Resonance Rayleigh Scattering Spectra Research Articles

Design of resonance Rayleigh scattering and spectrofluorimetric methods for the determination of the antihistaminic drug, hydroxyzine, based on its interaction with 2,4,5,7-tetraiodofluorescein: Evaluation of analytical eco-scale and greenness/whiteness algorithms.

In this work, two validated approaches were used for estimating hydroxyzine HCl for the first time using resonance Rayleigh scattering (RRS) and spectrofluorimetric techniques. The suggested approaches relied on forming an association complex between hydroxyzine HCl and 2,4,5,7-tetraiodofluorescein (erythrosin B) reagent in an acidic media. The quenching in the fluorescence intensity of 2,4,5,7-tetraiodofluorescein by hydroxyzine at 551.5nm (excitation = 527.5nm) was used for determining the studied drug by the spectrofluorimetric technique. The RRS approach is based on amplifying the RRS spectrum at 348 nm upon the interaction of hydroxyzine HCl with 2,4,5,7-tetraiodofluorescein. The spectrofluorimetric methodology and the RRS methodology produced linear results within ranges of 0.15-1.5μg ml-1 and 0.1-1.2μg ml-1, respectively. LOD values for these methods were determined to be 0.047 μg ml-1 and 0.033 μg ml-1, respectively. The content of hydroxyzine HCl in its pharmaceutical tablet was estimated using the developed procedures with acceptable recoveries. Additionally, the application of four greenness and whiteness algorithms shows that they are superior to the previously reported method in terms of sustainability, economics, analytical performance, and practicality.

Development of Eco-Friendly Scattering and Fluorimetric Methods for the Determination of Clemastine Through Its Interaction with Eosin Y: Assessment of Whiteness, Blueness, and Greenness Tools.

For the first time, clemastine was estimated in this work utilizing two validated resonance Rayleigh scattering (RRS) and fluorimetric methods. The methods relied on forming an association complex in an acidic medium between eosin Y reagent and clemastine. In the spectrofluorimetric approach, the investigated drug was quantified by quenching the fluorescence-emission intensity of eosin Y at 543.5nm. The RRS method relied on enhancing the RRS spectrum at 331.8nm, which is produced when eosin Y interacts with clemastine. Suitable conditions were established for the reaction to achieve maximum sensitivity. The linear values obtained from the spectrofluorimetric approach and the RRS method fall into the ranges of 0.2-1.5µg mL- 1 and 0.25-2.0µg mL- 1, respectively. It was established that the detection limits for these methods were 0.045µg mL- 1 and 0.059µg mL- 1, respectively. The developed methodologies yielded acceptable recoveries when used to estimate the quantity of clemastine in its pharmaceutical tablet dosage form. Regarding the use of greener solvents that were chosen, the suggested and reported methods were compared with the help of the Green Solvents Selecting (GSST) tool for assessing hazardous solvents to achieve sustainability. Furthermore, analytical Eco scale and comprehensive assessments of whiteness, blueness, and greenness were carried out utilizing Modified NEMI, ComplexGAPI, and AGREE evaluation tools. Additionally, recently developed tools such as BAGI and RGB 12 were applied to assess the blueness and the whiteness of the suggested methods.

Study on the interaction between erythrosine B and the cardiac drug amiodarone using fluorescence, scattering, and absorbance spectra and their analytical application.

In an acidic buffered solution, erythrosine B can react with amiodarone to form an association complex, which not only generates great enhancement in resonance Rayleigh scattering (RRS) spectrum of erythrosine B at 346.5 nm but also results in quenching of fluorescence spectra of erythrosine B at λemission= 550.4 nm/λexcitation= 528.5nm. In addition, the formed erythrosine B-amiodarone complex produces a new absorbance peak at 555 nm. The spectral characteristics of the RRS, absorbance, and fluorescence spectra, as well as the optimum analytical conditions, were studied and investigated. As a result, new spectroscopic methods were developed to determine amiodarone by utilizing erythrosine B as a probe. Moreover, the ICH guidelines were used to validate the developed RRS, photometric, and fluorimetric methods. The enhancements in the absorbance and the RRS intensity and the decrease in the fluorescence intensity of the used probe were proportional to the concentration of amiodarone in ranges of 2.5-20.0, 0.2-2.5, and 0.25-1.75 μg/mL, respectively. Furthermore, limit of detection values were 0.52 ng/mL for the spectrophotometric method, 0.051 μg/mL for the RRS method, and 0.075 μg/mL for the fluorimetric method. Moreover, with good recoveries, the developed spectroscopic procedures were applied to analyze amiodarone in its commercial tablets.

