Study on the co-luminescence system Sm-Gd-BPMPHD-CTMAB and its analytical application

It has been found that the Sm-BPMPHD-CTMAB ion association system shows a strong fluorescence intensity. In this system some rare earth ions, such as Lu³⁺, Y³⁺, Gd³⁺ and Tb³⁺, exert an evident fluorescence enhancement effect. The formation conditions of the system and the factors affecting the columinescence effect were studied in detail in order to determine trace amounts of Sm³⁺. Under optimum conditions a linear relationship was obtained between the fluorescence intensity and the Sm³⁺ concentration in the range of 5.0×10^?8–8.0×10^?6 mol·L^?1. The detection limit of Sm³⁺ was 2.0×10^?8 mol·L^?1. The determination gave satisfactory results.     

Enhanced Luminescence of Europium by Gadolinium and Its Application

Abstract

The fluorescence enhancement of the Eu-dibenzoylmethane(DBM)- cetylpyridinium-chloride (CPC) system was studied. The fluorescence intensity of the system can be greatly increased by Gd³⁺ in the presence of triethanolamine(TEA). The optimum conditions for enhanced fluorescence of the Eu-Gd-DBM-CPC system were examined. It was a linear function of the Eu³⁺ concentration in the range of 1.0×10^?10～1.0×10^?8 mol dm^?3 under the optimized conditions. The detection limit was 2.6 × 10¹¹ mol dm^?3 in an aqueous solution at pH=7.5～9.5.

The Eu-Gd-DBM-CPC system was applied to the determination of europium in rare earth oxides with satisfactory results. The mechanism of enhanced fluorescence was discussed.     

Fluorescence Enhancement of Rare Earths by Yttrium and its Application

Abstract

A study of the enhancement effect on the fluorescence intensity of the Eu³⁺–-thenoyltrifluoroacetone (TTA)–-cetyltri–-methylammonium bromide (CTMAB) and the Dy³⁺ pyrocatechol–-3,5-disulphonic acid (Tiron) systems by Y³⁺has been carried out. In the presence of yttrium the fluorescence intensity of the systems was enhanced by a factor of about 100 and 15, respectively. The fluorescence intensity was a linear function of the concentration of europium or dysprosium in the range 1.0 × 10^?10–-1.0 × 10^?8mol dm^?3 and 8.0 × 10^?8–-9.0 × 10^?6mol dm^?3, respectively. The detection limit was 1.0 × 10^?11mol dm^?3 and 1.0 × 10^?10mol dm^?3, respectively. The standard addition method was used for the determination of europium or dysprosium in rare earth oxides and gave satisfactory results. The mechanism of enhanced fluorescence was proposed.     

The europium/samarium-2-benzoyl-indane-1,3-dione-cetyltrimethylammonium bromide fluorescence system and its analytical application

The fluorescence system of the Eu³⁺ (or/and Sm³⁺)-2-benzoyl-indane-1,3-dione(BID)-cetyltrimethylammonium bromide (CTMAB) was investigated at excitation wavelengths of 350 nm, and emission wavelengths at 612 nm for europium and 565, 606 and 650 nm for samarium, respectively. The system was used for the determination of Eu and Sm in rare earth oxides and of BID in water. Europium or/and samarium could be determined in the range of 1.0 × 10^–9–1.0 × 10^–5 mol/L and 2.0 × 10^–8–5.0 × 10^–5 mol/L, respectively; 1.0 × 10^–6–2.0 × 10^–5 mol/L of BID could also be determined. Received: 5 March 1997 / Revised: 6 August 1997 / Accepted: 20 September 1997     

The europium/samarium-2-benzoyl-indane-1,3-dione-cetyltrimethylammonium bromide fluorescence system and its analytical application

The fluorescence system of the Eu³⁺ (or/and Sm³⁺)-2-benzoyl-indane-1,3-dione(BID)-cetyltrimethylammonium bromide (CTMAB) was investigated at excitation wavelengths of 350 nm, and emission wavelengths at 612 nm for europium and 565, 606 and 650 nm for samarium, respectively. The system was used for the determination of Eu and Sm in rare earth oxides and of BID in water. Europium or/and samarium could be determined in the range of 1.0 × 10^–9–1.0 × 10^–5 mol/L and 2.0 × 10^–8–5.0 × 10^–5 mol/L, respectively; 1.0 × 10^–6–2.0 × 10^–5 mol/L of BID could also be determined. Received: 5 March 1997 / Revised: 6 August 1997 / Accepted: 20 September 1997     

