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Journal articles on the topic 'Atomic fluorescence detection'

Author: Grafiati

Published: 4 June 2021

Last updated: 12 February 2022

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1

Zhang, Xiaogang, Shengnan Zhang, Duo Pan, Peipei Chen, Xiaobo Xue, Wei Zhuang, and Jingbiao Chen. "Hanle Detection for Optical Clocks." Scientific World Journal 2015 (2015): 1–6. http://dx.doi.org/10.1155/2015/614737.

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Considering the strong inhomogeneous spatial polarization and intensity distribution of spontaneous decay fluorescence due to the Hanle effect, we propose and demonstrate a universe Hanle detection configuration of electron-shelving method for optical clocks. Experimental results from Ca atomic beam optical frequency standard with electron-shelving method show that a designed Hanle detection geometry with optimized magnetic field direction, detection laser beam propagation and polarization direction, and detector position can improve the fluorescence collection rate by more than one order of magnitude comparing with that of inefficient geometry. With the fixed 423 nm fluorescence, the improved 657 nm optical frequency standard signal intensity is presented. The potential application of the Hanle detection geometry designed for facilitating the fluorescence collection for optical lattice clock with a limited solid angle of the fluorescence collection has been discussed. The Hanle detection geometry is also effective for ion detection in ion optical clock and quantum information experiments. Besides, a cylinder fluorescence collection structure is designed to increase the solid angle of the fluorescence collection in Ca atomic beam optical frequency standard.

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2

Sabé, Rosa, Roser Rubio, and Lydia Garcı́a-Beltrán. "Selenium determination in urine with atomic fluorescence detection." Analytica Chimica Acta 436, no. 2 (June 2001): 215–21. http://dx.doi.org/10.1016/s0003-2670(01)00966-7.

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3

D'Ulivo+, A., and S. Rapsomanikis. "Improvements in the Atomic Fluorescence Detection of Mercury." Analytical Letters 30, no. 11 (August 1997): 2109–22. http://dx.doi.org/10.1080/00032719708001725.

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4

Selwyn, Gary S. "Atomic arsenic detection by ArF laser‐induced fluorescence." Applied Physics Letters 51, no. 3 (July 20, 1987): 167–68. http://dx.doi.org/10.1063/1.98910.

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5

Lewkowicz, Aneta, Robert Bogdanowicz, Piotr Bojarski, Mattia Pierpaoli, Ignacy Gryczyński, Anna Synak, Michał Mońka, et al. "The Luminescence of 1,8-Diazafluoren-9-One/Titanium Dioxide Composite Thin Films for Optical Application." Materials 13, no. 13 (July 6, 2020): 3014. http://dx.doi.org/10.3390/ma13133014.

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The investigation of innovative label-free α-amino acids detection methods represents a crucial step for the early diagnosis of several diseases. While 1,8-diazafluoren-9-one (DFO) is known in forensic application because of the fluorescent products by reacting with the amino acids present in the papillary exudate, its application for diagnostic purposes has not been fully investigated. The stabilization of DFO over a transparent substrate allows its complexation with biomolecules for the detection of α-amino acids. In this study, DFO was immobilized into a titanium dioxide (TiO2) matrix for the fluorescence detection of glycine, as a target α-amino acid (a potential marker of the urogenital tract cancers). The DFO/TiO2 composite was characterized by atomic force microscopy, spectroscopic ellipsometry, fluorescence spectroscopy and fluorescence microscopy. The performed fluorescent studies indicate spectacular formation of aggregates at higher concentration. The measurements performed using various fluorescence and microscopic techniques together with the suitable analysis show that the aggregates are able to emit short-lived fluorescence.

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6

Bramanti, Emilia, Chandra Sortino, Cristina Lomonte, Massimo Onor, Roberto Zamboni, Giorgio Raspi, and Alessandro D’Ulivo. "Hydrophobic interaction chromatography coupled with atomic fluorescence spectrometric detection." Talanta 63, no. 2 (May 2004): 383–89. http://dx.doi.org/10.1016/j.talanta.2003.11.002.

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7

Biedermann, G. W., X. Wu, L. Deslauriers, K. Takase, and M. A. Kasevich. "Low-noise simultaneous fluorescence detection of two atomic states." Optics Letters 34, no. 3 (January 29, 2009): 347. http://dx.doi.org/10.1364/ol.34.000347.

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8

Masamba, W. R., B. W. Smith, R. J. Krupa, and J. D. Winefordner. "Atomic and Ionic Fluorescence in an Inductively Coupled Plasma Using Hollow Cathode Lamps Pulsed at High Currents as Excitation Sources." Applied Spectroscopy 42, no. 5 (July 1988): 872–78. http://dx.doi.org/10.1366/0003702884428851.

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Hollow cathode lamps pulsed at high currents were used as atomic and ionic fluorescence sources to excite atoms and ions in an inductively coupled plasma. Atomic fluorescence was measured for Cu, Ag, Zn, Al, Cr, and Mo, while ionic fluorescence was measured for Cu, Cr, Zn, and Sr. Limits of detection for atomic fluorescence were found to be better than those obtained by a commercial atomic fluorescence instrument operated under the same conditions, and calibration curves were linear over a range of approximately 104.

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9

Smith, Benjamin W., Mark R. Glick, Ken N. Spears, and James D. Winefordner. "A Comprehensive Table of Atomic Fluorescence Detection Limits and Experimental Conditions." Applied Spectroscopy 43, no. 3 (March 1989): 376–414. http://dx.doi.org/10.1366/0003702894202896.

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A comprehensive table of atomic fluorescence spectrometry results has been compiled and arranged by element. Data tabulated include excitation and fluorescence wavelengths, atom reservoir, excitation source, limits of detection, and comments concerning experimental peculiarities and types of samples analyzed.

