There was a significant catalytic effect of trace Gd(III) ions on the oxidative reaction of potassium persulfate with Saffron T in the acetic acid–sodium acetate buffer solution. Thus, a catalytic kinetic fluorimetry...There was a significant catalytic effect of trace Gd(III) ions on the oxidative reaction of potassium persulfate with Saffron T in the acetic acid–sodium acetate buffer solution. Thus, a catalytic kinetic fluorimetry method for the determination of trace Gd(III) ions was established. The factors such as acidity, concentration of reagents, reaction time, and temperature as well as influence of coexisting ions were discussed. The optimum reaction conditions were established. The apparent rate constant and apparent activation energy of the reaction were determined. The linear range is 0.02–0.10 lgáml-1,and the detection limit is 7.27 9 10-4lgáml-1. This method was used for the determination of gadolinium in the samples of lanthanum acetate with RSD of 0.9 %–3.1 %.展开更多
Terbium can form a ternary complex having a ratio of 1:1:1 with acetylacetone and EDTA. By adding cetyl pyridinium chloride into the above system, a marked enhancement of fluorescence intensity is observed and the ter...Terbium can form a ternary complex having a ratio of 1:1:1 with acetylacetone and EDTA. By adding cetyl pyridinium chloride into the above system, a marked enhancement of fluorescence intensity is observed and the ternary complex becomes more stable than before. For analytical application, the derivative spectrofluorimetric method has high sensitivity and the effect of foreign ions is very low. The optimum conditions were obtained. The calibration graph is linear over 5～100μg/mL.展开更多
The derivative fluorimetric characteristics of Tb—SDS and Tb—SDS—phenanthroline systems have been studied. The optimum conditions were obtained. The 2nd—derivative spectrofluorimetric method in the systems has bee...The derivative fluorimetric characteristics of Tb—SDS and Tb—SDS—phenanthroline systems have been studied. The optimum conditions were obtained. The 2nd—derivative spectrofluorimetric method in the systems has been applied to the determination of trace amounts of terbium, in rare earth ore and their oxides. The results are satisfactory.展开更多
Amphiphiles,including surfactants,have emerged as indispensable elements in materials science and pharmaceutical science,and their functions are highly relying on the critical micelle concentration(CMC)[1,2].Numerous ...Amphiphiles,including surfactants,have emerged as indispensable elements in materials science and pharmaceutical science,and their functions are highly relying on the critical micelle concentration(CMC)[1,2].Numerous fluorimetry-based probes have been developed to measure CMCs[3](Fig.S1).However,CMC measurements using these probes suffer from a time-consuming and laborious procedure and large uncertainties,primarily due to their poor photo-stabilities and highly fluctuating fluorescence backgrounds.展开更多
A new time-resolved fluorimetric method for the measurement of natural killer (NK) cell cytotoxicity has been developed by labelling the target cell K562 with a new synthesized fluorescence marker KLUK. The method has...A new time-resolved fluorimetric method for the measurement of natural killer (NK) cell cytotoxicity has been developed by labelling the target cell K562 with a new synthesized fluorescence marker KLUK. The method has advantages of higher sensitivity, time-saving, good reproducibility and has no radioactivity problems. A satisfactory result is obtained by comparing it with 51Cr release method. It demonstrates that the new marker provides an alternative to currently used radioactive markers for the assessment of in vitro cellular cytotoxicity.展开更多