Validated spectrofluorimetric and resonance Rayleigh scattering methods for determining naftidrofuryl in varied pharmaceutical samples based on its interaction with erythrosin B.

Naftidrofuryl is a vasodilator medication used for treating cerebral and peripheral vascular diseases. In this study, two spectroscopical techniques, spectrofluorimetric and resonance Rayleigh scattering (RRS), were utilized to quantify naftidrofuryl in its pharmaceutical samples. The developed methodologies in this study rely on a facile process of forming an association complex between erythrosine B reagent and naftidrofuryl under acidic conditions. The fluorimetric assay is based on the ability of naftidrofuryl to quench and decrease the native fluorescence intensity of the reagent when measured at = 550 nm ( = 526 nm). Under similar reaction conditions, the RRS method relies on the observed amplification in the RRS spectrum of the reagent at a wavelength of 577 nm following its interaction with naftidrofuryl. The methods exhibited linearity within the ranges of 0.2 1.6 μg/mL (r2 = 0.999) and 0.1 1.4 μg/mL (r2 = 0.9994), with LOQ values of 0.146 and 0.099 μg/mL, and LOD values of 0.048 and 0.032 μg/mL, for the fluorometric and the RRS methods, respectively. Moreover, the quenching between the dye and naftidrofuryl was studied by Stern-Volmer analysis, and the methodologies were experimentally optimized and validated. Additionally, acceptable recoveries were achieved when the procedures were applied to determine naftidrofuryl in pharmaceutical samples.

A cholesterol benzoate RRS probe for the determination of trace ammonium ions

The measurement of NH4+ has attracted considerable attention with the increase of NH4+ emissions in sewage caused by human activities. So far, a variety of photometric and fluorescence methods for the detection of NH4+ have been researched and summarized, but there is no report about the use of liquid crystals (LCs) cholesteryl benzoate (CB) as a resonance Rayleigh scattering (RRS) probe to determine ammonium ions. In the NaAc-HAc buffer solution with pH = 4.80, the yellow compounds 3,5 diacetyl-1,4 dihydrolutidine (DDL) generated by the reaction of NH4+ with acetylacetone (AT) and formaldehyde (HCHO) act as the energy receiver and CB as the donor. Because the RRS spectrum of CB overlaps with the DDL absorption spectrum, resonance Rayleigh scattering energy transfer (RRS-ET) occurs. When the NH4+ concentration increased, the generated DDL increased, and the RRS-ET also increased, so the RRS intensity of the system at 395 nm decreased. For this reason, a fast and sensitive CB RRS-ET method was established to apply to the detection of NH4+ in water. The detection range was 1.00 × 10−3 − 4.66 μg/mL, and the detection limit was 6.62 × 10−3 μg/mL. Using this method to analyze and detect NH4+ in environmental water samples, the precision and recovery rate were between 1.30–9.30% and 95.5–109.9%, respectively. Therefore, this method has the advantages of sensitivity and simplicity.

Resonance Rayleigh Scattering Spectra of the Lead–Xylenol Orange–Crystal Violet System and Their Analytical Applications

A new method for determining lead by resonance Rayleigh scattering (RRS) has been proposed and its operation mechanism has been discussed. In pH 5.0 HAc–NaAc buffer solution, Pb(II) reacted with xylenol orange (XO) to form a chelating anion ([Pb (H2In)] 2–), which further reacted with crystal violet (CV) to form ternary ionic complexes, resulting in the enhancement of RRS intensity. The RRS intensity increases linearly with the concentration of Pb(II) in the range of 2.00 × 10–3–2.00 × 10–2 mg/L under optimal experimental conditions along with the detection limit of 9.2 × 10–5 mg/L. This method is a promising approach for the selective and sensitive determination of Pb(II) in tea.

