Characterization of chemiluminescence from singlet oxygen under laminar flow conditions in a micro-channel and its quenching with beverages

Singlet oxygen was generated by reaction of sodium hypochlorite and hydrogen peroxide in a micro-channel. The two reagent solutions were delivered into the micro-channel by a syringe pump, providing a laminar flow liquid-liquid interface. The chemiluminescence from the singlet oxygen was emitted in the collapse of the interface due to molecular diffusion under laminar flow conditions. The chemiluminescence intensity was observed continuously and stably for each combination of reagents fed into the micro-channel; while, in the normal batch-type reactor the chemiluminescence peaks from singlet oxygen were observed within ca. 5 s. The features of the chemiluminescence emitted under laminar flow conditions were examined by changing the concentrations of sodium hypochlorite and hydrogen peroxide; the concentrations of 2.5 mM sodium hypochlorite and 7.5 mM hydrogen peroxide provided highest chemiluminescence intensities without bubble formation. Also, the effects of beverages, such as green tea, coffee, white wine, red wine, and sake (rice wine), on the chemiluminescence intensity as well as the concentrations of sodium hypochlorite and hydrogen peroxide were examined. The chemiluminescence intensities observed with addition of the beverages to the reagents decreased in the following orders; green tea > coffee > red wine > rice wine > white wine (being added to sodium hypochlorite); coffee > white wine > green tea > red wine > rice wine (being added to hydrogen peroxide). It was found that coffee decreased the chemiluminescence intensity (ca. 33% chemiluminescence decrease) without altering the concentrations of sodium hypochlorite or hydrogen peroxide. The cause of the decrease in chemiluminescence with coffee is discussed.     

铁氰化钾-钙黄绿素抑制化学发光法测定利福平

在碱性条件下,利福平对铁氰化钾-钙黄绿素化学发光体系有较强的抑制作用,结合流动注射分析技术,建立了一种化学发光测定利福平的新方法。考察了介质浓度、发光试剂浓度等因素的影响,在优化实验条件下,该方法对利福平的检出限为6.81×10-2mg/L,线性范围为0.5~100 mg/L,对50 mg/L的利福平连续进行11次平行测定,其相对标准偏差为0.86%,该方法已成功用于滴眼液及胶囊中利福平含量的测定。     

微流控层流技术的研究

基于微型通道自身的层流特点而发展起来的多相层流技术,从最初的液-液微萃取开始,由于其结构加工简单、操作方便和分析功能强大,已逐渐发展成为一种加工分析方法,为微流控分析的研究应用打开了一个崭新的局面。本文概述了层流的基本原理,总结了近10年来在这方面的研究,包括层流界面间的分子扩散、转移现象和化学反应,以及层流刻蚀加工技术及其在制备纳米材料和在生命医学方面的应用。具体介绍了应用层流技术进行微芯片的加工制作,微型反应器的制备,离子、分子的分离分析,聚合物薄膜的形成和应用,微通道内有机合成反应的控制,溶液的浓度梯度控制以及在免疫检测中的应用,对细胞、生物大分子的操作控制,以及对生物试剂的预处理分析等。     

微流控层流技术的研究

基于微型通道自身的层流特点而发展起来的多相层流技术,从最初的液-液微萃取开始,由于其结构加工简单、操作方便和分析功能强大,已逐渐发展成为一种加工分析方法,为微流控分析的研究应用打开了一个崭新的局面。本文概述了层流的基本原理,总结了近10年来在这方面的研究,包括层流界面间的分子扩散、转移现象和化学反应,以及层流刻蚀加工技术及其在制备纳米材料和在生命医学方面的应用。具体介绍了应用层流技术进行微芯片的加工制作,微型反应器的制备,离子、分子的分离分析,聚合物薄膜的形成和应用,微通道内有机合成反应的控制,溶液的浓度梯度控制以及在免疫检测中的应用,对细胞、生物大分子的操作控制,以及对生物试剂的预处理分析等。     