The phenomenon of fluorescence enhancement for the system of terbium( Ⅲ ) with trimesic acid [ ben-zene-1, 3, 5-tricarboxylic acid (TMA)] in the presence of an excase of La￣(3+) in gelatin aqusous solution wasstudi...The phenomenon of fluorescence enhancement for the system of terbium( Ⅲ ) with trimesic acid [ ben-zene-1, 3, 5-tricarboxylic acid (TMA)] in the presence of an excase of La￣(3+) in gelatin aqusous solution wasstudied. The fluorescence intensity of Tb￣Ⅲ -TMA system can be greatly increased by La￣(3+) , which causedthe largest enhancement of the fluorescence intensity over two orders of magnitude. The intermolecular transfer of energy was responsible for the mechanism of the fluorascence enhancement. Gelatin plays animportant role for the stabilization of the system. The system, having the maximum excitation and emis-sion wavelengths at 260 nm and 549 nm, respectively, shows a constant fluorescence interisity over the pHrange 4～6. The fluorescence intensity is a linear function of Tb￣(3+) concentration in the range of 8. 0 ×10 ￣(-9)～ 2. 6 × 10￣(-7) mol· L￣(-1) and the limit of detection is 2.0 × 10￣(-9) mol·L￣(-1) . The optimized procedurewas used for the determination of trace amount of terbium in rare earth oxides and international standardreference rocks with satisfactory results.展开更多
A novel fluorimetric method for determination of laccase activity in organic solvents is proposed,based on the oxidation ofo-phenylenediamine(1,2-diaminobenzene,OPDA)catalyzed by laccase yielding 2,3-diaminophenazine....A novel fluorimetric method for determination of laccase activity in organic solvents is proposed,based on the oxidation ofo-phenylenediamine(1,2-diaminobenzene,OPDA)catalyzed by laccase yielding 2,3-diaminophenazine.The optimal conditions for laccase in organic media areT=55°C,pH=6.5,1.0×10^(-2)mol/L OPDA,1.25 mL ethanol,1.25 mL 1,4-dioxane and 1.25 mL acetone.The linear range of the method proposed in ethanol,1,4-dioxane and acetone media were 0.44–19.33,0.11–20.85,0.38–21.05 U with the detection limit of 0.088,0.022,0.076 U,respectively.The proposed method has been applied to the analysis of laccase activity of real samples with more accurate and sensitive than that of the previous method reported.展开更多
A simple and highly sensitive method for the determination of triamcinolone acetonide in pharmaceutical formulations is presented.The approach is based on the fluorescence of production of triamcinolone acetonide oxid...A simple and highly sensitive method for the determination of triamcinolone acetonide in pharmaceutical formulations is presented.The approach is based on the fluorescence of production of triamcinolone acetonide oxidized by concentrated sulfuric acid.The effect of H2SO4,β-cyclodextrin(β-CD),solvent and cetyltrimethylammonium bromide(CTMAB)were discussed.And two analytical systems were established.One is CTMAB system,the linear range is 0–4.6×10^(-6)mol/L,and the detection limit is 3.59×10^(-8)mol/L.The other isβ-CD and ethanol system,the linear range is 0–2.3×10^(-6)mol/L and the detection limit is 1.91×10^(-8)mol/L.The selectivity of analysis,the analytical figures of optimization,and the accuracy of the method are demonstrated with the determination of triamcinolone acetonide in pharmaceutical preparations.展开更多
Ce(Ⅲ)-ALC-F complex can react with hsDNA to form an electrochemically non-active supermolecular complex Ce(Ⅲ)-ALC-F-DNA in the buffer solution of (CH2)6N4(pH=4.9), which results in the decrease of the peak current o...Ce(Ⅲ)-ALC-F complex can react with hsDNA to form an electrochemically non-active supermolecular complex Ce(Ⅲ)-ALC-F-DNA in the buffer solution of (CH2)6N4(pH=4.9), which results in the decrease of the peak current of Ce(Ⅲ)-ALC-F. This method can be applied to determine DNA concentration. In addition, by using fluorimetric and UV-spectrophotometric methods with studies of denatured DNA and the effect of NaCl solution , it is also found that the binding mode is intercalation.展开更多
