Fluorometric Study Research Articles

Benzo-Crown-Ether Functionalized O-BODIPY Probes for Cations - A Selective Fluorescent Probe for Ba2.

Herein, we report the synthesis and sensing characteristics of 4,4'-methoxy-substituted BODIPY fluorescent probes (O-BODIPYs) 3, 4 and 5 equipped with differently sized benzo-crown ethers (cf. Scheme 1, 3 (benzo-15-crown-5), 4 (benzo-18-crown-6) and 5 (benzo-21-crown7)). O-BODIPYs 3, 4 and 5 exhibited in comparison to their known F-BODIPY analogues 3a, 4a and 5a (cf. Scheme 1) an improved solubility in aqueous medium and higher fluorescence quantum yields. Fluorometric study in aqueous solutions of 3, 4 and 5 in the presence of different cations show cation induced fluorescence enhancements (FE). Compared to the benzo-crown ether substituted F-BODIPY analogues 3a, 4a and 5a, we found for the free O-BODIPYs 3, 4 and 5 higher fluorescence quantum yields (φf) but lower cation induced FEs. We show that in aqueous medium the fluorescence quenching process (OFF switching), a photoinduced electron transfer, in O-BODIPYs 3, 4 and 5 is less effective and consequently sensitive and selective ON switching of the fluorescence by cations, too. Albeit these observations the novel benzo-21-crown-7 equipped fluorescent probe 5 exhibits a good fluorometric Ba2+ selectivity and Ba2+ sensitivity in conjunction to their aqueous solubility.

Fluorometric study of molecular association of pectin and algin with ferulic and p-coumaric acids: Evaluation of association capacity of dietary fibers towards antioxidants

Antioxidants undergo molecular association with dietary fibers in plant foods, and the actual nutritional functions depend on the conditions of association. As an approach to quantitative interpretation of the association effects, the present study proposes a method to evaluate association capacity, based on fluorometric titration of ferulic and p-coumaric acids with pectin and algin. The titration curve is formulated on the model that active sites on a fiber chain consist of segments each capable of binding to a single antioxidant molecule. The average segment sizes NS determined from observed curves range from 5 to 12 monomer units, and the mean association constant KA from 5 × 104 to 18 × 104 M−1 per segment, depending on fiber–antioxidant combinations. These parameters suggest that, although individual monomer units have weak binding forces, each segment involves multiple binding sites so that accumulating forces lead to the high thermodynamic stability of the molecular associates; the association capacity is presented by the half association concentration of antioxidant CG1/2 = 2Cm/NS – 2/KA at a monomer-based fiber concentration Cm. The extended application of the method to selected fiber–nutrient combinations would help to describe the association at molecular levels and to design better nutritional agents.

Detection of mercury(ii) in aqueous media using bodipy-functionalized magnetic fluorescent sporopollenin.

Pollution from heavy metal ions has become a major issue worldwide. Water pollution, particularly with heavy metals like mercury, is a global problem. Developing environmentally friendly, low-cost, high-efficiency, sensitive, and selective sensors for the detection of mercury(ii) ions in aqueous environments has attracted great interest in industry and academia. In this research paper, a bodipy-functionalized magnetic fluorescent MSp-TAB hybrid material was developed for detecting mercury(ii) in aqueous media. The magnetic fluorescent MSp-TAB hybrid material was characterized using FT-IR, SEM, EDX, XRD, and TGA. We studied the influence of diverse factors such as contact time, temperature, and pH on the detection of Hg(ii). The fluorometric study demonstrated that the developed magnetic-fluorescent hybrid material was sensitive/selective for Hg(ii) ions in the absence and presence of interfering ions with a limit of detection (LOD) of 2.72 μM. In conclusion, the developed magnetic fluorescent MSp-TAB hybrid material has demonstrated its applicability and potential for accurate, sensitive, and practical detection of Hg(ii) in tap water samples.

