Search

Rhodamine B (Rh B) was used to decorate an amphipathic block polymers (β-CD-[P(AA- co-MMA)-b-PVP](4)) in this study. First, after activated by 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, rhodamine B was marked with hydroxyethyl methacrylate (HEMA) through ester exchange reaction. Second, the labeled amphipathic block polymers (β-CD-[P(AA-(HEMA-RhB)-MMA)-b-PVP](4)) were synthesized after polymerization reaction of double bones between Rh B-HEMA and other reactants. Finally, the structure of product was measured by FT-IR spectra and fluorospectro photometer (FLUORO). The critical micelle concentration of Rh B-labeled and unlabeled amphipathic block polymers were 4.96×10(-3), 5.09×10(-3)mg·L(-1), respectively, indicating no change of their micellization behavior. In vivo tissue distribution and whole- body fluorescent imaging were studied by vinpocetine (VP)-loaded polymeric micelles which were prepared through a solvent evaporation method. Compared to the result of in vivo tissue distribution and whole-body fluorescence imaging, a similar bio-distribution behavior of VP-loaded polymeric micelles was found. Those proved the successful fluorescence modification with a labeling yield of 4.13%. With in vivo fluorescence imaging technology, we established a fluorescence method for modification of amphipathic block polymers.

Se is a necessary trace element for human and animals, but the excess intake of Se caused poison. Thus, it is very important to determination of Se in foods and water. The target of this study is development of a new, sensitive and selective hydride generation-molecular fluorescence method for the determination of Se. In 0. 36 mol . L-1 sulfuric acid, NaBH4 as reducing agent, Se (IV) is reduced to H2 Se. Usin3-g I solution as absorption liquid3, I- is reduced to I- by H2Se. When adding rhodamine 6G, Rhodamine 6G and I3- form association particles, which lead to the fluorescence intensity decreased. When Se(IV) existing, Rhodamine 6G and I3- bind less, And the remaining amount of Rhodamine 6G increase. So the fluorescence intensity is enhanced. The analytical conditions were optimized, a 0. 36 ml . L-1 H2SO4, 21. 6.g . L-1 NaBH4, 23.3 µm . L-1 rhodamine 6G, and 50 µmol . L-1 KI3 were chosen for use. When the excitation wavelength is at 480nm, the Rayleigh scattering peak does not affect the fluorescence recording, and was selected for determination of Se. Under the selected conditions, Se(IV) concentration in the 0. 02~0. 60 µg . mL-1 range and the increase value of the fluorescence intensity (ΔF) at 562 nm linear relationship. The linear regression equation is ΔF562 nm =12. 6c + 20. 9. The detecton limit was 0.01 µ.g . L-1. The influence of coexistence substances on the hydride generatin-molecular fluorescence determination of 5. 07 X10(-6) mol . L-1 Se(IV) was considered in details. Results showed that this new fluorescence method is of high selectivity, that is, 0. 5 mmol. L-1 Ba2+, Ca2+, Zn2+ and Fe3+, 0. 25 mmol . L-1 . Mg2+, 0. 05 mmol . L-1 K+, 0. 2 mmol . L-1 Al3+, 0. 025 mmol . L-1 Te(VI) do not interfere with the determination. The influence of Hg2+, CD2+ and Cu2+ that precipitate with Se(IV), can be eliminated by addition of complex reagent. This hydride generation-molecular fluorescence method has been applied to determination of trace Se in water samples,

The application of microbubble technology for ozonation wastewater treatment could enhance ozone mass transfer, improve ozonation performance and increase ozone utilization efficiency. The ozone microbubbles were used to treat synthetic acid red 3R wastewater in the present study, and compared to ozone conventional bubbles. The ozone mass transfer and ozonation characteristics of acid red 3R were investigated when ozone microbubbles and ozone conventional bubbles were applied. The results confirmed the enhanced ozone mass transfer using microbubbles. The ozone mass transfer coefficient using microbubbles was 3.6 times higher than that using conventional bubbles under the same conditions. Simultaneously, the ozone decomposition coefficient using microbubbles was 6.2 times higher than that using conventional bubbles, which would be favorable for *OH generation. The ozonation rate and mineralization efficiency of acid red 3R could be improved significantly using ozone microbubbles. A TOC removal efficiency of 78.0% was achieved using ozone microbubbles, which was about 2 times higher than that using ozone conventional bubbles. The ozone utilization efficiency using microbubbles was much higher that using conventional bubbles during ozonation treatment of acid red 3R. The average ozone utilization efficiencies were 97.8% and 69.3% when microbubbles and conventional bubbles were used, respectively. The oxidative ability of ozone microbubbles could be increased by enhancing *OH generation, and as a result, the oxidative reaction of degradation intermediates was accelerated by ozone microbubbles. Especially, the mineralization ability of small organic acid intermediates using ozone microbubbles was about 1.6 times higher than that using ozone conventional bubbles.

