavelength synchronous spectrofluorimetry was used for the analysis of riboflavin in anchovies. Synchronous fluorescence spectra were recorded between 300 and 600 nm at a scan rate of 240 nm min^–1 and with excitation and emission slit-widths both set to 5 nm. The excitation-emission wavelength difference was 65 nm. The fluorescence was measured by peak-area base between 430–509 nm. Recovery was higher than 90.8%. Received: 22 December 1997 / Revised: 25 February 1998 / Accepted: 25 March 1998     

甲基炔诺酮的荧光分析法研究

基于甲基炔诺酮与浓H2 SO4反应后水解产物的荧光性质 ,建立了一种测量甲基炔诺酮的荧光光度分析新方法。系统地研究了甲基炔诺酮与浓H2 SO4的反应条件及三碳以下的低级醇对产物荧光性质的影响。本法检测限为 1 89×1 0 - 7mol·L- 1 ,荧光强度与浓度在 0mol·L- 1 ～ 1 2 8× 1 0 - 5mol·L- 1 范围内呈良好线性关系 ,方法相对标准偏差为 1 7%     

盐酸罂粟碱的荧光光谱分析法研究

以荧光光谱法研究了经过浓H2 SO4 酸化处理后的盐酸罂粟碱的荧光光谱特征 ,测定了盐酸罂粟碱与 β 环糊精的包络反应常数和热力学参数 ,且在1 0 6× 1 0 -7～ 3 1 8× 1 0 -6mol L范围内荧光强度与盐酸罂粟碱的浓度呈良好线性关系 ,提出了在β 环糊精介质体系中测定盐酸罂粟碱含量的新方法。检测限为 3.2 0× 1 0 -8mol L。     

分光光度测定总黄酮法的适用性

为建立测定天南星总黄酮含量的方法,通过比较黄酮及苷、黄酮醇及3位苷共12个化合物的NaNO2-Al(NO3)3-NaOH法和AlCl3-KAc法的紫外和可见光谱,分析了分光光度测定总黄酮法的适用性.结果显示,与相应方法的有关原理相矛盾,尤其是芹菜素及苷在两方法中均未有相应现象产生.为此,进行了新方法研究,比较了各黄酮在三乙胺介质中的紫外可见光谱,结果显示, 黄酮及苷和3-黄酮醇苷最大吸收均红移;将三乙胺法应用于天南星,方法验证结果符合含量测定要求,对照品夏佛托苷在1.54～21.5 mg/L范围内与吸光度有良好线性关系(r=0.9997),平均回收率为99.3%(RSD=1.1%, n=9).方法重现性好,可操作性强.适用性研究表明, 3种方法均只适用于部分黄酮类成分分析.     

Computerized data acquisition and processing for Shpol'skii high-resolution spectrofluorimetry

The program described provides simultaneously digital control of a high-resolution spectrofluorimeter, acquisition of analog signals and data storage, and contains graphics processing to visualize spectra. Automatic evaluation software, which evaluates peak heights and calculates concentrations is included. The program runs on an IBM PC-AT2 (or compatible) equipped with interface cards; it is composed of distinct modules which are obtained through a menu. The system has been applied to the determination of 13 polynuclear aromatic hydrocarbons (PAHs); it offers high selectivity, excellent detection limits, and rapidity of data acquisition. Results obtained for 9 PAHs in a standard urban dust (SRM-1649) were satisfactory.     

竞争包合荧光光度法测定诺氟沙星

以中性红(NR)为荧光探针,利用羟丙基-β-环糊精(HP-β-CD)能够与中性红(NR)形成包合物,从而使中性红的荧光强度大大增强,而诺氟沙星的加入使NR-HP-β-CD体系的荧光猝灭,以此建立了荧光猝灭法测定诺氟沙星的新方法。在优化的实验条件下,诺氟沙星工作曲线的线性范围为:6.3×10-8～1.3×10-6mol/L,检出限为:1.9×10-8mol/L。方法可用于环境水样中痕量诺氟沙星的测定,回收率在98.4%～104.0%之间。     

Flow injection analysis for the determination of thiabendazole and fuberidazole in water by spectrofluorimetry