fluorescence enhancement phenomenon shown by adding scandium ion to thesamarium-thenoyltrifluoroacetone (TTA)-cetyltrimethylammonium bromide(CTMAB)-Triton X-100(TX-100) system was observed and the effect of the condi-...fluorescence enhancement phenomenon shown by adding scandium ion to thesamarium-thenoyltrifluoroacetone (TTA)-cetyltrimethylammonium bromide(CTMAB)-Triton X-100(TX-100) system was observed and the effect of the condi-tions on the system was studied in detail. The excitation and emission wavelengthswere 370 nm, 565 nm, 603 nm and 645 nm, respectively. The optimum conditionsforming Sm-Sc-TTA-CTMAB-TX-100 system were that the concentration of Sc￣(3+)was equal to 5.0× 10￣(-5) mol/L, pH was 7. 7. Under these conditions, the fluores-cence intensity can be increased about 10 times higher than that of the system con-taining no Sc￣(3+) , and it was a linear function of the concentration of samariumn therange of 1. 0 × 10￣(-9)-4. 0 × 10￣(-7) mol/L. The detection limit was 6. 0 ×10￣(-10) mol/L.This system was used for the spectrofluorimetric determination of samarium withsatisfactory results. The nature of enhanced fluorescence was explained using in-tramolecular and intermolecular energy transfer theory.展开更多
A new fluorescence catalyie methad for dereiatio of NADH was pos.This mehod NADH and H_(2)O_(2).Under the optimum conditions,the cali bration graph for the determination of NADH is in the range of 1.6×10^(-7)-2.0...A new fluorescence catalyie methad for dereiatio of NADH was pos.This mehod NADH and H_(2)O_(2).Under the optimum conditions,the cali bration graph for the determination of NADH is in the range of 1.6×10^(-7)-2.0×10^(-5)mol/L,and the detect limit is 4.1×10^(-8)mol/L.The relative standard deviation is 4.6%for 1.0×10^(-6)mol/L(n=9).展开更多
A new spectrofluorimetric method for determination of trace terbium based on its reaction with 2.6-his-(1'-phenyl-3'-methyl-5'- pyridinediacyl (H_2PMBPP) and N- cetylpyridium bromide (CPB). at an apparent ...A new spectrofluorimetric method for determination of trace terbium based on its reaction with 2.6-his-(1'-phenyl-3'-methyl-5'- pyridinediacyl (H_2PMBPP) and N- cetylpyridium bromide (CPB). at an apparent pH=5.0 provided by a hexamethylenetetramine (5% w/w)-hydrochloric acid buffer,is propesed. The calibration graph is linear in the ran ge from展开更多
A simple and selective method for the determination of epinephrine is put forward, which is an improved modification of the trihydroxyindole method. Experiment indicated that in borax buffer (pH=8.7) and with mercapto...A simple and selective method for the determination of epinephrine is put forward, which is an improved modification of the trihydroxyindole method. Experiment indicated that in borax buffer (pH=8.7) and with mercaptoethanol as the reducing reagent, dopa and dopamine did not form fluorescence products, so it is possible to determine epinephrine selectively.展开更多
This study aimed to identify new compounds capable of decreasing pancreatic lipase(PL)catalytic activity.A panel of structurally related chalcones with hydroxy and chloro substituents was chosen,and their inhibitory e...This study aimed to identify new compounds capable of decreasing pancreatic lipase(PL)catalytic activity.A panel of structurally related chalcones with hydroxy and chloro substituents was chosen,and their inhibitory eff ects on the targeted enzyme were assessed.This work also optimized the conditions for UV/Vis spectrophotometric and fluorimetric microanalysis systems and,whenever possible,a structure–activity relationship analysis was performed.The obtained results showed the eff ectiveness of both methodologies in assessing the inhibition of PL catalytic activity.Some of the tested chalcones exhibited notable inhibitory eff ects on PL activity.Remarkably,the presence of hydroxy or chloro substituents appears to enhance the observed inhibitory activities of these compounds.展开更多