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10

Pappas, Dimitri, Tiffany L. Correll, Nathan C. Pixley, Benjamin W. Smith, and J. D. Winefordner. "Detection of Mie Scattering Using a Resonance Fluorescence Monochromator." Applied Spectroscopy 56, no. 9 (September 2002): 1237–40. http://dx.doi.org/10.1366/000370202760295502.

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The use of a resonance fluorescence monochromator (RFM) is described as a method for detecting Mie scatter. The detector has a spectral resolution limited by the atomic vapor used in the system (400 MHz for cesium). The RFM is used to detect Mie scatter from a particulate suspension, and deconvolution methods are used to extract the Mie scatter spectrum from the instrument response. The Mie scattering linewidth (140 MHz) is close to the literature value (100 MHz for air). Methods to reduce the linewidth of atomic vapor filters are briefly described.

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11

Knox, Randy, William R. Kammin, and David Thomson. "Atomic fluorescence determination of mercury in fresh water ecosystems." Journal of Automatic Chemistry 17, no. 2 (1995): 65–71. http://dx.doi.org/10.1155/s1463924695000113.

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This paper reports on an investigation into determining nanogram/l quantities of mercury in marine and fresh water matrices using a cold vapour generation of mercury, followed by fluorescence detection. Samples were prepared for analysis using a free bromine oxidation technique. A high efficiency gas-liquid separator was used to enhance the detection of mercury. For fresh water, typical method detection limits (MDL) were determined at less than 1 nanogram/l (ng/l). For near shore seawater, the MDL was 1.2 ng/l. Method spikes, which were performed at 20 ng/l, showed mean recoveries within US EPA Contract Laboratory Protocol (CLP) acceptance criteria. System blanks averaged 0.12 ng/l, and recoveries of NIST 1641c diluted to 29.4 ng/l averaged 93.4%. A number of local rivers and streams were sampled, and mercury was determined. All results to date indicate mercury levels below the US EPA chronic water quality criteria for mercury.

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12

Goldsmith, J. E. M. "Two-step saturated fluorescence detection of atomic hydrogen in flames." Optics Letters 10, no. 3 (March 1, 1985): 116. http://dx.doi.org/10.1364/ol.10.000116.

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13

Gao, Rong, Zhibin Wu, Li Wang, Jiao Liu, Yijun Deng, Zhihua Xiao, Jun Fang, and Yunshan Liang. "Green Preparation of Fluorescent Nitrogen-Doped Carbon Quantum Dots for Sensitive Detection of Oxytetracycline in Environmental Samples." Nanomaterials 10, no. 8 (August 8, 2020): 1561. http://dx.doi.org/10.3390/nano10081561.

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Nitrogen-doped carbon quantum dots (N-CQDs) with strong fluorescence were prepared by a one-step hydrothermal method using natural biomass waste. Two efficient fluorescent probes were constructed for selective and sensitive detection of oxytetracycline (OTC). The synthesized N-CQDs were characterized by UV-visible absorption spectra, fluorescence spectra, Fourier transform infrared spectroscopy (FT-IR), X-ray photon spectroscopy (XPS), atomic force microscopy (AFM), and high-resolution transmission electron microscopy (HRTEM), which proved that the synthesized N-CQDs surface were functionalized and had stable fluorescence performance. The basis of N-CQDs detection of OTC was discussed, and various reaction conditions were studied. Under optimized conditions, orange peel carbon quantum dots (ON-CQDs) and watermelon peel carbon quantum dots (WN-CQDs) have a good linear relationship with OTC concentrations in the range of 2–100 µmol L−1 and 0.25–100 µmol L−1, respectively. ON-CQDs and WN-CQDs were both successfully applied in detecting the OTC in pretreated tap water, lake water, and soil, with the recovery rate at 91.724–103.206%, and the relative standard deviation was less than 5.35%. The results showed that the proposed N-CQDs proved to be green and simple, greatly reducing the detection time for OTC in the determination environment.

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14

Suzuki, Yoshio. "Development of Lectin Modified Fluorescent Magnetic Particles for Highly Sensitive Detection of Glycoconjugates." Sensors 21, no. 16 (August 17, 2021): 5512. http://dx.doi.org/10.3390/s21165512.

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I conducted this study to develop an improved method for glycome detection using fluorescent magnetic beads, whose surfaces were modified using lectins, for the highly sensitive detection of saccharides or glycoproteins via fluorescence quenching using a novel fluorescence emitter and quencher pair. The emitter (Cy3 fluorophore) was incorporated into magnetic beads, and a fluorescence quencher (cyanopyranyl group) was bound to glycomes via covalent bonding. The fluorescence intensities of fluorescent magnetic beads containing lectins decreased specifically in the presence of glycomes, which was a result of fluorescence quenching from Cy3 to cyanopyranyl groups due to the formation of a stable complex between lectins and glycome. Fluorescence intensities were plotted as a function of glycoprotein concentration, and good linear relationships were observed. This method enabled the fluorescent reading-out of a series of lectin-glycome interactions on the basis of recognition selectivity and affinity of immobilized lectins without tedious washing processes. Moreover, a simple profiling process was performed using this assay for diverse glycoconjugates, which not only included simple saccharides but also glycoproteins and glycome in cell lysates. These results clearly indicate that the combination of magnetic beads with the novel emitter-quencher pair enabled the highly sensitive detection of lectin-glycome interactions.

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15

Borisova, Ekaterina, Borislav Vladimirov, and Latchezar Avramov. "5-ALA Mediated Fluorescence Detection of Gastrointestinal Tumors." Advances in Optical Technologies 2008 (August 31, 2008): 1–7. http://dx.doi.org/10.1155/2008/862081.

