Simultaneous determination of paracetamol and tramadol in pharmaceutical tablets by derivative UV-Vis absorption spectrophotometry

A comparative study of the use of first derivative zero order crossing spectra for the resolution of Paracetamol and Tramadol hydrochloride in mixtures has been achieved showing the success of the first derivative method in resolving and quantifying both compounds. Using the first derivative, rather than the second derivative, results in improved signal to noise ratio. The absorption spectra of prepared mixtures were scanned in the range of 200-500 nm. The linear concentration ranges were 25-112 and 6-48 µg mL-1 for paracetamol and Tramadol hydrochloride, respectively. The method has been successfully used for prediction of concentrations of both compounds in mixtures with good selectivity, high sensitivity and extremely low relative error. Statistical comparison was performed using t-test at 95% confidence level. There was no significant statistical difference between the results obtained by the first derivative method and the accepted values for both compounds. Also, the percentage errors were very low which adds to the merits of our work in terms of both sensitivity and accuracy

Synthesis and Applications of a New Polysiloxane-Immobilized Macrocyclic Ligand System

Insoluble porous solid, macrocyclic 22-membered ring, 1-oxa-6,9,12,15,18-pentaaza-2,22-disilacyclododocosane polysiloxane ligand system has been prepared by the reaction of a macro-silane agent with tetraethylorthosilicate. The macro-silane agent was prepared by the reaction of imino-bis(N-2-aminoethylacetamide) ligand with 3-iodopropyltrimethoxysilane in 1:3 molar ratio. The new prepared polysiloxane system exhibits variable potentials for the extraction of metal ions (Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Ag+, Cd2+, Hg2+, and Pb2+) from aqueous solutions. The ligand system shows high capacity to extract silver, lead, and mercury. Chemisorption of the metal ions by the ligand system at the optimum conditions was found in the order Ag + > Pb2+ > Hg2+ > Cu2+ > Ni2+ > Fe3+ > Co2+ > Cd2+ > Zn2+

Dye-sensitized solar cells using dyes extracted from flowers, leaves, parks, and roots of three trees

In this paper, eleven natural dyes were collected from three trees and used as photosensitizers for dye sensitized solar cells (DSSCs). The cells were fabricated using TiO2 as a semiconducting layer deposited on transparent fluorine doped tin oxide (FTO) conductive glass using doctor blade method. The absorption spectra of the extracts were performed in the spectral range from 400 nm to 750 nm. The JV characteristic curves of all fabricated cells were measured and analyzed. The parameters related to the solar cell performance were determined. Moreover, the impedance spectroscopy of the cell with the best performance was investigated

Electrical properties of organic light emitting diodes with post fabrication heat and electric field treatments

The current work presents post-fabrication heat treatment and a combined external electric field-heat post-fabrication treatments for organic light emitting diodes (OLEDs). The devices were fabricated in the same run with a standard device without annealing for comparison, with an identical structure of ITO/PVK/Rhodamine B/Pb. After depositing the Rhodamine B layer on the PVK film, the samples were thermally annealed at different temperatures before depositing Pb. Some of the samples were thermally annealed without any external electric field while others were treated by an external electric field during heating. It is found that the annealing temperature of PVK/Rhodamine B layers increases the turn-on voltage of the device. On the other hand, in the electric field-heat treatment, the turn-on voltage is observed to decrease and the maximum current density of the device is dramatically enhanced

ELECTROLUMINESCENCE FROM A SINGLE LAYER OF POLY(N-VINYLCARBAZOLE) DOPED WITH A NEW 1,2,4-TRIAZOLE DERIVATIVE

We report light emission from a single layer thin film device. This device is comprised of a hole transporting polymer, poly(N-vinylcarbazole) (PVK) doped with a new luminescent 1,2,4-triazole derivative sandwiched between an indium tin oxide electrode (ITO) and an aluminum electrode. We have studied the current versus voltage (I-V) characteristics, the electroluminescence versus voltage (EL-V) characteristics, and the lifetime of the device. Thinner samples revealed a lower EL threshold voltage VT compared with the conventional organic light emitting diodes (OLEDs) reported in the literature. This VT increased with increasing the sample thickness

