Study on the absorption and fluorescence and resonance Rayleigh scattering spectra of Cu (II)-fluoroquinolone chelates with erythrosine and their applications

In pH 4.2-5.0 Britton-Robinson buffer solution medium, fluoroquinolone antibiotics (FLQs), such as ciprofloxacin (CIP), norfloxacin (NOR), ofloxacin (OF), levofloxacin (LEV), lomefloxacin (LOM), and sparfloxacin (SPA), react with Cu (II) to form chelate cations, which further bind with erythrosine to form the ion association complexes. They can result in the changes of the absorption spectra. Simultane- ously, erythrosine fades obviously and the maximum fading wavelength is located at 526 nm. The fad- ing reactions have high sensitivities. Thus, new spectrophotometries of determination for these drugs are developed. The ion-association reactions result in the quenching of fluorescence, which also have high sensitivities. The detection limits for six antibiotics are in the range of 7.1-12.2 μg·L?1. Furthermore, the reactions can result in the enhancement of resonance Rayleigh scattering (RRS). The maximum scattering peaks of six ion-association complexes are located at 566 nm, and there are two small RRS peaks at 333 nm and 287 nm. The detection limits for fluoroquinolone antibiotics are in the range of 1.70 -3.10 μg·L?1 for RRS method. Among the above three methods, the RRS method has the highest sen- sitivity. In this work, we investigated the spectral characteristics of the absorption, fluorescence and RRS, the optimum conditions of the reactions, and the properties of the analytical chemistry. In addi- tion, the mechanism of reactions were discussed by density function theory (DFT) and AM1 methods.     

Novelty Filtering Using Phase Conjugate Wave in Organic Dye-Doped Polymer Films

A real-time detection of a moving object was demonstrated by taking the subtraction between cross-polarized phase conjugate waves with fast and slow response times with two kinds of dye-doped phase conjugators. One consists of superposed films of an erythrosin-B-doped film and a methyl-orange-doped film, and the other is a film dispersed with both dyes. The relative phase between cross-polarized phase conjugate waves by the both dye-dispersed films was stable.     

Liquid-liquid extraction of copper(II) with cryptand 222 with erythrosine B as the counter-ion

Copper is extracted at pH 5.5 with 3 × 10^–4 M cryptand 222 in dichloromethane with 3 × 10^–4 M erythrosine B as the counter-ion. It can be stripped with 0.5M perchloric acid and determined by atomic absorption spectrometry at 324.7 nm. Copper has been separated from multicomponent mixtures containing zinc, mercury, iron, cobalt, nickel and manganese, which are generally encountered in environmental samples.     

Inductive-resonant triplet-triplet annihilation in solid solutions of erythrosine

Experimental investigations of annihilation-induced delayed fluorescence and phosphorescence of frozen ethylene glycol solutions activated by erythrosine were carried out. It is found that the kinetics of the annihilation-induced delayed fluorescence is nonexponential in the initial stage, and approaches an exponential decay at later stages with the lifetime equal to half the triplet-state lifetime. It is shown that experimental data agree well with the theory proposed to describe triplet-triplet annihilation by an inductive-resonant mechanism in solid solutions of complex organic molecules. Belarusian State University, 4, F. Skorina Ave., Minsk, 2200050, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 5, pp. 629–632, September–October, 1997.     

Rapid Spectrophotometric Method for Determining Erythrosine,Amaranth and Tartrazine in Ternary Mixtures

Abstract

A very simple spectrophotometric method using measurements at zero-crossing wavelength is described for resolving ternary mixtures of the food colorants Erythrosine (E-127), Amaranth (E-123) and Tartrazine (E-102). Calibration graphs are linear up to 14 mg/L of Erythrosine and 28 mg/L for Tartrazine and Amaranth. RSD of 0.80, 0.85 and 1.84% were obtained for nine standards of 8 mg/L of Erythrosine, 8 mg/L of Tartrazine and 8 mg/L of Amaranth, respectively. Detection limits of 0.052, 0.934 and 0.123 mg/L were obtained for Erythrosine, Tartrazine and Amaranth, respectively. This method was satisfactorily used for determining synthetic mixtures of these colorants in different ratios and it was successfully applied to a commercial product containing the three dyes; no separation step is required. The results were compared with those obtained by liquid chromatography and very similar values were found by both methods.     