Design and synthesis of two armed molecular receptor for recognition of Gd3+ metal ion and its computational study

New receptor P henylene‐ B is‐ M ethylfuran‐yl‐2‐ M ethyele A cetohydrazide ( PBMMA ) has been synthesized by condensation of hydrazide and 5‐methyl furfural. Synthesized receptor has been fully characterized by IR, ¹H NMR, ¹³C NMR, mass spectroscopic and thermo gravimetric analysis. The receptor PBMMA shows selective recognition potential towards Gd³⁺ ion when tested with several metal ions such as Na⁺, K⁺, Mg²⁺, Cu²⁺, Cd²⁺, Hg²⁺, Y³⁺, La³⁺, Eu³⁺, Sm³⁺, Gd³⁺, Re⁶⁺ and Th⁴⁺ ion as their sulfates by UV–visible and fluorescence spectroscopic studies. Binding nature of PBMMA with Gd³⁺ ion was further studied by mass spectroscopic and cyclic voltammetric studies. The stoichiometry of PBMMA‐ Gd³⁺ ion has been established, 1:1 by Benesi‐Hildebrand plot method and method of continuous variation (Job's plot) with association affinity K = 6.491 × 10⁴ M^?1. In addition to these, molecular docking, molecular dynamic stimulation and binding energy of complex; through Density Function theory ?595.66 kcal/mol has also indication of strong binding. The electron transfer energy of Higher occupied molecular orbital (HOMO) to Lower unoccupied molecular orbital (LUMO) is about 4.186 eV and 295 nm for PBMMA‐Gd³⁺ Complex.     

Study of the Fluorescence Enhancement of Eu-Y-DEM-Dibenzoylmethane-Ammonia System

Abstract

The fluorescence enhancement and solvent effect of Eu-dibenzoylmethane-ammonia system was studied. The fluorescence intensity of the system can be greatly increased by y³⁺. The maximum fluorescence intensity was obtained at pH 8.9 – 9.5. The fluorescence intensity is a linear function of Eu²⁺ in the range of 1.0x10^?9 M -4.0x10^?8 M. The detection limit is 1.1x10^?10 M. The optimized procedure is applied to the determination of europium in lanthanide oxide samples.     

Fluorescence enhancement of the europium-yttrium-diphacinone-ammonia system

A study of the enhanced (ca. 100 ×) fluorescence intensity of the Eu³⁺-diphacinone-ammonia system by Y³⁺ was made using a colloidal suspension. The excitation and emission wavelengths were 330 and 612 nm, respectively. The fluorescence intensity was a linear function of the concentration of europium in the range 6.0 × 10^?11–8.0 × 10^?7 M. The detection limit was 8.0 × 10^?14 M. The standard addition method was used for the determination of europium in rare earth oxides, with satisfactory results.     

Selective fluorescence quenching of biologically important acidic and non-acidic indoles by trivalent lanthanide ions and analysis of mixtures by a fluorimetric quenching method

The effects of several lanthanide(II)(Ln³⁺)ions(Dy³⁺,Er³⁺,Eu³⁺,Nd³⁺,Yb³⁺) on the room-temperature fluorescence spectra of 2-indolecarboxylic acid, 5-indolecarboxylic acid, 5-methoxy-2-indolecarboxylic acid and 3-indoleacetic acid were investigated. It was found that the fluorescence quenching by Ln³⁺ ions is much more efficient for the acidic compounds than for non-acidic indoles. Stern-Volmer relationships were obtained for most acidic indoles in the Ln³⁺ concentration range 10^?7–10^?4 M, with quenching constants ranging between 3 × 10³ and 4.6 × 10⁵ l mol^?1. A fluorimetric quenching method was developed for the quantitative analysis of binary mixtures of acidic and non-acidic indoles.     

Simultaneous spectrofluorimetric determination of terbium,samarium and europium with hexafluoroacetylacetone-trioctylphosphine oxide and Triton X-100

In aqueous solution, the fluorescence intensity is a linear function of concentration in the ranges 1.0 × 10^?4-1.0 × 1.0^?6 M Sm and 1.0 × 10^?6-1.0 × 10^?8 M Tb and Eu. The optimum conditions are 1 × 10^?3 M hexafluoroacetylacetone, 1 × 10^?4 M trioctylphosphine oxide and 0.05% Triton X-100 at pH 3.0.     