Electrochemical oxidation degradation of azo dyes has become a widely used method in recent years. Iron phosphomolybdate (FePMo12) was synthesized with molybdophosphoric acid and ferric salt. Morphology and microstructure of catalyst were chararerized by IR spectrometry and X-ray diffraction. The heteropolyanion showed a Keggin structure. Electrochemical oxidation of acid red 3R was investigated in the presence of FePMo12 supported on modified 4A molecular sieve (4A) as packing materials in the reactor. The results showed that the optimal technological conditions for decolorization of acid red 3R simulated wastewater were as follows: active component load 3% , electrolytic voltage 22 V, initial pH 4, air-flow 0.08 m3 h- ', electrode span 3.0 cm. Under the opñrrizd conditions, the decolorization efficiency, COD and TOC removal efficiencies reached 75.3% , 65.4% and 46.0% after 90 min, respectively. With the addition of NaCI to the dyes solution during electrolysis, the decolorization efficiency increased, while the effect of Na2SO4 on the degradation was negative. The efficiency of degradation and mineralization of the acid red 3R were estimated based on the absorbance measurements by UV-vis. It shows that the conjugated structure of dye was destroyed primarily.

Supported phosphotungstic acid catalysts on gamma-Al2O3 (HPW/gamma-Al2O3) were prepared by solution impregnation and characterized by FTIR, XRD, TG-DTA and SEM. The heteropolyanion shows a Keggin structure. Electro-chemical oxidation of Acid Red 3R was investigated in the presence of HPW supported on gamma-Al2O3 as packing materials in the reactor. The results show that HPW/gamma-Al2O3 has a good catalytic activity for decolorization of Acid Red 3R. When HPW loading was 4.6%, pH value of Acid Red 3R was 3, the voltage was 25.0 V, air-flow was 0.04 m3 x h(-1), and electrode span was 3.0 cm, the decolorization efficiency of Acid Red 3R can reach 97.6%. The removal rate of color had still about 80% in this electro-chemical oxidation system, after HPW/gamma-Al2O3 was used for 10 times, but active component loss existed. The interim product was analyzed by means of Vis-UV absorption spectrum. It shows that the conjugated structure of dye is destroyed primarily.

A higher selective and sensitive probe for the detection of Fe(III) in aqueous media was made using 2,4-Diisocyanatotoluene (TDI) as a bridge to couple Fe3 O4 nanoparticles(NPs) and Rhodamine-6G hydrazide. The characterization of composite materials with Infrared spectra(IR), Thermal Gravimetric analysis(TGA) and Transmission Emission Microscopy(TEM) points to the graft of Rhodamine-6G hydrazide onto the surface of the Fe3O4. The obvious color change of the probe solution from light grey to pink upon the addition of Fe3+ demonstrated the probe could be used for "naked-eye" detection of Fe3+ in water at pH 7. The presence of 1 equivalent (10 micromol x L(-1) microm) of each of these metal ions, including Mn2+, Ni2+, Y2+, Eu3+, Ce3+, La3+, Pr3+, Cd2+, Cr3+, Sm3+, Fe2+, Cu2+ and Zn2+ ions, did not demonstrate any obvious fluorescence change of the probe water solution, which confirmed the probe was a probe with remarkable selectivity for Fe3+. And the fluorescence images of HeLa cells in physiological solutions after incubation with Fe3+ and then further incubated with the probe leading to a strong intracellular fluorescence, which suggested the probe could penetrate the HeLa cell membrane and could respond to Fe3+ in intracellular within living cells.

