流动注射化学发光法测定样品中的白藜芦醇

白藜芦醇具有抗菌、抗氧化、抗衰老、抗癌的作用[1-2],能阻碍血小板凝聚、调节血脂,防止低密度脂蛋白氧化,能抑制生物体内过氧化作用,能消除自由基。植物体内的白藜芦醇作为一种植物抗毒素而存在,其结构同己烯雌酚,有雌激素作用。白藜芦醇在虎杖,花生,葡萄,桑椹中含量最高,白藜     

Electrogenerated chemiluminescence from thiol-capped CdTe quantum dots and its sensing application in aqueous solution

In this paper, the electrogenerated chemiluminescence (ECL) from thiol-capped CdTe quantum dots (QDs) was reported. The ECL emission was occurred at −1.1 V and reached a maximum value at −2.4 V when the potential was cycled between 0.0 and −2.5 V. The reduced species of CdTe QDs could react with the coreactants to produce the ECL emission. The CdTe QD concentration (6.64 × 10⁻⁷ mol L⁻¹) of ECL is lower than that (1.0 × 10⁻³ mol L⁻¹) of chemiluminescence (CL). Based on the enhancement of light emission from thiol-capped CdTe QDs by H₂O₂ in the negative electrode potential, a novel method for the determination of H₂O₂ was developed. The light intensity was linearly proportional to the concentration of H₂O₂ between 2.0 × 10⁻⁷ and 1.0 × 10⁻⁵ mol L⁻¹ with a detection limit of 6.0 × 10⁻⁸ mol L⁻¹. Compared with most of previous reports, the proposed method has higher sensitivity for the determination of H₂O₂. In addition, the ECL spectrum of thiol-capped CdTe QDs exhibited a peak at around 620 nm, which was substantially red shifted from the photoluminescence (PL) spectrum, suggesting the surface states play an important role in this ECL process.     

A carbon quantum dots‐enhanced chemiluminescence method for the determination of gallic acid in food samples

In this work, we show that gallic acid can significantly inhibit the chemiluminescence (CL) intensity of carbon quantum dots (CQDs)‐enhanced K₃Fe(CN)₆–luminol system. Under optimum conditions, the decrease in the CL intensity is proportional to the concentration of gallic acid over the range 0.01–1.0 μM, and the detection limit is 1.0 nM. The relative standard deviation of repeated intraday and interday determinations of gallic acid was 1.2–4.2%. This method was successfully applied to the determination of gallic acid in food samples, with recoveries in the range 94.0–103.0%. A possible mechanism of CL is discussed.     

碳点的性质及其在化学发光分析中的研究进展

碳点是一种新型的荧光碳纳米颗粒,与传统的半导体量子点相比,碳点具有毒性低、生物相容性好、原料丰富廉价、光稳定性好等特点,得到引了化学、材料和生物等各领域科学家的高度关注。 本文介绍了碳点的基本概念和性质、探讨了碳点在化学发光领域的应用研究进展并进行了展望。     

Simultaneous determination of cobalt and chromium by ion chromatography with chemiluminescence detection and its application to glass analysis

A method is described for the simultaneous determination of very low levels of Co and Cr by high performance ion chromatography coupled with a chemiluminescence detection system. 0.1M K₂SO₄ solutions, adjusted to pH 3.0, were used as eluent to separate Co(II) and Cr(III) between them and from interferents. The detection system was the chemiluminescence of luminol/ H₂O₂ in alkaline medium catalyzed by such transition metals. Using a matrix solution analogous to soda-lime silica glass (dissolved in acids) calibration graphs were linear up to 0.5 ng ml^–1 for cobalt and up to 250 ng ml^–1 for chromium. The corresponding calculated detection limits (3 s) in such matrix were 0.05 ng ml^–1 and 15 ng ml^–1 for Co and Cr, respectively. The relative standard deviations were 1.4% at 0.5 ng ml^–1 Co level and 2.8% at the 200 ng ml^–1 Cr level. No interferences were observed from the more common metals, particularly those present in glass samples. The ion chromatography/ chemiluminescent method proposed has been successfully applied to the analysis of Co and Cr in glasses.     

