Fluorescence spectrum

A new anthracene derivative of calix[4]arene was synthesized as a highly fluorescent compound. This compound was examined for its fluorescent properties towards different metal ions (Li+, Na+, Mg2+, Ca2+, Ba2+, Ni2+, Cu2+, Zn2+, Pb2+) by UV and fluorescence spectroscopy. On complexation by alkaline earth metal cations and transition metal cations, the fluorescence spectrum was quenched. In particular, Ca2+ caused greater than 98% quenching of the anthracene derivative of calix[4]arene.

8p langthannam 29-12-2021 11 0   Download

The inclusion complexation of flavanone with β -cyclodextrin was studied by ultraviolet absorption, steady state fluorescence, time-resolved fluorescence, and 2D ROESY nuclear magnetic resonance spectroscopic techniques. A 1:1 stoichiometric ratio was determined for the inclusion of flavanone with β -cyclodextrin. The Stern–Volmer constant for the accessible fraction of the binding of flavanone with β -cyclodextrin, and the binding constant for the flavanone–β - cyclodextrin complex are reported.

14p langthannam 29-12-2021 18 1   Download

A rhodamine B derivative containing 1,2,4-triazole as subunit was characterized as an “off–on” type Cu2+ - selective fluorescent probe. It exhibited high selectivity and sensitivity for Cu2+ in ethanol–water solution (9:1, v:v, pH 7.0, 20 mM HEPES) and underwent ring opening. A prominent fluorescence enhancement at 570 nm was observed in the presence of Cu2+ with the change in the absorption spectrum, and a 1:1 metal–ligand complex was formed.

7p langthannam 29-12-2021 10 0   Download

Glutamic functionalized water-soluble perylene diimide, N, N’-di (l-glutamic amine)-perylene-3,4,9,10- tetracarboxylic diimide (GAPTCD) has three absorbance maxima at 469, 498, and 534 nm and two emission peaks at 550 and 587 nm. Owing to the highly negative electrostatic potential of the perylene plane, the perylene derivative showed good water solubility and strong fluorescence in alkali and neutral solutions. Both the absorbance and emission intensities decreased with the decreasing of pH from 9.66 to 5.92.

8p langthannam 29-12-2021 12 0   Download

A fluorescent probe based on benzoyl hydrazine was synthesized and characterized as an Al3+-selective fluorescent probe. This probe showed good selectivity towards Al 3+ compared to other common ions. Under optimized experimental conditions, the probe exhibited a linear dynamic response for Al 3+ from 5.0 × 10−7 to 4.5 × 10−6 M with a detection limit of 1.3 × 10−7 M in ethanol–water solution (9:1, v:v, pH 6.8, 20 mM HEPES). Furthermore, it was used for imaging of Al3+ in living cells with satisfying results.

9p langthannam 29-12-2021 6 0   Download

A fluorescent probe based on silicon quantum dots (SiQDs) was developed for the selective and sensitive detection of oxytetracycline (OTC) via the inner filter effect (IFE). The water-soluble fluorescent SiQD was synthesized based on the reaction of 3-Aminopropyltriethoxysilane (APTES) and sodium citrate as precursors by the one-pot hydrothermal process. The strong fluorescence emission of quantum dots (QDs) was obtained at 440 nm when excited at 350 nm and OTC had a broad absorption band between 200 and 400 nm.

10p tudichquannguyet 29-11-2021 11 1   Download

Evolution occurred exclusively under the full spectrum of sunlight. Conscription of narrow regions of the solar spectrum by specific photoreceptors suggests a common strategy for regulation of genetic pathways. Fluorescent light (FL) does not possess the complexity of the solar spectrum and has only been in service for about 60 years. If vertebrates evolved specific genetic responses regulated by light wavelengths representing the entire solar spectrum, there may be genetic consequences to reducing the spectral complexity of light.

18p vibeauty 23-10-2021 7 0   Download

Cannabis possesses a rich spectrum of phytochemicals i.e. cannabinoids, terpenes and phenolic compounds of industrial and medicinal interests. Most of these high-value plant products are synthesised in the disk cells and stored in the secretory cavity in glandular trichomes.