Simultaneous anodic stripping voltammetric determination of lead and cadmium with a carbon paste electrode modified by tributyl phosphate

A novel chemiluminescence (CL) flow sensor has been developed for the monitoring of iron(III). The analytical reagents involved in the CL reaction, including luminol and hexacyanoferrate(II) were both immobilized on an anion-exchange resin column. When sodium sulfate solution was passed through the column, these two reagents were eluted from the resins and then mixed with an iron(III) stream. By the fast reaction between iron(III) and hexacyanoferrate(II), the complex Prussian Blue was generated, which could catalyse the luminol oxidation by dissolved oxygen in alkaline aqueous solution to produce CL. The CL emission intensity was correlated with the standard iron(III) concentration in the range 0.01-Smgl^–1, and the detection limit was 7 × 10^–3mgl^–1 iron(III). A complete analysis, including sampling and washing, could be performed in l min with a relative standard deviation of less than 5%. The sensor was stable for over 200 times and has been applied successfully to the determination of iron in blood samples.     

Chemiluminescence from singlet oxygen that was detected at two wavelengths and effects of biomolecules on it

We developed the detection apparatus that equipped with the two-photomultiplier tubes for chemiluminescence from singlet oxygen. Singlet oxygen was generated with reaction between sodium hypochlorite and hydrogen peroxide. The chemiluminescence from singlet oxygen, the dimol light emission (ca. 634 nm) and the monomol light emission (ca. 1270 nm), was observed simultaneously for the same reaction cell. The effects of sodium azide as an antioxidant, human serum albumin, and α-amino acids on the chemiluminescence based on the both emissions were examined; the observed chemiluminescence could provide direct information with regard to the reaction between singlet oxygen and antioxidant/biomolecules. The apparent rate constants for quenching singlet oxygen in the presence of human serum albumin were calculated to be ca. 3.3 × 10⁹ and ca. 8.8 × 10⁸ M⁻¹ s⁻¹ for the dimol and monomol light emissions, respectively, under the present conditions. The chemiluminescence intensities of the dimol emission decreased in the presence of His, Asp, Phe, Ser, and Tyr, and that of the monomol decreased in the presence of Cys and Trp. The chemiluminescence observed in the presence of biomolcules was discussed together with the reactivities of sodium hypochlorite and hydrogen peroxide to biomolecules.     

Uses of the transit time distribution in kinetic flow systems

We investigate the distribution of transit or residence times of a trace reactant in laminar flow. We present measurements of this distribution for hydrogen atoms in a typical flow system, and show that the results are consistent with known theory and previous measurements of the diffusion coefficient. The use of the measured distribution as a diagnostic of flow behavior is discussed. It is also shown that the measured or calculated transit time distribution can provide a convenient means of correcting results of kinetic measurements for the departure from plug flow. In the case of firstorder, and also second-order decay of a single reactant, this correction is a useful approximation to the more rigorous solution of the partial differential equation for diffusion and reaction in laminar flow. Effects of the deviation from plug flow on a complex rection system are illustrated qualitatively for the H + NO₂ titration system.     

Single-molecule resolution of interfacial fibrinogen behavior: effects of oligomer populations and surface chemistry

Through the use of single-molecule total internal reflection fluorescence microscopy, the dynamic behavior of fibrinogen was observed at the interface between aqueous solution and various solid surfaces. Multiple populations of objects were observed, as characterized by surface residence times, interfacial diffusion, and fluorescence intensity. On all surfaces, populations exhibited direct links between surface residence time, rate of diffusion, and fluorescence intensity. In particular, longer-lived populations diffused more slowly and exhibited greater fluorescence intensity, leading to the conclusion that the objects represented fibrinogen monomers and discrete oligomer populations (dimers, trimers, etc.), and that these oligomer populations play an important role in the protein-surface interaction because of their long surface residence times. Two or three diffusive modes were observed for most populations, indicating that protein aggregates have multiple mechanisms for interaction with solid substrates. In addition, the fastest diffusive mode is believed to represent a hopping mode that often precedes desorption events. Surprisingly, a monolayer of 5000 Da poly(ethylene glycol) (PEG5000) increased surface residence time and slowed diffusion of fibrinogen relative to bare fused silica or hydrophobically modified fused silica, suggesting that the mechanism of PEG resistance to protein adhesion is more sophisticated than the simple repulsion of individual proteins.     

