Chemiluminescence Intensity Research Articles

Decreased Production of the Superoxide Anion Radical in Neutrophils Exposed to a Near-Null Magnetic Field

This paper reports that pre-incubation of a neutrophil suspension in the presence of a near-null magnetic field produced using a system of magnetic shields (a residual constant magnetic field not greater than 20 nT) results in a considerable decrease in the intensity of neutrophil lucigenin-dependent chemiluminescence. The addition of the NADPH oxidase inhibitor diphenyliodonium to the incubation medium reduced the chemiluminescence intensity in both the experimental and the control samples (geomagnetic field). It should be noted that the differences observed between the groups, which were caused by the exposure to a near-null magnetic field, are almost the same both at lower (2.5, 5, and 10 μM) and higher (50 and 100 μM) diphenyliodonium concentrations. In contrast, the addition of 2,4-dinitrophenol, an uncoupler of oxidative phosphorylation in mitochondria, in concentrations starting from 5 μM and up to 200 μM almost completely eliminated the difference between the control and experimental samples, which was observed at low inhibitor concentrations, or in its absence.

Specifically immobilizing His-tagged allergens to magnetic nanoparticles for fast and quantitative detection of allergen-specific IgE in serum samples

Fast and accurate detection of specific IgE (sIgE) is essential for diagnosis of allergic diseases. In this study, we developed a nano-capturer Fe3O4@SiO2-NTA based on magnetic nanoparticles with surface modification of Ni-NTA moieties. Results showed that our immunosensor based on the specifically immobilization of recombinant allergen protein on the Fe3O4@SiO2-NTA could realize fast, high efficiency and low-cost detection of sIgEs in serum samples. In vitro experiments demonstrated that the chemiluminescence (CL) response of the immunosensor to sIgEs showed an obviously discrimination between positive and negative serum samples. The CL intensity values were proportional to the sIgE concentrations in the range of 2.52–14.02 ng/mL with detection limit of 0.35 ng/mL, which offered a promising platform for fast and quantitative determination of sIgEs. Furthermore, our method was successfully utilized for allergic disease diagnosis in 46 serum samples and satisfied results were achieved in comparison with the commercial ELISA kit. In particular, by simply changing various recombinant allergen proteins immobilized on the surface of Fe3O4@SiO2-NTA, our strategy showed great potential for high-throughput analysis of allergen screening.

Bifunctionalized Prussian blue analogue particles oxidize luminol to produce chemiluminescence without other oxidants

In this paper, a novel chemiluminescence (CL) system was constructed based on the oxidizing properties of Fe-Co-Co. Fe-Co-Co, a prussian blue analogue (PBA), can significantlyenhance the CL intensity of luminol under alkaline conditions more than 95 times without the addition of other oxidants. Moreover, the CL intensity of luminol-Fe-Co-Co system is 29 times higher than that of the luminol-potassium ferricyanide (K3[Fe(CN)6]) system, because of the synergy of bimetals and the catalytic performance of nanomaterials. When adding dopamine (DA) into this new system, the CL intensity decreased. Based on this, we developed a new method to detect DA. The signal intensity of the chemiluminescence system is linearly related to the concentration of DA in the range of 0.1–5.0 μM, and the detection limit of DA is 0.06 μM. Finally, this CL method has been successfully used for the determination of DA in human serum samples.

Quantitative Measurement of OH* and CH* Chemiluminescence in Jet Diffusion Flames.

Quantitative measurement of chemiluminescence is a challenging work that limits the development of combustion diagnostics based on chemiluminescence. Here, we present a feasible method to obtain effective quantitative chemiluminescence data with an integrating sphere uniform light source. Spatial distribution images of OH* and CH* radiation from methane laminar diffusion flames were acquired using intensified charge-coupled device (CCD) cameras coupled with multiple lenses and narrow-band-pass filters. After the process of eliminating background emissions by three filters and the Abel inverse transformation, the chemiluminescence intensity was converted to a radiating rate based on the uniform light source. The simulated distributions of OH* and CH* agree well with the experimental results. It has also been found that the distribution of OH* is more extensive and closer to the flame front than that of CH*, demonstrating that OH* is more representative of the flame structure. Based on the change in the reaction rate of different formation reactions, OH* distributions can be divided into three regions: intense section near the nozzle, transition section in the middle of the flame, and secondary section downstream the flame, whereas CH* only exists in the first two regions. In addition, as the velocity ratio of methane and co-flowing air increases, the main reactions become more intense, while the secondary reaction of OH* becomes weaker.