Determination of risperidone at picogram level in human urine by luminol—H2O2 chemiluminescence

A simple flow-injection chemiluminescence method with synergistic enhancement has been investigated for the rapid and sensitive determination of antipsychotic risperidone. The synergistic action was significant in the chemiluminescence system of luminol—hydrogen peroxide with risperidone as an enhancer. The increased chemiluminescence intensity was correlated with risperidone concentration within the range from 10 pg mL⁻¹ to 1.0 ng mL⁻¹ with relative standard deviations lower than 5.0 % and the detection limit of 4 pg mL⁻¹. At a flow rate of 2.0 mL min⁻¹, the flow-injection chemiluminescence method exhibited both a high sensitivity and excellent selectivity giving a throughput of 120 times per hour. The proposed method was successfully applied to determine the risperidone content in human urine without any pretreatment. It was found that the excretive amounts of risperidone reached their maximum after taking 2.0 mg of risperidone for 1 h, with a total excretive ratio of 17.37 % in 8.5 h.     

Enhancement of peroxyoxalate chemiluminescence intensity by surfactants and its application to detect detergent

Enhancement of peroxyoxalate chemiluminescence (PO-CL) intensity by a surfactant in the H₂O₂/bis(2,4,6-trichlorophenyl)oxalate (TCPO)/rhodamine B system was described. The effects of 15 surfactants were evaluated by comparing the ratio of a relative CL intensity (RCI) with surfactant to that of the blank in each system. In preliminary study, H₂O₂/imidazole-HNO₃ buffer/TCPO/rhodamine B system was used to study the effects of surfactants on PO-CL intensity. Fourteen surfactants reduced the CL intensity at the 2% concentration, where their relative CL intensities ranged from 0.6 to 93.5%. Some of these phenomena may be caused by a notable change of pH that was occurred by adding the surfactant.Additionally, enhancement of PO-CL intensity was studied by using system (1) H₂O₂/TCPO/rhodamine B and (2) H₂O₂/imidazole-HNO₃ buffer/TCPO/systems. In the system 1, the favorable enhancement of CL intensity (ranged from 124 to 472%) was observed with 9 surfactants at the 0.5% concentration. This result suggested that several surfactants might play a role as a catalyst in the PO-CL reaction. There was no tendency to enhance CL intensity among the surfactant types. In the system 2, the enhancement of CL intensity was also observed by adding with 11 surfactants, which might be mainly caused by the fluorescent impurities of surfactants used.Furthermore, detection of detergent commercially available was applied by using the system 1.     

π‐Conjugated Carbon Radicals at Graphene Oxide to Initiate Ultrastrong Chemiluminescence

Graphene oxide has widely been employed in various fields, but its structure and composition has still not been fully understood. Here we report that freshly prepared graphene oxide exhibits a large number of π‐conjugated carbon radicals at its π‐network plane, which result from the addition reaction of hydroxyl radicals from H₂O₂ onto the conjugated double bonds of graphene oxide. The π‐conjugated carbon radicals can directly initiate the long‐lasting visible chemiluminescence of luminol, which is even stronger than that obtained when horseradish peroxidase and H₂O₂ are used. Previously, graphene oxide was mainly reported to be a quencher of chemiluminescence instead. Remarkably, the reacted radicals can be regenerated, thereby enabling the repetitive initiation of chemiluminescence by re‐treatment of graphene oxide. The results reported here provide a new understanding of the structure, properties, and applications of graphene oxide.     

An ultrasensitive and highly selective determination method for quinones by high-performance liquid chromatography with photochemically initiated luminol chemiluminescence