The three types of structure of the pyrenebutyric acid of fiber optic chemical film sensor were stud-ied by fluorescence multiple quenching. They are, for different test samples and purposes, respectively general, thr...The three types of structure of the pyrenebutyric acid of fiber optic chemical film sensor were stud-ied by fluorescence multiple quenching. They are, for different test samples and purposes, respectively general, three-way and combined. A tri-cup method was designed to demonstrate the multiple quenching of response mechanism, and a relationship formula of mathematical approach was established. The response mechanism was shown to include the dynamic quenching , inner-filter effects and/or resonance energy transfer. To show the response characterization in a series of organic and inorganic quenchers, a new concept of apparent quenching coefficient Kq was advanced. This kind of sensor has been used in continuous and in situ monitoring of the dissolution rate of drug tablets, on line and in situ monitoring of some organic therapeutic drugs in biological fluid and Cr( VI ) in industrial waste water. The measured data were examined and compared with HPLC or HPTLCS. Test results show that the sensors and apparatus are sta-ble and reliable, and their responses to analyte are reversible and rapid, reaching the practical application level.展开更多
The fluorescence behavior of two near-infrared (NIR) chromophores with linear alkyl chains of different lengths, 2-[4'chloro-7'(3'ethyl-2'benzothiazolinylidene)-3',5'-(1''',3'&#...The fluorescence behavior of two near-infrared (NIR) chromophores with linear alkyl chains of different lengths, 2-[4'chloro-7'(3'ethyl-2'benzothiazolinylidene)-3',5'-(1''',3'''-propanediyl)-1',3',5'-heptantriene-1'-yl]-3-ethylbenzo- thiazolium iodide (Probe I) and 2-[4'chloro-7'(3'hexadecyl-2'benzothiazolinylidene)-3',5'-(1''',3'''-propanediyl)- 1',3',5'-heptantriene-1'-yl]-3-ethylbenzothiazolium iodide (Probe II), in aqueous solution containing different con-centrations of surfactants was studied. The fluorescence of the probe with a short chain (probe I) was completely quenched in water and aqueous solution containing a low concentration (below the critical micelle concentration, CMC) of surfactant Triton X-100. However, the fluorescence reappeared and reached maximum rapidly once the concentration of the surfactant approached the CMC. The probe with a long chain (probe II) displayed a similar fluorescence behavior but more dramatically fluorescent recovery in Triton X-100 system, which gave a direct in-dication for the micelle forming process and provided a simple method for the determination of the critical micelle concentration of the surfactant. The CMC values determined by this method were in good agreement with those ob-tained by other techniques. The fluorescence behavior of the two probes in other surfactant systems was also inves-tigated.展开更多
Tetracycline antibiotics could be degraded after being beated in boiling-water bath in alkaline solution (in KOH medium).The fluorescence excitation and emission wavelengths of the degradation products changed and the...Tetracycline antibiotics could be degraded after being beated in boiling-water bath in alkaline solution (in KOH medium).The fluorescence excitation and emission wavelengths of the degradation products changed and the fluorescence intensity increased by 5-190 folds as compared with that of antibiotics themselves It was considered that there occurred a nucleophilic ring rupture reaction to form the degradation products with lactome structure The mteraction of the lone pair electrons of oxygen on the degradation products with the conjugated π electrons induced the in crease of the delocalization for the conjugated electron system in the molecule and thus enhanced the fluorescence intensity.展开更多
基金financially supported by the Natural Science Foundation of Shandong Province (No. Y2008B26)
文摘There was a significant catalytic effect of trace Gd(III) ions on the oxidative reaction of potassium persulfate with Saffron T in the acetic acid–sodium acetate buffer solution. Thus, a catalytic kinetic fluorimetry method for the determination of trace Gd(III) ions was established. The factors such as acidity, concentration of reagents, reaction time, and temperature as well as influence of coexisting ions were discussed. The optimum reaction conditions were established. The apparent rate constant and apparent activation energy of the reaction were determined. The linear range is 0.02–0.10 lgáml-1,and the detection limit is 7.27 9 10-4lgáml-1. This method was used for the determination of gadolinium in the samples of lanthanum acetate with RSD of 0.9 %–3.1 %.