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Delta-aminolevulinic acid/protoporphyrin IX is applied for fluorescent tumor detection in the upper part of gastrointestinal tract. The 5-ALA is administered per os six hours before measurements at dose 20 mg/kg weight. High-power light-emitting diode at 405 nm is used as an excitation source. Special opto-mechanical device is built to use the light guide of standard video-endoscopic system. Through endoscopic instrumental channel a fiber is applied to return information about fluorescence to microspectrometer. In such way, 1D detection and 2D visualization of the lesions' fluorescence are received, and both advantages and limitations of these methodologies are discussed in relation to their clinical applicability. Comparison of the spectra received from normal mucosa, inflammatory, and tumor areas is applied to evaluate the feasibility for development of simple but effective algorithm based on dimensionless ratio of the fluorescence signals at 560 and 635 nm, for differentiation of normal/abnormal gastrointestinal tissues.

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16

Madden, M. C., R. Wong, and D. C. Wherry. "Trace Element Detection by X-Ray Fluorescence." Microscopy and Microanalysis 4, S2 (July 1998): 348–49. http://dx.doi.org/10.1017/s1431927600021863.

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Due primarily to the absence of Bremsstrahlung radiation, fluorescent spectra obtained with x-ray excitation of a sample have a lower background than those obtained with electron excitation. This can be used to detect elements in liquids at very low concentrations under certain conditions. The technique consists of placing a small measured volume of liquid to be analyzed for trace elements on a thin, low atomic number film; evaporating the liquid to dryness; placing it under an x-ray beam; and obtaining a fluorescent spectra. The residue from the evaporated liquid contains any trace elements present, which then produce characteristic peaks in the fluorescent spectrum. These peaks can be used to measure concentrations quantitatively.This technique has been around for some time, but with detection limits at the parts per million (ppm) level. Although there are many definitions of detection limit, the most commonly used one is from Burton:

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17

Hewett, Jacqueline, Tracy McKechnie, Wilson Sibbett, James Ferguson, Colin Clark, and Miles Padgett. "Fluorescence detection of superficial skin cancers." Journal of Modern Optics 47, no. 11 (September 2000): 2021–27. http://dx.doi.org/10.1080/09500340008232454.

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18

Cox, M. E., and B. Dunn. "Detection of oxygen by fluorescence quenching." Applied Optics 24, no. 14 (July 15, 1985): 2114. http://dx.doi.org/10.1364/ao.24.002114.

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19

Iglesias, Ignacio. "Fluorescence tomographic microscopy by wavefront detection." Optics Letters 35, no. 7 (March 31, 2010): 1103. http://dx.doi.org/10.1364/ol.35.001103.

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20

Dramićanin, Tatjana, Lea Lenhardt Acković, Ivana Zeković, and Miroslav D. Dramićanin. "Detection of Adulterated Honey by Fluorescence Excitation-Emission Matrices." Journal of Spectroscopy 2018 (July 2, 2018): 1–6. http://dx.doi.org/10.1155/2018/8395212.

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Honey is a frequent target of adulteration through inappropriate production practices and origin mislabelling. Current methods for the detection of adulterated honey are time and labor consuming, require highly skilled personnel, and lengthy sample preparation. Fluorescence spectroscopy overcomes such drawbacks, as it is fast and noncontact and requires minimal sample preparation. In this paper, the application of fluorescence spectroscopy coupled with statistical tools for the detection of adulterated honey is demonstrated. For this purpose, fluorescence excitation-emission matrices were measured for 99 samples of different types of natural honey and 15 adulterated honey samples (in 3 technical replicas for each sample). Statistical t-test showed that significant differences between fluorescence of natural and adulterated honey samples exist in 5 spectral regions: (1) excitation: 240–265 nm, emission: 370–495 nm; (2) excitation: 280–320 nm, emission: 390–470 nm; (3) excitation: 260–285 nm, emission: 320–370 nm; (4) excitation: 310–360 nm, emission: 370–470 nm; and (5) excitation: 375–435 nm, emission: 440–520 nm, in which majority of fluorescence comes from the aromatic amino acids, phenolic compounds, and fluorescent Maillard reaction products. Principal component analysis confirmed these findings and showed that 90% of variance in fluorescence is accumulated in the first two principal components, which can be used for the discrimination of fake honey samples. The classification of honey from fluorescence data is demonstrated with a linear discriminant analysis (LDA). When subjected to LDA, total fluorescence intensities of selected spectral regions provided classification of honey (natural or adulterated) with 100% accuracy. In addition, it is demonstrated that intensities of honey emissions in each of these spectral regions may serve as criteria for the discrimination between natural and fake honey.

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21

Ye, Xiu, Haoying Wang, Lisha Yu, and Jinping Zhou. "Aggregation-Induced Emission (AIE)-Labeled Cellulose Nanocrystals for the Detection of Nitrophenolic Explosives in Aqueous Solutions." Nanomaterials 9, no. 5 (May 7, 2019): 707. http://dx.doi.org/10.3390/nano9050707.

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Aggregation-induced emission (AIE) active cellulose nanocrystals (TPE-CNCs) were synthesized by attaching tetraphenylethylene (TPE) to cellulose nanocrystals (CNCs). The structure and morphology of TPE-CNCs were characterized by FT-IR, XRD, ζ-potential measurements, elemental analysis, TEM, atomic force microscopy (AFM), and dynamic laser light scattering (DLS). Fluorescent properties of TPE-CNCs were also further studied. Unlike aggregation-caused quenching (ACQ), TPE-CNCs emitted weak fluorescence in the dilute suspensions, while emitting efficiently in the aggregated states. The AIE mechanism of TPE-CNCs was attributed to the restriction of an intramolecular rotation (RIR) process in the aggregated states. TPE-CNCs displayed good dispersity in water and stable fluorescence, which was reported through the specific detection of nitrophenolic explosives in aqueous solutions by a fluorescence quenching assay. The fluorescence emissions of TPE-CNCs showed quantitative and sensitive responses to picric acid (PA), 2,4-dinitro-phenol (DNP), and 4-nitrophenol (NP), and the detection limits were 220, 250, and 520 nM, respectively. Fluorescence quenching occurred through a static mechanism via the formation of a nonfluorescent complex between TPE-CNCs and nitrophenolic analytes. A fluorescence lifetime measurement revealed that the quenching was a static process. The results demonstrated that TPE-CNCs were excellent sensors for the detection of nitrophenolic explosives in aqueous systems, which has great potential applications in chemosensing and bioimaging.