Quinones are a class of compounds of substantial toxicological and pharmacological interest. An ultrasensitive and highly selective chemiluminescence (CL) method was newly developed for the determination of quinones based on the utility of photochemically initiated luminol CL. The method involved ultraviolet (UV) irradiation of quinones to generate reactive oxygen species (ROS) through the unique photosensitization reaction accompanied with the photolytical generation of 3,6-dihydroxyphthalic acid (DHPA) from quinones. The photoproducts were detected by luminol CL reaction. Interestingly, it was noticed that DHPA had enhancement effect for the luminol CL. The generation of the enhancer (DHPA) in association with the oxidant (ROS) in the photochemical reaction greatly increases the sensitivity and selectivity of the proposed luminol CL method. In order to elucidate the type of ROS produced by the photosensitizaion reaction in relation to the proposed CL reaction, we investigated the quenching effect of selective ROS scavengers in the luminol CL. Although several ROS were generated, superoxide anion was the most effective ROS for the generated CL. Moreover, the enhancement mechanism of DHPA for luminol CL was confirmed. The enhancement was found to be through the formation of stabilized semiquinone anion radical that provided long-lived CL. The generation of the semiquinone radical was confirmed by electron spin resonance technique. Furthermore, we developed an HPLC method with on-line photochemical reaction followed by the proposed CL detection for the determination of four quinones. A luminol analogue, L-012, was used for its high sensitivity. The detection limits for quinones obtained with the proposed method (S/N = 3) were in the range 1.5–24 fmol that were 10–1000 times more sensitive compared with the previous methods. Finally, the developed HPLC-CL system was successfully applied for the determination of quinones in airborne particulate samples collected at Nagasaki city.     

异元素掺杂碳点的制备及其在生物成像中的应用

荧光碳点具有良好的生物相容性和优良的抗光漂白能力,因此碳点在生物荧光成像方面的应用潜力受到广泛关注,但是碳点相对较低的荧光量子产率和缺乏近红外荧光发射的缺陷限制了碳点在荧光成像分析中的应用.随着异元素掺杂对碳点结构和荧光性质的改善,碳点被越来越广泛地用于生物成像.本文对近年来元素掺杂碳点的合成方法、异元素掺杂对碳点光学性质的影响和元素掺杂碳点在成像分析中的进展进行了综述,并对其应用前景进行了展望.     

Electrogenerated chemiluminescence from CdS nanotubes and its sensing application in aqueous solution

Electrogenerated chemiluminescence (ECL) of CdS nanotubes in aqueous solution and its sensing application were studied by entrapping the CdS nanotubes in carbon paste electrode. Two ECL peaks were observed at −0.9 V (ECL-1) and −1.2 V (ECL-2), respectively, when the potential was cycled between 0 and −1.6 V. The electrochemically reduced nanocrystal species of CdS nanotubes could collide with the oxidized species in an annihilation process to produce the peak of ECL-1. The electron-transfer reaction between the reduced CdS nanocrystal species and oxidant coreactants such as S₂O₈²⁻, H₂O₂, and reduced dissolved oxygen led to the appearance of the ECL-2 peak. Based on the enhancing effect of H₂O₂ on ECL-2 intensity, a novel CdS ECL sensor was developed for H₂O₂ detection. The sensor exhibited a detection limit of 0.1 μM and a linear range from 0.5 μM to 0.01 mM. The relative standard deviations of five replicate determinations of 5 μM H₂O₂ was 2.6%. In addition, the ECL spectrum in aqueous solution also exhibited two peaks at 500 and 640 nm, respectively.     

An ultrasensitive post chemiluminescence reaction of ammonium in NBS-dichlorofluorescein system and its application

A strong post chemiluminescence (PCL) phenomenon was observed when ammonium was injected into the reaction mixture after the finish of CL reaction of N-bromosuccinimide (NBS) and dichlorofluorescein. Based on this, a sensitive flow injection PCL method was established for the determination of ammonium. The possible CL mechanism of the reaction was proposed based on a series of experiments. The PCL intensity responded linearly to the concentration of ammonium in the range 3.0 × 10⁻¹¹-1.0 × 10⁻⁷ g mL⁻¹ with a detection limit of 1 × 10⁻¹¹ g mL⁻¹. The relative standard deviation (R.S.D.) was 1.4% for 1.0 × 10⁻⁹ g mL⁻¹ ammonium (n = 11). This method had been applied to the determination of ammonium in samples of mineral water, tap water and river water.     