基金Project supported by the National Natural Science Foundation of China
文摘Terbium can form a ternary complex having a ratio of 1:1:1 with acetylacetone and EDTA. By adding cetyl pyridinium chloride into the above system, a marked enhancement of fluorescence intensity is observed and the ternary complex becomes more stable than before. For analytical application, the derivative spectrofluorimetric method has high sensitivity and the effect of foreign ions is very low. The optimum conditions were obtained. The calibration graph is linear over 5～100μg/mL.
基金Project supported by the National Natural Science Foundation of China
文摘The derivative fluorimetric characteristics of Tb—SDS and Tb—SDS—phenanthroline systems have been studied. The optimum conditions were obtained. The 2nd—derivative spectrofluorimetric method in the systems has been applied to the determination of trace amounts of terbium, in rare earth ore and their oxides. The results are satisfactory.
基金supported by Shanghai Municipal Commission of Science and Technology,China(Grant No.:19XD1400300)the National Natural Science Foundation of China(Grant Nos.:821040821,82273867,and 82030107).
文摘Amphiphiles,including surfactants,have emerged as indispensable elements in materials science and pharmaceutical science,and their functions are highly relying on the critical micelle concentration(CMC)[1,2].Numerous fluorimetry-based probes have been developed to measure CMCs[3](Fig.S1).However,CMC measurements using these probes suffer from a time-consuming and laborious procedure and large uncertainties,primarily due to their poor photo-stabilities and highly fluctuating fluorescence backgrounds.
基金Project supported by the National Natural Science Foundation of China.
文摘A new time-resolved fluorimetric method for the measurement of natural killer (NK) cell cytotoxicity has been developed by labelling the target cell K562 with a new synthesized fluorescence marker KLUK. The method has advantages of higher sensitivity, time-saving, good reproducibility and has no radioactivity problems. A satisfactory result is obtained by comparing it with 51Cr release method. It demonstrates that the new marker provides an alternative to currently used radioactive markers for the assessment of in vitro cellular cytotoxicity.
文摘The phenomenon of fluorescence enhancement for the system of terbium( Ⅲ ) with trimesic acid [ ben-zene-1, 3, 5-tricarboxylic acid (TMA)] in the presence of an excase of La￣(3+) in gelatin aqusous solution wasstudied. The fluorescence intensity of Tb￣Ⅲ -TMA system can be greatly increased by La￣(3+) , which causedthe largest enhancement of the fluorescence intensity over two orders of magnitude. The intermolecular transfer of energy was responsible for the mechanism of the fluorascence enhancement. Gelatin plays animportant role for the stabilization of the system. The system, having the maximum excitation and emis-sion wavelengths at 260 nm and 549 nm, respectively, shows a constant fluorescence interisity over the pHrange 4～6. The fluorescence intensity is a linear function of Tb￣(3+) concentration in the range of 8. 0 ×10 ￣(-9)～ 2. 6 × 10￣(-7) mol· L￣(-1) and the limit of detection is 2.0 × 10￣(-9) mol·L￣(-1) . The optimized procedurewas used for the determination of trace amount of terbium in rare earth oxides and international standardreference rocks with satisfactory results.
基金Supported by the National Natural Science Foundation of China and the Special Founds of State Education Committee for Doctorate Research
文摘A novel fluorimetric method for determination of laccase activity in organic solvents is proposed,based on the oxidation ofo-phenylenediamine(1,2-diaminobenzene,OPDA)catalyzed by laccase yielding 2,3-diaminophenazine.The optimal conditions for laccase in organic media areT=55°C,pH=6.5,1.0×10^(-2)mol/L OPDA,1.25 mL ethanol,1.25 mL 1,4-dioxane and 1.25 mL acetone.The linear range of the method proposed in ethanol,1,4-dioxane and acetone media were 0.44–19.33,0.11–20.85,0.38–21.05 U with the detection limit of 0.088,0.022,0.076 U,respectively.The proposed method has been applied to the analysis of laccase activity of real samples with more accurate and sensitive than that of the previous method reported.
