Time-resolved fluorescence and chemometrics-assisted excitation-emission fluorescence for qualitative and quantitative analysis of scopoletin and scopolin in Erycibe obtusifolia Benth.

This paper presents a new strategy for qualitative identification of scopoletin and scopolin in Erycibe obtusifolia Benth using time-resolved (lifetimes) fluorescence and quantitative analysis with chemometrics-assisted excitation-emission matrix (EEM) fluorescence. Due to the significant spectral overlapping among analytes and interference, the use of the more selective time-resolved fluorescence is proposed for qualitative identification in quality control of traditional Chinese medicine (TCM) for the first time. Using the strategy of combining EEM fluorescence with second-order calibration method, i.

A comparison of several second-order algorithms for simultaneous determination of neomangiferin and mangiferin with severe spectral overlapping in Anemarrhenae Rhizoma.

This work presents a greener approach for simultaneous determination of neomangiferin and mangiferin, the major bioactive constituents with severe spectral overlapping in Anemarrhenae Rhizoma, combining the sensitivity of molecular fluorescence and the selectivity of chemometric multivariate calibration algorithms. In this study, we compared the analytical performance of two group chemometric algorithms including trilinear algorithms such as parallel factor analysis (PARAFAC), alternating trilinear decomposition (ATLD), self-weighted alternating trilinear decomposition (SWATLD) and alternating penalized trilinear decomposition (APTLD), and PLS-based methods such as unfolded partial least-squares or the multi-dimensional partial least-squares, both combined with residual bilinearization (U-PLS/RBL, N-PLS/RBL). The statistical parameters for the validation set of the second calibration were evaluated through the relative error of prediction (REP%), the average recovery (Rec%), and the root mean square error of prediction (RMSEP).

Simultaneous determination of α-asarone and β-asarone in Acorus tatarinowii using excitation-emission matrix fluorescence coupled with chemometrics methods.

A chemometrics-assisted excitation-emission matrix (EEM) fluorescence method was proposed for simultaneous determination of α-asarone and β-asarone in Acorus tatarinowii. Using the strategy of combining EEM data with chemometrics methods, the simultaneous determination of α-asarone and β-asarone in the complex Traditional Chinese medicine system was achieved successfully, even in the presence of unexpected interferents. The physical or chemical separation step was avoided due to the use of "mathematical separation".

[Study on Fluorescence Properties of Flavanone and Its Hydroxyl Derivatives].

Flavanone derivatives are important active ingredients of natural medicine, so the synthesis of these compounds is one of the research hotspots of organic synthesis. Nevertheless, there is little research on fluorescence properties of these compounds up to now. Fluorescence properties of flavanone and 6 kinds of hydroxyl derivatives are studied in this paper.

[Fabrication and Characterization of Planar Luminescent Solar Concentrator Waveguides Based on LR305 Dye].

Photovoltaic power generation is one of the best ways to utilize solar energy, but the cost of electricity is very high. To reduce the cost of photovoltaic power generation, in this paper, a type of planar luminescent solar concentrator waveguides based on Lumogen F Red 305 (LR305) dye with each size of 50 mm×50 mm×5 mm was proposed with radical polymerization method. The optical properties and photo-electricity outputs of the waveguides were characterized.

[Fluorescence enhancement of flavoxate hydrochloride in alkali solution and its application in pharmaceutical analysis].

Fluorescence enhancement reaction of flavoxate hydrochloride (FX) in strong alkali solution was studied, the mechanism of the reaction was investigated, and a novel fluorimetric method for analysis of FX in drug sample was established. FX has no intrinsic fluorescence, but it can slowly produce fluorescence in strong alkali solution. Heating can promote the fluorescence enhancement reaction.

[Fluorimetric analysis of camptothecin in Chinese herbal medicine common Camptotheca fruit].

Three-dimensional (3D) fluorescence spectra and thin layer fluorescence chromatogram of common Camptotheca fruit (CCF) crude drug, camptothecin (CPT) and 10-hydroxycamptothecin (HCPT) have been studied, and a novel fluorimetric method for determination of CPT in CCF crude drug has been established. In 3D fluorescence spectra, CPT presented 3 fluorescence peaks with excitation wavelengths lambdaex of 215, 255 and 365 nm, separately, and all peaks with emission wavelength lambdaem of 430 nm. HCPT presented 4 fluorescence peaks with lambdaex of 220, 265, 325 and 375 nm, separately, and all peaks with lambdaem of 555 nm.

[Synthesis and characterization of chromium doped Y3Al5O12 compound pigment].

The authors synthesized a new kind of green pigment via co-precipitation method by doping Y3Al5O12 with Cr+. The size of the pigment particles is around 200 nm as observed under scanning electron microscope. XRD results demonstrate that the pigment crystalline form of the pigment is yttrium alluminium garnet.

[Synthesis and characterization of mixed metal oxide pigments].

In the present work, aluminum chloride and various soluble salts of doping ions were dissolved in water. In addition, urea and polyvinyl pyrrolidone (PVP) were also dissolved in the above aqueous solution under supersonic treatments. Then the solutions were heated to induce the hydrolysis of urea so that soluble aluminum and doping ions convert into insoluble hydroxide or carbonate gels.

[Fluorescence spectra and absorption spectra of carvacrol].