Resonance Light-Scattering Enhancement Effect of the Y(III)–PUFX–Eosin System and its Fluorescence Study

Highly sensitive and rapid method for the determination of prulifloxacin (PUFX) has been developed on the basis of ion association reaction of PUFX, Y(III) and eosin Y (EY). In pH 6.5 BR buffer medium, PUFX reacts with Y(III) to form a 2:1 cationic chelate which further reacts with EY to form 2:1 ion-association complex. As a result, not only the spectra of absorption are changed, but quenching of fluorescence and significant enhancement of resonance Rayleigh scattering (RRS) is observed. Furthermore, a new RRS spectrum would appear, and the maximum RRS wavelength was located at about 375 nm. The fluorescence quenching (FQ) and enhanced RRS intensity were directly proportional to the PUFX concentration in the ranges of 1.5 – 7.6 μg mL–1 and 0.004 – 3.0 μg mL–1 with detection limits 8.5 ng mL–1 and 1.1 ng mL–1, respectively. The optimum conditions of RRS method and the effects of coexisting substances on the reaction were investigated. In addition the composition of ion-association complexes, the reaction mechanism, the energy transfer between absorption, fluorescence and RRS and reasons for RRS enhancement were discussed. The methods were applied to the determination of PUFX in pharmaceutical samples with satisfactory results.

Characterization of the Interaction Between Caffeine and Soybean Selenoprotein by Spectroscopic and Cyclic Voltammetric Methods

The quantitative interaction of soybean selenoprotein (SSP) with caffeine (CAF) has been studied by fluorescence, cyclic voltammetry and resonance Rayleigh scattering (RRS) spectra. Fluorescence results demonstrate that the quenching of SSP, induced by CAF, can mainly be attributed to static quenching, and the relative contribution of dynamic quenching is about 0.37% by using a Stem–Volmer analysis. The binding constant (K a) and binding sites (n) of the formed SSP/CAF complex at 293 K calculated from the fluorescence quenching results were found to be 4.29 × 104 L·mol−1 and 1.22, respectively, which is relatively consistent with the corresponding values obtained by cyclic voltammetry. Based on Forster’s theory, the average binding distance (r) between CAF and SSP was found to be 3.03 nm. The interaction mechanism between CAF and SSP was also supported by inspecting the RRS spectra. The effect of CAF on the conformation of SSP was investigated by using the fluorescence phase diagram and circular dichroism spectra. The experimental results show that SSP binding to CAF follows the two-state model and the helical content of SSP decreases after the interaction. In addition, the effect of CAF on the antioxidant activity of SSP was revealed by ultraviolet spectrophotometry. According to the results, SSP/CAF possesses significantly higher antioxidant activity than the control soybean selenoprotein.

A resonance Rayleigh scattering sensor for detection of Pb2+ ions via cleavage-induced G-wire formation

A resonance Rayleigh scattering (RRS) aptasensor was fabricated for detection of Pb2+via hairpin-like label-free substrate and G-wire for signal amplification. A hairpin-like DNA substrate contains a sequence in the loop labeled with ribonucleobase A and c-myc sequence in the stem. When hybridized with 8–17 DNAzyme in the presence of Pb2+, the sequence in the loop was activated and cleaved. Hundreds of c-myc sequences departing from the 8–17 DNAzyme yield nanowires superstructure called G-wire in the presence of Mg2+. The polymer G-wire was demonstrated by the RRS spectrum, polyacrylamide gel electrophoresis, and AFM. The RRS intensity was enhanced by the product G-wires, and the RRS signal at 370nm was linear with the logarithm of Pb2+ concentration in the range of 2.0nM to 5.0μM. This method was selective for Pb2+ even coexisting with other metal ions at high concentrations and was successfully applied to the determination of Pb2+ in real samples. The aptasensor holds a great promise for universal RRS sensing platform for sensitive detection of various metal ions just by changing the sequence of the probe in the loop and DNAzyme.