Flow injection chemiluminescence determination of isoniazid using luminol and silver nanoparticles

The effect of silver colloidal nanoparticles (AgNPs) on the luminol–isoniazid system was investigated. It was found that AgNPs could act as a nanocatalyst on the luminol–isoniazid system to generate chemiluminescence (CL). The CL emission spectrum of the luminol–isoniazid–AgNPs system showed a peak with a maximum at 425 nm. It was suggested that the luminophor species was the excited state 3-aminophthalate. The reduction of dissolved O₂ to H₂O₂ by isoniazid and decomposition of H₂O₂ to the oxygen-related radicals were attributed to the catalytic effect of AgNPs. Under optimized conditions, the CL signal intensity was linear with the isoniazid concentration in the range of 10–1000 ng mL^{− 1}, with the correlation coefficient of 0.9996. The limit of detection was 2.7 ng mL^{− 1} isoniazid. The relative standard deviations for seven repeated measurements of 60 and 200 ng mL^{− 1} isoniazid were 1.4 and 2.4%, respectively. The effect of potent interfering compounds on the CL signal intensity of the proposed luminol–isoniazid–AgNPs system was investigated. The proposed method was successfully applied to the determination of isoniazid in a pharmaceutical sample.     

Study on the chemiluminescence behavior of bovine serum albumin with luminol and its analytical application

In this paper, the luminescence behavior of bovine serum albumin (BSA) and luminol was first studied by flow injection chemiluminescence (CL). It was found that the hyperchromic effect of luminol in the presence of BSA led to the acceleration of the electrons transferring rate of excited 3-aminophthalate, which greatly enhanced the CL intensity of luminol/dissolved oxygen reaction. The increments of CL intensity were proportional to the concentrations of BSA with a linear range from 0.01 to 7 nmol L(-1). It was also found that azithromycin could inhibit the CL intensity of luminol/BSA reaction. The decrements of CL intensity were logarithm over the concentrations of azithromycin ranging from 0.1 to 700 ng mL(-1). At a flow rate of 2.0 mL min(-1), a complete analytical process, which included sampling and washing, could be performed within 30s with relative standard deviations of less than 3.1%. This proposed method was successfully applied in assaying azithromycin in pharmaceutical and human serum samples with recoveries from 91.0 to 104.3%. The possible luminescence mechanism of luminol/BSA/azithromycin reaction was discussed in detail by CL, UV and fluorescence methods.     

类石墨相氮化碳量子点（g-CNQDs）用于水质中三硝基苯酚的检测

基于类石墨相氮化碳量子点( g-CNQDs)建立了一种高效、灵敏、简单的荧光化学传感器用于检测水相中的三硝基苯酚( TNP)。 g-CNQDs是一种新型纳米半导体材料,具有很好的水溶性、生物相容性、环境友好、良好荧光特性,无毒性,通过简单的固相反应法,制备了g-CNQDs材料,探讨了g-CNQDs与TNP之间的相互作用(如仔-仔共轭作用、氢键相互作用和静电作用)引起的g-CNQDs荧光猝灭过程。此荧光传感器响应速度快,对TNP具有良好的选择性。实验结果表明,本方法在0.1~100 nmol/L和0.1~100μmol/L的浓度范围内呈现良好的线性关系,检出限为0.05 nmol/L ( S/N=3)。 g-CNQDs材料在化学传感器方面有很好的应用前景,利用此荧光传感器对实际水样中的TNP进行了检测,为监测水环境中TNP提供了新方法。     

Multivariate calibration applied to the time-resolved chemiluminescence for the simultaneous determination of morphine and its antagonist naloxone

A novel alternative for the simultaneous determination of compounds with similar structure is described, using the whole chemiluminescence-time profiles, acquired by the stopped-flow technique, in combination with mathematical treatments of multivariate calibration. The proposed method is based on the chemiluminescent oxidation of morphine and naloxone by their reaction with potassium permanganate in an acidic medium, using formaldehyde as co-factor. The whole chemiluminescence-time profiles, acquired using the stopped-flow technique in a continuous-flow system, allowed the use of the time-resolved chemiluminescence (CL) data in combination with multivariate calibration techniques, as partial least squares (PLS), for the quantitative determination of both opiate narcotics in binary mixtures.In order to achieve overcoat the additivity of the CL profiles and beside to obtain CL profiles for each drug the most separated as possible in the time, the optimum chemical conditions for the CL emission were investigated. The effect of common emission enhancers on the CL emission obtained in the oxidation reaction of these compounds in different acidic media was studied. The parameters selected were sulphuric acid 1.0 mol L⁻¹, permanganate 0.2 mmol L⁻¹ and formaldehyde 0.8 mol L⁻¹. A calibration set of standard samples was designed by combination of a factorial design, with three levels for each factor and a central composite design. Finally, with the aim of validating the chemometric proposed method, a prediction set of binary samples was prepared. Using the multivariate calibration method proposed, the analytes were determined in synthetic samples, obtaining recoveries of 97-109%.     