基金Supported by the National Natural Science Foun-dation of China(20275028)
文摘A simple and highly sensitive method for the determination of triamcinolone acetonide in pharmaceutical formulations is presented.The approach is based on the fluorescence of production of triamcinolone acetonide oxidized by concentrated sulfuric acid.The effect of H2SO4,β-cyclodextrin(β-CD),solvent and cetyltrimethylammonium bromide(CTMAB)were discussed.And two analytical systems were established.One is CTMAB system,the linear range is 0–4.6×10^(-6)mol/L,and the detection limit is 3.59×10^(-8)mol/L.The other isβ-CD and ethanol system,the linear range is 0–2.3×10^(-6)mol/L and the detection limit is 1.91×10^(-8)mol/L.The selectivity of analysis,the analytical figures of optimization,and the accuracy of the method are demonstrated with the determination of triamcinolone acetonide in pharmaceutical preparations.
文摘Ce(Ⅲ)-ALC-F complex can react with hsDNA to form an electrochemically non-active supermolecular complex Ce(Ⅲ)-ALC-F-DNA in the buffer solution of (CH2)6N4(pH=4.9), which results in the decrease of the peak current of Ce(Ⅲ)-ALC-F. This method can be applied to determine DNA concentration. In addition, by using fluorimetric and UV-spectrophotometric methods with studies of denatured DNA and the effect of NaCl solution , it is also found that the binding mode is intercalation.
文摘fluorescence enhancement phenomenon shown by adding scandium ion to thesamarium-thenoyltrifluoroacetone (TTA)-cetyltrimethylammonium bromide(CTMAB)-Triton X-100(TX-100) system was observed and the effect of the condi-tions on the system was studied in detail. The excitation and emission wavelengthswere 370 nm, 565 nm, 603 nm and 645 nm, respectively. The optimum conditionsforming Sm-Sc-TTA-CTMAB-TX-100 system were that the concentration of Sc￣(3+)was equal to 5.0× 10￣(-5) mol/L, pH was 7. 7. Under these conditions, the fluores-cence intensity can be increased about 10 times higher than that of the system con-taining no Sc￣(3+) , and it was a linear function of the concentration of samariumn therange of 1. 0 × 10￣(-9)-4. 0 × 10￣(-7) mol/L. The detection limit was 6. 0 ×10￣(-10) mol/L.This system was used for the spectrofluorimetric determination of samarium withsatisfactory results. The nature of enhanced fluorescence was explained using in-tramolecular and intermolecular energy transfer theory.
文摘A new fluorescence catalyie methad for dereiatio of NADH was pos.This mehod NADH and H_(2)O_(2).Under the optimum conditions,the cali bration graph for the determination of NADH is in the range of 1.6×10^(-7)-2.0×10^(-5)mol/L,and the detect limit is 4.1×10^(-8)mol/L.The relative standard deviation is 4.6%for 1.0×10^(-6)mol/L(n=9).
基金The authors are gratelbl for financial supports IYom the National Natural Science roundation of Chinathe Educational Commiss
文摘A new spectrofluorimetric method for determination of trace terbium based on its reaction with 2.6-his-(1'-phenyl-3'-methyl-5'- pyridinediacyl (H_2PMBPP) and N- cetylpyridium bromide (CPB). at an apparent pH=5.0 provided by a hexamethylenetetramine (5% w/w)-hydrochloric acid buffer,is propesed. The calibration graph is linear in the ran ge from
文摘A simple and selective method for the determination of epinephrine is put forward, which is an improved modification of the trihydroxyindole method. Experiment indicated that in borax buffer (pH=8.7) and with mercaptoethanol as the reducing reagent, dopa and dopamine did not form fluorescence products, so it is possible to determine epinephrine selectively.