Objective: To synthesize a tumor-targeting cell-penetrating peptide (CPP) and evaluate its biological activity and cytotoxicity in vitro., Methods: With fluorenylmethyloxycarbonyl (Fmoc) as the protective group of α-amino acid, the tumor-targeting CPP were synthesized with stepwise amino acid extension using solid-phase synthesis method. 5-carboxytetramethylrhodamine was added for fluorescence labeling in the presence of the coupling agents HATU and DMF. The purity of the CPP was measured by high-performance liquid chromatography and its molecular weight measured by mass spectrometry. Fluorescence microscope was used to assess the cell-penetrating activity?of the CPP in hepatocellular carcinoma cell lines SMMC-7721 and normal hepatocellular cell lines LO2. The growth activity of CPP-treated SMMC-7721 cells was measured by MTT assay., Results: With a purity of 96.05% and a relative molecular mass of 3504.9, the synthesized CPP showed no translocation activity in normal hepatocellular cell lines LO2, but showed strong ability to translocate into SMMC-7721 cells without affecting the biological activity of the cells., Conclusion: Using Fmoc solid-phase synthesis method, we have successfully synthesized the CPP with tumor-targeting activity.

In this study, polyelectrolyte microcapsules have been fabricated by biocompatible ferrosoferric oxide nanoparticles (Fe3O4 NPs) and poly allyamine hydrochloride (PAH) using layer by layer assembly technique. The Fe3O4 NPs were prepared by chemical co-precipitation, and characterized by transmission electron microscopy (TEM) and infrared spectrum (IR). Quartz cell also was used as a substrate for building multilayer films to evaluate the capability of forming planar film. The result showed that Fe3O4 NPs were selectively deposited on the surface of quartz cell. Microcapsules containing Fe3O4 NPs were fabricated by Fe3O4 NPs and PAH alternately self-assembly on calcium carbonate microparticles firstly, then 0.2 molL(-1) EDTA was used to remove the calcium carbonate. Scanning electron microscopy (SEM), Zetasizer and vibrating sample magnetometer (VSM) were used to characterize the microcapsule's morphology, size and magnetic properties. The result revealed that Fe3O4 NPs and PAH were successfully deposited on the surface of CaCO3 microparticles, the microcapsule manifested superparamagnetism, size and saturation magnetization were 4.9 +/- 1.2 microm and 8.94 emu x g(-1), respectively. As a model drug, Rhodamin B isothiocyanate labeled bovine serum albumin (RBITC-BSA) was encapsulated in microcapsule depended on pH sensitive of the microcapsule film. When pH 5.0, drug add in was 2 mg, the encapsulation efficiency was (86.08 +/- 3.36) % and the drug loading was 8.01 +/- 0.30 mg x m(L-1).

Mixed crystal TiO2 nanoparticles were prepared from a precursor of TiO2 by hydrothermal-steam method. The effects of the reaction temperature and the reaction time on the photocatalytic activity of the brookite TiO2 were studied. The TiO2 samples were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Photocatalytic degradation of organic dye sulforhodamine B (SRB) under UV light (lambda < or = 387 nm) was used as probe reaction to evaluate the properties of the TiO2. The result showed that TiO2 prepared under 150 degrees C for 24 h had high photocatalytic activity. The size of the mixed crystal TiO2 was 14.20 nm. Brookite and anatase phase of the mixed crystal TiO2 were 63.6% and 36.4%, respectively. The dye discoloration and degradation rates were tracked, and the intermediate products hydrogen peroxide (H2O2) and hydrogen radicals (*OH) were determined during the photocatalytic experiments. The results indicated that photocatalytic degradation of brookite TiO2 mainly referred to the *OH radical mechanism. After 5 h, the mineralization and oxidation rates of SRB and 2,4-DCP mineralization were 89% and 78%, respectively. The catalyst showed good stability with no significant changes in catalytic properties after 5 cycles of SRB photocatalytic degradation experiments.

