Micelle Stabilized Room Temperature Phosphorescence Research Articles

Simplex optimization of the variables affecting the micelle-stabilized room temperature phosphorescence of 6-methoxy-2-naphthylacetic acid and its kinetic determination in human urine

This article reports the kinetic determination of 6-methoxy-2-naphthylacetic acid (6-MNA), the major metabolite of nabumetone, from micelle-stabilized room temperature phosphorescence (MS–RTP) measurements made by using the stopped-flow mixing technique. This methodology allows one to determine analytes in complex matrices without the need for a tedious separation process. It also shortens analysis times substantially. The proposed method uses simplex methodology to optimize the chemical and instrumental variables affecting the phosphorescence. It was applied to the determination of 6-MNA in human urine. The maximum phosphorescence signal is obtained within only 10 s after the sample is prepared. The maximum slope of the kinetic curve, which corresponds to the maximum rate of the phosphorescence development, is measured at λ ex = 273 nm and λ em = 516 nm. Least-squares regression was used to fit experimental data, and the detection limit, repeatability, and standard deviation for replicate samples were determined.

Determination of the pesticide napropamide in soil, pepper, and tomato by micelle-stabilized room-temperature phosphorescence.

A selective and sensitive method for determining napropamide by room-temperature phosphorescence in SDS micelles is proposed and applied to the determination of this substance in a technical formulation and in spiked soil, pepper, and tomato samples. The use of phosphorescence enhancers such as sodium dodecyl sulfate (micellar agent), thallium (I) nitrate (external heavy atom), and sodium sulfite (deoxygenation agent) was studied and optimized to obtain maximum sensitivity. The determination was performed in 66 mM SDS, 30 mM thallium (I) nitrate, and 8 mM sodium sulfite. Taking into account both maximum phosphorescence intensity and the time required to reach that, a pH value of 7.2 was selected. After the samples were left standing at room temperature for 10 min, the phosphorescence was totally developed. The intensity was then measured at lambda(ex) = 282 nm and lambda(em) = 528 nm. The calibration graph was linear for 50-600 ng mL(-1) napropamide. The detection limit, according to the error propagation theory, was 16 ng mL(-1). The method has been demonstrated for the analysis of soils, peppers, and tomatoes, but, because of matrix interference, the method of standard additions was applied to determine napropamide in the vegetable samples. Recoveries from all these matrixes of added napropamide were near 100%.

Method for the Quantitative Determination of 1-Naphthaleneacetic Acid in Spiked Canned Pineapple Samples by Micelle-Stabilized Room Temperature Phosphorescence.

This paper presents a convenient method for the determination of 1-naphthaleneacetic acid (NAA) plant growth regulator in spiked canned pineapple samples by micellar-stabilized room temperature phosphorescence with sodium dodecyl sulfate as a micellar medium, thallium nitrate as an external heavy atom, and sodium sulfite as an oxygen scavenger. A multivariate optimization approach using the type of central composite blocked cube-star design was carried out. The analytical curve of NAA gives a linear dynamic range of 70-500 ng mL(-)(1) with a detection limit of 21 ng mL(-)(1) and precision of 2.37% (n = 7). A mean recovery value of 98.6% was obtained for 250 ng mL(-)(1) NAA in the pineapple samples.

Study on micelle stabilized room temperature phosphorescence behaviour of pyrene by laser induced time resolved technique

Room temperature phosphorescence (RTP) decay generally follows a first order exponential law P t= P 0e −t/ τ in the micelle system. The pre-exponential factor (or transient phosphorescence intensity) P 0 and phosphorescence lifetime τ can be used to qualitatively indicate the probability of intersystem crossing ( S 1- T 1) (ISC) and radiationless deactivation ( T 1- S 1) of the phosphors in micelle system. These two factors indirectly reflect the inducing effect of heavy atoms on the probability of ISC of phosphor and the preservation of micelle to phosphor. In this paper, P 0 and τ of pyrene were measured by a laser induced time resolved technique. The effects of the concentration of heavy atom species, surfactant SDS, as well as pH, on the above parameters were studied.

Experimental Studies of the Factors That Influence 1-Naphthaleneacetamide Determination by Micelle-stabilized Room-temperature Phosphorescence

A micelle-stabilized room-temperature phosphorescence (MS-RTP) method was developed for the determination of the phytohormone 1-naphthaleneacetamide residues in fortified pear samples. The proposed method is based on the use of a micellar medium obtained by the surfactant sodium dodecyl sulfate in the presence of thallium nitrate as an external heavy atom salt. To avoid oxygen quenching, sodium sulfite solution was used. To establish the optimum experimental variables, a complete and exhaustive statistical analysis of the experimental data by a multivariate optimization approach was performed. MS-RTP spectra were obtained and successfully used to determine 1-naphthaleneacetamide by the established method without further separation, with a detection limit of 25 ng ml - 1 . The precision (RSD ≤ 2.55%) and recovery (≥ 91.9%) were satisfactory.