The fluorescence and resonance Rayleigh scattering spectra study on the interactions of palladium (II)-Nootropic chelate with Congo red and their analytical applications

A highly sensitive detection approach of resonance Rayleigh scattering spectra (RRS) is firstly applied to analyzing nootropic drugs including piracetam (PIR) and oxiracetam (OXI). In HCl-NaAc buffer solution (pH=3.0), the OXI chelated with palladium (II) to form the chelate cation [Pd2·OXI]2+, and then reacted with Congo red (CGR) by virtue of electrostatic attraction and hydrophobic force to form binary complex [Pd2·OXI]. CGR2, which could result in the great enhancement of RRS. The resonance Rayleigh scattering signal was recorded at λex=λem=375nm. This mixture complex not only has higher RRS, but also makes contribution to significant increase of fluorescence, and the same phenomena also were discovered in PIR. The enhanced RRS intensity is in proportion to the PIR and OXI concentration in the range of 0.03–3.0μgmL−1, and the detection limit (DL) of RRS method for PIR and OXI is 2.3ngmL−1 and 9.7ngmL−1. In addition, the DL of fluorescence method for PIR and OXI is 8.4μgmL−1 and 19.5μgmL−1. Obviously, the RRS is the highly sensitive method, and the recoveries of the two kinds of nootropic drugs were range from 100.4% to 101.8.0% with RSD (n=5) from 1.1% to 3.1% by RRS method. This paper not only investigated the optimum conditions for detecting nootropics with using RRS method, but also focused on the reasons for enhancing RRS intensity and the reaction mechanism, which in order to firm and contract the resultant. Finally, The RRS method has been applied to detect nootropic drugs in human urine samples with satisfactory results.

Determination of Egg Yolk Immunoglobulin by Resonance Light Scattering of Affinity-Labeled Au Nanoparticles

Chicken egg yolk immunoglobulin (IgY) is the only antibody existing in chicken egg yolk, which has many significant advantages. We developed an immunity affinity biosensor system based on resonance Rayleigh scattering (RRS) and using immunity affinity rabbit anti-chicken IgY (anti-IgY) labeling Au nanoparticles (AuNPs). This system was rapid and sensitive for IgY detection due to the IgY-anti-IgY affinitive immunity interaction. The RRS and absorption spectra of AuNPs and the binding system were analyzed. In addition, the effects of several factors on the scattering intensity were investigated. Under optimal conditions, RRS intensity of anti-IgY-AuNPs increase linearly with an increasing concentration of IgY from 4 to 200 ng/mL. The limit of detection was 1.92 ng/mL. This rapid and selective IgY detection method was used in synthetic samples and egg products with recoveries between 89.86 and 110.25 %, thereby demonstrating the feasible and practical application of this assay.

A simple and rapid method for direct determination of Al(III) based on the enhanced resonance Rayleigh scattering of hemin-functionalized graphene-Al(III) system

A novel method for direct determination of Al(III) by using hemin-functionalized graphene (H-GO) has been established based on the enhancement of resonance Rayleigh scattering (RRS) intensity. The characteristics of RRS spectra, the optimum reaction conditions, and the reaction mechanism have been investigated. In this experiment, the Al(III) would exist in sol–gel Al(OH)3 species under the condition of pH5.9 in aqueous solutions. When H-GO existed in the solution, the sol–gel Al(OH)3 would react with H-GO and result in enhancement of RRS intensity, owing to the enhanced hydrophobicity of H-GO surface. Therefore, a simple and rapid sensor for Al(III) was developed. The increased intensity of RRS is directly proportional to the concentration of Al(III) in the range of 10nM–6μM, along with a detection limit of 0.87nM. Moreover, the sensor has been applied to determination of Al(III) concentration in real water and aspirin tablet samples with satisfactory results. Therefore, the proposed method is promising as an effective means for selective and sensitive determination of Al(III).

