基于荧光分析技术的大鼠肠灌流液中H_2S含量测定

荧光素汞在碱性条件下具有很强的荧光,H2S能与荧光素汞结合,使其荧光猝灭,据此建立了一种荧光法测定大鼠肠灌流液中H2S含量的方法。在0.1mol·L-1 NaOH溶液中,以Na2S作为H2S供体,荧光素汞浓度为5.0×10-5 mol·L-1,Na2S浓度为1.0×10-5 mol·L-1时,以498nm为激发波长,在522nm处测定此二元体系的荧光强度。结果表明,在4.0×10-7~2.0×10-6 mol·L-1范围内,H2S浓度与荧光强度的下降程度呈良好的负相关性,r=0.998 0,精密度实验RSD=4.59%(n=7),检出限3.5×10-8 mol·L-1,样品中H2S含量分别为1.01×10-6和1.15×10-6 mol·L-1,加标回收率为95.8%~101.0%。该方法操作简单,灵敏度高,稳定性好,可准确测定肠灌流液中H2S含量,为内源性H2S的测定提供了依据。     

Functionalised, photostable, fluorescent polystyrene nanoparticles of narrow size-distribution

Fluorescent nanoparticles continue to be of wide interest, as they have many advantages over single fluorescent molecules for biological imaging and sensing applications, such as increased fluorescence intensity and reduced photobleaching. In the following work, styrene was copolymerised with a newly synthesised, fluorescein-based, vinylic crosslinking monomer, by emulsion polymerisation, to create a series of different sized fluorescent nanoparticles (35-100 nm), each of narrow size-distribution. The particles were found to be highly fluorescent and with lower photobleaching compared to fluorescein isothiocyanate (FITC), offering an attractive alternative. The fluorescence excitation and emission spectra were recorded, being similar to fluorescein, but with interesting variation in the excitation spectra. The particles also have a wide range of potential uses, such as examining particle uptake activity of a macrophage cell line, also demonstrated. The nanoparticles were coated with albumin to provide functionality for potential conjugation to biological targeting agents.     

毛细管电泳分离-激光诱导荧光检测血清中的巴氯芬

首次将新合成的柱前衍生试剂6-氧-（N-琥珀酰亚胺乙酸酯）-9-（2′-甲氧羰基）荧光素（SAM F）用于巴氯芬（B aclofen）的衍生标记,并采用毛细管电泳分离-激光诱导荧光（CE-L IF）法分离检测衍生物。研究表明,在磷酸盐缓冲溶液（pH=7.5）介质中,30℃下10m in即可完成衍生反应。反应物在pH 5.6,35mm o.lL-1的磷酸盐缓冲溶液中12m in内达到分离,检出限为6×10-10m o.lL-1。本法用于血清中巴氯芬的分析测定,回收率为95.8%—101.0%。     

Fluorescein thiocarbamyl amino acids as internal standards for migration time correction in capillary sieving electrophoresis

A number of algorithms have been developed to correct for migration time drift in capillary electrophoresis. Those algorithms require identification of common components in each run. However, not all components may be present or resolved in separations of complex samples, which can confound attempts for alignment. This paper reports the use of fluorescein thiocarbamyl derivatives of amino acids as internal standards for alignment of 3-(2-furoyl)quinoline-2-carboxaldehyde (FQ)-labeled proteins in capillary sieving electrophoresis. The fluorescein thiocarbamyl derivative of aspartic acid migrates before FQ-labeled proteins and the fluorescein thiocarbamyl derivative of arginine migrates after the FQ-labeled proteins. These compounds were used as internal standards to correct for variations in migration time over a two-week period in the separation of a cellular homogenate. The experimental conditions were deliberately manipulated by varying electric field and sample preparation conditions. Three components of the homogenate were used to evaluate the alignment efficiency. Before alignment, the average relative standard deviation in migration time for these components was 13.3%. After alignment, the average relative standard deviation in migration time for these components was reduced to 0.5%.     