Chemiluminescence for rapid detection of free radicals in starch samples

Using the electron paramagnetic resonance (EPR) signal intensity for heat-treated rice starch (RS), a chemiluminescence (CL) method was established for the rapid determination (<40 s) of the free radical content in starch samples. Results showed that the initial CL intensity of hydration for RS samples was significantly correlated with the signal intensity measured using EPR, validating this CL method for detecting RS radicals. This method could also be used to detect free radical content in starches from other sources. It was speculated that the correlation coefficients between two intensities was associated with the differences of crystalline structures and granular sizes among starches. These results provide the possibility that the CL method could be used to detect starch radicals and compensate for the limitations of EPR method to detect free radicals in starch samples with high moisture content.

Detection of tannic acid exploiting carbon dots enhanced hydrogen peroxide/potassium ferricyanide chemiluminescence

Recently, ultra-weak chemiluminescence (CL) systems have become one of the focuses of increasing attention. As one of them, H2O2-K3Fe(CN)6 system had also been studied. However, no attempts had been made to investigate the analytical applications of this system based on carbon dots (CDs). In this paper, nitrogen-doped carbon dots (FNCDs) were synthesized using formaldehyde as a coreactant, and it acted as a new fluorophore instead of conventional fluorescent dyes to enhance the CL signal of H2O2-K3Fe(CN)6 system, in which the excited-state FNCDs was the final emitting species, and was probably produced by the electron transfer and energy from reactive oxygen species. Interestingly, tannic acid (TA) could dramatically suppress the CL intensity of FNCDs-H2O2-K3Fe(CN)6 system. Under the optimum conditions, a linear relationship existed between reduced CL intensity and logarithm of TA concentration in range between 0.2 and 10.0 μM with a detection limit of 39.3 nM. The method was applied to the quantitative analysis of TA concentration in red wine.

Development of luminol-fluorescamine-PVP chemiluminescence system and its application to sensitive tyrosinase determination

Fluorescamine is a popular fluorescent probe. We report for the first time that luminol chemiluminescence (CL) can be enhanced by fluorescamine in the presence of PVP. The CL intensity of luminol-fluorescamine-PVP is about 26 times stronger than that of luminol. Both the removal of oxygen and the addition of superoxide dismutase (SOD) decrease CL intensity, thiourea and NaN3 have little effect on CL intensities, indicating that O2•− is critical for CL. Interestingly, o-quinone generated from phenol by tyrosinase obviously inhibited the CL intensity. Inspired by such quenching effect on the luminol-fluorescamine-PVP CL system, a sensitive CL sensing for the determination of tyrosinase activity was developed. The method can detect tyrosinase in the range of 0.07–1.5 μg mL−1 (0.19–4.02 U mL−1) with the detection limit of 0.035 μg mL−1 (0.094 U mL−1). Moreover, this method exhibits satisfied recoveries for the spiked human serum samples.

Effects of Cavity Location on Ethylene–Air Continuous Rotating Detonation in a Cavity-based Annular Combustor

ABSTRACT To settle the realization difficulty of continuous rotating detonation (CRD) fueled by hydrocarbon, a cavity-based annular combustor scheme was proposed in our previous study, and its feasibility was well demonstrated. This paper mainly focuses on effects of the cavity location on CRD. The results show that the CRD operating range reduces, as the cavity moves downstream. When cavity is arranged in the detonation zone, the cavity-stabilized flame is coordinated with the reaction zone of detonation. The cavity can intensify the CRD initiation, and CRD waves propagate as co-rotating two-wave mode with higher outlet pressure, higher frequency, and higher stability. When cavity is downstream arranged out the detonation zone, it has little impact on improving the CRD initiation. CRD waves propagate as counter-rotating two-wave mode with lower outlet pressure, lower frequency, and poor stability. In these cases, the majority of reaction zone of detonation concentrates on the upstream annular part, and the cavity-stabilized flame is separated from the reaction zone of detonation, acting as afterburning. A new quantitative approach, the axial distribution of chemiluminescence intensity, has been proposed in this paper, and the separation and move processes of cavity-stabilized flame are verified quantitatively based on it.