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22

Seltzer, M. D., Martha Schulz Hendrick, and R. G. Michel. "Photomultiplier gating for improved detection in laser-excited atomic fluorescence spectrometry." Analytical Chemistry 57, no. 6 (May 1985): 1096–100. http://dx.doi.org/10.1021/ac00283a030.

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23

Goldsmith, J. E. M., and Normand M. Laurendeau. "Single-laser two-step fluorescence detection of atomic hydrogen in flames." Optics Letters 15, no. 10 (May 15, 1990): 576. http://dx.doi.org/10.1364/ol.15.000576.

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24

Lee, Dong-Ryoung, Young-Duk Kim, Dae-Gab Gweon, and Hongki Yoo. "Dual-detection confocal fluorescence microscopy: fluorescence axial imaging without axial scanning." Optics Express 21, no. 15 (July 18, 2013): 17839. http://dx.doi.org/10.1364/oe.21.017839.

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25

Wang, Yue, Huan Feng, Haibo Li, Xinyi Yang, Hongmin Jia, Wenjun Kang, Qingtao Meng, Zhiqiang Zhang, and Run Zhang. "A Copper (II) Ensemble-Based Fluorescence Chemosensor and Its Application in the ‘Naked–Eye’ Detection of Biothiols in Human Urine." Sensors 20, no. 5 (February 29, 2020): 1331. http://dx.doi.org/10.3390/s20051331.

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Quick and effective detection of biothiols in biological fluids has gained increasing attention due to its vital biological functions. In this paper, a novel reversible fluorescence chemosensor (L-Cu2+) based on a benzocoumarin-Cu2+ ensemble has been developed for the detection of biothiols (Cys, Hcy and GSH) in human urine. The chemosensing ensemble (L-Cu2+) contains a 2:1 stoichiometry structure between fluorescent ligand L and paramagnetic Cu2+. L was found to exclusively bond with Cu2+ ions accompanied with a dramatic fluorescence quenching maximum at 443 nm and an increase of an absorbance band centered at 378 nm. Then, the in situ generated fluorescence sluggish ensemble, L-Cu2+, was successfully used as a chemosensor for the detection of biothiols with a fluorescence “OFF-ON” response modality. Upon the addition of biothiols, the decomplexation of L-Cu2+ led to the liberation of the fluorescent ligand, L, resulting in the recovery of fluorescence and absorbance spectra. Studies revealed that L-Cu2+ possesses simple synthesis, excellent stability, high sensitivity, reliability at a broad pH range and desired renewability (at least 5 times). The practical application of L-Cu2+ was then demonstrated by the detection of biothiols in human urine sample.

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26

Nie, Shuming, Daniel T. Chiu, and Richard N. Zare. "Real-time observation of single molecules by confocal fluorescence microscopy." Proceedings, annual meeting, Electron Microscopy Society of America 53 (August 13, 1995): 60–61. http://dx.doi.org/10.1017/s0424820100136672.

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The ability to detect, identify, and manipulate individual molecules offer exciting possibilities in many fields, including chemical analysis, materials research, and the biological sciences. A particularly powerful approach is to combine the exquisite sensitivity of laser-induced fluorescence and the spatial localization and imaging capabilities of diffraction-limited or near-field optical microscopes. Unlike scanning tunneling microscopy (STM) and atomic force microscopy (AFM), which lack molecular specificity, optical spectroscopy and microscopy techniques can be used for real-time monitoring and molecular identification at nanometer dimensions or in ultrasmall volumes.We report the use of confocal fluorescence microscopy coupled with a diffraction-limit laser beam and a high-efficiency photodiode for real-time detection of single fluorescent molecules in solution at room temperature. Rigler and Eigen have also demonstrated single-molecule detection with a confocal microscope and fluorescence correlation spectroscopy. The probe (or sampling) volume is effectively an elongated cylinder, with its radius being determined by optical diffraction and length by spherical aberration.

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27

Cava-Montesinos, Patricia, M. Luisa Cervera, Agustín Pastor, and Miguel de la Guardia. "Determination of Ultratrace Bismuth in Milk Samples by Atomic Fluorescence Spectrometry." Journal of AOAC INTERNATIONAL 86, no. 4 (July 1, 2003): 815–22. http://dx.doi.org/10.1093/jaoac/86.4.815.

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Abstract A sensitive procedure was developed for determination of bismuth (Bi) in milk samples by hydride generation atomic fluorescence spectrometry (HG–AFS) after microwave-assisted sample digestion with HNO3 and H2O2. The method provides a sensitivity of 1832 fluorescence units (ng/mL) with a detection limit of 0.01 ng/mL, which corresponds to 20 pg absolute limit of detection, equivalent to 0.50 ng/g in the original sample. Application of the methodology to cow milk samples from the Spanish market showed the presence of Bi at a concentration of 11.8–28.8 ng/g, which compared well with data obtained after dry ashing of samples and with data obtained by inductively coupled plasma–mass spectrometry after microwave-assisted digestion.

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28

Buckley, Steven G., Christopher J. Damm, Wolfgang M. Vitovec, Lee Anne Sgro, Robert F. Sawyer, Catherine P. Koshland, and Donald Lucas. "Ammonia detection and monitoring with photofragmentation fluorescence." Applied Optics 37, no. 36 (December 20, 1998): 8382. http://dx.doi.org/10.1364/ao.37.008382.