Synthesis of N, S co-doped carbon quantum dots (N,S-CQDs) for sensitive and selective determination of mercury (Hg2+) in Oreochromis niloctus (Tilapia fish)

This study reported the synthesis of green-emitting N,S-doped carbon quantum dots (N,S-CQDs) through a one-step, facile, and fast hydrothermal technique using citric acid, glutamine, and Na2S as the carbon, nitrogen, and sulphur sources respectively. The fluorescence efficiency of the developed nanosensor was investigated by varying the duration of synthesis (4, 5, and 6 h). Characterization of the N-CQDs was achieved using Fourier-Transform Infra-red Spectroscopy (FTIR), High-resolution transmission electron microscope (HRTEM), ultraviolet–visible spectroscopy (UV–Vis), and X-Ray diffraction analysis (XRD). The as-synthesized N,S-CQDs are small (average size of 3.45 ± 0.86 nm), spherical, and displayed green emission (535 nm) with a fluorescent quantum yield (QY) of 10.35%. FTIR analysis reveals carboxylic, hydroxyl, and conjugated amide functional groups. The fluorometric study showed that the developed nanosensor was selective and sensitive towards Hg2+ ions in the midst and absence of interfering ions with a detection limit (LOD) of 28.9 nM. The static quenching mechanism was proposed based on lifetime and UV results. Furthermore, it was used as a nanoprobe for Hg2+ determination in Oreochromis niloctus with recoveries of 96.7–108.6% (RSD < 4.1%), indicating the as-synthesized N,S-CQDs have potentials as a nanoprobe for Hg2+ determination in sea foods.

Facile aqueous synthesis of ZnCuInS/ZnS–ZnS QDs with enhanced photoluminescence lifetime for selective detection of Cu(ii) ions

Abstract Quaternary quantum dots (QDs) have recently gained more attention due to their low toxicity, tunable wavelength, reduced or no blueshift emission upon overcoating, improved photoluminescence (PL) quantum yield, and PL lifetime when compared to their binary (II–VI) and ternary (I–III–VI) counterparts. In this work, the aqueous synthesis of ZnCuInS/ZnS–ZnS multi-shell quaternary QDs as a nanosensor for the selective detection of Cu2+ ions was reported. The as-synthesized QDs were spherical, with a particle diameter of 3.66 ± 0.81 nm, and emitted in the first near-infrared window (725 nm) with an average decay PL lifetime of 43.69 ns. The X-ray diffraction analysis showed that the QDs were of the wurtzite structure, while the Fourier transform infrared spectroscopy confirmed GSH capping through the sulphur–metal bond. Furthermore, the fluorometric study shows that the developed multi-shell QDs were selective towards Cu2+ ions compared to other metal ions via fluorescence quenching with a limit of detection of 1.4 µM, which is below the acceptable limit in drinking water.

Fluorometric study on the amine-catalysed Suzuki–Miyaura coupling

Fluorometric study on the amine-catalysed Suzuki–Miyaura coupling

Non-Covalent Binding of Tripeptides-Containing Tryptophan to Polynucleotides and Photochemical Deamination of Modified Tyrosine to Quinone Methide Leading to Covalent Attachment.

A series of tripeptides TrpTrpPhe (1), TrpTrpTyr (2), and TrpTrpTyr[CH2N(CH3)2] (3) were synthesized, and their photophysical properties and non-covalent binding to polynucleotides were investigated. Fluorescent Trp residues (quantum yield in aqueous solvent ΦF = 0.03–0.06), allowed for the fluorometric study of non-covalent binding to DNA and RNA. Moreover, high and similar affinities of 2×HCl and 3×HCl to all studied double stranded (ds)-polynucleotides were found (logKa = 6.0–6.8). However, the fluorescence spectral responses were strongly dependent on base pair composition: the GC-containing polynucleotides efficiently quenched Trp emission, at variance to AT- or AU-polynucleotides, which induced bisignate response. Namely, addition of AT(U) polynucleotides at excess over studied peptide induced the quenching (attributed to aggregation in the grooves of polynucleotides), whereas at excess of DNA/RNA over peptide the fluorescence increase of Trp was observed. The thermal denaturation and circular dichroism (CD) experiments supported peptides binding within the grooves of polynucleotides. The photogenerated quinone methide (QM) reacts with nucleophiles giving adducts, as demonstrated by the photomethanolysis (quantum yield ΦR = 0.11–0.13). Furthermore, we have demonstrated photoalkylation of AT oligonucleotides by QM, at variance to previous reports describing the highest reactivity of QMs with the GC reach regions of polynucleotides. Our investigations show a proof of principle that QM precursor can be imbedded into a peptide and used as a photochemical switch to enable alkylation of polynucleotides, enabling further applications in chemistry and biology.