Determination of Mancozeb and Maneb using flow injection chemiluminescence detection

ABSTRACTA rapid flow injection chemiluminescence method is developed to determine mancozeb and maneb fungicides in natural water samples in the range 0.0025–0.25 ppm (R2 = 0.9996, n = 6) and 0.01–0.75 ppm (R2 = 0.9994, n = 6) with limit of detections of 0.001 and 0.005 ppm (S/N = 3), relative standard deviations of 1.75% and 1.8% and 200 h–1injection throughputs, respectively. The method is based on diperiodatonickelate(IV)-rhodamine 6-G-Brij-35 chemilu-minescence reaction in potassium hydroxide medium enhanced by mancozeb and maneb. Several other oxidising agents instead of diperiodatonickelate(IV) are checked and diperiodatoargentate(III) enhanced appreciably the emission chemiluminescence intensity. Mancozeb and maneb are extracted from water samples by solid-phase extraction technique with the calculated recoveries in the range of 92–108% and relative standard deviations of 1.41–2.67%. The probable chemiluminescence mechanism is proposed with the help of UV-Vis spectrophotometric and CL studies.

A Smart Advanced Chemiluminescence-Sensing Platform for Determination and Imaging of the Tissue Distribution of Natural Antioxidants.

Antioxidants have gained marked attention owing to their ability to prevent the oxidation of biological components and to protect the body from reactive oxygen species, thereby maintaining human health. Thus, antioxidant-rich dietary supplements and natural foods can be effective against oxidative stress and can even act as chemopreventive agents. Therefore, a simple and rapid assay for evaluation of antioxidant capacity and assessment of their distribution profile in natural sources is vital. Herein, we report a rapid, innovative chemiluminescence (CL) platform for evaluation and visualization of antioxidant capacity. We found that intense and long-lasting CL was formed upon the redox reaction of quinones, e.g., menadione, with antioxidants, e.g., l-ascorbic acid, in the presence of luminol. The produced CL intensities were proportional to the antioxidants' concentrations with a detection limit of 0.18 μM for the model antioxidant, l-ascorbic acid. As the formed CL was long-lasting, it could be easily captured and detected with a charge-coupled device (CCD) camera. To evaluate the quantification ability of the CCD camera, we developed a smart and fast microplate-based assay based on photographing the generated CL with a cooled CCD camera. The photographed CL intensities were linearly proportional with the antioxidant concentrations, and then the method was applied for photographing multiple food sample extracts. Ultimately, we utilized our method for the distribution profiling of antioxidant capacity in food cut sections. Samples were dipped in luminol and then in quinone, followed by CCD camera photography, without the need for any pulverization/extraction procedure, giving precise antioxidant distribution information.

Cobalt-doped hydroxyapatite nanoparticles as a new eco-friendly catalyst of luminol-H2O2 based chemiluminescence reaction: Study of key factors, improvement the activity and analytical application.

In this study, a novel catalyst based on hydroxyapatite doped by cobalt for chemiluminescence reaction of luminol oxidation by H2O2 was suggested for the first time. The catalyst nanoparticles were synthesized by a hydrothermal method and characterized by various methods including density functional theory calculations. The impact of nanoparticles sizes, surface composition, contact efficiency and crystallinity on chemiluminescence intensity were investigated. The maximum chemiluminescence intensity was obtained for polycrystalline nanoparticles. This phenomenon was studied in detail and applied for chemiluminescence analysis for the first time. The chemiluminescence determination of sulfonamides as model analytes was considered. The sensing was based on sulfonamides-dependent quenching of the chemiluminescence intensity in the presence of novel catalyst existed as an aqueous suspension.