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29

Uchikawa, K., S. Saikan, H. Ohsawa, and T. Suga. "Fluorescence detection of femtosecond accumulated photon echo." Optics Letters 16, no. 1 (January 1, 1991): 13. http://dx.doi.org/10.1364/ol.16.000013.

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30

Suzuki, Yoshio. "Development of Fluorescent Reagent Based on Ligand Exchange Reaction for the Highly Sensitive and Selective Detection of Dopamine in the Serum." Sensors 19, no. 18 (September 12, 2019): 3928. http://dx.doi.org/10.3390/s19183928.

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A new fluorescent probe (BDP-Fe2+) was developed for targeting dopamine, with a boron–dipyrromethenyl (BDP) group as the fluorophore and a Fe2+ complex as the ligand exchange site. The free form of BDP-Fe2+ in solution displayed weak fluorescence emission, while it showed strong fluorescence emission after interaction with dopamine due to the release of Fe2+ from BDP-Fe2+, confirming the binding of Fe2+ to dopamine. The increase in fluorescence intensity was concentration-dependent, and a good linear relationship was observed between the fluorescence intensity and dopamine concentration. The detection limit of dopamine by BDP-Fe2+ was 1.1 nM, indicating a 20-fold higher sensitivity than that of previously reported compounds. The reaction of BDP-Fe2+ with dopamine was not affected by the presence of foreign substances, allowing the highly selective detection of dopamine in the human serum sample. The results of this study indicate that the novel compound BDP-Fe2+ is a reliable fluorescent molecular probe for the detection of dopamine and can be widely employed in diverse scientific areas.

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31

Rieu, Jean-Paul, Frédéric Ronzon, Christophe Place, Fairouz Dekkiche, Benjamin Cross, and Bernard Roux. "Insertion of GPI-anchored alkaline phosphatase into supported membranes: a combined AFM and fluorescence microscopy study." Acta Biochimica Polonica 51, no. 1 (March 31, 2004): 189–97. http://dx.doi.org/10.18388/abp.2004_3610.

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A new method based on combined atomic force microscopy (AFM) and fluorescence microscopy observations, is proposed to visualize the insertion of glycosylphosphatidyl inositol (GPI) anchored alkaline phosphatase from buffer solutions into supported phospholipid bilayers. The technique involves the use of 27 nm diameter fluorescent latex beads covalently coupled to the amine groups of proteins. Fluorescence microscopy allows the estimation of the relative protein coverage into the membrane and also introduces a height amplification for the detection of protein/bead complexes with the AFM. The coupling of the beads with the amine groups is not specific; this new and simple approach opens up new ways to investigate proteins into supported membrane systems.

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32

Jia, Jia, Zhou Long, Chengbin Zheng, Xi Wu, and Xiandeng Hou. "Metal organic frameworks CAU-1 as new photocatalyst for photochemical vapour generation for analytical atomic spectrometry." Journal of Analytical Atomic Spectrometry 30, no. 2 (2015): 339–42. http://dx.doi.org/10.1039/c4ja00360h.

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33

Gómez Martín, J. C., J. Blahins, U. Gross, T. Ingham, A. Goddard, A. S. Mahajan, A. Ubelis, and A. Saiz-Lopez. "In situ detection of atomic and molecular iodine using Resonance and Off-Resonance Fluorescence by Lamp Excitation: ROFLEX." Atmospheric Measurement Techniques 4, no. 1 (January 19, 2011): 29–45. http://dx.doi.org/10.5194/amt-4-29-2011.

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Abstract. We demonstrate a new instrument for in situ detection of atmospheric iodine atoms and molecules based on atomic and molecular resonance and off-resonance ultraviolet fluorescence excited by lamp emission. The instrument combines the robustness, light weight, low power consumption and efficient excitation of radio-frequency discharge light sources with the high sensitivity of the photon counting technique. Calibration of I2 fluorescence is achieved via quantitative detection of the molecule by Incoherent Broad Band Cavity-enhanced Absorption Spectroscopy. Atomic iodine fluorescence signal is calibrated by controlled broad band photolysis of known I2 concentrations in the visible spectral range at atmospheric pressure. The instrument has been optimised in laboratory experiments to reach detection limits of 1.2 pptv for I atoms and 13 pptv for I2, for S/N = 1 and 10 min of integration time. The ROFLEX system has been deployed in a field campaign in northern Spain, representing the first concurrent observation of ambient mixing ratios of iodine atoms and molecules in the 1–350 pptv range.

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34

Gómez Martín, J. C., J. Blahins, U. Gross, T. Ingham, A. Goddard, A. S. Mahajan, A. Ubelis, and A. Saiz-Lopez. "In situ detection of atomic and molecular iodine using resonance and off-resonance fluorescence by lamp excitation: ROFLEX." Atmospheric Measurement Techniques Discussions 3, no. 4 (August 25, 2010): 3803–49. http://dx.doi.org/10.5194/amtd-3-3803-2010.

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Abstract. We demonstrate a new instrument for in situ detection of atmospheric iodine atoms and molecules based on atomic and molecular resonance and off-resonance ultraviolet fluorescence excited by lamp emission. The instrument combines the robustness, light weight, low power consumption and efficient excitation of radio-frequency discharge light sources with the high sensitivity of the photon counting technique. Calibration of I2 fluorescence is achieved via quantitative detection of the molecule by incoherent broad band cavity-enhanced absorption spectroscopy. Atomic iodine fluorescence signal is calibrated by controlled broad band photolysis of known I2 concentrations in the visible spectral range at atmospheric pressure. The instrument has been optimised in laboratory experiments to reach detection limits of 1.2 pptv for I atoms and 20 pptv for I2, for S/N=1 and 10 min of integration time. The ROFLEX system has been deployed in a field campaign in Northern Spain, representing the first concurrent observation of ambient mixing ratios of iodine atoms and molecules in the 1–350 pptv range.