Potential fertilizer of spermatozoa in porcine epididymal tail post-orchiectomy.

The aim of this study was to determine the potential fertilizing of spermatozoa from the epididymal tail in different periods of time post-orchiectomy (P-OQ). Therefore, the study was approached in two stages. In the first stage, the orchiectomy was performed in 30 adult pigs. The testicles were stored at 5.00 ˚C in physiological saline solution for 5, 24, 48, 72, 96 and 120 hr. The spermatozoa were obtained by backflushing the vas deferens. The spermogram and fluorometric study were performed for each sample to evaluate the exposure of phosphatidyl-serine (PS) and acrosome reaction (AR). The second stage included the fertilization test, 16 prepubertal sows were selected, after synchronizing the oestrous cycle and the post-cervical artificial insemination was performed with the refrigerated sperm samples from each P-OQ time. The percentage of live sperm remained without significant changes until 96 hr P-OQ. An increase in the percentage of spermatozoa that showed a PS exposure was observed. The premature AR was evident after 72 hr. Considering that the artificial insemination was performed ensuring a minimum number of live sperms, no significant differences were observed in the number of embryos and corpora lutea. The results indicated that pig sperm collected from the epididymal tail P-OQ and stored for 5 and up to 72 hr at 5.00 ˚C had viable characteristics and maintained their fertilization ability. However, there was an increase in the loss of phospholipid asymmetry of the plasma membrane as time increased (72 and 96 hr), therefore, sperm viability was decreased.

Photodynamic antimicrobial chemotherapy (PACT) using riboflavin inhibits the mono and dual species biofilm produced by antibiotic resistant Staphylococcus aureus and Escherichia coli.

Multispecies biofilms play a significant role in persistent infections. Furthermore, by interspecies transfer of antibiotic resistance genes, multispecies biofilms spread antibiotic resistance. The purpose of this study was to investigate the effect of Photodynamic Antimicrobial Chemotherapy (PACT) using riboflavin on mono and multi species biofilms. For this we used two clinically relevant opportunistic pathogens species E. coli and S. aureus as mono-species and multispecies biofilms. We did broth dilution assay for antibacterial, crystal violet assay for biofilms and fluorometric study for reactive oxygen species (ROS) and extracellular polymeric substance (EPS) production by phenol-HCl method. Antibacterial study revealed that photo-illuminated riboflavin shows bactericidal effect against each bacteria and their mix culture. E. coli was found to be little more resistant than S. aureus. Crystal violet assay revealed photo-illuminated riboflavin shows anti-biofilms activity against both mono and mix species biofilms. But mix species biofilms were more resistant to PACT than mono species biofilms. Further study revealed this may be due to the interaction between different EPS production, hence in mix species biofilms EPS production is less affected after PACT than mono species biofilms. We found photo-illuminated riboflavin increased the intracellular ROS production. Photo-illuminated riboflavin shows bactericidal and anti-biofilms effect against each bacteria and their mix culture. Photo-illuminated increased intracellular ROS production, which may induce the oxidative stress and destroy the respiratory system of bacteria.

Association behavior of bile salts binary mixtures in an aqueous system: A tensiometric and fluorometric study

AbstractBile salts are steroidal surfactants consisting of 2 to 12 monomers to form a micelle. The most important physiological property of bile salts is the solubilization of cholesterol. The bile salts make mixed micelle with phospholipids that enhance the bile salts ability to solubilize cholesterol. The mixed micelle formation in aqueous solution between two bile salts (sodium taurocholate [NaTC] and sodium deoxycholate [NaDC]) mixtures has been studied by tensiometric and fluorometric studies. The nonideal mixing behavior was examined for mixed systems, and synergism was found for the current mixed systems. Rubingh and Rosen models were used to analyze the bile salt‐bile salt binary mixtures, and the interaction parameters, as well as mixed micelle compositions at bulk and interface, have been computed as well as discussed one by one. The values of were achieved to be negative for all studied systems. In the solution mixtures, as the content of NaTC increases, the formation of micelles becomes slightly less favorable.