Flow-injection analysis (FIA) is proposed for determining thiabendazole (TBZ) and fuberidazole (FBZ) by Spectrofluorimetry. A pH 2 aqueous solution was found to be the optimal solvent for the rapid, precise and sensitive fluorescence analysis of both fungicides. Linear dynamic graphs were established over a concentration range of two orders of magnitude. Limits of detection were 0.7ng/ml for TBZ and 0.1 ng/ml for FBZ. Relative standard deviations were 0.5 and 0.8% for TBZ and FBZ, respectively. The method was applied to the determination of both compounds in spiked river and tap water samples, with satisfactory recoveries.On leave from the Department of Analytical Chemistry and Food Technology, University of Castilla-La Mancha, E-13071-Ciudad Real, Spain     

Rapid assay for procaine penicillin G in pharmaceutical dosages by spectrofluorimetry

A method for the spectrofluorimetric determination of procaine penicillin G is proposed (lambda(ex) = 294 nm, lambda(em) = 348 nm) for concentrations between 0.10 and 1.0 ppm. The method was performed in ethanol/water medium (60% V/V), at apparent pH 9.9 provided by adding ammonium/ammonia buffer solution with pH = 10.0. The effect of other penicillins on the determination of procaine penicillin G was examined over a wide range of concentrations, interferences were not observed in the range of studied concentrations. The method was successfully applied to assay all Spanish commercialized injections containing procaine penicillin G, penicillin G and/or benzathine penicillin G.     

荧光光谱法间接测定叶绿素的含量

叶绿素中的镁可被氢离子置换而形成去镁叶绿素。本文首次提出用荧光光谱法测定叶绿素中的镁而间接测定叶绿素的方法。在氨性溶液中,以7-碘-8-羟基喹啉-5-磺酸(铁试剂)作荧光试剂,省去了叶绿素标准物质。     

Solid-phase reactor flow-injection on-line oxidizing spectrofluorimetry for determination and dissolution studies of folic acid

A simple, sensitive and specific flow-injection spectrofluorimetric method has been developed for the determination of folic acid in pharmaceuticals. The method is based on use of a lead dioxide solid-phase reactor for on-line oxidation of folic acid into a strongly fluorescent compound with a maximum excitation wavelength of 281 nm and an emission wavelength of 450 nm. Under optimum conditions the fluorescence intensity of oxidation product is proportional to the concentration of folic acid over the range 0.008–2.5 g mL^–1. The detection limit is 0.0001 g mL^–1, the relative standard deviation is 0.85% for 11 replicate determinations of 0.05 g mL^–1 folic acid, and the sample throughput is 20 h^–1. In combination with an on-line filter and dilution, an automated drug-dissolution system was established. The proposed method has been successfully applied to the determination of folic acid in pharmaceutical preparations and dissolution testing.     

Simultaneous determination of propranolol and pindolol by synchronous spectrofluorimetry

A completely automated method to determine the most common parameters in cured meat products is proposed. The approach to full automation is based on the coupling of a robotic station for development of preliminary operations (namely weighing of the sample, grinding, leaching, filtration and transport to the aspiration zone) and a continuous unsegmented manifold for derivatisation and spectrophotometric monitoring of the reaction coloured products. This assembly works in an unattended fashion thus eliminating the bottleneck produced by the determination of these parameters in routine laboratories. The good agreement between results obtained by the proposed method and those from conventional methods for target analytes confirms its excellent performance and usefulness.     

Determination of the fungicide dichlone by normal and first-derivative spectrofluorimetry

The influence of solvents on the sensitivity of the spectrofluorimetric determination of dichlone (2,3-dichloro-1,4-naphthoquinone) is discussed. Linear normal and first-derivative calibration graphs are established for 10–50 μg ml^?1 dichlone; relative standard deviations are 3.8 and 2.2%, respectively. Application to synthetic mixtures is described.     

Increased apparent sensitivity by means of constant-energy synchronous spectrofluorimetry

Synchronous fluorescence scanning at constant wavenumber (i.e., energy) difference between excitation and emission brings several improvements when compared to the classical spectrofluorimetry or to the method of synchrnous wavelength scanning. When quantitative results are required, the constant energy-difference technique should be used whenever the difference between the excitation and emission wavelengths exceeds the difference between the wavelengths of the Rayleigh and Raman peaks. Otherwise, the technique brings only minor advantages in comparison with synchronous wavelength scanning.     

