First-derivative Synchronous Spectrofluorimetry Research Articles

Novel Method for Determination of Anthracene by Coupling Dispersive Liquid-Liquid Extraction to First-Derivative Synchronous Spectrofluorimetry

A novel method could be adopted successfully for determination of anthracene in environmental samples, utilizing dispersive liquid-liquid extraction followed by first-derivative synchronous fluorimetry at a constant wavelength difference Δλ = 165 nm, where a linear calibration curve was obtained in a concentration range of 0.5-100 ng mL(-1) at 244 nm. The detection limit was 0.1 ng mL(-1). The method can be easily adopted for determination of anthracene in aqueous media including tap water and river water. The recoveries obtained were 85.40-108.02%. The proposed method was validated according to International Conference of Harmonization (ICH) guide lines and successfully applied to determine anthracene in pure form and in water samples including real life water samples from different sources. All the results obtained were compared with those of published method, where no a significant difference was observed.

Simultaneous Determination of Lomefloxacin and Ciprofloxacin in Dairy Products by First-Derivative Synchronous Spectrofluorimetry

A simple, sensitive and quick assay to simultaneously determine lomefloxacin (LFLX) and ciprofloxacin (CPLX) had been developed by using zero-crossing first derivative constant wavelength synchronous spectrofluorimetry. Due to their similar molecule structures, it was difficult to analysis and determine LFLX and CPLX simultaneously by conventional fluorometry. In order to improve the sensitivity, aluminium ion was used to significantly enhance their endogenous fluorescent intensity. The different experimental parameters affecting the synchronous fluorescence intensity of the two fluoroquinolone drugs were carefully studied and optimized. The proposed method was successfully applied for the determination of the two drugs in milk samples.

Simultaneous Determination of Labetalol and Furosemide by First-Derivative Synchronous Spectrofluorimetry

A rapid, simple and highly sensitive first derivative synchronous spectrofluorimetric method was developed for the simultaneous analysis of a binary mixture of labetalol HCl (LBT) and furosemide (FUR) without prior separation. The method was based upon measuring the first derivative of synchronous fluorescence spectra of the two drugs at Deltalambda = 130 nm in aqueous ethanol (55% V/V). The different experimental parameters affecting the synchronous fluorescence of the studied drugs were carefully studied and optimized. The first derivative amplitude-concentration plots were rectilinear over the range of 0.10 to 1.00 microg/mL and 0.05-0.50 microg/mL with lower detection limits of 0.0149 and 7 x 10(-3) microg/mL and quantification limits of 0.045 and 0.021 microg/mL for LBT and FUR, respectively. The proposed method was successfully applied for the determination of the studied drugs in synthetic mixtures. The results obtained were in good agreement with those obtained by the reference methods.

Determination of boldine in drug formulations by first-derivative synchronous spectrofluorimetry

A simple and sensitive method is proposed for the determination of boldine by first-derivative synchronous spectrofluorimetry based on its native fluorescence in 0.1 N sulphuric acid. The constant wavelength difference ( Δλ = λ cm - λ c chosen to optimize the determination is 90 nm. The linear concentration range of application is between 2.0 and 50.0 wg I- −1 of boldine. the detection limit 0.4 wg l −1 and the relative standard deviation at a concentration of 25 μg l −1 was 2.19%. The method has been satisfactorily applied to the determination of boldine in pharmaceutical formulations.

Simultaneous determination of carbaryl and azinphos-methyl in water by first-derivative synchronous spectrofluorimetry

A method is proposed for the simultaneous determination of the pesticides carbaryl (CBL) and azinphos-methyl (AZM) in water by first-derivative synchronous spectrofluorimetry. It is based on the alkaline hydrolysis of both pesticides to their metabolites 1-naphthol (from CBL) and anthranilic acid (from AZM). The constant wavelength difference chosen to optimize the determination is Δλ=λem−λex=103 nm. CBL is measured at 302/405 nm and AZM at 333/436 nm. The calibration graphs are linear between 2.0 and 500.0 ng/ml for CBL and between 1.2 and 500.0 ng/ml for AZM with detection limits of 0.62 ng/ml and 0.35 ng/ml, respectively. The precision of the method (RSD) is 2.4% at the 80.0 ng/ml level for CBL and 2.5% at the 80.0 ng/ml level for AZM. The method is applied to the determination of both analytes in samples of natural waters.