A silver nanorod resonance rayleigh scattering-energy transfer analytical platform for trace tea polyphenols

The stable silver nanorod (AgNR) sol in red was prepared by the two-step procedure of NaBH4–H2O2 and citrate heating reduction, and it exhibited a strong resonance Rayleigh scattering (RRS) peak at 346nm. In pH 3.8 HAc–NaAc buffer solution, tea polyphenols (TP) reacted with ammonium molybdate (AM) to form yellow organic molybdate (OM) as receptor that was closed to the donor of AgNR, the RRS energy transfer (RRS-ET) takes place, owing to the overlapping between the AgNR RRS spectra and OM absorption spectra. When TP concentration increased, the RRS intensity decreased due to the RRS-ET increasing. So, a simple and sensitive AgNR surface plasmon RRS-ET analytical platform was fabricated to detect trace TP in the range of 0.05–0.85μg/mL, with a detection limit of 0.03μg/mL TP. The TP in tea samples was analyzed by this RRS-ET analysis platform, with satisfactory results.

Studies on the interaction of heparin with lysozyme by multi-spectroscopic techniques and atomic force microscopy

The interaction between heparin (Hep) and lysozyme (Lyso) in vitro was studied by fluorescence, UV–vis, circular dichroism (CD), resonance Rayleigh scattering (RRS) spectroscopy and atomic force microscopy (AFM) under normal physiological conditions. UV–vis spectra of Lyso showed the absorbance was significantly increased with the addition of Hep. Fluorescence studies revealed that the emission quenching of Lyso with Hep was initiated by static quenching mechanism. CD spectral studies showed that Hep induced conformational changes in the secondary structure of Lyso. RRS spectra of Lyso showed the intensity of scattering was significantly increased with the addition of Hep and the enhanced RRS intensities were proportional to the concentration of Hep in a certain range. Thus, a new RRS method using Lyso as a probe could be used for the determination of Hep. The detection limit for Hep was 3.9ngmL−1. In addition, the shape of the complex was characterized by AFM. The possible reaction mechanism and the reasons for the enhancement of RRS intensity had been discussed through experimental results.

Study on interactions of aminoglycoside antibiotics with calf thymus DNA and determination of calf thymus DNA via the resonance Rayleigh scattering technique.

A simple and sensitive resonance Rayleigh scattering (RRS) spectra method was developed for the determination of calf thymus DNA (ctDNA). The enhanced RRS signals were based on the interactions between ctDNA and aminoglycoside antibiotics (AGs) including kanamycin (KANA), tobramycin (TOB), gentamicin (GEN) and neomycin (NEO) in a weakly acidic medium (pH 3.3-5.7). Parameters influencing the method were investigated. Under optimum conditions, increments in the scattering intensity (∆I) were directly proportional to the concentration of ctDNA over certain ranges. The detection limit ranged from 12.2 to 16.9 ng/mL. Spectroscopic methods, including RRS spectra, absorption spectra and circular dichroism (CD) spectroscopy, coupled with thermo-denaturation experiments were used to study the interactions, indicating that the interaction between AGs with ctDNA was electrostatic binding mode.

Green synthesis of curcumin conjugated nanosilver for the applications in nucleic acid sensing and anti-bacterial activity

Silver nanoparticles (Ag NPs) are often synthesized by chemical and physical methods. Natural and non-toxic molecules are recently being replaced for nanoparticles preparation. In this paper we have used curcumin, which interacts with Ag+ and subsequently synthesizes silver nanoparticles. Further continuation of the reaction often makes aggregation and forms dark brown/black silver oxide. Presence of glycerol in the reaction mixture gives mono-disperse curcumin conjugated Ag NPs, which can be made stable by capping with polyvinylpyrolidone (PVP). XRD data confirm that curcumin conjugated Ag NPs are crystalline in nature with a mean crystalline size of 13.27nm. The Ag NPs are spherical and in the range of 10–50nm though their hydrodynamic radius is found to be higher, ∼294nm, due to polyvinylpyrolidone capping and aggregation of nanoparticles in solution. The production of curcumin conjugated Ag NPs follows first order kinetics and the effect of curcumin concentration during formation of Ag NPs indicates a linear enhancement in the production of Ag NPs with an increase in concentration of curcumin. These curcumin conjugated silver nanoparticles show anti-bacterial activity and can successfully determine nucleic acid (DNA and RNA) in the concentration range 100–1000ng/mL with a linear regression coefficient >0.997 using Resonance Rayleigh Scattering spectra.

Multidimensional optical sensing platform for detection of heparin and reversible molecular logic gate operation based on the phloxine B/polyethyleneimine system.