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35

Du, Chenxu, Chaoqun Ma, Jiao Gu, Lei Li, and Guoqing Chen. "Fluorescence Sensing of Caffeine in Tea Beverages with 3,5-diaminobenzoic Acid." Sensors 20, no. 3 (February 3, 2020): 819. http://dx.doi.org/10.3390/s20030819.

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A rapid, selective and sensitive method for the detection of caffeine in tea infusion and tea beverages are proposed by using 3,5-diaminobenzoic acid as a fluorescent probe. The 3,5-diaminobenzoic acid emits strong fluorescence around 410 nm under the excitation of light at 280 nm. Both the molecular electrostatic potential analysis and fluorescent lifetime measurement proved that the existence of caffeine can quench the fluorescence of 3,5-diaminobenzoic acid. Under the optimal experimental parameters, the 3,5-diaminobenzoic acid was used as a fluorescent probe to detect the caffeine aqueous solution. There exists a good linear relationship between the fluorescence quenching of the fluorescent probe and the concentration of caffeine in the range of 0.1–100 μM, with recovery within 96.0 to 106.2%, while the limit of detection of caffeine is 0.03 μM. This method shows a high selectivity for caffeine. The caffeine content in different tea infusions and tea beverages has been determined and compared with the results from HPLC measurement.

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Choe, Donghwan, Haeri So, Soyoung Park, Hangyul Lee, Ju Byeong Chae, Jiwon Kim, Ki-Tae Kim, and Cheal Kim. "An Indole-Based Fluorescent Chemosensor for Detecting Zn2+ in Aqueous Media and Zebrafish." Sensors 21, no. 16 (August 19, 2021): 5591. http://dx.doi.org/10.3390/s21165591.

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An indole-based fluorescent chemosensor IH-Sal was synthesized to detect Zn2+. IH-Sal displayed a marked fluorescence increment with Zn2+. The detection limit (0.41 μM) of IH-Sal for Zn2+ was greatly below that suggested by the World Health Organization. IH-Sal can quantify Zn2+ in real water samples. More significantly, IH-Sal could determine and depict the presence of Zn2+ in zebrafish. The detecting mechanism of IH-Sal toward Zn2+ was illustrated by fluorescence and UV–visible spectroscopy, DFT calculations, 1H NMR titration and ESI mass.

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37

Goldsmith, J. E. M., and R. J. M. Anderson. "Imaging of atomic hydrogen in flames with two-step saturated fluorescence detection." Applied Optics 24, no. 5 (March 1, 1985): 607. http://dx.doi.org/10.1364/ao.24.000607.

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Goldsmith, J. E. M., R. J. M. Anderson, and L. R. Williams. "Time-resolved two-photon-excited fluorescence detection of atomic hydrogen in flames." Optics Letters 15, no. 1 (January 1, 1990): 78. http://dx.doi.org/10.1364/ol.15.000078.

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Jain, Ayush, Yejun Wang, and Waruna D. Kulatilaka. "Three-photon-excited laser-induced fluorescence detection of atomic hydrogen in flames." Optics Letters 44, no. 24 (December 5, 2019): 5945. http://dx.doi.org/10.1364/ol.44.005945.

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40

D�bele, H. F., M. H�rl, M. R�wekamp, and B. Reimann. "Detection of atomic oxygen by laser-induced fluorescence spectroscopy at 130 nm." Applied Physics B Photophysics and Laser Chemistry 39, no. 2 (February 1986): 91–95. http://dx.doi.org/10.1007/bf00694803.

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Davis, C. L., B. W. Smith, and J. D. Winefordner. "A Miniature Glow Discharge for Laser Excited Atomic Fluorescence Detection of Lead." Microchemical Journal 52, no. 3 (December 1995): 383–95. http://dx.doi.org/10.1006/mchj.1995.1112.

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42

Stockwell, P. B., and W. T. Corns. "The role of atomic fluorescence spectrometry in the automatic environmental monitoring of trace element analysis." Journal of Automatic Chemistry 15, no. 3 (1993): 79–84. http://dx.doi.org/10.1155/s1463924693000136.

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Considerable attention has been drawn to the environmental levels of mercury, arsenic, selenium and antimony in the last decade. Legislative and environmental pressure has forced levels to be lowered and this has created an additional burden for analytical chemists. Not only does an analysis have to reach lower detection levels, but it also has to be seen to be correct. Atomic fluorescence detection, especially when coupled to vapour generation techniques, offers both sensitivity and specificity.Developments in the design of specified atomic fluorescence detectors for mercury, for the hydride-forming elements and also for cadmium, are described in this paper. Each of these systems is capable of analysing samples in the part per trillion (ppt) range reliably and economically. Several analytical applications are described.

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DACOSTA, RALPH S., YING TANG, TUULA KALLIOMAKI, RAYMOND M. REILLY, ROBERT WEERSINK, ALISHA R. ELFORD, NORMAN E. MARCON, and BRIAN C. WILSON. "IN VIVO NEAR-INFRARED FLUORESCENCE IMAGING OF HUMAN COLON ADENOCARCINOMA BY SPECIFIC IMMUNOTARGETING OF A TUMOR-ASSOCIATED MUCIN." Journal of Innovative Optical Health Sciences 02, no. 04 (October 2009): 407–22. http://dx.doi.org/10.1142/s1793545809000759.