Fluorescein-based fluorescent and colorimetric chemosensors for copper in aqueous media

Two new fluorescein-based chemosensors for Cu²⁺ were designed with highly selective “off-on” behavior, one of them working in both absorption and emission, the other only in absorption. Binding to Cu²⁺ binding is reversible, as indicated by the bleaching of the color when the metal is extracted. The compounds form the basis for rapid, selective and sensitive Cu²⁺ chemosensors in aqueous media.     

极谱法检测水体中的孔雀石绿

基于荧光素(SF)在pH=7.0的B-R缓冲溶液中可以产生一灵敏的还原峰,而孔雀石绿(MG)可以与荧光素络合而抑制荧光素的峰电流,建立了一种检测水体中孔雀石绿含量的极谱新方法。最佳测定体系为:1.2×10-5 mol/L的荧光素-9.0mL B-R缓冲溶液(pH=7.0)。在此体系中,于起始电位-0.40V,峰电位-0.85V,孔雀石绿含量在20~100μg/L范围内与峰电流呈线性关系,检出限为7.5μg/L。该方法用于环境水样中孔雀石绿的检测,回收率为90.5%~105.6%。     

A sodium ion selective optode based on fluorescein octadecyl ether octadecyl ester and application in beverage and urine assay

A fast responsive sodium ion selective fluorescent optode membrane mounted on an optical fiber has been developed. The sensing membrane contained fluorescein octadecyl ether octadecyl ester (FODEE), potassium tetrakis(4-chlorophenyl) borate (KTpClPB) and a calix[4]arene tetraester in a plasticized poly(vinyl chloride) (PVC) matrix. It exhibited a reversible response to Na⁺ in 0.5 mol/l of HCl in the concentration range of 1.0×10⁻⁶ to 0.1 mol/l. The selectivity, response time, reproducibility and lifetime of the optode membrane were discussed. The practical use of this sensor was demonstrated by real sample analysis in complex sample solutions such as beverage and urine samples.     

Interaction of Fluorescein with Felodipine: A Spectrofluorometric and Thermodynamic Study

The interaction between fluorescein and felodipine (FLD) was investigated by the spectrofluorometric method. The fluorescence of FLD was quenched by fluorescein and quenching is in accordance with the Stern-Volmer relation. The binding constants of fluorescein with FLD were obtained at different temperatures. The binding constant and number of binding sites at different temperatures were calculated yielding the corresponding thermodynamic parameters ΔS, ΔH and ΔG. The distance r between the donor (FLD) and acceptor (fluorescein) molecules was obtained according to the fluorescence resonance energy transfer. The optimum conditions for the fluorometric determination of fluorescein were studied and the quenching method was successfully applied to estimate the fluorescein concentration of the pharmaceutical sample directly.     

荧光光度法测定食用酒精中氰化物含量的研究

基于无色荧光素在铜离子和氰化物存在下,能够被氧化生成荧光素的原理,拟定了一个高灵敏度的氰化物的荧光测定法。方法不仅精密度高、准确度好,而且操作简单快速,检出下限为6.8×10-3ng·m1-1,运用于食用酒精中氰化物含量的测定,结果满意。     

Synthesis of isomerically pure carboxylate- and sulfonate-substituted xanthene fluorophores

Xanthene-based fluorophores such as fluorescein and rhodamine are typically prepared by acid-catalyzed condensation of the appropriate resorcinol or 3-aminophenol with phthalic anhydride. Condensation of substituted phthalic anhydride species results in functionalized fluorophores that are formed as mixed isomers. Crystallization approaches to isomer separation have been reported elsewhere for symmetric fluorescein carboxylates. We describe crystallization-based separation of protected fluorescein sulfonates and coupling conditions to form sulfonamides, precursors for carboxylate-substituted rhodamines, and precursors for asymmetrically substituted fluoresceins and rhodafluors.