Light Emission Resulting from Hydroxylamine-Induced Singlet Oxygen Formation of Oxidizing LDL Particles

Abstract— Oxidation of low-density lipoprotein (LDL) by low amounts of cupric ions resulted in the formation of singlet oxygen (₁O₂, ₁DL_g) when hydroxylamine (NH2OH) was added. Direct evidence on this excited species came from partial spectral resolution of the emitted light in the red spectral region (634 nm and 703 nm), which can be attributed to the dimol decay of singlet oxygen. Additional evidence for the existence of singlet oxygen came from the enhancing effect of deuterium oxide buffer (D20) on chemiluminescence intensity and the quenching effect of sodium azide. A linear correlation between NH2OH-de-pendent chemiluminescence intensity and the amount of diene conjugates (DC) formed in this reaction was observed. Removal of adventitious transition metals by adequate chelators prevented chemiluminescence in this system; NH2OH was also found to efficiently decrease metabolites of lipid peroxidation (LPO). Our findings are consistent with a sequence of reactions in which NH2OH first converts transition metals to their reduced state, thereby stimulating the formation of alkoxy- and peroxy-radicals. Peroxyradicals decompose in a bimolecular Russel reaction to hydroxyl compounds and singlet oxygen while the majority of alkoxy radicals are eliminated by a secondary reaction with NH2OH. Identical effects were observed when reducing antioxidants such as ascorbic acid or trolox C were used instead of hydroxylamine.     

流动注射化学发光法测定头孢噻肟钠

基于在碱性介质中头孢噻肟钠对鲁米诺-K3Fe(CN)6化学发光体系的增强作用,建立了流动注射化学发光测定头孢噻肟钠的新方法.头孢噻肟钠的质量浓度与化学发光强度的变化在2.4～30 mg/L和60～300 mg/L范围内呈良好的线性关系,检出限为0.63 mg/L,对浓度为30 mg/L的头孢噻肟钠进行9次平行测定,相对标准偏差(RSD)为1.0%.该法简便、快速、可靠,将其用于头孢噻肟钠针剂的测定,结果令人满意.     

Chemiluminescence flow sensor for the determination of ascorbic acid with immobilized reagents

A novel flow sensor based on chemiluminescence (CL) for the determination of ascorbic acid has been proposed. The analytical reagents, luminol and ferricyanide, were both immobilized on an anion-exchange resin column. The CL signal produced by the reaction between luminol and ferricyanide, which were eluted from the column through sodium phosphate injection, was decreased in the presence of ascorbic acid. The CL emission intensity was linear with ascorbic acid concentration in the range 0.01-0.8 mug ml(-1); the detection limit was 5.5 x 10(-3) mug ml(-1). The whole process, including sampling and washing, could be completed in 1 min with a relative standard deviation of less than 5%. The sensor could be reused more than 100 times and has been applied successfully to the analysis of ascorbic acid in pills and vegetables.     

