Resonance Rayleigh Scattering Spectra Research Articles

Resonance Rayleigh scattering spectra for studying the interaction of heparin with some basic phenothiazine dyes and their analytical applications

In near neutral medium, binding of heparin with some basic phenothiazine dyes such as methylene blue (MB), Azure B or toluidine blue (TB) can result in a significant enhancement of resonance Rayleigh scattering (RRS) and appearance of a new RRS spectrum. Their maximum scattered wavelengths appear at 346, 338 and 329nm for MB, Azure B and TB, respectively. The optimum conditions of these reactions, the influencing factors and the relationship between the RRS intensity and the concentration of heparin have been investigated. A new method for the determination of trace amounts of heparin based on the RRS method has been developed. The methods exhibit high sensitivities, the detection limits for heparin are 9.0ngml−1 for MB, 14.5ngml−1 for Azure B and 26.0ngml−1 for TB. Among them the MB is the most sensitive and has better selectivity, so it was applied to the determination of heparin in heparin sodium injection samples with satisfactory results. The mechanisms of the effect are discussed.

Resonance Rayleigh Method for the Determination of Proteins with Orange G

In pH 0.6 - 2.0 HCl-sodium acetate buffer solution, proteins react with an acidic monoazo dye such as Orange G, Methyl Orange, Methyl Red and Orange IV to form a combination product. This results in a significant enhancement of resonance Rayleigh scattering (RRS) and a new RRS spectrum appears. Owing to the fact that Orange G-protein system is the most sensitive, it was taken as an example to study. The RRS spectral characteristics of its combination product and the optimum condition for the reaction were investigated. The intensity of RRS is directly proportional to the concentration of protein in the range of 0 - 5.0 microg/mL. The method has high sensitivity; its detection limits are 2.6 ng/mL for BSA, 3.4 ng/mL for HAS and 7.1 ng/mL for alpha-chymotrypsin, respectively. A new method for the determination of trace amounts of proteins on the basis of RRS spectra has been developed.

Resonance Rayleigh-scattering method for the determination of proteins with some monoazo dyes of chromotropic acid.

In a weak acid medium, protein reacts with a monoazo dye of chromotropic acid, such as Chromazol KS (CALKS), Acid Chrome Dark Blue (ACDB), Chrome Blue SE (CBSE), Acid Chrome Blue K (ACBK), Chlorophosphonazo I (CPAI), Arsennazo I (AAI) and Chromotrope 2R (CT2R), to form a combination product. This results in a significant enhancement of the resonance Rayleigh-scattering (RRS) intensity, and the corresponding RRS spectrum appears. The characteristics of the RRS spectra of the combination products and the optimum conditions for the reactions were investigated. The intensity of RRS is directly proportional to the concentration of protein in a certain range. The RRS methods have high sensitivity for the determination of protein, the detection limits for bovine serum albumin (BSA) are 10.0 - 30.2 ng/ml, and the sensitivity order is CALKS > AAI = CPAI > ACBK = CT2R > ACDB > CBSE. The selectivity for CALKS has been examined, and the method was applied to the determination of a microg amount of protein in a synthetic sample with satisfactory results.

Resonance Rayleigh scattering method for the determination of trace amounts of cadmium with iodide-basic triphenylmethane dye systems.

In dilute phosphoric acid solution, cadmium (II) reacts with a large excess of I- to form [CdI4]2- which reacts further with basic triphenylmethane dyes such as crystal violet (CV), ethyl violet (EV), methyl violet (MV), brilliant green (BG) or malachite green (MG) to form an ion-association complex. This results in a significant enhancement of resonance Rayleigh scattering (RRS) intensity and the appearance of new RRS spectra. The characteristics of RRS spectra of the ion-association complexes, the influencing factors and the optimum conditions of these reactions have been investigated. The intensity of RRS is directly proportional to the concentration of cadmium from 0 to 60 ng mL(-1) for EV and MV systems, 0 to 80 ng mL(-1) for CV system, and 0 to 100 ng mL(-1) for BG and MG systems. The methods exhibit high sensitivities and the detection limits for cadmium are between 0.35 and 2.00 ng mL(-1) depending on the different reaction systems. The new RRS method was applied to the direct determination of traces of cadmium in pure zinc and synthetic water samples.

Resonance Rayleigh scattering method for the determination of trace amounts of cadmium with iodide–rhodamine dye systems

Resonance Rayleigh scattering (RRS) of cadmium(II)–iodide–rhodamine dye systems and their analytical application have been studied. In dilute phosphoric acid, rhodamine dyes such as rhodamine B (BRhB), ethylrhodamine B (ERhB), butylrhodamine B (BRhB) and rhodamine 6G (Rh6G) have characteristic RRS spectra and their maximum RRS wavelengths ( λ max) are at 575 nm for RhB, ERhB and BRhB, and 545 nm for Rh6G. In the presence of a large excess of I −, cadmium(II) forms [CdI 4] 2−, which further reacts with a rhodamine dye to form an ion-association compound. This results in significant enhancement of RRS intensity and the appearance of new spectra with λ max at 610 nm for RhB, ERhB and BRhB systems and 585 nm for the Rh6G system. The characteristics of the RRS spectra of the ion-association compounds, the affecting factors and the optimum conditions of these reactions have been investigated. The intensity of RRS is directly proportional to the concentration of cadmium in the range 0–1.0 μg/25 ml for all the systems. The methods have high sensitivities and the detection limits for cadmium are 0.60–1.26 ng ml −1 depending on the reaction system; the Rh6G system is the most sensitive. A new method for the determination of trace cadmium on the basis of RRS is described.