Xanthene Dyes and Green LED for the Inactivation of Foodborne Pathogens in Planktonic and Biofilm States

This study evaluated the rose bengal‐ and erythrosine‐mediated photoinactivation against Salmonella Typhimurium and Staphylococcus aureus planktonic and sessile cells using green LED as a light source. The free‐living or 2‐day‐old biofilm cells were treated with different concentrations of the photosensitizing agents and subjected to irradiation. Only 5 min photosensitization with rose bengal at 25 nmol L^?1 and 75 μmol L^?1 completely eliminated S. aureus and S. Typhimurium planktonic cells, respectively. Erythrosine at 500 nmol L^?1 and 5 min of light exposure also reduced S. aureus planktonic cells to undetectable levels. Eradication of S. aureus biofilms was achieved when 500 μmol L^?1 of erythrosine or 250 μmol L^?1 of rose bengal was combined with 30 min of irradiation. Scanning electron microscopy allowed the observation of morphological changes in planktonic cells and disruption of the biofilm architecture after photodynamic treatment. The overall data demonstrate that rose bengal and erythrosine activated by green LED may be a targeted strategy for controlling foodborne pathogens in both planktonic and sessile states.     

盐酸丁卡因-赤藓红反应体系的吸收光谱及分析应用

建立一种测定盐酸丁卡因的分光光度新方法。 在pH=4.0的Britton-Robinson（BR）缓冲溶液中,盐酸丁卡因（TC·HCl）与赤藓红（ET）形成1∶1的离子缔合物,导致溶液的吸收光谱变化,除在516 nm处产生明显的褪色作用外,并在558 nm处出现增色现象。 TC·HCl在0.1×10^-6~7.2×10^-6 g/mL范围内其质量浓度与褪色波长和增色波长处的吸光度变化值均呈良好的线性关系。 褪色法和增色法的摩尔吸光系数（ε）分别为3.30×10⁴和2.22×10⁴ L/(mol·cm)。 当用双波长叠加法时,ε值为5.52×10⁴ L/(mol·cm)。 研究了适宜的反应条件和分析化学性质,并结合量子化学AM1法讨论了反应机理。 方法用于人血清及尿样中盐酸丁卡因的含量测定,回收率在98.1%~103.3％之间。     

Inhibitory Effects of Erythrosine/Curcumin Derivatives/Nano-Titanium Dioxide-Mediated Photodynamic Therapy on Candida albicans

This study focuses on the role of photosensitizers in photodynamic therapy. The photosensitizers were prepared in combinations of 110/220 µM erythrosine and/or 10/20 µM demethoxy/bisdemethoxy curcumin with/without 10% (w/w) nano-titanium dioxide. Irradiation was performed with a dental blue light in the 395–480 nm wavelength range, with a power density of 3200 mW/cm² and yield of 72 J/cm². The production of ROS and hydroxyl radical was investigated using an electron paramagnetic resonance spectrometer for each individual photosensitizer or in photosensitizer combinations. Subsequently, a PrestoBlue^® toxicity test of the gingival fibroblast cells was performed at 6 and 24 h on the eight highest ROS-generating photosensitizers containing curcumin derivatives and erythrosine 220 µM. Finally, the antifungal ability of 22 test photosensitizers, Candida albicans (ATCC 10231), were cultured in biofilm form at 37 °C for 48 h, then the colonies were counted in colony-forming units (CFU/mL) via the drop plate technique, and then the log reduction was calculated. The results showed that at 48 h the test photosensitizers could simultaneously produce both ROS types. All test photosensitizers demonstrated no toxicity on the fibroblast cells. In total, 18 test photosensitizers were able to inhibit Candida albicans similarly to nystatin. Conclusively, 20 µM bisdemethoxy curcumin + 220 µM erythrosine + 10% (w/w) nano-titanium dioxide exerted the highest inhibitory effect on Candida albicans.     

The Orientation of the Phosphorescence Dipole Moment of Erythrosine B Within Its Molecular Frame

For an unequivocal interpretation of time-resolved phosphorescence depolarization measurements on dye molecules in biophysical systems, the orientation of the transition dipole moments within the frame of the dye has to be known. The goal of this work is to find the orientation of the phosphorescence dipole moment of erythrosine B within its molecular frame. To this end, we first determine four difference angles, exciting a molecule in two of its absorption bands and measuring the fluorescence and phosphorescence anisotropy for each excitation wavelength. The next step is to position the transition dipole moments within the molecular frame, combining the results of angle-resolved fluorescence depolarization measurements with the measured difference angles. It is shown that the phosphorescence dipole moment is tilted out of the plane of the molecule. Additionally, we find that the phosphorescence dipole moment is located above the fluorescence dipole moment and not above the absorption dipole moment. This induces an extra difference angle between the absorption and the phosphorescence dipole moments which in the past has been interpreted erroneously as a larger tilt out of the plane of the molecule.