A fluorometric study on the effect of DNA methylation on DNA interaction with graphene quantum dots

DNA methylation plays an important role in development process which contributes to genome stability and also regulates gene expression and gene silencing. Detection of genome regions with altered 5-methylcytosine distribution at a genome-wide scale is very important for early detection of gene silencing related diseases. In the present study as a continuation of studies on DNA methylation, the interactions between graphene quantum dots (GQDs) and unmethylated and methylated deoxyribonucleic acid (DNA) fragment were investigated. Based on above interaction a novel GQDs-DNA nanoassembly was developed. Two types of DNA including unmethylated and methylated sequences were interacted with GQDs and contributed to the formation of unmethylated and methylated nanoassemlies. Analysis of the interaction indicated that the GQDs could bind to DNA fragments and led to different fluorescence pattern in two different mechanisms and could provide an efficient biosensing platform for label free and sensitive fluorescent assay of DNA. The excitation and emission wavelengths of experiment were 380 and 480 nm respectively. Fluorescence intensity of unmethylated DNA concentration were detectable from methylated DNA in linear range from 10.0−10M to 10.0–6M and the detection limit was estimated at 7.3 × 10–11 M. Above interaction was not observed in methylated DNA, indicated of distinguished interaction effect. Herein we further showed that GQDs could induce B-DNA to A-DNA form in methylated structure of DNA. The methylation sensitivity of the experiment was also testified by methylation sensitive restriction process. It was assumed that the involvement of methylation alteration in DNA structure could alter not only mechanism of DNA/GDQs interaction but also helical structure of DNA.

Rapid removal of tetracycline antibiotics from water by coagulation-flotation of sodium dodecyl sulfate and poly(allylamine hydrochloride) in the presence of Al(III) ions

Abstract A coagulation-flotation method using an anionic surfactant, sodium dodecyl sulfate (SDS), and a cationic polyelectrolyte, poly(allylamine hydrochloride) [PAH], was designed for rapid removal of tetracycline antibiotics from water. The method was conducted by adding electrically equivalent amounts of SDS and PAH followed by feeding air bubbles. The air bubbles vigorously mixed water and induced the coagulation of SDS-PAH complex to from agglutinative coagulum on water surfaces. In the presence of Al(III) ions, tetracycline in water was collected to the coagulum as an hydrophobic ion-pair of the Al(III)-chelate with a dodecyl sulfate ion ( m / z = 736). Fluorometric study using a molecular probe, N -phenyl-1-naphthylamine, suggested the formation of hydrophobic region in SDS-PAH complex as well as air/water interfaces for the sorption of the hydrophobic ion-pair. Combined use of 20 mg L −1 SDS, 6.5 mg L −1 PAH, and 1 mg L −1 Al(III) ions allowed nearly complete ( > 99%) removal of tetracycline from water within 5 min. SDS concentration remaining in the treated water was 0.12 ± 0.05 mg L −1 , being lower than Japanese water regulation (0.2 mg L −1 ) of total anionic surfactants. Other tetracyclines and fluoroquinolone antibiotics as well as different acidic and basic pharmaceuticals were nearly completely (>96%) removed from water. Applicability to wastewater treatment was examined by using secondary effluents and synthesized hospital wastewaters.

1,4‐Disubstituted 1,2,3‐Triazole‐ and 1,5‐Disubstituted 1,2,3‐Triazole–based Bis‐Sulfonamides in Selective Fluorescence Sensing of ATP

Abstract1,4‐ and 1,5‐Disubstituted 1,2,3‐triazole scaffolds as surrogate of amide with large dipole moment have been utilized to access two isomeric naphthylthiourea‐based chemosensors 1 and 2 in appreciable overall yields. The easily synthesizable chemosensors 1 and 2 are designed to recognize anions and also to realize a comparative view on their sensing potentials. Different inorganic phosphates and a group of phosphorylated nucleosides such as ATP, ADP and AMP are selectively recognized by these chemosensors in semi aqueous system. The fluorometric study revealed that both the sensors sensed ATP selectively in CH3CN/H2O (4/1,v/v) by showing considerable increase in emission. 1,4‐Disubstituted triazole‐based sensor 1 has been established to be more effective than the 1,5‐disubstituted triazole‐based sensor 2 in selective sensing of ATP.