Resonance Rayleigh scattering for the determination of cationic surfactants with Eosin Y

Resonance Rayleigh scattering (RRS) of cationic surfactants–Eosin Y systems and their analytical application have been studied. In aqueous solution at pH 2∼3, Eosin Y reacts with a monomer of cationic surfactants (CS), such as Zephiramine (Zeph), tetradecylpyridinium bromide (TPB), cetylpyridinium bromide (CPB), cetylpyridinium chloride (CPC) and cetyltrimethylammonium bromide (CTMAB), to form an ion associate and a new RRS spectrum appears. The spectral characteristics of the five ion associates are similar and their maximum scattering wavelengths (λmax) are all at 313 nm. The intensity of RRS at λmax of the ion associate is directly proportional to the concentration of CS in the range of 0∼3.0 μg/25 mL. The technique has high sensitivity for the determination of CS; their detection limit is between 5.57 ng/mL and 7.60 ng/mL depending on the CS. In this case, most metal and non-metal ions, NH4 + and some anionic surfactants do not interfere, so that the method has a good selectivity. It can be applied to the determination of trace amounts of cationic surfactants in water samples.

Resonance Rayleigh scattering of chromium(VI)-iodide-basic triphenylmethane dye systems and their analytical application

Resonance Rayleigh scattering (RRS) of chromium(VI)-iodide-basic triphenylmethane dye (BPTMD) systems and their analytical applications have been studied. In dilute phosphoric acid solution in the presence of excess I −, chromium(VI) oxidizes I − producing I 2, which binds I − to form I − 3 and I − 3 further reacts with a basic triphenylmethane dye such as crystal violet (CV), ethyl violet (EV), malachite green (MG), brilliant green (BG) and iodine green (IG) to form an ion-association complex. This results in the significant enhancement of RRS intensity and the appearance of new RRS spectra. The characteristics of RRS spectra of the ion-association complexes, the affecting factors and the optimum conditions of these reactions have been investigated. The intensity of RRS is directly proportional to the concentration of chromium(VI) in the range 0–1.5 μg/25 ml for the CV system and 0–1.0 μg/25 ml for the other systems. The methods have very high sensitivity and the detection limits for Cr(VI) are 0.065–5.6 ng ml −1 depending on the different reaction systems; the CV system is the most sensitive. A new method for the indirect determination of trace chromium(VI) on the basis of RRS has been advanced.

Resonance Rayleigh Scattering for an Indirect Determination of Trace Amounts of Selenium(IV) with Iodide-Basic Triphenylmethane Dye Systems

The resonance Rayleigh scattering (RRS) spectra of selenium(IV)/iodide/basic triphenylmethane dye systems have been studied. Intense RRS appears when selenium(IV) reacts with iodide and a basic triphenylmethane dye, such as Crystal Violet (CV), Ethyl Violet (EV), Brilliant Green (BG), Malachite Green (MG) and Iodine Green (IG), to form an ion-association complex. The characteristics of the RRS spectra of the ion-association complexes and the suitable conditions for the reactions were investigated. The intensity of RRS is directly proportional to the concentration of selenium(IV) in the range 0 - 0.30 μg/25 ml for the CV and EV systems, and 0 - 0.40 μg/25 ml for other systems. The RRS methods have very high sensitivities for an indirect determination of selenium(IV); the detection limits are between 0.094 ng/ml and 0.86 ng/ml for different dye systems. A new way to determine trace amounts of selenium based on the RRS spectra of the ion-association complex has been developed.

Resonant Rayleigh Scattering for the Determination of Trace Amounts of Mercury (II) with Thiocyanate and Basic Triphenylmethane Dyes

Intense resonance Rayleigh scattering (RRS) appears when mercury (II) reacts with thiocyanate and a basic triphenylmethane dye (BTPMD), such as crystal violet (CV), ethyl violet (EV), brilliant green (BG), malachite green (MG) or indine green (IG), to form an ion-association complex of the type (BTPMD)2[Hg(SCN)4]. The characteristics of RRS spectra of the ion-association complexes and suitable conditions for the reactions were investigated. The intensity of RRS is directly proportional to the concentration of mercury (II) in the range of 0±2.0 μg/25 ml. The RRS methods have very high sensitivities for determination of mercury (II); their detection limits are between 1.68 ng/ml and 6.00 ng/ml on different dye systems. The effects of foreign ions and ways to improve the selectivity were studied. The new highly sensitive methods for the determination of trace amounts of mercury based on the RRS of the ion-association complexes have been developed.

Anticonvulsant properties of levetiracetam in mice are not shared by nootropic drugs

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 = 375 nm. 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 0.03–3.0 μg mL− 1, and the detection limit (DL) of RRS method for PIR and OXI is 2.3 ng mL− 1 and 9.7 ng mL− 1. In addition, the DL of fluorescence method for PIR and OXI is 8.4 μg mL− 1 and 19.5 μg mL− 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.