鲁米诺-铁氰化钾化学发光体系对盐酸环丙沙星的测定

环丙沙星对NaOH介质中的鲁米诺-铁氰化钾的化学发光具有较强的增敏作用,据此建立了一种新的测定痕量环丙沙星药物的流动注射化学发光法。讨论了介质浓度、发光试剂浓度等因素的影响,在最佳实验条件下,环丙沙星的质量浓度在2.0×10-5~1.2×10-4g.L-1范围内与发光强度呈良好线性关系,检出限为1.2×10-6g.L-1,11次平行测定4.0×10-5g.L-1环丙沙星的相对标准偏差为3.2%。该方法已用于环丙沙星片剂的测定,所得结果与标示值相符。     

PEROXIDASE MEDIATED CHEMILUMINESCENCE WITH PHENOL DERIVATIVES. PHYSICO-CHEMICAL PARAMETERS AND USES IN BIOLOGICAL ASSAYS

Abstract— The influence of pH and concentration of reagents on the chemiluminescence emitted during peroxidase mediated oxidation of phenol derivatives was studied. Maximal light emission was determined under conditions where chemiluminescence due to auto-oxidation was negligible. With phloroglucinol and purpurogallin as substrates, a direct proportionality was obtained between the concentration of peroxidase and the maximal light emission. p-Phenylenediamine enhances 8-fold the light emitted with purpurogallin. With resorcinol as substrate the relation between concentration of enzyme and maximal light emission gives an S-shaped curve. With pyrogallol the light emitted is proportional to the square of the concentration of peroxidase.     

Chemiluminescence study of polymer oxidative stability

The application of the chemiluminescence technique to the study of polymer oxidative stability is discussed. For the initial stages of oxidation a sigmoidal change in the chemiluminescence intensity with time is justified when the experiment is performed isothermally at high oxygen pressure, whereas at low oxygen pressure and constant heating rate an exponential increase in the chemiluminescence intensity is expected. For advanced stages of oxidation depending on the ratio between the initial and equilibrium levels of hydroperoxides, the intensity of emitted light may either grow or decay until the equilibrium concentration of hydroperoxides is established. Two major parameters of an autocatalytic oxidation (induction time and oxidation rate) can be obtained by carrying out the experiment in an oxygen atmosphere at constant temperature. Alternatively, the extent of oxidation in a certain temperature region can be evaluated when a constant-heating-rate experiment is conducted under nitrogen.     

Flow—injection Chemiluminescence Determination of Reserpine in Medicine and Biological Fluids with Controlled—Reagent—Release Technology

A sensitive and rapid chemiluminescence(CL) flow injection with controlled-reagent-release technology for the determination of reserpine was proposed.The Cl reagents,luminol and dichromate,uses in this sensor,were all immobilized on anion-exchange resin.Through injection of 100μl of water,the reagents on the anion-ex-change resin column were eluted and in the presence of reserpine ,the CL intensity was decreased,by which reserpine could be sensed.Reserpine was quantified by measuring the decrement of CL intensity,which was observed linear with the logrithm of reserpine concentration in the rage of 1.0-500.0ng/mL,and the limit of detection was 0.4ng/mL(3σ)with a relative standard deviation of less than 3.0?The proposed procedure was applied in the assay of reserpine in pharmaceutical preparation and biological fhuids without any pre-treatment process and with sampling frequencies of 72 times per hour.     

Near-ultraviolet chemiluminescence from the reaction of ammonia with hypobromite in aqueous solution

The chemiluminescence arising from the oxidation of ammonium chloride by sodium hypobromite in aqueous alkaline solution includes a series of peaks in the near-ultraviolet, which is not commonly observed in liquid-phase chemiluminescence. The dominant peak in that region has an intensity maximum at 292 nm and smaller peaks are observed at 313, 334 and 356 nm. The emitted photons are of similar energy to the Vergard-Kaplan transition of molecular nitrogen, a major product of this reaction. However, the spectral distribution is different to that of previously reported gas-phase chemiluminescence attributed to the Vergard-Kaplan transition.     