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Background and Aims: Accurate endoscopic detection of premalignant lesions and early cancers in the colon is essential for cure, since prognosis is closely related to lesion size and stage. Although it has great clinical potential, autofluorescence endoscopy has limited tumor-to-normal tissue image contrast for detecting small preneoplastic lesions. We have developed a molecularly specific, near-infrared fluorescent monoclonal antibody (CC49) bioconjugate which targets tumor-associated glycoprotein 72 (TAG72), as a contrast agent to improve fluorescence-based endoscopy of colon cancer. Methods: The fluorescent anti-TAG72 conjugate was evaluated in vitro and in vivo in athymic nude mice bearing human colon adenocarcinoma (LS174T) subcutaneous tumors. Autofluorescence, a fluorescent but irrelevant antibody and the free fluorescent dye served as controls. Fluorescent agents were injected intravenously, and in vivo whole body fluorescence imaging was performed at various time points to determine pharmacokinetics, followed by ex vivo tissue analysis by confocal fluorescence microscopy and histology. Results: Fluorescence microscopy and histology confirmed specific LS174T cell membrane targeting of labeled CC49 in vitro and ex vivo. In vivo fluorescence imaging demonstrated significant tumor-to-normal tissue contrast enhancement with labeled-CC49 at three hours post injection, with maximum contrast after 48 h. Accumulation of tumor fluorescence demonstrated that modification of CC49 antibodies did not alter their specific tumor-localizing properties, and was antibody-dependent since controls did not produce detectable tumor fluorescence. Conclusions: These results show proof-of-principle that our near-infrared fluorescent-antibody probe targeting a tumor-associated mucin detects colonic tumors at the molecular level in real time, and offer a basis for future improvement of image contrast during clinical fluorescence endoscopy.

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Nawrot, Witold, Kamila Drzozga, Sylwia Baluta, Joanna Cabaj, and Karol Malecha. "A Fluorescent Biosensors for Detection Vital Body Fluids’ Agents." Sensors 18, no. 8 (July 24, 2018): 2357. http://dx.doi.org/10.3390/s18082357.

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The clinical applications of sensing tools (i.e., biosensors) for the monitoring of physiologically important analytes are very common. Nowadays, the biosensors are being increasingly used to detect physiologically important analytes in real biological samples (i.e., blood, plasma, urine, and saliva). This review focuses on biosensors that can be applied to continuous, time-resolved measurements with fluorescence. The material presents the fluorescent biosensors for the detection of neurotransmitters, hormones, and other human metabolites as glucose, lactate or uric acid. The construction of microfluidic devices based on fluorescence uses a variety of materials, fluorescent dyes, types of detectors, excitation sources, optical filters, and geometrical systems. Due to their small size, these devices can perform a full analysis. Microfluidics-based technologies have shown promising applications in several of the main laboratory techniques, including blood chemistries, immunoassays, nucleic-acid amplification tests. Of the all technologies that are used to manufacture microfluidic systems, the LTCC technique seems to be an interesting alternative. It allows easy integration of electronic and microfluidic components on a single ceramic substrate. Moreover, the LTCC material is biologically and chemically inert, and is resistant to high temperature and pressure. The combination of all these features makes the LTCC technology particularly useful for implementation of fluorescence-based detection in the ceramic microfluidic systems.

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Dong, Haowei, Xingshuang An, Yaodong Xiang, Fukai Guan, Qi Zhang, Qingqing Yang, Xia Sun, and Yemin Guo. "Novel Time-Resolved Fluorescence Immunochromatography Paper-Based Sensor with Signal Amplification Strategy for Detection of Deoxynivalenol." Sensors 20, no. 22 (November 18, 2020): 6577. http://dx.doi.org/10.3390/s20226577.

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Immunoassay has the advantages of high sensitivity, high specificity, and simple operation, and has been widely used in the detection of mycotoxins. For several years, time-resolved fluorescence immunochromatography (TRFIA) paper-based sensors have attracted much attention as a simple and low-cost field detection technology. However, a traditional TRFIA paper-based sensor is based on antibody labeling, which cannot easily meet the current detection requirements. A second antibody labeling method was used to amplify the fluorescence signal and improve the detection sensitivity. Polystyrene fluorescent microspheres were combined with sheep anti-mouse IgG to prepare fluorescent probes (Eu-IgGs). After the probe fully reacted with the antibody (Eu-IgGs-Abs) in the sample cell, it was deployed on the paper-based sensor using chromatography. Eu-IgGs-Abs that were not bound to the target were captured on the T-line, while those that were bound were captured on the C-line. The paper-based sensor reflected the corresponding fluorescence intensity change. Because a single molecule of the deoxynivalenol antibody could bind to multiple Eu-IgGs, this method could amplify the fluorescence signal intensity on the unit antibody and improve the detection sensitivity. The working standard curve of the sensor was established under the optimum working conditions. It showed the lower limit of detection and higher recovery rate when it was applied to actual samples and compared with other methods. This sensor has the advantages of high sensitivity, good accuracy, and good specificity, saving the amount of antibody consumed and being suitable for rapid field detection of deoxynivalenol.

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Hedde, Per Niklas, Tim Abram, Tam Vu, Weian Zhao, and Enrico Gratton. "Fluorescence lifetime detection with particle counting devices." Biomedical Optics Express 10, no. 3 (February 12, 2019): 1223. http://dx.doi.org/10.1364/boe.10.001223.

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Chen, Piaopiao, Peng Yang, Rongxing Zhou, Xi Yang, Junbo Chen, and Xiandeng Hou. "Selective reduction-based, highly sensitive and homogeneous detection of iodide and melamine using chemical vapour generation-atomic fluorescence spectrometry." Chemical Communications 54, no. 37 (2018): 4696–99. http://dx.doi.org/10.1039/c8cc01186a.