The structures of three rhodamine derivatives were optimized by means of DFT/B3LYP method, and the data of the structural parameters and thermodynamic parameters of the excited state and ground state of the three rhodamine derivatives and their vibrational spectra and frontier molecular orbital energy level were obtained. On the basis of fully optimized structures of excited state and ground state, their gas absorption and emission spectra were studied by time-dependent density functional theory (TD-DFT), while the effects of their structural features on thermal stability, frontier molecular orbital and spectra properties were fully analyzed. The results indicate that the compound a has the lowest reverse movement degree of terminal amino among these molecules, and in contrast, the compound b was better conjugated and planar, the reverse movement degree of terminal amino improved, the gas absorption and emission spectra were red shifted, and it has the longest maximum emission wavelength and the lowest thermal stability among these molecules. The compound c was best conjugated and planar, its thermal stability and energy of HOMO were the highest, its HOMO-LUMO gap was most narrow, and it has the longest maximum absorption wavelength. It was found that the reverse movement degree of terminal amino of compound c improved compared to b, so its maximum emission wavelength was blue shifted.

Chitosan was used for the removal of Acid Red 3R from aqueous solutions. Batch adsorption studies were carried out to investigate adsorption kinetics and thermodynamics and the effect of coexisting pH, NaCl, and Cu2+ on adsorption. Experimental data were exploited for kinetic and thermodynamic evaluations related to the adsorption processes. The kinetic data correlated well with the pseudo-second-order kinetic model, indicating the chemical sorption via complex formation/ion exchange. The equilibrium data were well fitted by three isotherm models, namely, Langmuir, Freundlich and Dubinin-Radushkevich (D-R) equations. Moreover, adsorption of Acid Red 3R onto the chitosan was found to be strongly depending on solution temperature and pH. However, the addition of sodium chloride was found to have little effect on the adsorption process. Thermodynamic studies revealed the adsorption process was exothermic in natural. The adsorption free energies derived from D-R equation were in range of 9.5-10.7 kJ x mol(-1), implying that the sorption process is a chemical ion-exchange mechanism. In addition, adsorption capacity of chitosan to Acid Red 3R was found to be greatly enhanced in the presence of Cu2+. A model correlating the concentration of Cu2+ with the enhanced amount of dye adsorbed was established.

Natural Soil was used as catalyst to degrade Sulforhodamine B (SRB) and 2,4-Dichlorophenol(DCP) under visible irradiation (vis, lambda > 420 nm). The influences of [Soil] and [H2O2]0 on degradation were analysed, and the reaction kinetics and mechanism of degradation were studied by UV-Vis, fluorescence spectra and IR. Results indicated, SRB can be degraded availably by chosen Soil/H2O2/vis system. Depigmentation can complete in 240 min,COD was removed by 90.44% in 10 h,and DCP was removed by 80.55% in 240 min. Fluorescence spectra results show that highly active oxide species *OH was produced in the reaction. IR results indicate SRB was degraded to small molecular, such as amine substances and carbonyl compounds. Catalyst activity did not exhibit any significant loss after used 5 recycles. Degradation mechanism is heterogeneous Fenton-like process related with *OH.

A technique for temperature control and measurement in microfluidic systems was developed. The technique is easy to be implemented in an analytical lab and the experimental setup is relatively simple and inexpensive. The parts for temperature measurement include a CCD camera, a fluorescence microscope and an image acquisition card. The spatial distribution and the temporal variation of temperature in microfluids were measured. The method is non-invasive and the spatial and temporal resolutions were 0. 8 microm and 40 ms, respectively a thermal control device was built using indium-tin-oxide (ITO) coated glass as heater, taking advantage of its transparent quality. The temperature could be controlled with a precision of +/-0.1 degrees C. The image processing procedure was optimized and the efficacy of the method was demonstrated.

Decoloration and bioaugmentation on azo dye are investigated by using immobilized genetically engineered strain Escherichia coli JM109 (pGEX-AZR) on marcroporous foam carriers. The kinetics of the acid red GR decolorization by the immobilized E. coli JM109 (pGEX-AZR) accords with Andrews model proved by our experiments, and the kinetic parameters, mu(max,c), K(c) and K(ic), are found to be 49.2 mg x (g x h)(-1), 710.43 mg x L(-1) and 681.62 mg x L(-1) respectively. For continuous operating in the anaerobic SBRs with 10% inoculation of Escherichia coli JM109 (pGEX-AZR) on marcroporous foam carriers for 32 d, both the tolerance to red GR concentration shock and the colorific removal in the bioaugmented anaerobic SBRs are higher than the control system, and the acid red GR decoloration rate reached 90%. Changes in microbial community have been detected by the RISA, in which the introduced immobilized GEM and preponderant mixed culture were subsisted steadily in sludge systems.

