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1.
The efficiency of excited-state interaction between Tb3+ and the industrial product Cilostazol (CIL) has been studied in different solvents. High luminescence intensity peak at 545 nm
of terbium complex in acetonitrile was obtained. The photophysical properties of the green emissive Tb3+ complex have been elucidated, the terbium was used as optical sensor for the assessment of CIL in the pharmaceutical tablets
and body fluids at pH 3.1 and λex = 320 nm with a concentration range 1.0 × 10−9–1.0 × 10−6 mol L−1 of CIL, correlation coefficient of 0.998 and detection limit of 7.5 × 10−10 mol L−1. 相似文献
2.
Youssef AO 《Journal of fluorescence》2012,22(3):827-834
A new, simple, sensitive and selective spectrofluorimetric method for the determination of Hydrochlorothiazide was developed
in acetonitrile at pH 6.2. The Hydrochlorothiazide can remarkably enhance the luminescence intensity of the Tb3+ ion doped in sol–gel matrix at λex = 370 nm. The intensity of the emission band of Tb3+ ion doped in sol–gel matrix was increased due to the energy transfer from the triplet excited state of Hydrochlorothiazide
to (5D4) excited energy state of Tb3 ion. The enhancement of the emission band of Tb3+ ion doped in sol–gel matrix at (5D4→7 F5) 545 nm was directly proportion to the concentration of Hydrochlorothiazide with a dynamic ranges of 5.0 × 10−10—5.0 × 10−6 mol L−1 and detection limit of 2.2 × 10−11 mol L−1. 相似文献
3.
This paper explores an ultra-sensitive luminescence method for the determination of Ketoprofen (KP) in pharmaceutical formulations.
The technique is indirect and exploits the luminescence enhancement of terbium (Tb3+) by complexation with KP (Tb3+–KP), which was monitored at respective excitation and emission wavelengths of λ
ex = 258 nm and λ
em = 549 nm. The effect of varying the Tb3+ concentration and using multiple solvents was examined to determine optimal experimental conditions. Maximum sensitization
was accomplished in the presence of methanol where the most favourable condition for the formation of the complex was recorded
at a level of 1.0 × 10−5 M of Tb3+. Under these optimum experimental conditions, linear calibration curve was obtained in the range of 2.8 × 10−7–3.1 × 10−6 M with a detection limit of 8.7 × 10−8 M. The technique was validated with ‘working’ reference standards and produced relative standard deviations < 2% indicating
that the reproducibility was highly acceptable. The proposed method was successfully applied to assays of KP in pharmaceutical
formulations with average recoveries of 92–98%. The results were found to be in good agreement with those obtained by HPLC.
The method is highly suited for general applications of this nature. 相似文献
4.
Attia MS Mahmoud WH Ramsis MN Khalil LH Othman AM Hashem SG Mostafa MS 《Journal of fluorescence》2011,21(4):1739-1748
A simple and sensitive spectrofluorimetric method for determination of trace amount of doxycycline hydrochloride (DC) in pharmaceutical
tablets and serum samples was developed. In ammonia buffer solution of pH 8.9 the doxycycline hydrochloride can remarkably
enhance the luminescence intensity of the Sm3+ ion in Sm3+- DC complex at λex = 400 nm. The produced luminescence intensity of Sm3+- DC complex in DMSO is in proportion to the concentration of DC and used as optical sensor for its determination. The dynamic
range for the determination of DC is 1 × 10−8 – 5 × 10−6 mol L−1 and in case of quantum yield calculations is 7 × 10−9 – 5 × 10−6 mol L−1 with detection limit of 6.5 × 10−10 mol L−1. The enhancement mechanism of the luminescence intensity in the Sm3+- DC system has been also discussed. A comparison with other spectrofluorimetric methods for tetracycline derivatives in which
Eu3+ ion is used instead of Sm3+ ion is also studied. 相似文献
5.