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Yang, Yue, Tong Zou, Zhezhe Wang, Xinxin Xing, Sijia Peng, Rongjun Zhao, Xu Zhang, and Yude Wang. "The Fluorescent Quenching Mechanism of N and S Co-Doped Graphene Quantum Dots with Fe3+ and Hg2+ Ions and Their Application as a Novel Fluorescent Sensor." Nanomaterials 9, no. 5 (May 13, 2019): 738. http://dx.doi.org/10.3390/nano9050738.

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The fluorescence intensity of N, S co-doped graphene quantum dots (N, S-GQDs) can be quenched by Fe3+ and Hg2+. Density functional theory (DFT) simulation and experimental studies indicate that the fluorescence quenching mechanisms for Fe3+ and Hg2+ detection are mainly attributed to the inner filter effect (IFE) and dynamic quenching process, respectively. The electronegativity difference between C and doped atoms (N, S) in favor to introduce negative charge sites on the surface of N, S-GQDs leads to charge redistribution. Those negative charge sites facilitate the adsorption of cations on the N, S-GQDs’ surface. Atomic population analysis results show that some charge transfer from Fe3+ and Hg2+ to N, S-GQDs, which relate to the fluorescent quenching of N, S-GQDs. In addition, negative adsorption energy indicates the adsorption of Hg2+ and Fe2+ is energetically favorable, which also contributes to the adsorption of quencher ions. Blue fluorescent N, S-GQDs were synthesized by a facile one-pot hydrothermal treatment. Fluorescent lifetime and UV-vis measurements further validate the fluorescent quenching mechanism is related to the electron transfer dynamic quenching and IFE quenching. The as-synthesized N, S-GQDs were applied as a fluorescent probe for Fe3+ and Hg2+ detection. Results indicate that N, S-GQDs have good sensitivity and selectivity on Fe3+ and Hg2+ with a detection limit as low as 2.88 and 0.27 nM, respectively.

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Jeffery, Jinny, Amy R. Frank, Stephanie Hockridge, Hagen Stosnach, and Seán J. Costelloe. "Method for measurement of serum copper, zinc and selenium using total reflection X-ray fluorescence spectroscopy on the PICOFOX analyser: Validation and comparison with atomic absorption spectroscopy and inductively coupled plasma mass spectrometry." Annals of Clinical Biochemistry: International Journal of Laboratory Medicine 56, no. 1 (August 16, 2018): 170–78. http://dx.doi.org/10.1177/0004563218793163.

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Background Total reflection X-ray fluorescence is a comparably new method for the measurement of trace elements in biological samples. Methods Results obtained by total reflection X-ray fluorescence were compared to atomic absorption spectroscopy for Cu and Zn and inductively coupled plasma mass spectrometry for Cu, Zn and Se in patient serum. The total reflection X-ray fluorescence assay was characterized for accuracy; recovery; intra- and inter-assay imprecision (using patients’ samples, external quality assurance and quality control materials); limit of blank; limit of detection; linearity; interference and stability of prepared samples. Results Minimal sample preparation is required for total reflection X-ray fluorescence and simultaneous multi-elemental analysis is possible in clinical samples. There was a small positive bias for Cu and Zn measurements using total reflection X-ray fluorescence compared to atomic absorption spectroscopy and inductively coupled plasma mass spectrometry and a significant negative bias for Se measurements by total reflection X-ray fluorescence relative to inductively coupled plasma mass spectrometry. Recovery, imprecision and linearity were acceptable. The limit of detection was shown to be 1.2 μmol/L for serum Cu, 1.8 μmol/L for serum Zn and 0.2 μmol/L for serum Se. Conclusions Measurement of Cu and Zn in serum samples using total reflection X-ray fluorescence would be a viable alternative to atomic absorption spectroscopy or inductively coupled plasma mass spectrometry. The volatility of some Se compounds results in lower Se results being reported using total reflection X-ray fluorescence and further work would be necessary to identify whether total reflection X-ray fluorescence has an acceptable clinical sensitivity and specificity for the assessment of Se deficiency. Measurement of copper, zinc and selenium on whole blood samples is possible using total reflection X-ray fluorescence which may provide a more accurate assessment of trace element deficiency for patients with an acute phase response.

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Kim, Yoonjeong, Eunryeol Shin, Woong Jung, Mi Kyoung Kim, and Youhoon Chong. "A Near-infrared Turn-on Fluorescent Sensor for Sensitive and Specific Detection of Albumin from Urine Samples." Sensors 20, no. 4 (February 24, 2020): 1232. http://dx.doi.org/10.3390/s20041232.

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A readily synthesizable fluorescent probe DMAT-π-CAP was evaluated for sensitive and selective detection of human serum albumin (HSA). DMAT-π-CAP showed selective turn-on fluorescence at 730 nm in the presence of HSA with more than 720-fold enhancement in emission intensity ([DMAT-π-CAP] = 10 μM), and rapid detection of HSA was accomplished in 3 s. The fluorescence intensity of DMAT-π-CAP was shown to increase in HSA concentration-dependent manner (Kd = 15.4 ± 3.3 μM), and the limit of detection of DMAT-π-CAP was determined to be 10.9 nM (0.72 mg/L). The 1:1 stoichiometry between DMAT-π-CAP and HSA was determined, and the displacement assay revealed that DMAT-π-CAP competes with hemin for the unique binding site, which rarely accommodates drugs and endogenous compounds. Based on the HSA-selective turn-on NIR fluorescence property as well as the unique binding site, DMAT-π-CAP was anticipated to serve as a fluorescence sensor for quantitative detection of the HSA level in biological samples with minimized background interference. Thus, urine samples were directly analyzed by DMAT-π-CAP to assess albumin levels, and the results were comparable to those obtained from immunoassay. The similar sensitivity and specificity to the immunoassay along with the simple, cost-effective, and fast detection of HSA warrants practical application of the NIR fluorescent albumin sensor, DMAT-π-CAP, in the analysis of albumin levels in various biological environments.

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