Synergistic effect of Chromotrope 2R as a novel sensitizer for chemiluminescence reactions of potassium permanganate: Determination of naproxen and naltrexone

A novel chemiluminescence (CL) reaction was proposed to determine naproxen and naltrexone based on the synergistic effect of Chromotrope 2R in the CL system of acidic KMnO4. Eight dyes including Chromotrope 2R, Rhodamine 6G, Amido black 10B, Eosin Y, Amaranth, Brilliant blue, Orange G and Victoria blue were evaluated, and Chromotrope 2R produced the highest signal and signal to background for the analytes, namely ascorbic acid, citric acid, oxalic acid, tartaric acid, maleic acid, thiourea, codeine, pholcodine, naproxen and naltrexone. Among these species, naproxen and naltrexone were chosen as model analytes. In the proposed method, the weak CL intensity of acidic KMnO4-naoproxen (or other analytes) increased significantly in the presence of Chromotrope 2R, and the CL intensity was proportional to naproxen (or naltrexone) concentration. The CL reaction mechanism was investigated through UV–Vis, fluorescence and CL spectra. Under optimal conditions, the CL intensity was found to be linearly proportional with the naproxen and naltrexone concentrations respectively in the range of 23–4600 μg mL−1 and 1.3–238.7 μg mL−1. The limits of detection for naproxen and naltrexone were 4.7 and 0.1 μg mL−1, respectively. The relative standard deviation (n = 7) for 161.2 μg mL−1 naproxen and 13.6 μg mL−1 naltrexone was 4.8% and 5.9%, respectively. This method was used for determination of naproxen in drug formulations and naltrexone in synthetic samples.

Diesel/syngas co-combustion in a swirl-stabilised gas turbine combustor

Multiphase fuel combustion was carried out in a swirl-stabilised combustor with the aim of expanding the fuel flexibility of the gas turbine for, at least, land-based applications. Improved capability of the gas turbine in this regard will not only augur well for energy security but also could be useful in tackling harmful emissions. In the study, varying amounts of syngas was premixed with air and swirled into a burning diesel spray, the flowrate of which was altered to maintain the same heat output at all times. Across the several heat outputs tested, the range of stable flame operation was found to reduce as gas content of fuel mix increased. Moreover, for a combined heat output of 15 kW and a global equivalence ratio of 0.7, a steady increase in flame stability was noted and NOx emissions were found to decrease while CO emissions increased as syngas content in fuel mix increased from 10% to 30%. The increase in flame stability, achieved at the cost of lower heat release rate, was attributed to the changes in reacting flow dynamics evinced by the C2* and CH* species chemiluminescence intensity variation as well as chemical kinetics analysis. The NOX and CO emissions trend was ascribed to increasingly inefficient combustion due to the poorer spray quality obtained from pressure atomiser as liquid flow rate reduces and further worsened by the lower heat release rate and decreasing adiabatic flame temperature as gas ratio of combusted fuel increases.

Detection of resistance genes from Pseudomonas aeruginosa using immunomagnetic isolation and chemiluminescence

Pseudomonas aeruginosa (P. aeruginosa) is a common opportunistic and nosocomial bacterial pathogen. Various multi-resistance mechanisms present across numerous P. aeruginosa strains counteract conventional antimicrobial therapy, thereby becoming a great challenge. This study aimed to establish the application of immunomagnetic isolation and chemiluminescence to detect the presence of extended spectra of β-lactamases encoding genes: blaTEM and blaVEB; metallo-beta-lactamases encoding gene: blaVIM; aminoglycoside modifying enzymes encoding gene: aac(6)II, ant(3)I; and the specific gene for P. aeruginosa, gyrB. P. aeruginosa was specifically selected using the immunomagnetic nanoparticles (IMNPs) in the six parallel bacterial plates counting, proving that they are reliable. Then, the high efficiency of IMNPs@Probes in targeting the resistance genes of P. aeruginosa was demonstrated using the results of chemiluminescent intensities of blaTEM, blaVEB, blaVIM aac(6)II, ant(3)I, and gyrB (more than 10 times higher than that of the control). Sixty-eight in situ clinical samples were tested for the presence of these resistance genes, and one more blaTEM and three more blaVIM individuals were detected using this method compared to the traditional PCR. Thus, the application of our method in clinical screening is specific, accurate, and reliable, and it could be useful in the administration of appropriate treatment.