A rapid, simple and sensitive spectrofluorimetric method for determination of trace amount of ofloxacin was developed. At
pH 5.1 the ofloxacin enhances the luminescence intensity of the Eu3+ ion in Eu3+- ofloxacin complex at λex = 365 nm. The produced luminescence intensity of Eu3+-ofloxacin complex was in proportional to the concentration of ofloxacin. The working range for the determination of ofloxacin
was 5.0 × 10-9–5.0 × 10-6 mol L-1 with lower detection limit (LOD) and quantitative detection limit (QDL) of 3 × 10-9 and 9 × 10-9 mol L-1, respectively. The enhancement mechanism of the luminescence intensity in the Eu3+-ofloxacin system has been also explained. The method revealed good selectivity for ofloxacin in the presence of coexisting
substances and used successfully for the assay of ofloxacin in pharmaceutical preparations and serum. A comparison with other
standard methods was also discussed. 相似文献
6.
The fluorescence system of the norfloxacin-Tb3+- sodium dodecylbenzene sulfonate (SDBS) was investigated in this paper. The experiments indicated that the fluorescence intensity
of the Tb3+-SDBS was greatly enhanced by the norfloxacin. On the basis of the above findings, a sensitive fluorimetric method for determining
the norfloxacin was established. The fluorescence intensity was measured by a 1-cm quartz cell with the excitation wavelength
of 290 nm and the emission wavelength of 545 nm. The enhanced fluorescence intensity of the system (Δ F) showed a good linear
relationship with the concentration of norfloxacin in the range of 5.0×10−9 mol L−1–2.0×10−6 mol L−1, its correlation coefficient was 0.9991 and the detection limit (S/N=3) was 1.2×10−9 mol L−1. The presented method was used to determine the norfloxacin in real pharmaceutical samples. The luminescence mechanism was
also discussed in detail. In the fluorescence system of the norfloxacin-Tb3+-SDBS, the SDBS not only acted as the surfactant, but also acted as the energy donor. 相似文献
7.
In our study, terbium-acetylacetone (Tb-acac) composite nanoparticles have been prepared under vigorous ultrasonic irradiation.
The nanoparticles are water soluble, stable and have extremely narrow emission bands and high internal quantum efficiencies.
They were used as fluorescence probes in the determination of enoxacin (Enox) based on the fluorescence enhancement of nanoparticles
through fluorescence resonance energy transfer (FRET). The influence of buffer solution on the fluorescence intensity was
investigated. Under the optimum conditions, the fluorescence intensity of the Tb-acac-Enox system is linearly proportional
to the Enox concentration in the Enox concentration range of 2 × 10−7–1 × 10−4 M. The correlation coefficient for the calibration curve was 0.9976. The limit of detection as defined by IUPAC, C
LOD = 3S
b/m (where S
b is the standard deviation of the blank signals and m is the slope of the calibration graph) was found to be 3 × 10−8 M. The relative standard deviation (RSD) for six repeated measurements of 1 × 10−4 M Enox was 1.35%. The method was applied to the determination of Enox in pharmaceutical formulation and recovery results
were obtained from urine samples. 相似文献
8.
A novel, simple, sensitive and selective spectrofluorimetric method was developed for the determination of trace amounts of
chlorzoxazone and Ibuprofen in pharmaceutical tablets using optical sensor Eu-Tetracycline HCl doped in sol–gel matrix. The
chlorzoxazone or Ibuprofen can remarkably enhance the luminescence intensity of Eu-Tetracycline HCl complex doped in a sol–gel
matrix in dimethylformamide (DMF) at pH 9.7 and 6.3, respectively, λex = 400 nm. The enhancing of luminescence intensity peak of Eu-Tetracycline HCl complex at 617 nm is proportional to the concentration
of chlorzoxazone or Ibuprofen a result that suggested profitable application as a simple optical sensor for chlorzoxazone
or Ibuprofen assessment. The dynamic ranges found for the determination of chlorzoxazone and Ibuprofen concentration are 5 × 10−9–1 × 10−4 and 1 × 10−8–7 × 10−5 mol L−1, and the limit of detection (LOD) and quantitation limit of detection (LOQ) are 3.1 × 10−10 , 9.6 × 10−10 and 5.6 × 10−10, 1.7 × 10−9 mol L−1, respectively. 相似文献
9.