In Vitro Monitoring of Picogram Levels of Captopril in Human Urine Using Flow Injection Chemiluminescence with Immobilized Reagent Technique

Abstract

A flow‐injection procedure for detection of captopril using a Co²⁺‐captopril complex formed on line based enhancement of luminol and dissolved oxygen chemiluminescence is described. The chemiluminescence reagents, luminol and Co²⁺, were both immobilized on ion exchange resin in the flow injection system. When captopril solution flowed through the immobilized Co²⁺ column, the Co²⁺‐captopril (1:2) complex formed on line could greatly enhanced the chemiluminescence intensity generated from the reaction between luminol and dissolved oxygen. The increment of chemiluminescence emission was correlated with the captopril concentration in the range from 7 to 1000 pg mL^?1, and the detection limit was 2 pg mL^?1 (3σ). One analysis cycle, including sampling and washing, could be accomplished in 0.5 min with relative standard deviations of less than 3.0% (n=11). The proposed method was applied directly in the assay of human urine without any pretreatment and it was found that the captopril concentration reached its maximum after being administrated orally for 1.5 hours, with the mean excretion ratio in 6.5 hours of 54.3% in the body of volunteers. The possible chemiluminescence mechanism was discussed.     

地塞米松磷酸钠的流动注射-化学发光分析法的研究

实验了地塞米松磷酸钠在K3Fe（CN）6-鲁米诺、KMnO4-鲁米诺、KIO4-鲁米诺、H2O2-鲁米诺体系中的化学发光现象。结果表明,地塞米松磷酸钠能够显著增强K3Fe（CN）6-鲁米诺体系和KMnO4-鲁米诺体系的化学发光强度,而在另外两个体系中没有增强作用。结合流动注射技术,分别在K3Fe（CN）6-鲁米诺体系和KMnO4-鲁米诺体系中建立了测定地塞米松的新方法。方法的线性范围分别为1.0×10^-7-1.0×10^-5g/mL和6.0×10^-8-1.0×10^-5g/mL,检出限分别为3.0×10^-8g/mL和2.0×10^-8g/mL,相对标准偏差分别为1.6%和1.9%（1.0×10^-6g/mL地塞米松,n=11）。此法已用于针剂和片剂样品的测定,结果与药典方法没有显著性差异。     

SPECTRAL ANALYSES OF LOW LEVEL CHEMILUMINESCENCE OF A SHORT LIFETIME USING A HIGHLY SENSITIVE POLYCHROMATIC SPECTROMETER INCORPORATING A TWO DIMENSIONAL PHOTON-COUNTING TYPE DETECTOR

Abstract— Spectral analyses of low level chemiluminescence were carried out by using a newly developed polychromatic spectrometer in which a diffracted photon emission was detected simultaneously using a two dimensional photon-counting device. The spectrometer was sensitive in the 400–800 nm wavelength range. Low level chemiluminescence generated in a 1 nM luminol solution could be detected as a spectrum, showing a peak at 430 nm. Short lifetime photon emission from singlet oxygen showed only two peaks at around 630 and 700 nm in this highly time-resolved spectroscopy. Lipid peroxidation of linoleic acid by the lipoxygenase emitted a low intensity peak centered at 440 nm, but singlet oxygen emission arising from the decomposition of lipid peroxide was not observed. An injured cotyledon of a soybean seedling gave a broad emission centered at 725 nm in the absence of hydrogen peroxide, while in its presence a different emission peak appeared at a shorter wavelength (515 nm). Oxygenated, fluorescent components in the soybean seedling may be the emitting species. Singlet oxygen and triplet carbonyl groups were shown to be unlikely sources of the emission.     

Monitor for measuring the total concentration of reactive hydrocarbons in ambient air based on their chemiluminescence reaction with oxygen atoms

The monitor functions by measuring the intensity of the chemiluminescence radiation at 309 nm which is emitted during the reaction of hydrocarbons with O(³p) atoms. The system comprises a specially-developed stable source of atomic oxygen, a detection unit for measuring the intensity of the chemiluminescence radiation and a device for preconcentration of the hydrocarbons to be determined. The sensitivity of the monitor depends on the concentration and reactivity of the hydrocarbons, and is greatest for unsaturated compounds. For butadiene, the detection limit is 3 ppb, and response is linear over the range 0–2500 ppb. The monitor can also serve as a detector for unsaturated hydrocarbons in gas chromatography.