A multidimensional optical sensing platform which combines the advantages of resonance Rayleigh scattering (RRS), fluorescence, and colorimetry has been designed for detection of heparin. Phloxine B, a fluorescein derivative showing the special RRS spectrum in the long wavelength region, was selected to develop an easy-to-get system which can achieve switch-on sensing to obtain high sensitivity. The noise level of RRS in the long wavelength region is much weaker, and the reproducibility is much better; in this way, the sensitivity and selectivity can be improved. In the absence of heparin, the phloxine B and polyethyleneimine (PEI) form a complex through electrostatic interaction. Thus, the RRS signal at 554 nm is low; the phloxine B fluorescence is quenched, and the absorption signal is low. In the presence of heparin, competitive binding occurred between phloxine B and heparin toward PEI; then, phloxine B is gradually released from the phloxine B/PEI complex, causing obvious enhancement of the RRS, fluorescence, and absorption signals. Besides, the desorption of phloxine B is less effective for the heparin analogues, such as hyaluronic acid and chondroitin sulfate. In addition, the system presents a low detection limit of heparin to 5.0 × 10(-4) U mL(-1) and can also be applied to the detection of heparin in heparin sodium injection and 50% human serum samples with satisfactory results. Finally, the potential application of this method in reversible on-off molecular logic gate fabrication was discussed using the triple-channel optical signals as outputs.

A rapid and sensitive resonance Rayleigh scattering spectra method for the determination of quinolones in human urine and pharmaceutical preparation

A new method based on resonance Rayleigh scattering (RRS) was proposed for the determination of quinolones (QNS) at the nanogram level. In pH 3.3-4.4 Britton-Robinson buffer medium, quinolones such as ciprofloxacin, pipemidic acid (PIP), lomefloxacin (LOM), norfloxacin (NOR) and sarafloxacin (SAR) were protonated and reacted with methyl orange (MO) to form an ion-pair complex, which then further formed a six-membered ring chelate with Pd(II). As a result, new RRS spectra appeared and the RRS intensities were enhanced greatly. RRS spectral characteristics of the MO-QNS-Pd(II) systems, the optimum conditions for the reaction, and the influencing factors were investigated. Under optimum conditions, the scattering intensity (∆I) increments were directly proportional to the concentration of QNS with in certain ranges. The method had high sensitivity, and the detection limits (3σ) ranged from 6.8 to 12.6 ng/mL. The proposed method had been successfully applied for the determination of QNS in pharmaceutical formulations and human urine samples. In addition, the mechanism of the reaction system was discussed based on IR, absorption and fluorescence spectral studies. The reasons for the enhancement of scattering spectra were discussed in terms of fluorescence-scattering resonance energy transfer, hydrophobicity and molecular size.

Study on the interaction between albendazole and eosin Y by fluorescence, resonance Rayleigh scattering and frequency doubling scattering spectra and their analytical applications

In pH 3.25–3.35 Britton–Robinson (BR) buffer solution, albendazole (ABZ) could react with eosin Y (EY) to form a 1:1 ion-association complex, which not only results in the quenching of fluorescence, but also resulted in the great enhancement of resonance Rayleigh scattering (RRS) and frequency doubling scattering (FDS). Furthermore, a new RRS spectrum will appear, and the maximum RRS wavelength was located at about 356nm. The detection limit for ABZ were 21.51ngmL−1 for the fluorophotometry, 6.93ngmL−1 for the RRS method and 12.89ngmL−1 for the FDS method. Among them, the RRS method had the highest sensitivity. The experimental conditions were optimized and effects of coexisting substances were evaluated. Meanwhile, the influences of coexisting substances were tested. The methods have been successfully applied to the determination of ABZ in capsules and human urine samples. The composition and structure of the ion-association complex and the reaction mechanism were discussed.

Study on Resonance Rayleigh Scattering Spectra, Non-linear Scattering Spectra of Alizarin Red-Cetylpyridinium Bromide-Lead System and its Analytical Application

Study on Resonance Rayleigh Scattering Spectra, Non-linear Scattering Spectra of Alizarin Red-Cetylpyridinium Bromide-Lead System and its Analytical Application