基金Open access funding provided by FCT|FCCN(b-on)financial support from Fundacao para a Ciência e Tecnologia and Ministério da Ciência,Tecnologia e Ensino Superior(FCT/MCTES)by projects UID/50006-Laboratório Associado para a Química Verde-Tecnologias e Processos Limpos,UIDB/04378/2020(UCIBIO),and LA/P/0140/2020(i4HB)through PT national funds,as well as by project EXPL/MED-QUI/0815/2021。
文摘This study aimed to identify new compounds capable of decreasing pancreatic lipase(PL)catalytic activity.A panel of structurally related chalcones with hydroxy and chloro substituents was chosen,and their inhibitory eff ects on the targeted enzyme were assessed.This work also optimized the conditions for UV/Vis spectrophotometric and fluorimetric microanalysis systems and,whenever possible,a structure–activity relationship analysis was performed.The obtained results showed the eff ectiveness of both methodologies in assessing the inhibition of PL catalytic activity.Some of the tested chalcones exhibited notable inhibitory eff ects on PL activity.Remarkably,the presence of hydroxy or chloro substituents appears to enhance the observed inhibitory activities of these compounds.
基金Project supported by the National Natural Science Foundation of China and Science Foundation of Ministry of Public Health of China.
文摘The three types of structure of the pyrenebutyric acid of fiber optic chemical film sensor were stud-ied by fluorescence multiple quenching. They are, for different test samples and purposes, respectively general, three-way and combined. A tri-cup method was designed to demonstrate the multiple quenching of response mechanism, and a relationship formula of mathematical approach was established. The response mechanism was shown to include the dynamic quenching , inner-filter effects and/or resonance energy transfer. To show the response characterization in a series of organic and inorganic quenchers, a new concept of apparent quenching coefficient Kq was advanced. This kind of sensor has been used in continuous and in situ monitoring of the dissolution rate of drug tablets, on line and in situ monitoring of some organic therapeutic drugs in biological fluid and Cr( VI ) in industrial waste water. The measured data were examined and compared with HPLC or HPTLCS. Test results show that the sensors and apparatus are sta-ble and reliable, and their responses to analyte are reversible and rapid, reaching the practical application level.
基金Project supported by the National Natural Science Foundation of China (No. 29775021).
文摘The fluorescence behavior of two near-infrared (NIR) chromophores with linear alkyl chains of different lengths, 2-[4'chloro-7'(3'ethyl-2'benzothiazolinylidene)-3',5'-(1''',3'''-propanediyl)-1',3',5'-heptantriene-1'-yl]-3-ethylbenzo- thiazolium iodide (Probe I) and 2-[4'chloro-7'(3'hexadecyl-2'benzothiazolinylidene)-3',5'-(1''',3'''-propanediyl)- 1',3',5'-heptantriene-1'-yl]-3-ethylbenzothiazolium iodide (Probe II), in aqueous solution containing different con-centrations of surfactants was studied. The fluorescence of the probe with a short chain (probe I) was completely quenched in water and aqueous solution containing a low concentration (below the critical micelle concentration, CMC) of surfactant Triton X-100. However, the fluorescence reappeared and reached maximum rapidly once the concentration of the surfactant approached the CMC. The probe with a long chain (probe II) displayed a similar fluorescence behavior but more dramatically fluorescent recovery in Triton X-100 system, which gave a direct in-dication for the micelle forming process and provided a simple method for the determination of the critical micelle concentration of the surfactant. The CMC values determined by this method were in good agreement with those ob-tained by other techniques. The fluorescence behavior of the two probes in other surfactant systems was also inves-tigated.
基金Project supported by the National Natural Science Foundation of Chinathe Provincial Natural Science Foundation of Fujian
文摘Tetracycline antibiotics could be degraded after being beated in boiling-water bath in alkaline solution (in KOH medium).The fluorescence excitation and emission wavelengths of the degradation products changed and the fluorescence intensity increased by 5-190 folds as compared with that of antibiotics themselves It was considered that there occurred a nucleophilic ring rupture reaction to form the degradation products with lactome structure The mteraction of the lone pair electrons of oxygen on the degradation products with the conjugated π electrons induced the in crease of the delocalization for the conjugated electron system in the molecule and thus enhanced the fluorescence intensity.