A fluorometric study of modification of bovine serum albumin with structural analogues of taurine chloramine

We studied the effects of taurine chloramine and its structural analogues, antiplatelet agents, on the tertiary structure of bovine serum albumin by recording changes in its fluorescence spectrum. BSA was chosen as a model of the extracellular part of the purine P2Y12 receptor in platelets. For the detection of weak spectral shifts of the protein fluorescence, the index, which represents the ratio of the two light sums measured from approximately the middle of the spectrum towards the short- and longwave limits of its registration, was used. Administration of N-chlorotaurine and its analogues N-acetyl-N-chlorotaurine and N-isopropyl-N-chlorotaurine in albumin solution in equimolar concentrations cause weakening and red shift of the tryptophanyl fluorescence of the protein, indicating reorganization of the protein’s tertiary structure, thereby changing the properties of the microenvironment of tryptophan residues, primarily, Trp 134. All these changes are probably due to a covalent modification of the sulfhydryl group of Cys34 residue. It was hypothesized that chloramines of taurine have the ability to inhibit the activity of the ADP P2Y12 receptor in platelets due to the modification of its sulfhydryl group and that the inhibitory effect on the ADP-binding site has an allosteric character.

Interaction between antidepressant drug and anionic surfactant in low concentration range in aqueous/salt/urea solution: A conductometric and fluorometric study

Abstract Aqueous/salt/urea micellar solutions of amphiphilic antidepressant drug amitriptyline hydrochloride (AMT) and anionic surfactant sodium dodecylbenzenesulfonate (SDBS) have been examined by conductivity and fluorescence measurements at different temperatures and composition. From the conductometric study, values of critical micelle concentration ( cmc ) of drug have been evaluated and analyzed in terms of effect of surfactant on the hydrophobic nature of AMT–SDBS complex. The values of critical micelle concentration ( cmc ) and other aggregation parameters, micellar mole fraction ( X 1 ) and interaction parameters ( β ) were obtained and discussed in detail. In mixtures of AMT and SDBS, the synergistic interactions in mixed micelles formation increases with the raise in mole fraction of surfactant in absence and attendance of salt/urea. Thermodynamic parameters of the mixtures in aqueous as well as in salt/urea solution have been evaluated by means of a pseudo-phase model. The effect of NaCl shows the salting-out effect, which promotes aggregate formation of AMT and SDBS as well as their mixed systems at lower concentration relative to aqueous solution. The micelle aggregation number ( N agg ) of drug increases with the raise in surfactant mole fraction in mixtures. N agg value of individual and mixed amphiphiles rises in the presence of electrolyte while reduces in the occurrence of urea.

Aggregation and microenvironmental properties of gemini and conventional mixed surfactants systems: A fluorometric study

Aggregation behavior of cationic gemini (hexanediyl-1,5-bis(dimethylcettylammonium bromide) (16-5-16)) surfactant with conventional single chain surfactants cetyltrimethylammonium bromide (CTAB) and tetradecyltrimethylammonium bromide (TTAB) were studied with the help of fluorescence measurements. Fluorescence probe is a proficient technique for examining the surfactant-surfactant interaction and aggregation. The micelle aggregation number (Nagg) was measured using steady-state fluorescence quenching method. The micelle aggregation numbers of binary combinations fall between those of constituent surfactants. The micropolarity (I1/I3), binding constant (Ksv) and dielectric constant (Dexp) of mixed systems were determined from the ratio of peaks intensity in the pyrene fluorescence spectrum. The I1/I3 values were found to be more than >1, showing more polar environment around pyrene in the mixed micelle as compared to the pure micelles.

Interaction of selected volatile flavour compounds and salt-extracted pea proteins: Effect on protein structure and thermal-induced gelation properties

Characterization of the impact of protein–flavour interactions on protein structure and thermally-induced salt-extracted pea protein gels with selected volatile flavours was studied using a fluorometric method (intrinsic) and small-strain dynamic oscillatory rheology. By monitoring intrinsic fluorescence of protein–flavour mixtures, conformational changes in proteins due to flavour binding were noted with long chain aldehydes resulting in higher degrees of protein unfolding in comparison with ketones. Protein gel forming properties were significantly altered as a function of flavour class (aldehyde and ketone), chain length (6–8 carbon number) and flavour concentrations (0, 250, 500, 1000 ppm). Addition of homologues aldehydes and ketones at 250 ppm decreased gel storage (G′) and loss (Gʺ) moduli with long chain aldehydes possessing more prominent effects. Interestingly, protein gel strength was restored with increasing concentration and chain length of aldehydes accompanied by gradual decreases of gelling points, while elasticity and gelling points of protein–ketone mixtures remained constant. The additional protein denaturation observed in the fluorometric study could account for the formation of stronger gels during thermally-induced gel formation. A flavour-induced protein structure/function relationship was presented. In addition, flavour binding produced changes in G′ during both heating and cooling phases of gelation. For aldehydes, the change in G′ during heating had a more predominant effect, whereas the cooling phase was more responsible for the decrease in Gʹ for ketone flavours.