Fluorescence spectra and absorption spectra of carvacrol, an active component of Chinese herbal medicines, have been studied. The ionization constant and fluorescence quantum yield of carvacrol were measured according to spectral data. Under the condition of pH < 2.

[Using barium fluoride fine particles as stationary phase for TLC/FTIR analysis].

In situ TLC/FTIR technique has tremendous potential in the analysis of complex mixtures. However, the progress in this technique was quite slow. The reason is that conventional stationary phase such as silica gel etc.

[Preliminary investigation on the formation mechanism of CCL4-water-cetyl trimethyl ammonium bromide (CTAB) gel].

Gels are gaining extensive interest owing to their versatile applications in fields such as drug delivery, tissue engineering, cosmetics, templated materials and food industry. Surfactants have an ability to self-assemble into a variety of supramolecular aggregate structures and morphologies. Of particular interest in resent years are surfactant-based gels, one special class of materials due to surfactant assemblies resulting in viscoelastic solid-like rheological behaviors.

[Fluorescence spectra and quantum yield of TiO2 nanocrystals synthesized by alcohothermal method].

Fluorescence spectra and fluorescence quantum yield of TiO2 nanocrystals were studied. Using tetra n-butyl titanate as a starting material, a facile alcohothermal technique was used to synthesize TiO2 nanocrystals. As can be seen from the transmittance electron microscopy (TEM) image, TiO2 nanocrystals with a relatively uniform particle size distribution of < 10 nm are present in the transparent sol.

[Fluorescence spectra of Bletilla striata aqueous extraction].

Three-dimensional fluorescence spectrum and ultraviolet absorption spectrum of Bletilla striata extraction drawn by boiling water were reported. Three fluorescence peaks, located at lambda(ex)/lambda(em) = 227/299 nm, 271/299 nm and 258/ 389 nm respectively, were observed in the three-dimensional fluorescence spectrum. Among them, the two former peaks having the same emission wavelengths were produced by one fluorescent component, while the latter peak was produced by another.

[Fluorescence spectra of Dichroa febrifuga aqueous extraction].

Fluorescence spectra of chang shan (Dichroa febrifuga Lour) aqueous extraction were studied. In the three-dimensional fluorescence contour spectrum, three fluorescence peaks of quinazoline alkaloids, which are the active components of chang shan, were observed. The excitation wavelengths of the peaks were 235, 270 and 320 nm, respectively, and the emission wavelength of all the peaks was 430 nm.

[Fluorescence spectra and fluorescence quantum yield of triton X-100].

Fluorescence spectra and fluorescence quantum yield of triton X-100 (TX) aqueous solution are reported. In strong acidic solutions, TX gives no fluorescence. When pH > 1, TX gives a strong and steady fluorescence with the maximum excitation wavelengths at 229 and 275 nm, and the maximum emission wavelength at 302 nm, respectively.

[Spectral properties, protonation and fluorescence quantum yield of ciprofloxacin].

Fluorescence spectra, ultraviolet absorption spectra, and protonation of Ciprofloxacin (CIP) at different pH values have been studied. Fluorescence quantum yield of CIP under neutral condition has been measured. In HCl medium with [H+] > 1 mol x L(-1), CIP molecules (simplified as HL) may accept three protons to exist as H4L3+ with very weak fluorescence, and its maximum fluorescence emission wavelength (lambdamax) is 456 nm.

[Resonance light scattering of 4-(2-pyridylazo)-resorcinol (PAR)].

Mechanism and influence factors of resonance light scattering (RLS) spectra of 4-(2-pyridylazo)-resorcinol (PAR) aqueous solution were studied. In weak acidic solutions, strong RLS of PAR can be observed. The spectral feature of RLS is related to the absorption spectra of PAR.

[Fluorescence spectra and protonation of ofloxacin].

Fluorescence spectra, ultraviolet spectra and protonation of Ofloxacin (OFL) at different pH values have been studied. In strong acidic solutions, OFL molecule might accept two protons to exist as ternary acid H3L2+ with a maximum emission wavelength (lambdamax) at 505 nm. Along with the increase in pH value, fluorescence spectrum of OFL changed, an iso-fluorescence point at 352 nm was found in the fluorescence excitation spectra, and at the same time, isosbestic points were found in its UV absorption spectra.

[Ultraviolet absorption spectra of iodine, iodide ion and triiodide ion].

Ultraviolet absorption spectra of iodine I2, iodide ion I(-) and triiodide ion I3(-) were studied, and molar absorptivities of these species were determined. Absorption spectrum of I2 aqueous solution appears as an absorption peak at 203 nm with a molar absorptivity of 1.96 x 10(4) L x mol(-1) x cm(-1).

[Resonance light scattering of rhodamine B].

The characteristic and mechanism of resonance light scattering (RLS) of Rhodamine B (RhB) were studied. In acidic solutions with pH from -0.38 to 4.

[Fluorescence spectra and fluorescence quantum yield of sulfosalicylic acid].

Fluorescence spectra and fluorescence quantum yield of sulfosalicylic acid (SSA) have been studied. Under the condition of pH<2, SSA has no fluorescence. With the increase in pH value, fluorescence intensity of SSA increases.

[Resonance light scattering of aurintricarboxylic acid].

Resonance light scattering (RLS), absorption and fluorescence spectra of aurintricarboxylic acid (ATA) were studied. In solutions with pH 3.7 to pH 11.