A novel photo-catalytic reactor of three-phase internal circulation fluidized bed was employed to the photodegradation of Rhodamine B with TiO2/SiO2 carried on porous silica as photocatalyst. The degradation kinetics of Rodaming B is investigated in the reactor. It is found that the degradation of Rodaming B conform hyperbola model, the reciprocal of degradation rate 1/X is proportional to the reciprocal of time 1/t. The reaction rate constant has no relation with initial reactant concentration and is proportional to the light density and volumetric rate of energy absorption. The reaction rate conforms the experiment results quite well, the average relative error being less 3.25%.

Boron doped CeO2/TiO2 mixed oxides photocatalysts were prepared by adding boric acid and cerous nitrate during the hydrolyzation of titanium trichloride and tetrabutyl titanate. XRD, UV-Vis DRS and XPS techniques were used to characterize the crystalline structure, light absorbing ability and the chemical state of Boron element in the photocatalyst sample. The photocatalytic activities were evaluated by monitoring the degradation of acid red B under UV irradiation. These results indicate that the wavelengths at adsorbing edge are affected by the content of cerous nitrate and the maximum absorption wavelength is about 481 nm when the mole ratio of Ce/Ti is 1.0. For higher dosage of Cerium, the absorbance edge shifts to blue slightly. The prepared photocatalyst is composed of anatase TiO2 and cubic CeO2 when calcined at 500 degrees C. An increase in the calcination temperature transforms the crystalline structure of the titanium oxides from anatase to rutile, and has no obvious influence on crystalline structure of CeO2 but crystallites growth up. The absorbance edge decreases drastically with the increase of calcination temperature. With a view to the stability of photocatalyst and utilization of sun energy, 500 degrees C of calcination temperature is recommended. The XP spectrum for B1s exhibits that only a few boron ions dope into titania and ceria matrix, others exist in B2O3. The photocatalytic activity increases with increase of cerous nitrate dosage, and decreases drastically due to higher dosage (the mol ratio of Ce/Ti > 0.5). After 10 min UV irradiation, 96% of acid red B is degraded completely over photocatalyst under optimum reaction condition.

A new method for the determination of trace arsenic was developed by using fluorescence resonance energy transfer from acridine orange (AO) to rhodamine B (RB). It was found that under the condition of lambda(ex)/lambda(em) = 470/580 nm, effective energy transfer could occur between AO and RB in the dodecyl benzene sodium sulfonate solution. The fluorescence intensity of RB was diminished by molybdoarsenide which was formed by the reaction of arsenic (V) with molybdate in sulfuric acid medium. The detection limit of this method was 2. 56 microg x L(-1). This method was used for the determination of trace arsenic in tea. The range of determination for arsenic was 0.01-0.25 mg x L(-1). The relative standard deviation for the determination of arsenic was 0.48%-0.64%. The recoveries for the addition of 0.01-0.03 mg x L(-1) arsenic were 98%-103%. The method has been applied to the determination of arsenic with satisfactory results.

Acid red B (ARB) solution with pH = 3 was electrolyzed in a two-chamber cell using Pt/C gas diffusion electrode (GDE) as cathode. The color and COD removal ratio in cathode chamber were 94.2% and 66.8% respectively; and the color and COD removal ratio in anode chamber were 73.3% and 56.6% respectively, which indicated that O2 can be reduced to H2O2 and x OH in the cathode chamber, then ARB was degraded. Through IR and GC-MS analysis for the intermediates of ARB in the cathode chamber, 20 intermediates have been detected, including 14 esters, 3 acids and 3 compounds with -NO2 or N-OH groups and the probable degradation pathway of ARB in the cathode chamber was given.