Simultaneous determination of carbaryl and o-phenylphenol residues in waters by first-derivative synchronous solid-phase spectrofluorimetry

A spectrofluorimetric method for the simultaneous determination of carbaryl (CBL) and o-phenylphenol (OPP) residue mixtures in waters has been developed. Carbaryl was hydrolysed in alkaline medium to give 1-naphthol. This compound and o-phenylphenol were fixed on QAE Sephadex A-25 gel at pH 10.75. The fluorescence of the gel, packed in a 1-mm silica cell, was measured directly with a solid-surface attachment. Overlapping of conventional fluorescence spectra is resolved by using first-derivative synchronous spectrofluorimetry and allows for the complete resolution of the mixture. The range of application is between 0.4 and 25.0 ng/ml for OPP and 0.8 and 25.0 ng/ml for CBL. The detection limits for o-phenylphenol and carbaryl were 0.1 and 0.2 ng/ml, respectively. The accuracy and precision of the method are reported. The method is suitable for determination of carbaryl and o-phenylphenol residues in natural waters. Recoveries from 95 to 105% have been obtained for natural waters spiked with CBL and OPP.

Simultaneous determination of yohimbine and boldine by first-derivative synchronous spectrofluorimetry

A method for the simultaneous determination of yohimbine and boldine in mixtures by first-derivative synchronous spectrofluorimetry has been developed. The method is based on their native fluorescence in 0.1N sulphuric acid medium. The constant wavelength difference chosen to optimize the determination was Δλ=λem -λem=82 nm. Yohimbine was measured at λex//λem= 285/367 nm, and boldine at λex/λem=272/354 nm. The range of application is 10–500 μg/l for yohimbine and 1–50 μg/l for boldine. The method was applied to the determination of yohimbine and boldine in synthetic mixtures and pharmaceuticals, with errors generally ⩽2%. Relative standard deviations were about 2%.

Simultaneous determination of propranolol and hydralazine by derivative synchronous spectrofluorimetry

First-derivative synchronous spectrofluorimetry was applied to the simultaneous resolution of propranolol and hydralazine in pharmaceutical preparations. Chemical and instrumental parameters were optimized for the determination of mixtures of these drugs. The analysis is performed by measuring the first-derivative synchronous spectra at certain selected pairs of excitation and emission wavelengths where the responses exhibit no contribution to each other. The optimization of the synchronous scanning path was accomplished by analysis of the three-dimensional excitation-emission matrices.

Determination of boron with chromotropic acid by first-derivative synchronous spectrofluorimetry

A method for the determination of traces of boron by first-derivative synchronous spectrofluorimetry is proposed. It is based on the formation of a fluorescent complex with chromotropic acid at pH 6.7. The constant wavelength difference chosen to optimize the determination is Δλ=λem−λex=24 nm. The range of application is between 2.0 and 20.0 μ/l of boron, the detection limit 0.4 μg/l and the relative standard deviation 3.2%. A study was made of the influence of several ions as potential interferents. The method has been satisfactorily applied to the determination of boron in plants, fertilizers and natural waters.

Analysis of mixtures of oxytetracycline and riboflavine by first-derivative synchronous spectrofluorimetry

The simultaneous determination of oxytetracycline and riboflavine in mixtures by first-derivative synchronous spectrofluorimetry is described. The proposed method is based on the formation of a fluorescent complex between aluminium and oxytetracycline, and on the native fluorescence of riboflavine. The constant wavelength difference between the excitation and emission wavelengths in a synchronous scan has been optimized by analysing the multi-dimensional information obtained on the excitation–emission matrices. The combination of synchronous scanning spectrofluorimetry and differentiation of the spectra allows for the complete resolution of the mixture. The method has been applied to the determination of these drugs in pharmaceutical preparations.

Simultaneous determination of molybdenum and tungsten by first-derivative synchronous spectrofluorimetry

A method for the simultaneous determination of molybdenum and tungsten in mixtures by first-derivative synchronous spectrofluorimetry is described. The method is based on the formation of fluorescent complexes with carminic acid at pH 5.1. The constant wavelength difference chosen to optimise the determination was Δλ=λem.-λex.= 50 nm. Molybdenum was measured at λex./λem.= 550/600 nm and tungsten at λex./λem.= 561/611 nm. The range of application is between 1 and 12 µM molybdenum and between 1 and 6 µM tungsten. The accuracy and precision of the method are reported.

A simple and rapid fluorometric method for the estimation of 1-(2-hydroxy-3-isopropylamino-propoxy)-naphthalene hydrochloride, propranolol, in blood

First-derivative synchronous spectrofluorimetry was applied to the simultaneous resolution of propranolol and hydralazine in pharmaceutical preparations. Chemical and instrumental parameters were optimized for the determination of mixtures of these drugs. The analysis is performed by measuring the first-derivative synchronous spectra at certain selected pairs of excitation and emission wavelengths where the responses exhibit no contribution to each other. The optimization of the synchronous scanning path was accomplished by analysis of the three-dimensional excitation-emission matrices.