Investigations of mixed surfactant systems of lauryl alcohol-based bissulfosuccinate anionic gemini surfactants with conventional surfactants: A fluorometric study

In this study, fluorescence techniques have been utilized to investigate the association and aggregation properties of aqueous solutions of a pure lauryl alcohol-based bis-sulfosuccinate anionic gemini surfactant (BSGSLA1,8) with a flexible methylene (CH2)8 spacer. In addition to the fluorescence interaction behaviour of surfactant solutions of BSGSLA1,8 mixed with conventional surfactants, surfactant formulations using the anionic (sodium dodecyl sulphate (SDS)), cationic (cetyl trimethyl ammonium bromide (CTAB)) and non-ionic surfactants (Triton X-100) used in industrial applications were also studied. The aggregation number and micropolarity of the pure and mixed surfactant systems were investigated using steady-state fluorescence spectroscopy. The electrolyte effect of different concentrations of sodium chloride (NaCl) on the aggregation number and micropolarity was also explored for pure BSGSLA1,8. The best synergistic behaviour of BSGSLA1,8 was obtained with SDS compared to CTAB and Triton X-100. The maximum reduction of the pyrene intensity ratio (I1/I3) was observed with a BSGSLA1,8 and SDS mixed surfactant solution. The enhanced I1/I3 value of the mixed gemini Triton X-100 solution showed that mixed system is not as compact as pure BSGSLA1,8 surfactant micelles in the non-ionic surfactant.

In situ Ca2+ titration in the fluorometric study of intracellular Ca2+ binding

Imaging with Ca2+-sensitive fluorescent dye has provided a wealth of insight into the dynamics of cellular Ca2+ signaling. The spatiotemporal evolution of intracellular free Ca2+ observed in imaging experiments is shaped by binding and unbinding to cytoplasmic Ca2+ buffers, as well as the fluorescent indicator used for imaging. These factors must be taken into account in the interpretation of Ca2+ imaging data, and can be exploited to investigate endogenous Ca2+ buffer properties. Here we extended the use of Ca2+ fluorometry in the characterization of Ca2+ binding molecules within cells, building on a method of titration of intracellular Ca2+ binding sites in situ with measured amounts of Ca2+ entering through voltage-gated Ca2+ channels. We developed a systematic procedure for fitting fluorescence data acquired during a series of voltage steps to models with multiple Ca2+ binding sites. The method was tested on simulated data, and then applied to 2-photon fluorescence imaging data from rat posterior pituitary nerve terminals patch clamp-loaded with the Ca2+ indicator fluo-8. Focusing on data sets well described by a single endogenous Ca2+ buffer and dye, this method yielded estimates of the endogenous buffer concentration and Kd, the dye Kd, and the fraction of Ca2+ inaccessible cellular volume. The in situ Kd of fluo-8 thus obtained was indistinguishable from that measured in vitro. This method of calibrating Ca2+-sensitive fluorescent dyes in situ has significant advantages over previous methods. Our analysis of Ca2+ titration fluorometric data makes more effective use of the experimental data, and provides a rigorous treatment of multivariate errors and multiple Ca2+ binding species. This method offers a versatile approach to the study of endogenous Ca2+ binding molecules in their physiological milieu.

Mixed micellization of gemini surfactant with nonionic surfactant in aqueous media: a fluorometric study

Herein we report on the study of the interactions between alkanediyl-α,ω-type cationic dimeric (gemini) surfactant and the nonionic Triton X-100 in aqueous medium. The critical micelle concentrations of binary mixtures were determined by fluorometric study. Using the regular solution theory for the analysis of the experimental data, the attractive nature of interactions and synergistic behavior of gemini surfactant and Triton X-100 mixture were demonstrated. The micelle aggregation number was measured using steady state fluorescence quenching method. The micropolarity, binding constant and dielectric constant of mixed systems were determined from the ratio of peak’s intensity (I 1/I 3) in the pyrene fluorescence emission spectrum.