Chemiluminescence (CL) of the reaction system tetracycline–H2O2–Fe(II)/(III)–Eu(III) was used for the determination of tetracycline hydrochloride in water, pharmaceutical preparations,
and honey. The CL spectrum registered for this system shows emission bands typical of Eu(III) ions, with a maximum at λ ∼ 600 nm,
corresponding to the electronic transitions of 5D0 → 7F1 and 5D0 → 7F2. A strong chemiluminescence intensity characteristic of europium(III) ions in the system tetracycline–H2O2–Fe(II)/(III)–Eu(III), as contrasted to the emission of the system tetracycline–H2O2–Fe(II)/(III) without Eu(III), proves that the Eu(III) ion plays the role of a chemiluminescence sensitizer, accompanying
tetracycline oxidation in the Fenton system (H2O2–Fe(II)/(III)). A linear dependence was observed for the integrated CL light intensity on the tetracycline concentration in
the range of 2 × 10−7 to 3 × 10−5 mol l−1 with the detection limit of 5 × 10−8 mol l−1 in aqueous solution. 相似文献
10.
A sensitive time- resolved luminescence method for the determination of meloxicam (MX) in methanol and in aqueous solution
is described. The method is based on the luminescence sensitization of europium (Eu3+) by formation of ternary complex with MX in the presence of 1,10- phenanthroline as coligand, Tween-80 as surfactant and
gadolinium ion as a co-luminescence reagent. The signal for Eu- MX-1, 10- phenanthroline is monitored at λex = 360 nm and λem = 620 nm. Optimum conditions for the formation of the complex in aqueous system were 0.01 M TRIS buffer, pH 8.0, 1,10- phenanthroline
(6.0 × 10−6 M) , Gd3+ (7.0 × 10−6 M), Tween-80 (0.28%) and 1.75 mM of Eu3+ which allows the determination of 20–800 ppb of MX with limit of detection (LOD) of 7 ppb. The relative standard deviations
of the method range between 0.1 and 1.1% indicating excellent reproducibility of the method. The proposed method was successfully
applied for the assay of MX in pharmaceutical formulations, plasma and in urine samples. Average recoveries of 99.8 ± 1.1%,
100.2 ± 0.9% and 100.9 ± 1.1% were obtained for MX in tablet, plasma and urine sample respectively. 相似文献
11.
Based on the micelle synergism mechanism, a simple and sensitive flow injection chemiluminescence (FI-CL) method for the assay
of lornoxicam was described. The CL signal generated from the reaction of Ce (IV) with lornoxicam in acidic solution was very
weak, while the interfusion of sodium dodecyl benzene sulfonate (SDBS) resulted in a highly CL intensity. Under the optimum
experimental conditions, the CL intensity was proportional to lornoxicam concentration over the range 1.0 × 10−10–7.3 × 10−8 g/mL with a detection limit of 4.9 × 10−11 g/mL (3σ). The relative standard deviation for 11 replicate measurements of 3.0 × 10−9 g/mL of lornoxicam was 1.9%. The proposed method was successfully applied for the assay of lornoxicam in pharmaceuticals,
human serum and urine with excellent recovery. The possible mechanism of CL reaction was also discussed briefly. 相似文献
12.
Marcolan M Martins PA Pedrosa VA Rodrigues MR de Oliveira HP Codognoto L 《Journal of fluorescence》2011,21(2):733-738
A simple, rapid and effective analytical method based on fluorescence spectroscopy for the determination of coumarin in pharmaceutical
formulations without pre-treatment or pre-concentration step was development. Coumarin had maximum excitation and emission
at 310 nm and 390 nm, respectively. Optimum conditions for the detection of coumarin were investigated. Under optimized conditions,
we observed a linear behavior for the sign of coumarin in the concentration range of 2.5 × 10−6 to 1.0 × 10−4 mol L−1, with linearity of 0.998 and sensitivity of 2.9 × 1010 u.a/mol L−1. The proposed method was validated in terms of accuracy, precision and specificity of coumarin using the standard addition
and external calibration. It was noted that the results support (P < 0.05), indicating that the matrices were not an interference in the determination of coumarin by fluorescence spectroscopy.