Study on a Fluorometric Method for the Determination of Protein in Serum Using Quercetin‐Lanthanum (III)‐Sodium Dodecyl Benzene Sulfonate‐Protein System

Abstract

It was found that the fluorescence intensity of lanthanum (III) (La³⁺)‐quercetin (Qu) complex is greatly enhanced by proteins in the presence of sodium dodecyl benzene sulfonate (SDBS). Based on this finding, a new fluorimetric method for the determination of proteins was developed. Under optimum conditions, the enhanced intensity of fluorescence is in proportion to the concentration of proteins in the range of 2.5×10^?8 to 1.0×10^?5 g/mL for bovine serum albumin (BSA), 5.0×10^?8 to 1.5×10^?5 g/mL for human serum albumin (HSA), and 1.0×10^?7 to 1.5×10^?5 g/mL for egg albumin (EA). Their detection limits (S/N=3) are 5.0×10^?9 g/mL, 7.0×10^?9 g/mL, and 2.1×10^?8 g/mL, respectively. The interaction mechanism was also studied.     

Rapid Determination of Minocycline in Pharmaceutical Formulations and Human Urine/Serum Samples Based on the Minocycline-Europium-Sodium Dodecylbenzene Sulfonate Luminescence System

Abstract

A new luminescence method based on the minocycline (MNC)-europium (Eu³⁺)-sodium dodecylbenzene sulfonate (SDBS) system was developed for the determination of MNC. SDBS formed a ternary complex with MNC-Eu³⁺ and significantly enhanced the luminescence intensity of Eu³⁺. The enhanced luminescence intensity showed a good linear relationship with the concentration of MNC over the range of 4.0 × 10^?7 ～ 1.0 × 10^?5 mol L^?1 with a detection limit of 2.0 × 10^?8 mol L^?1. This method is rapid and sensitive, and has been successfully applied for the determination of MNC in capsules and human urine/serum samples. The luminescence mechanism is also studied.     

Study of Fluorescence System of Gmanylic Acid-Tb3+ and the Determination of Gmanylic Acid

Abstract

It was found that gmanylic acid (GMP) can be selectively completed with Tb³⁺ at pH 6.0-6.6, which then emits strong fluorescence characteristic of Tb³⁺. This reaction can be used for the determination of GMP in presence of adenylic acid (AMP), uridylic acid (UMP) and cylidylic acid (CMP). A linear relationship is obtained between the fluorescence intensity and GMP concentration in the range of 2.0×10^?7 - 1.0×10^?4M. The detection limit is 2.0×10^?8 M. The results showed that the composition ratio and apparent stability constant of GMP-Tb complex were 1:1 for GMP Tb³⁺- and 2.3×10^?5, respectively.     

Determination of Fluoride Ions in Mouthwash Samples by a PVC Membrane Samarium(III) Sensor

Abstract

In this study, a new ion-selective electrode for Sm³⁺ is described, illustrating 2-[(E)-1-(1H-pyrrol-2-yl)methylidene]-1-hydrazinecarbothioamide (PMH) in a poly(vinylchloride) (PVC) membrane with nitrobenzene (NB) as a plasticizer and sodium tetraphenyl borate (NaTPB) as an anionic additive. The proposed sensor exhibited a Nernstian response for Sm³⁺ ions over a wide concentration range between 1.0 × 10^?2 and 1 × 10^?6 M, with a detection limit of 5.2 × 10^?7 M in the pH range of 4.2–8.5. Moreover, the sensor displayed the Nernstian slope of 19.8 ± 0.3 mV per decade, having a fast response time within 10 s over the entire concentration range. This electrode presented very good selectivity and sensitivity toward the Sm³⁺ ions over a wide variety of cations, including alkali, alkaline earth, transition-metal, and heavy-metal ions. It was used as an indicator electrode in the potentiometric titration of Sm³⁺ ions with EDTA. The membrane sensor was also applied to the determination of fluoride ions in mouthwash samples.     

Graphite Electrode Coated with a 7,16‐Dibenzyl‐1,4,10,13‐tetraoxa‐7,16‐diazacyclooctadecane‐Multiwalled Carbon Nanotube Composite as Sensor For Detection of Samarium

A composite multiwalled carbon nanotube polyvinyl chloride electrode based on 7,16‐dibenzyl‐1,4,10,13‐tetraoxa‐7,16‐diazacyclooctadecane (DBDA18C6) as Sm³⁺ ionophore is reported. This potentiometric sensor showed a wide linear working range, 1×10^?2–1×10^?8 M, Nernstian slope, 20.2±0.48 mV per decade and a limit of detection, 6.3±0.36×10^?9 M. It works in the pH range 2.5–8.5 and shows a good selectivity over a number of metal ions. It has been found suitable for the analysis of ores and industrial effluents. The electrode surface is characterized by FRA and AFM.     