A Flow Injection Chemiluminescence Method for the Determination of Retinol in Pharmaceutical Formulations by Using Luminol-Diperiodatoargentate(III) Reaction.

In this paper, a chemiluminescence (CL) method is proposed for retinol determination by combining flow injection (FI) methodology. The CL reaction is based on the oxidation of luminol by diperiodatoargentate(III) (DPA) in the presence of retinol. Under the optimum conditions, the relative CL intensity was linear to the concentration of retinol over the range 5.0×10-3-14 mg L-1 (y=347.26x+2.5944, R2=0.9999, n=8) with limit of detection (LOD) of 1.5×10-3 mg L-1 (S/N=3) and limit of quantification (LOQ) of 5.0×10-3 mg L-1 (S/N=10). The relative standard deviation (RSD) was from 1.04-3.4% over the range studied and injection throughputs of 150 h-1. The method was satisfactorily applied to retinol in pharmaceutical formulation samples. The samples were saponified and extracted with liquid-liquid extraction using ether as an extractant. The possible CL mechanism is supported by CL and UV-visible spectrophotometric studies.

Understanding chemiluminescence in catalytic oxidation of CO and hydrocarbons

A chemiluminescence (CL) instrument was developed to understand the CL behavior of catalytic oxidation of CO and hydrocarbons, which are major processes occurring in catalytic converters. The instrument is based on the cooperation among a gas mixer, a custom-made CL analyzer, and an on-line gas chromatography. The concept of the CL method was formulated by thoroughly investigating the CL emission during the catalytic oxidation of CO and C3H6 in the presence of O2 and/or NO under both stoichiometric and non-stoichiometric conditions. All the oxidation reactions were found to be CL-active, where the CL intensity increased exponentially with the temperature. The steady-state measurements showed good linearity between the CL intensity and the reaction rates, demonstrating that the CL emission is a direct product of the reactions. It was also found that the CL intensity per CO2 production was different among the reactions, most plausibly due to both/either the presence of multiple CL processes and/or the difference in the heat of the reactions. Based on the linear correlation between the CL intensity and the reaction rate, a feasibility study was successfully demonstrated for rapid catalyst evaluation in C3H6 oxidation.

A chemiluminescence reaction consisting of manganese(IV), sodium sulfite, and sulfur- and nitrogen-doped carbon quantum dots, and its application for the determination of oxytetracycline.

Sulfur- and nitrogen-doped carbon quantum dots (S,N-CQDs) were prepared by a solid-phase hydrothermal method from cysteine and citric acid and characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, and FTIR spectroscopy. These QDs were exploited as enhancers to amplify the chemiluminescence (CL) of manganese(IV)-sodium sulfite reaction. S,N-CQDs exceptionally enhanced the CL intensity of this system, around 900-fold. This effect was attributed to the energy transfer from SO2*, produced by reaction of Mn(IV) with SO32-, to S,N-CQDs. The maximum wavelength of CL emission was 480nm, which confirmed that the final emitting species was S,N-CQDs. After optimization of reaction conditions, the analytical applicability of S,N-CQD-Mn(IV)-SO32- CL system was studied. In the presence of oxytetracycline, the CL intensity was significantly diminished. A linear relationship was observed between CL signal and the logarithm of oxytetracycline concentration in the range of 0.075-3.0μM with a detection limit of 25nM. This CL assay for oxytetracycline was used for analysis of spiked milk and water samples. Graphical abstractSchematic representation of the amplified chemiluminescence (CL) reaction consisting of sulfur- and nitrogen-doped carbon quantum dots (S,N-CQDs) Mn(IV) and Na2SO3. Sub-micromolar levels of oxytetracycline can be determined by using this system.