Under the conditions of 0.02 mol x L(-1) HCl-4.0 x 10(-4) mol x L(-1) KI-1.6 x 10(-5) mol x L(-1) Mo(VI), there is a fluorescence peak at 540 nm and a synchronous fluorescence peak at 540 nm for Rhodamine 6G (RhG). When there exists H2O2, it reacts with I- to form I3-. RhG and I3- combine to form an ion association particle. The particles exhibit three resonance scattering peaks at 320 nm, 400 and 595 nm respectively. And there is fluorescence quenching at 540 nm. H2O2 concentration in the range of 0.068-34 microg x mL(-1) is proportional to the resonance scattering peak at 400 nm. And a new resonance scattering spectral method has been described for the determination of H2O2 in water samples. The spectral results have verified that the formation of (RhG-I3)n association particles and the interface are the main factor that causes the fluorescence quenching and resonance scattering effects.

An energy transfer technique between acridine orange (AO) and rhodamine 6G (R6G) was studied, and the optimum experimental conditions of energy transfer were defined. It was found that the effective energy transfer could occur between AO and R6G in the dodecylbenzene sodium sulfonate solution with Na2 HPO4-citric acid buffer solution at pH 5.0. The fluorescence intensity of AO-R6G system was diminished by vitamin B12 in an alkalescence medium. Based on the AO-R6G energy transfer system anovel fluorescence quenching method for the determination of vitamin B12 has been developed. Under optimal conditious, the linear range of calibration curves for the determination of vitamin B12 was 0-3.0 x 10(-5) mol x L(-1). The detection limits were 4.8 x 10(-7) mol x L(-1) for Vitamin B12. Among six times of determination, the relative standard deviation was 0.51%-0.64%, and the recovery was 98.40% -103.62%. The method features good recurrence, rapidity of reaction, good stability, and few interfering substances. It can be satisfactorily used in the determination of the injection content of vitamin B12.

It is reported that the Rhodamine 6G fluorescence in water solution changes with different concentration SDS excited by a 532 nm laser. A small amount of SDS in Rhodamine 6G water solution will reduce the intensity of fluorescence. More SDS enhances R6G fluorescence. The enhancement ratio can reach up to 3.1 when SDS concentration is 6 x 10(-2) mol L(-1) in 5 x 10(-5) mol L(-1) R6G water solution. Dye laser threshold decreases when SDS concentration is 2 x 10(-2) mol x L(-1) in 1 x 10(-4) mol x L(-1) R6G water solution. The physical mechanism of the phenomena is analyzed by the absorption spectra of different concentration R6G water solutions and the fluorescence spectra of R6G water solutions adulterated with different concentration SDS.

An inhibitory kinetic fluorimetric method is reported for the determination of trace aniline. The proposed method is based on the inhibitory effect of aniline on the reaction of potassium periodate oxidation of rhodamine 6G in phosphoric acid medium. The detection limit is 7.2 ng x mL(-1), the linear range of the determination is 0.010-0.183 microg x mL(-1). This method has been applied to the determination of trace aniline in phenolic tubes and water samples with satisfactory results.

A novel three-phase internal circulating fluidized bed photocatalytic reactor was established and the radiation transformation in which was investigated. The experimental results indicate that with the interaction of gas and solid (gas flux > 0.3m3/h), the radiation transformation in the reactor along radial direction conforms to a definite exponential function, which agrees to formula Rose about the rules of light intensity distribution through evenly suspended particles. The value of radiation energy is affected by the initial light intensity, the concentration of photocatalyst and the thickness of liquid layer. The aerated gas amount only influence the state of the fluidized bed and has little effect on the distribution of light intensity along radical direction. Photocatalytic degradation of Rhodamine B indicate that the efficiency of three-phase internal circulating fluidized bed is much higher than slurry bed. The optimal catalyst concentration of this system is 10 - 12g/L.

The characteristic and mechanism of resonance light scattering (RLS) of Rhodamine B (RhB) were studied. In acidic solutions with pH from -0.38 to 4.10, the intensity of RLS increases with an increase in pH and reaches a maximum at nearly neutral pH. The change in RLS intensity with the wavelength was not accordant with Rayleigh scattering law. The fluorescence excitation and emission spectra of RhB overlap partly, and the RLS peak lies between the fluorescence excitation and emission peaks. In the three-dimensional fluorescence contour spectra of RhB, Rayleigh scattering line intersects fluorescence contour. In light polarization experiment, the polarization of RLS was measured to be P approximately = 0.1. All the above experimental facts reveal that the RLS of RhB is mainly resonance fluorescence. The mechanism of RLS enhancement by the increase in pH is that the formation of fluorescence species occurs in acid-base equilibrium. The RLS peak of RhB appears within the envelope of absorption, and light scattering is affected by light absorption, so, the relationship between RLS intensity and RhB concentration is not strictly linear.

