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The synthesis and spectral characterization of several tetra-substituted aluminum 2, 3-naphthalocyanine dyes for the determination of metal ions is reported. The synthesis is done by means of a homogeneous phase reaction, replacing the previously used heterogeneous method. The new scheme allows for improved product yields, higher purity, better product reproducibility and can be monitored at different...
A method for the quantitation of polycyclic aromatic hydrocarbons (PAHs) in indoor and outdoor air by high-performance liquid chromatography (HPLC) with a spectrofluorometric detection and programmed excitation and emission wavelength pairs is proposed. The mobile phase is a linear gradient of methanol-water. The relative standard deviations (n = 5) are in the range 0.38-1.7% at concentration levels...
The spectral features of the near-infrared (NIR) dye TG-170 in different solutions and its complexation with several metal ions were investigated. The absorbance maxima of the dye are at λ=819, 805, and 791 nm in dimethyl sulfoxide (DMSO), methanol, and a buffer of pH 5.9, respectively. These values match the output of a commercially available laser diode (780 nm), thus making use of such a source...
The effect of several surfactants on the formation of the fluorescent ternary complex oxalate-Alizarin Red S-zirconium(IV) has been studied. In weakly acidic medium and in the presence of cationic surfactants, such as cetylpyridinium chloride, total complex formation is achieved, whereas in aqueous medium or in the presence of non-cationic micelles no significant changes are obtained in comparison...
Polycyclic aromatic hydrocarbons (PAH) in the marine environment are currently of great concern due to their potential carcinogenicity. The standard methods of detection and quantification of PAH in seawater and sediments are costly, time-consuming and do not account for the heterogeneous nature of their distribution and sources. Laser-induced, time-resolved fluorescence spectroscopy may help to overcome...
The effects of various solvents on the ground and excited states of chloroaluminum (III) tetrasulphonated naphthalocyanine (AlNcS 4 ) were studied. Both the absorbance and fluorescence spectra were found to be influenced by the hydrogen bond donating ability of various solvents. As the hydrogen bond donating ability of the solvent increased, hypsochromic and bathochromic shifts in the absorbance...
The conditions presently in use for the fluorometric determination of H 2 O 2 in marine waters, by reacting H 2 O 2 with scopoletin in the presence of horseradish peroxidase (HRP) and measuring the quenching of the fluorescence intensity of scopoletin, are not the optimal conditions. Under the optimized conditions of a pH of 8.5–9.5, an excitation wavelength of 390...
Photoinduced electron transfer (PET) fluoroionophores (1b, 2b) that consist of diazacrown and two 9-anthryl pendants show fluorescent enhancement with various guest salts. The diaza-12-crown-4 derivative (2b) exhibited Zn 2+ selectivity and in the presence of this cation the host fluorescence intensity was increased by a factor of 182. The guest cation-induced fluorescence enhancement...
A sensitive fluorescence optosensing method for the determination of Hg(II) in water samples is described. The method, using a flow injection technique, is based on the immobilization on a non-ionic-exchanger solid support (packed in a flow cell placed in a conventional fluorimeter) of the thiochrome formed by the oxidation of thiamine with Hg(II) in a continuous flow carrier at pH 8.1. Experimental...
Spectrofluorimetric methods to determine cisatracurium and mivacurium are proposed and applied to the determination of both substances in human serum and to the determination of mivacurium in pharmaceuticals. The fluorimetric methods allow the determination of 5-500 ng ml -1 of mivacurium in aqueous solutions and 5-500 ng ml -1 of cisatracurium in water-acetonitrile solutions,...
This study focuses on the complex formed between α-cyclodextrin (CD) and the anti-inflammatory drug diclofenac in aqueous solution and also on its potential analytical applications. It was corroborated that the fluorescence emission band of diclofenac is significantly intensified in the presence of α-CD. From the changes in the fluorescence spectra, it was concluded that α-CD forms a 1:1 inclusional...
A fluorescent optode membrane for sodium ion that works on the basis of a cation-exchange mechanism has been developed. The plasticized poly(vinyl chloride) (PVC) membrane incorporating sodium-selective ionophore (4-tert-butylcalix[4]arene tetraacetic acid tetraethyl ester), acidic fluorescent pH indicator (5,10,15,20-tetraphenylporphine, TPP) and a lipophilic anionic site (potassium tetrakis(4-chlorophenyl)borate)...
Vitamin K 3 (menadione) is an oil-soluble vitamin and not naturally fluorescent but yields fluorescence when it is reduced. However, it is possible to yield a fluorescent derivative in the region of 407 nm in aqueous medium when complexed to β-cyclodextrin (CD). A 1:1 stoichiometric ratio and a formation constant of 373+/-34 l mol -1 were obtained for the binary inclusion complex...
The present paper describes a method for the fluorometric determination of uric acid in blood serum by its reaction with uricase (UOx). The procedure is based on the changes in fluorescence that take place during the enzymatic reaction of UOx with uric acid when the solution is excited at 287 nm and the emission is measured at 330 nm. A mathematical model which relates the analytical signal to the...
In this paper, a combination of a flow injection analysis (FIA) system with micellar-enhanced photochemically induced fluorescence (MEPIF) detection is presented as a powerful alternative for the rapid and sensitive analysis of chlorophenoxyacid herbicides. These compounds do not show native fluorescence but they can be photolysed into strongly fluorescence photoproducts after direct irradiation with...
A spectrofluorimetric method to determine acrivastine is proposed and applied to its determination in human urine and pharmaceuticals. The fluorimetric method allows the determination of 58-2000 ng ml -1 of acrivastine in aqueous solutions containing acetic acid-sodium acetate buffer (pH 6.5) with λ exc =230 nm and λ em =380 nm.
A method for the determination of salicylamide at concentrations between 25 and 350 ng ml -1 by use of matrix isopotential synchronous fluorescence spectrometry (MISF) in combination with derivative techniques is proposed. The method allows the determination of compounds in samples with unknown background fluorescence without the need for tedious pre-separation. Synchronous scans are...
The sequential injection (SIA) technique was applied in pharmacokinetic studies of the transporter-mediated passage of a model substrate, rhodamine 123 (Rho123), through the dually perfused rat term placenta. The method described was used for real-time monitoring of Rho123 concentrations in both the maternal and fetal compartments. Determination was processed by fluorescence detection (λ e ...
Fluorimetric and UV methods of detection for liquid chromatographic determination of phenothiazines (chlorpromazine, acetopromazine and propionylpromazine) were developed. The effects of several experimental parameters on the separation and the sensitivity of the methods were evaluated. The detection limits ranged from 31 to 350 ngml -1 . Optimized methods were successfully applied to...
The physicochemical characterization of the peptide sequences E2 (39-53) and E2 (32-59) corresponding to the structural protein E2 of the GB virus C was done by studying their interaction with model membranes. The peptides showed surface activity concentration dependent when injected beneath a buffered solution. This tendency to accumulate into the air/water interface suggested a potential ability...
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