Enhancement of on chip chemiluminescence signal intensity of tris(1,10-phenanthroline)-ruthenium(II) peroxydisulphate system for analysis of chlorpheniramine maleate in pharmaceutical formulations

The effect of detection chip geometry on chemiluminescence (CL) signal intensity of tris(1,10-phenanthroline)-ruthenium(II) peroxydisulphate system for analysis of chlorpheniramine maleate (CPM) in pharmaceutical formulations was investigated. It was observed that the design of the detection chip is very crucial and can play an important role in enhancing the CL signal intensity in this system. The CL signal intensity was enhanced 250% when a teardrop micromixer chip was used, compared to the commonly used serpentine chip geometry. The study was conducted using a multi-chip device. In this device, chip 1 was used to prepare and pump the reagent mixture, whereas chip 3 was used for pumping the sample. The two chips were connected to the teardrop chip (2) via silica capillary where detection took place. Non-linear regression curve fitting of the calibration data revealed that the calibration curves are best described by third order polynomial equation with excellent correlation coefficients (R² = 0.9998) for the concentration range 7.69 × 10⁻⁸ to 5.12 × 10⁻⁵ mol L⁻¹. A linear response is also observed over the range 7.69 × 10⁻⁸ to 1.28 × 10⁻⁵ mol L⁻¹ (R² = 0.9996) and the detection limit was found to be 5.49 × 10⁻⁸ mol L⁻¹. The device was successfully used for the analysis of CPM in tablets and a multi-component cough syrup. Results were reproducible with relative standard deviation (RSD) of 0.6-1.1%.     

Terbium Sensitized Luminescence for the Determination of Ketoprofen in Pharmaceutical Formulations

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.     

Study of the 133Ba nucleus with the ( \vec d , p) reaction

Excited states in ¹³³Ba were studied with the ¹³²Ba ( $ \vec d $ , p) ¹³³Ba reaction at 24.0MeV, with a polarized deuteron beam using the Munich magnetic spectrograph Q3D. Many unambiguous spin-parity assignments were made up to an excitation energy of 2.2MeV, which allow a detailed comparison with different theoretical calculations, such as the interacting boson-fermion model and the shell model.     

A sequential injection method for the determination of Tween-80 in natural water samples using a fluorescence enhancement of the dye Eosin-B.

A simple sequential injection (SI) method is reported for the determination of the non-ionic surfactant polyoxyethylene sorbitan monoleate (Tween-80). The proposed method is based on a fluorescence enhancement of the probe 4',5'-dibromo-2',7'-dinitro fluorescein, disodium salt (Eosin B) in the presence of a surfactant. The procedure is optimized using the univariate method of optimization. The optimum operating conditions are as follows: reagent concentration, 40 ppm; pH, 4.5; aspirated volumes of sample and reagent, 120 microL and 100 microL, respectively. With the optimum conditions described, linear calibration curves were obtained from 10-200 ppm. The detection limit was 1.7 ppm and the maximum relative standard deviation of the method was 2.7% (n = 5). The fluorescence excitation and emission were fixed at lambda(ex) = 545 mn and lambda(em) = 585 nm. The method was successfully applied to the determination of (TW-80) in natural water samples.     

Radiation Polymerization of 4-(Acryloylamido)benzonitrile: Zinc and Copper Complexes

The new polymer containing cyano groups was synthesized by γ-irradiation. The oximated polymer was prepared using hydroxylamine hydrochloride in basic medium. The characterization of monomer, polymer, and oximated ones was confirmed by infrared and nuclear magnetic resonance spectroscopy. The complex formation of the amidoxime salt towards Zn^II, Cu^II, and Zn^II/Cu^II mixture in aqueous solution was studied by atomic absorption spectroscopy, energy dispersive spectroscopy, and electron spin resonance spectrometry. The significant binding capacity of these metal ions revealed its selectivity to Zinc(II) ion. The thermal stability of polymers and complexed ones was investigated using thermogravimetry analysis. The change in their morphology was observed by scanning electron microscopy (SEM).     

A sequential injection method for the determination of piroxicam in pharmaceutical formulations using europium sensitized fluorescence

A simple, selective and sensitive luminescence method for the assay of piroxicam (PX) in pharmaceutical formulation is developed. The method is based on the luminescence sensitization of europium (Eu³⁺) by complexation with PX. The signal for PX–EU is monitored at λ_ex=358 nm and λ_em=615 nm. Optimum conditions for the formation of the complex in methanol were 0.01 M TRIS buffer and 0.2 mM of Eu³⁺ which allows the determination of 100–2000 ppb of pX in batch method and 100–1000 ppb with limit of detection (LOD) = 23.0 ppb using sequential injection analysis (SIA). The relative standard deviations of the method range between 2 and 3% indicating excellent reproducibility of the method. The proposed method was successfully applied for he assay of PX in pharmaceutical formulations (Feldene capsules and tablets). Average recoveries of 101.0±0.3 and 98.8±2.7% were obtained for capsules in methanol using batch and sequential injection (SI) methods, respectively.