In (CH2)6N4-HCl buffer solution and in the presence of OP emulsifier trace Ni(II) catalyzes strongly the decolorization reaction of Rhodamine B (RhB) by oxidizing with H2O2, and its catalytic extent is linear with the contents of Ni(II) in a certain range. Based on this study, a novel spectrophotometric method for determining Ni(II) was developed. The results show that the maximum absorption of the complex is at 550 nm, the detection limit of the method is 0.4 microg x L(-1) for Ni(II), and Beer's law is obeyed for Ni(II) in the range of 0-0.3 mg x L(-1). The method has been applied to the determination of Ni in FeNiCr alloys with satisfactory results.

In this paper, a new catalytic kinetic spectrophotometric method for the determination of trace amounts of ascorbic acid has been studied. The method is based on the activation effect of ascorbic acid on vanadium (V) catalyzed oxidation of deoxidized rhodamine B by potassium bromate in weak acidic medium at pH 4.5. The optimal experimental conditions have been discussed. The absorbance was measured at 555 nm. The linear range of the method was 0-7.0 microg x mL(-1). The detection limit for ascorbic acid was 2.5 x 10(-7) g x L(-1). The method has been applied to the determination of ascorbic acid in vitamin C tablet and tomato with satisfactory results.

Sonochemical degradation of azo dye Acid Red B (ARB) was studied in this paper. The effect of pH and ferrous ion concentrations on the process was investigated. The results show that decolorization of ARB proceeds faster in acidic medium. The production of H2O2 is proportional to sonication time. The presence of Fe(II), which could react with H2O2 to produce *OH, enhances the sonochemical decolorizatio and degradation of the dye. The decolorization rates of ARB are 2.17 and 2.75 times faster, respectively, when Fe(II) concentrations are 1.43 mg/L and 2.85 mg/L. The UV absorptions at 322 nm and 254 nm also reduce ARB dramatically.

Photo-Fenton method, the combination of Fenton reagent with light, is an efficient method for waste water treatment. In this paper, the degradation of rhodamine B (a kind of organic dye) using this method was researched. Through numerous experiments, the influences of five parameters including light source, pH, reaction time, dosage of Fenton reagent, and initial dye concentration were investigated intensively. In this paper, the mechanisms of this reaction have also been probed. It is concluded from the experiments that the irradiations of 450 W high-pressure mercury lamp and sun light can both accelerate the process of degradation effectively. Under optimal conditions, the overall color removal was more than 99.9% within 45 min; COD can be removed effectively at the same time.

A new system for the determination of dipyridamole with flow injection chemiluminescence was described. It is based on the chemiluminescence reaction of dipyridamole-potassium permanganate with rhodamine B. Tween-80 was found to be an enhancer of the chemiluminescence reaction. A method based on the enhanced chemiluminescence for dipyridamole determination has been developed. The method has high sensitivity, selectivity and good repeatability with a linear concentration range of 5.0 x 10(-8) - 5.0 x 10(-5) g x mL(-1), a detection limit of 1.7 x 10(-8) g x mL(-1) and a RSD of 1.1% (n = 11, cs = 1.0 x 10(-6) g x mL(-1)).

A new chemiluminescence-based method was proposed for selective quantitation of analgin in pharmaceutical preparation. The CL emission was generated by mixing analgin, polyethylene glycol-400 and rhodamine 6G in acidic medium. The analgin content could be determined by the CL intensity. No oxidants were used in the system, so it was difficult to explain why the CL emission was produced. The mechanism of CL emission remains under investigation. One of the advantages of this method is highly selective. No other pharmaceutical compounds and chemicals could produce CL emission whether they contain sulfuric group or not in the experiment. There was no disturbance in this method, which was different from others. Another advantage is high sensitivity. The quantitation range is from 0.01 to 10 microg x mL(-1) with a detection limit of 0.003 microg x mL(-1) for analgin. This is the lowest detection limit of any CL methods currently available for analgin determination. The proposed method was applied to the selective quantitation of analgin in pharmaceutical preparation.