Room temperature phosphorescence properties of dansyl chloride and its derivatives

Emission conditions and spectral properties of 5-dimethylaminonaphthalene sulfonylchloride (DNS-Cl) for micelle stabilized room temperature phosphorescence (MS-RTP) and solid substrate room temperature phosphorescence (SS-RTP) are studied. In sodium dodecyl sulphate micelle systems, MS-RTP emission of DNS-Cl can be induced with TINO 3 as heavy atom perturber and Na 2SO 3 for deoxygenation, λ ex λ em = 328 558 nm . The intensity of RTP is linear with the concentration of DNS-Cl in the range of 1 × 10 −7 to 4 × 10 −5 mol l −1. On several solid substrates, the SS-RTP of DNS-Cl can be achieved with lead acetate (Pb(AC) 2) as heavy atom perturber. On filter paper and for λ ex λ em = 335 575 nm , the linear range is 12 to 300 pmol DNS-Cl in 0.3 μl sample volume and the limit of detection is 12 pmol. On the other hand, the MS-RTP emission of derivative products for amino acid and ethanolamine can also be induced. Compared with that of DNS-Cl, not only the λ ex λ em of the derivative products show a clear shift to longer wavelengths, but also the optimal pH increased from 7 to 10. These results show that DNS-Cl can be used not only as a fluorescence reagent, but also for RTP.

Luminescence rule of polycyclic aromatic hydrocarbons in micelle-stabilized room-temperature phosphorescence

This paper studies the effect of the triplet energy on micelle-stabilized room-temperature phosphorescence (MS-RTP) of polycyclic aromatic hydrocarbons (PAHs). The results of the experiments show that it is difficult or impossible to induce MS-RTP of PAHs when the triplet energy is less than about 14 000 cm -1 , which may be a critical value for inducing MS-RTP of PAHs. In addition, this paper also discusses the effects of ring size and linearity on MS-RTP of PAHs

Micelle-stabilized room-temperature liquid phosphorimetry of metal chelates and its application to niobium determination

A detailed examination of 8-hydroxyquinoline and some of its derivatives as potential complexing reagents for the room-temperature phosphorescence determination of Nb(V) in micelles of different charge-type surfactants has been conducted. Enhanced fluorescence was observed in most cases. To observe analytical room-temperature phosphorescence (RTP), however, several essential requirements were identified: (1) charged micelles allowing electrostatic interaction with the oppositely charged binary complex have to be present, (2) external heavy atoms, ideally bromoform, should be added, (3) oxygen has to be expelled out of micelles, which is accomplished by Na/sub 2/SO/sub 3/ addition. Experimental conditions, including sunlight exposure, are optimized for the formation of the phosphorescent complex niobium(V)-ferron in micelles of cetyltrimethylammonium bromide. Two complexes of metal-ferron with stoichiometries of 1:1 and 1:3 are formed. The last complex constitutes the basis of a RTP method for the determination of Nb (detection limit, 4 ppb; +/-2% relative standard deviation at 500 ppb of Nb level). Therefore, the first example of the determination of a metal ion by micelle-stabilized RTP is reported along with an insight into possible mechanisms of these micellar reactions.

Micelle-stabilized room-temperature phosphorescence with synchronous scanning

The experimental requirements for synchronous wavelength scanning micelle-stabilized room temperature phosphorescence and the factors affecting peak resolution are presented and compared with those for synchronous wavelength scanning fluorescence. Identification of individual compounds in a four-component mixture is illustrated, and criteria to identify and minimize triplet state energy transfer are given. Considerable improvement in resolution of the synchronous peaks is obtained via second derivative spectra. 20 references, 7 figures, 2 tables.

Heavy atom and complexation effects on micelle stabilized room temperature phosphorescence of anthracene, acridine and phenazine

Micelle stabilized room temperature phosphorescence is reported for two pyridinic nitrogen molecules, phenazine and acridine and the carbocyclic analogue, anthracene. The formation of a complex between silver and the pyridinic nitrogen is proposed, through which silver enhances phosphorescence by both the external heavy atom effect and donor—acceptor complexation. Thallium forms a weaker complex and is much less effective in inducing phosphorescence in the pyridinic heterocycles. Apparent prototropic equilibria for acridine in micellar solution reflect substantial differences between bulk phase pH and apparent pH in the region of the micellar assembly where the acridine resides. Fluorescence quantum yields and wavelength maxima are reported for anthracene, acridine and phenazine in sodium dodecyl sulfate micellar solution.

Micelle-stabilized room-temperature phosphorescence characteristics of carbazole and related derivatives

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMicelle-stabilized room-temperature phosphorescence characteristics of carbazole and related derivativesMarie Skrilec and L. J. Cline LoveCite this: J. Phys. Chem. 1981, 85, 14, 2047–2050Publication Date (Print):July 1, 1981Publication History Published online1 May 2002Published inissue 1 July 1981https://doi.org/10.1021/j150614a019RIGHTS & PERMISSIONSArticle Views285Altmetric-Citations36LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (526 KB) Get e-Alerts

Analysis of micelle-stabilized room temperature phosphorescence in solution

Analysis of micelle-stabilized room temperature phosphorescence in solution