Highly Selective and Sensitive Membrane Sensors for Copper(II) Ion Based on a New Benzo‐Substituted Macrocyclic Diamide 6,7,8,9,10‐Hexahydro‐2H‐1,13,4,7,10‐benzodioxatriazacyclopentadecine‐3,11(4H,12H)‐dione

Novel PVC membrane (PME) and coated graphite (CGE) Cu²⁺‐selective electrodes based on 5,6,7,8,9,10‐hexahydro‐2H‐1,13,4,7,10‐benzodioxatriazacyclopentadecine‐3,11(4H,12H)‐dione are prepared. The electrodes reveal a Nernstian behavior over wide Cu²⁺ ion concentration ranges (1.0×10^?7–1.0×10^?1 M for PME and 1.0×10^?8–1.0×10^?1 M for CGE) with very low limits of detection (7.8×10^?8 M for PME and 9.1×10^?9 M for CGE). The potentiometric responses are independent of the pH of the test solutions in the pH range 2.7–6.2. The proposed electrodes possess very good selectivities for Cu²⁺ over a wide variety of the cations including alkali, alkaline earth, transitions and heavy metal ions. The practical utility of the proposed electrodes have been demonstrated by their use in the study of interactions between copper ions and human growth hormone (hGH) in biological systems, potentiometric titration of copper with EDTA and determination of copper content of a sheep blood serum sample and some other real samples.     

Preparation of Cu (II) imprinted polymer electrode and its application for potentiometric and voltammetric determination of Cu (II)

The Cu (II) imprinted polymer glassy carbon electrode (GCE/Cu-IP) was prepared by electropolymerization of pyrrole at GCE in the presence of methyl red as a dopant and then imprinting by Cu²⁺ ions. This electrode was applied for potentiometric and voltammetric detection of Cu²⁺ ion. The potentiometric response of the electrode was linear within the Cu²⁺ concentration range of 3.9 × 10^?6 to 5.0 × 10^?2 M with a near-Nernstian slope of 29.0 mV decade^?1 and a detection limit of 5.0 × 10^?7 M. The electrode was also used for preconcentration anodic stripping voltammetry and results exhibited that peak currents for the incorporated copper species were dependent on the metal ion concentration in the range of 1.0 × 10^?8 to 1.0 × 10^?3 M and detection limit was 6.5 × 10^?9 M. Also the selectivity of the prepared electrode was investigated. The imprinted polymer electrode was used for the successful assay of copper in two standard reference material samples.     

Fluorescence enhancement of the Eu-Tb-benzoylacetone-phenanthroline system

The Eu-benzoylacetone-phenanthroline system, which has strong fluorescence intensity, was studied. It was found that the fluorescence intensity can be greatly increased by La, Gd, Tb, Lu and Y, Tb giving the greatest enhancement (ca. two orders of magnitude). The maximum fluorescence intensity was obtained at pH 8.0. Beer's law was obeyed from 1.0 × 10^?9 to 2.0 × 10^?7 M Eu. The detection limit for europium was 2.0 × 10^?11 M.     

Flow-injection determination of iron(II), iron(III) and total iron with chemiluminescence detection

Iron(II) (1.0 × 10^?9–1.0 × 10^?6 M) is determined by the production of chemiluminescence in a luminol system in the absence of added oxidant. Iron(III) (2.0 × 10.8^?8–2.0 × 10^?6 M) is determined after reduction to iron(II) in a silver reductor mini-column in the flow system. Cobalt, chromium, copper and manganese interfere.     

Electronic excitation energy transfer between Tb3+ and Eu3+ in DMSO

Excitation of Tb³⁺ and Eu³⁺ in DMSO with 487 mμ, which corresponds to the ⁷F₆ → ⁵D₄ transition of Tb³⁺, is accompanied by a reduction in the fluorescence efficiency of Tb³⁺ as [Eu³⁺] increases and by the appearance of a weak emission from Eu³⁺. An average rate constant for both the fluorescence quenching of Tb³⁺ and the energy transfer from Tb³⁺ to Eu³⁺ with subsequent emission from the latter, was found to be (2.2 ± 0.4) × 10³ M^?1 sec^?1.