The results were favorable compared with those obtained by reference chromatographic methods. 相似文献
13.
A simple, sensitive and accurate method has been developed for spectrofluorimetric determination of cefixime in pure form
and pharmaceutical preparations. The method is based on the reaction of cefixime with 2-cyanoacetamide in the presence of
21% ammonia at 100 °C. The fluorescent reaction product showed maximum fluorescence intensity at λ 378 nm after excitation
at λ 330 nm. The factors affecting the derivatization reaction were carefully studied and optimized. The fluorescence intensity
versus concentration plot was rectilinear over the range of 0.02 to 4 μg mL−1 with correlation coefficient of 0.99036. The limit of detection (LOD) and limit of quantification (LOQ) was found to be 2.95 ng mL−1 and 9.84 ng mL−1, respectively. The proposed method was validated statistically and through recovery studies. The method was successfully
applied for the determination of cefixime in pure and dosage form with percent recoveries from 98.117% to 100.38%. The results
obtained from the proposed method have been compared with the official HPLC method and good agreement was found between them. 相似文献
14.
A new spectrofluorimetric method has been developed and validated for the quantification of ceftriaxone in bulk powder, pharmaceutical
formulations and spiked human plasma. The developed method is reproducible, accurate, sensitive and cost effective. In this
method, ceftriaxone was converted into a fluorescent compound by reacting with 0.8 M ethyl acetoacetate and 25% formaldehyde
in a buffered medium (pH = 4.2) at 90 °C. The excitation and emission wavelengths of the fluorescent reaction product are
316 nm and 388 nm respectively. Optimization of the experimental conditions affecting the condensation reaction were carefully
carried out and the optimum experimental conditions were incorporated in the procedure. The developed method has a broad linear
range (0.2–20 μg mL−1) with a correlation coefficient of 0.9992. The limit of detection (LOD) and limit of quantification (LOQ) was found to be
1.94 × 10−2 μg mL−1 and 6.47 × 10−2 μg mL−1 respectively. The common excipients and co-administered drugs were investigated for their interferences effect in the assay.
The developed method was validated statistically through recovery studies and successfully applied to ceftriaxone determination
in bulk powder, pharmaceutical formulations and spiked human plasma samples. The percent recoveries were found to be in the
range of 99.04–100.26% for bulk powder, 98.88–99.92% for pharmaceutical formulations and 94.22–98.48% for spiked human plasma.
The results were verified by comparing with reference literature HPLC method and were found in good agreement. 相似文献
15.
Plasticized polymer electrolytes composed of poly(methyl methacrylate) (PMMA) as the host polymer and lithium bis(trifluoromethanesulfonyl)imide
LiN(CF3SO2)2 as a salt were prepared by solution casting technique at different ratios. The ionic conductivity varied slightly and exhibited
a maximum value of 3.65 × 10−5 S cm−1 at 85% PMMA and 15% LiN(CF3SO2)2. The complexation effect of salt was investigated using FTIR. It showed some simple overlapping and shift in peaks between
PMMA and LiN(CF3SO2)2 salt in the polymer electrolyte. Ethylene carbonate (EC) and propylene carbonate (PC) were added to the PMMA–LiN(CF3SO2)2 polymer electrolyte as plasticizer to enhance the conductivity. The highest conductivities obtained were 1.28 × 10−4 S cm−1 and 2.00 × 10−4 S cm−1 for EC and PC mixture system, respectively. In addition, to improve the handling of films, 1% to 5% fumed silica was added
to the PMMA–LiN(CF3SO2)2–EC–PC solid polymer electrolyte which showed a maximum value at 6.11 × 10−5 S cm−1 for 2% SiO2. 相似文献
16.