Simultaneous determination of yohimbine and boldine by first-derivative synchronous spectrofluorimetry

A method for the simultaneous determination of yohimbine and boldine in mixtures by first-derivative synchronous spectrofluorimetry has been developed. The method is based on their native fluorescence in 0.1N sulphuric acid medium. The constant wavelength difference chosen to optimize the determination was =_em -_em=82 nm. Yohimbine was measured at _ex//_em= 285/367 nm, and boldine at _ex/_em=272/354 nm. The range of application is 10–500 g/l for yohimbine and 1–50 g/l for boldine. The method was applied to the determination of yohimbine and boldine in synthetic mixtures and pharmaceuticals, with errors generally 2%. Relative standard deviations were about 2%.Dedicated to Professor Fermin Capitán on his 72th birthday     

Gamma-ray dosimetry by spectrofluorimetry of phenylacetic acid solution

Aqueous solutions of phenylacetic acid have been evaluated for possible use in γ-ray dosimetry. When aerated aqueous phenylacetic acid solutions are irradiated, photoflourescent species are formed and identified as hydroxyphenylacetic acid. When excited by ultraviolet light at 280 nm, the radiation-induced product shows an emission spectrum with a maximum at 307 nm. The intensity of the emission peak at 307 nm (as well as the area under the peak from 290 to 350 nm) is a linear function of absorbed dose from 0.5 to 25 Gy. This aqueous dosimeter is about ten times more sensitive than that of the conventional ferrous sulfate solution (Fricke) dosimeter. The differences in response at dose rates in the range 0.0055–67 Gy/min are negligible. Conversely, at higher dose rates (170 Gy/min), although the response is linear with dose up to 135 Gy and with proper calibration can be used up to 350 Gy, the photofluorescence signal is somewhat greater than in the lower dose rate range. The estimated random uncertainty limits (1σ) of readings of absorbed dose by the dosimeter are approximately ±2% at a dose of 10 Gy. The fluorescence signal is very much affected by the hydrogen ion concentration of the solution and the intensity of the signal is greatest in the pH range 5–9.5. The radiation chemical yield of the fluorescing species is little influenced by moderate changes in the concentration of phenylacetic acid or by deaeration of the solution. The signal is stable up to at least four weeks, if the solution after irradiation is stored at low temperature (ca. 5°C). However, when stored at room temperature, and in room light, the signal is stable only up to about four days.     

Determination of ciprofloxacin in human urine and serum samples by solid-phase spectrofluorimetry

A method for the determination of trace amounts of ciprofloxacin has been developed, based on solid-phase spectrofluorimetry. The relative fluorescence intensity of ciprofloxacin fixed on Sephadex SP C-25 gel was measured directly after packing the gel beads in a 1-mm silica cell, using a solid-phase attachment. The wavelengths of excitation and emission were 272 and 448 nm, respectively. Using a sample volume of 1000 ml, the linear concentration range of application was 0.3-10.0 ng.ml(-1) of ciprofloxacin, with a R.S.D. of 1.2% (for a level of 4.0 ng.ml(-1)) and a detection limit of 0.1 ng.ml(-1). The method was applied to the determination of ciprofloxacin in human urine and serum samples. It was validated applying the standard addition methodology and using HPLC as a reference method. Recovery levels of the method reached 100% in all cases.     

Simultaneous determination of aluminium and beryllium by first-derivative synchronous solid-phase spectrofluorimetry

A method for the simultaneous determination of aluminium and beryllium in mixtures by first-deravative synchronous solid-phase spectrofluorimetry has been developed. Aluminium and beryllium reacted with morin to give fluorescent complexes, which were fixed on a dextran-type resin. The fluoresnce of the resin, packed in a 1-mm silica cell, was measured directly with a solid-surface attachment. The constant wavelength difference chosen to optimize the determination was Deltalambda = lambda(em) = 75 nm. Aluminium was measured at lambda(em)lambda = 445/520 nm and beryllium at lambda(em)lambda(em) = 430/505 nm. The range of application is between 0.5 and 5.0 ng/ml for both aluminium and beryllium. The accuracy and precision of the method are reported. The method has been successfully applied to the determination of aluminium and beryllium in synthetic mixtures and natural waters.