12p vishikamaru2711 29-04-2020 11 1   Download

In this research, the new fluorescent conjugated polymers based on 10-(Perylene-3-yl-10HPhenoxazine (PyP) and 9,9-dioctyl-9h-fluorene (PF) have been synthesized via direct arylation polymerization using Pd(OAc)2, PivOH and PCy3.HBF4 as catalyst system. The monomer based on phenothiazine has been synthesized via C-N coupling to obtain the 4-(10H-phenothiazine-10-yl)- N,N-diphenylaniline (PyP). The synthesized novel conjugated polymers based on PyP and PF have been characterized via 1 H NMR, GPC, FTIR, DSC, XRD, PL, and UV-Vis spectrum.

10p 035522894 26-03-2020 49 2   Download

In this paper, Origin is applyed to analyze samples and give some results about the fluorescence spectrum of SiO2-Al2O3 glass material, which is produced by Sol-Gel method.

8p vimoskva2711 02-01-2020 15 1   Download

In this paper, Origin is applyed to analyze samples and give some results about the fluorescence spectrum of SiO2-Al2O3 glass material, which is produced by Sol-Gel method. The emission spectra of two widebands with a peak around 1533nm and 1550nm, corresponding to the 4 I13/2→ 4 I15/2 transition.

8p vigustavia2711 19-12-2019 2 0   Download

The thermal stabilityofperoxidase fromleavesof theAfrican oil palm treeElaeis guineensis(AOPTP) at pH 3.0 was studied by differential scanning calorimetry (DSC), intrinsic fluorescence, CD and enzymatic assays.The spectral parameters asmonitoredby ellipticity changes in the far-UV CD spectrum of the enzyme as well as the increase in tryp-tophan intensity emission upon heating, together with changes in enzymatic activity with temperature were seen to be good complements to the highly sensitive but integral methodofDSC....

7p research12 29-04-2013 36 1   Download

The goal of this study was to relate conformational changes in the N-terminal domain of chicken troponin I (TnI) to Ca 2+ activation of the actin–myosin interaction.The two cysteine residues in this region (Cys48 and Cys64) were labeled with two sulfhydryl-reactive pyrene-containing fluorophores [N-(1-pyrene)maleimide, and N-(1-pyrene)-iodoacetamide].The labeled TnI showed a typical fluores-cence spectrum: two sharp peaks of monomer fluorescence and a broad peak of excimer fluorescence arising from the formation of an excited dimer (excimer)....

9p tumor12 20-04-2013 40 1   Download

The effects of high hydrostatic pressure (HHP) and urea on conformational transitions of humana-thrombin structure were studiedbyfluorescence spectroscopy andbymeasuring the catalytic activity of the enzyme. Treatment of thrombin with urea produced a progressive red shift in the center of mass of the intrinsic fluorescence emission spectrum, with a maximum displacement of 650 cm )1 . HHP (270 MPa) shifted the centre ofmass by only 370 cm )1 .HHP combined with a subdenaturing urea concentration (1.5M) displaced the centre of mass by
750 cm )1 ....

8p dell39 03-04-2013 26 2   Download

Genistein and daidzein, the major isoflavones present in soybeans, possess a wide spectrum of physiological and pharmacological functions. The bind-ing of genistein to human serum albumin (HSA) has been investigated by equilibrium dialysis, fluorescence measurements, CD and molecular visuali-zation. One mole of genistein is bound per mole of HSA with a binding constant of 1.5 ± 0.2·10 5 m )1 . Binding of genistein to HSA precludes the attachment of daidzein.

17p dell39 27-03-2013 37 3   Download

The interaction of an extrinsic probe (Nile red) with an enzyme (horse-radish peroxidase) in solution was investigated using fluorescence tech-niques. Nile red fluorescence is very environmentally sensitive and the presence of domains of differing polarity within the enzyme was ascer-tained by the decomposition of the Nile red emission spectrum.

9p dell39 27-03-2013 35 2   Download

LIF (laser-induced fluorescence) is a very popular CE detector – These have ~0.01 attomole sensitivity for fluorescent molecules (e.g. derivatized proteins). Direct absorbance (UV-Vis) can be used for organics. For inorganics, indirect absorbance methods are used instead, where a absorptive buffer (e.g. chromate) is displaced by analyte ions – Detection limits are in the 50-500 ppb range. Alternative methods involving potentiometric and conductometric detection are also used – Potentiometric detection: a broad-spectrum ISE – Conductometric detection: like IC...

21p qdung92ct 03-07-2012 63 6   Download