Jeon CW Khan MA Lee SH Karim MM Lee HK Suh YS Alam SM Chung HY 《Journal of fluorescence》2008,18(5):843-851
A simple and selective method to determine norfloxacin using an optical flow-through sensor has been developed. The present
sensor was prepared by packing anionic ion exchange resin in a glass tube, followed by introducing KMnO4 solution to the glass tube for immobilization on resin. The optical sensor is based on the emission intensity from the Tb(III)
solution sensitized by norfloxacin. The excitation of norfloxacin occurred by the chemiluminescence from the reaction of KMnO4 and Na2SO4 solutions. The effects of pH, concentration of Tb(III) ion, KMnO4 and Na2SO4 solutions and flow rate of the norfloxacin solution on the chemiluminescence intensity were studied to find the optimum experimental
conditions. The emission intensity increased linearly with increasing norfloxacin concentration from 1.0 × 10−3 to 1.0 × 10−8 M and the detection limit (3σ) was 8.7 × 10−9. The applicability of the present method was demonstrated by determination of norfloxacin in various pharmaceutical preparations
and serum sample. 相似文献
17.
The effect of temperature on the spectral luminescence characteristics of PbWO4:Tb3+ crystals with synchrotron and laser excitation is studied. If PbWO4:Tb3+ is excited by synchrotron radiation with λ = 88 nm at 300 K, a faint recombination luminescence of the impurity terbium is
observed against the matrix luminescence. When the temperature is reduced to 8 K, the luminescence intensity of PbWO4:Tb3+ increases by roughly an order of magnitude and the characteristic luminescence of the unactivated crystal is observed. Excitation
of PbWO4:Tb3+ by a nitrogen laser at 300 K leads to the appearance of emission from Tb3+ ions. At 90 K, a faint matrix luminescence is observed in addition to the activator emission. The formation of the luminescence
excitation spectra for wavelengths of 60–320 nm is analyzed and the nature of the emission bands is discussed. 相似文献
18.
A fluorimetric method based on fluorescence enhancement effect was developed for the determination of adenosine 5′-monophosphate
(AMP) with 9-anthracene carboxylic acid (9-ANCA)–cetyl trimethyl ammonium bromide (CTAB) system. Fluorescence intensity of
9-ANCA was decreased by the addition of CTAB but addition of AMP again rose the intensity of 9-ANCA gradually. The observed
fluorescence enhancement is attributed to the competitive binding reaction of 9-ANCA and adenosine to CTAB. The enhancement
in the fluorescence intensity was found proportional to the concentration of AMP over the range 2.0 × 10−4 to 1.2 × 10−3 mol dm−3. The ion pair complex is formed spontaneously between 9-ANCA and CTAB. Since the binding interaction is larger for the adenosine–CTAB
pair, the fluorophore 9-ANCA will be released. The quantum yield of free 9-ANCA is higher therefore its fluorescence observed
at 417 nm wavelength is enhanced. This mechanism of competitive molecular interaction is further confirmed by conductometric
measurements. The method was applied successfully for the determination of AMP from pharmaceutical sample. The method is more
selective, sensitive and relatively free from interferences. 相似文献
19.
20.
Water-soluble Mn2+-doped ZnS quantum dots (QDs) were prepared using mercaptoacetic acid as the stabilizer. The optical properties and structure
features were characterized by X-Ray, absorption spectrum, IR spectrum and fluorescence spectrum. In pH 7.8 Tris-HCl buffer,
the QDs emitted strong fluorescence peaked at 590 nm with excitation wavelength at 300 nm. The presence of sulfide anion resulted
in the quenching of fluorescence and the intensity decrease was proportional to the S2− concentration. The linear range was from 2.5 × 10−6 to 3.8 × 10−5 mol L−1 with detection limit as 1.5 × 10−7 mol L−1. Most anions such as F−, Cl−, Br−, I−, CH3CO2
−, ClO4
−, CO3
2−, NO2
−, NO3
−, S2O3
2−, SO3
2− and SO4
2− did not interfere with the determination. Thus a highly selective assay was proposed and applied to the determination of
S2− in discharged water with the recovery of ca. 103%. 相似文献