Not only dye monomer is the form of energy transfer but also dye dimer is the effective form of energy transfer. In this work, the energy transfer system of acridine orange (AO)-rhodamine B (RB) dimer was built for the determination of DNA as fluorescence probe. At the same time, the mechanism was also considered. Under the optimum experimental conditions, the linear range of this assay was 0.33-1.33 mg x L(-1) for fish sperm DNA and 0.33-3.33 mg x L(-1) for calf thymus DNA, the detection limit was 1.63 x 10(-3) mg x L(-1) for fish sperm DNA and 1.52 x 10(-3) mg x L(-1) for calf thymus DNA, respectively. The RSD for the determination of 1.00 mg x L(-1) DNA was 2.40% for fsDNA and 2.00% for ctDNA, respectively. The method was used for the determination of DNA in synthetic samples with satisfied results.

The electrochemical degradation of acid red B (ARB) with hydrogen peroxide and hypochlorite ion electrogenerated by paired electrooxidation technology was investigated. High performance liquid chromatography (HPLC) was used to inspect the degradation process of ARB. Through analyzing chromatographic survey and UV-Vis spectra, as well as the removal of CODCr, TOC and color in the anode and cathode cells, the degradation processes of ARB in different cells were different. The color removal in the cathode cell was slower than in the anode cell, but the CODCr and TOC removal, which were 71.70% and 56.40% respectively, was higher than the removal in the anode cell, which were 25.15% and 27.57%. It maybe result from the different oxidation capabilities of the electrogenerated substances in the anode and cathode cells.

A new catalytic fluorimetric method for the determination of trace oxalate has been developed. The method is based on the catalytic effect of oxalate on the oxidation of potassium dichromate with rhodamine B in sulfuric acid medium. The catalytic reaction takes place at 50 degrees C for 10 min in a water bath and is a pseudo-zero-order reaction. The regression equation of calibration graph is delta F = 8.42c (mg.L-1) + 3.81 (r = 0.9983), and measuring range is 0.4-12.0 mg.L-1, and the detection limit is 0.16 mg.L-1. Interferences of 30 diverse materials were examined. The method has been applied to the determination of oxalate in biological samples with satisfactory results.

A new catalytic-kinetics spectrophotometric method for the determination of horseradish peroxidase was developed. It was based on the catalytic effect of horseradish peroxidase (HRP) on the coloration reaction, in which the reduced rhodamine B was oxidized by H2O2 in pH 6.80 phosphate buffer. It was found that reduced rhodamine B stocking solution could be steady in 0.25% beta-CD solution. The kinetic behavior of the reaction and the effects of some experimental conditions were investigated and discussed in detail. The method has been applied to determine HRP with a satisfactory result. The calibration curve is linear over the range 15-250 pg.10 mL-1 of HRP (r = 0.9989). The limit of detection was 12 pg.10 mL-1 and the relative standard derivative RSD is 4.25% by determining for 20 pg.10 mL-1 HRP (n = 10).

Fluorescence of Rhodamine 6G in aqueous solution is effectively enhanced by using anionic sodium dodecylsulfate (SDS) surfactant. When the concentration of Rhodamine 6G is 5.47 x 10(-7) mol.L-1 and 5.47 x 10(-4) mol.L-1, maximal enhancement ratio can be 1.95 and 9.7, respectively. In the latter case, using SDS can reduce the threshold and improve the energy conversion efficiency of the dye laser of Rhodamine 6G. In the absence of SDS, the laser threshold power density is near 65 MW.cm-2. While in the present of SDS, the threshold is reduced to 0.8 MW.cm-2. The laser energy conversion efficiency can reach 25% when the pumping power density is 65 MW.cm-2. We also observed the red shifts of absorption spectrum, fluorescence spectrum and the dye laser spectrum in the present of SDS. The physical mechanism of the phenomena is discussed.

In this paper, we studied the charge transferring between silver nanoparticles and R6G molecules by UV-Vis absorption spectra, SERS and fluorescence spectra. The results indicate that the charge transferring process can be completed by forming complex between silver nanoparticles and R6G molecules. As a result, the absorption band of complex can be seen in the absorption spectra, the Raman modes of R6G are largely enhanced and the fluorescence of R6G is effectively quenched.