The second chemiluminescence emission of luminol-periodate-menadione sodium bisulfite system and its analytical application

In this paper, a new chemiluminescence phenomenon described as the second chemiluminescence emission was observed when menadione sodium bisulfite was injected into a reaction mixture of luminol and potassium periodate, in which luminol was oxidized by excess amount of potassium periodate for about 24 h. The mechanism of the second chemiluminescence emission was proposed based a series of experiments. Moreover, our experiment discovered that the second chemiluminescence intensity was a linear function of the concentration of menadione sodium bisulfite in the range of 2 × 10⁻⁹ to 4 × 10⁻⁵ g L⁻¹. Based on this phenomenon, a new flow-injection method for the determination of menadione sodium bisulfite has been established.     

荧光碳点的制备及应用研究进展

荧光碳点是一种新型的荧光纳米材料。它不仅具有优良的光学性能,而且具有良好的生物相容性,易于实现表面功能化,在生物传感、荧光探针等领域具有很好的应用潜力。本文就近几年来荧光碳点的研究进行了综述,简述了碳点的特性,着重介绍了荧光碳点制备和应用的最新进展,对碳点发展过程中尚待解决的问题进行了总结,并对未来的发展方向进行了展望。     

Gold nanorod-catalyzed luminol chemiluminescence and its selective determination of glutathione in the cell extracts of Saccharomyces cerevisiae

In this study, gold nanorods were firstly found to exhibit a tremendously higher catalytic activity towards luminol chemiluminescence (CL) than spherical gold nanoparticles. More importantly, ultra-trace aminothiols can cause a great CL decrease in the gold nanorod-catalyzed luminol system by the formation of Au-S covalent bonds on the ends of gold nanorods. Aminothiols can occupy the active sites of gold nanorods, and further interrupt the generation of the active oxygen intermediates. Other biomolecules including 19 standard amino acids, alcohols, organic acids and saccharides have no effect on gold nanorod-catalyzed luminol CL signals. Moreover, in order to evaluate the applicability and reliability of the proposed method, it was applied to the determination of glutathione in the cell extracts of Saccharomyces cerevisiae. Good agreements were obtained for the determination of glutathione in the cell extracts of S. cerevisiae between the present approach and a standard Alloxan method. The recoveries of glutathione were found to fall in the range between 96 and 105%. The calibration curve for glutathione was found to be linear from 0.05 to 100 nM, and the detection limit (S/N = 3) was 0.01 nM. The relative standard deviation (RSD) for five repeated measurements of 5.0 nM glutathione was 2.1%.     

Simultaneous stopped-flow determination of morphine and naloxone by time-resolved chemiluminescence

The first application of the flow analysis coupled with chemiluminescence detection and based on stopped-flow chemistry to the simultaneous determination of two components, using a two equation system, is described. The proposed method to determine simultaneously morphine and naloxone is based on the chemiluminescence oxidation of these compounds by their reaction with potassium permanganate in an acidic medium. The main feature of the system used is that the recording of the whole chemiluminescence intensity-versus-time profiles can be obtained, using the stopped-flow technique in a continuous-flow system. Then, the chemiluminescent signals obtained at two times of these profiles can be used to determine the concentration of both opiate narcotics. The effect of common emission enhancers on the chemiluminescence emission of these compounds in different acidic media, using the above-mentioned technique, was studied, in order to achieve the best conditions in which, the CL profiles of both compounds should be additive. The parameters selected were sulphuric acid 1.0 mol L⁻¹, permanganate 0.2 mmol L⁻¹ and formaldehyde 0.8 mol L⁻¹. Taken in account the different profiles of the transient CL signal obtained with each compounds, using the selected chemical conditions, two measurement times (1.4 and 4.8 s) of these responses curves were considered with the purpose to establish a simple 2 × 2 matrix calculation. Using the chemiluminiscent signals obtained at these times, a linear calibration graph was obtained for each one of the compounds between 0.01 and 1.00 mg L⁻¹ for morphine and 0.10–1.50 mg L⁻¹ for naloxone. The present chemiluminescence procedure was applied to the determination of both compounds in mixtures and was found to be satisfactory.