Core-shell Au@Pt Nanoparticles Catalyzed Luminol Chemiluminescence for Sensitive Detection of Thiocyanate.

In this study, core-shell Au@Pt nanoparticles (Au@Pt NPs) with peroxidase catalytic activity were synthesized by the seed-mediated method, and were used to catalyze the reaction of luminol-H2O2 to enhance the chemiluminescence (CL) intensity. It was found that thiocyanate (SCN-) can effectively inhibit the catalytic activity of Au@Pt NPs. Based on this phenomenon, a method to detect SCN- by using the Au@Pt NPs-catalytic luminol-H2O2 CL system was established, which has an ultra-low detection limit and an ultra-wide linear range, as well as the advantages of being simple and having low-cost and convenient operation. The research mechanism indicated that SCN- could be adsorbed on the surface of Au@Pt NPs and occupies the active sites of Pt nanostructures, which led to a decrease in the amount of Pt0 and a loss of the excellent catalytic activity of Au@Pt NPs. After optimizing the experimental conditions, this assay for detecting SCN- exhibited a good linear range from 5 to 180 nM, and the low detection limit was 2.9 nM. In addition, this approach has been successfully applied to the detection of SCN- in tap-water samples, which has practical application value and embodies good development prospects.

Study of oxidative stress parameters in patients with chronic obstructive pulmonary disease exacerbation

The purpose of the study was to perform comparative assessment of circulating diene conjugant (DC, rel. u.) and Schiff's bases (SB, rel. u.) levels, intensity of chemiluminescence (I max , rel. lum. u.) in serum and antioxidant activity (AOA) in patients with chronic obstructive pulmonary disease (COPD) exacerbation taking into consideration broncho-obstructive disorder severity. Materials and Methods. Patients ( n = 119; mean age – 62.0 ± 4.8 years) with COPD were studied. Forced expiratory volume in 1st second (FEV 1 ) in subjects, randomized in group 1 ( n = 31), was ³ 80%, in group 2 ( n = 43) – 79-50%, in group 3 ( n = 45) – &lt; 49%. The control group ( n = 21) comprised of healthy non-smoking volunteers of matching age. Results. It was established that changes in oxidative stress (OS) parameters in patients with COPD could be bidirectional depending on ventilation disorder severity. The level of SB was increased in association with disease severity increasing. High level of DC and I max in all studied subjects was progressively decreased in association with increasing bronchial obstruction severity. There was 2-times increase of AOA at COPD exacerbation in patients of group 2 and significant decrease of this parameter in association with severe bronchial obstruction (FEV 1 &lt; 49%) compared to controls. Conclusion. The associations between levels of studied OS parameters and bronchial obstruction degree in patients with moderate and severe broncho-obstructive disorders.

Determination of L-Cystine in Tablets Using the Chemiluminescence Method

Aim. To develop the method for the quantitative determination of L-cystine in sublingual tablets Elthacin ® using the method of chemiluminescence inhibition in the H 2 L (luminol) – Н 2 О 2 – Нb (hemoglobin) system. Materials and methods. The study objects were the pure substance of L-cystine of pharmaceutical grade and sublingual tablets Elthacin ® produced by the Medical Scientific-Production Complex “Biotics Ltd” (Russia) containing 70 mg of glycine, L-glutaminic acid and L-cystine in their composition. The intensity of chemiluminescence was measured on the device with a FEU-84-A photoelectric multiplier using an IMT-0.5 measuring instrument of low currents and a quick-acting automatic potentiometer. Results and discussion. The method of the L-cystine quantitative determination in tablets based on the inhibition of chemiluminescence in the H 2 L – H 2 O 2 – Hb system has been developed. The calibration graph was linear over the concentration range from 7 to 70 μg · mL –1 . No interferences were observed in the presence of common components of the tablets, such as glycine and L-glutaminic acid. RSD = ± 2.35 %, (δ = + 1.13 %), LOD (3S) = 4 μg · mL –1 , LOQ (10S) = 13 μg · mL –1 for the sublingual tablets Elthacin ® . Conclusions. The method proposed is promising for further research on the subject of its application for the determination of L-cystine in drugs.