Thermoelectricity Based on Cuo as a Semiconducting Material

In this paper, thermoelectricity based on copper(II) oxide CuO as semiconducting material is explored. The electrical properties of the samples were studied under different temperature gradients and pressures. Moreover, the effect of baking temperature was also investigated. CuO prepared using decomposition of Cu(NO3)2 as well as CuO nanopowder prepared using microwave-assisted synthesis technique were investigated and their results were compared. It was found that the current density can be enhanced with increasing the pressing pressure of the sample and when the sample undergoes a baking process. Moreover, it was found that the current density can be considerably enhanced with increasing the temperature gradient between the two ends of the sample. The CuO prepared using microwave-assisted synthesis technique was found to exhibit much better results over those of the CuO prepared using decomposition of Cu(NO3)2

New Efficient Organic Compounds In Dye-Sensitized Solar Cells

We demonstrate the use of three new organic photosensitizer compounds in dye sensitized solar cells (DSSCs). One of these compounds is a diazapentadiene derivative [1], while the other two compounds are triazole derivatives [1]. The construction of the cell involved use of a commercially available indium tin oxide (ITO) conductive electrode on which a thin layer of TiO2 was deposited by chemical vapor deposition (CVD). The other electrode was composed of a thin graphitic layer on ITO. A gelled iodine/iodide combination was used as the redox system. We have studied the current versus voltage (IV) characteristics and the power versus voltage of these DSSCs at a relatively low light intensity. The efficiency and the fill factor for each cell were consequently calculated

A SIMPLE METHOD FOR DETERMINATION AND CHARACTERIZATION OF IMIDAZOLINONE HERBICIDE (IMAZAPYR/IMAZAPIC) RESIDUES IN CLEARFIELD® RICE SOIL

A study was conducted to evaluate residues of imidazolinone (IMI) in soil. Samples were taken from three Clearfield® rice fields as IMI which have been used for six years. IMI herbicides (imazapic/imazapyr) were widely used in Clearfield® rice soils. To date, few studies are available on the residues of these herbicides, especially in the context of Malaysian soil. Therefore, for this purpose, high performance liquid chromatography (HPLC) with UV detection was performed using a Zorbax stable bond C18 (4.6× 250 mm, 5 µm) column, with two mobile phases. The average percentage recovery for imazapyr and imazapic varied from 76%-107% and 71-77%, with 0.1-5 µg/ml fortification level, respectively. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 1.05 and 4.09 for imazapic and 0.171 and 0.511 µg/ml for imazapyr respectively, in the top 15 cm. In the extracted soil sample, it was 0.19 µg/ml for imazapic and 0.04 µg/ml for imazapyr, respectively. Based on this study, a pre-harvest period of 40-60 day is suggested for rice crops after IMI application

Dyes Extracted from Safflower, Medicago Sativa, and Ros Marinus Oficinalis as Photosensitizers for Dye-sensitized Solar Cells

In this work, three extracts of plant leaves were used as sensitizers for dye-sensitized solar cells (DSSCs). These plants are Safflower, Medicago sativa and Ros marinus oficinalis. The natural dyes were extracted before and after grinding the plant leaves. The UV-VIS absorption spectra of the three extracts in ethyl alcohol solution were measured. The DSSCs were assembled using TiO2 films on Fluorine-doped tin oxide (FTO) coated glass. The DSSCs sensitized with the extracts of grinded leaves showed a better performance compared to those sensitized with un-grinded leaves with the highest efficiency of 0.115 % was obtained for the DSSC sensitized with Medicago sativa. The performance of the DSSCs sensitized with Safflower and Ros marinus oficinalis was significantly improved by acid treatment of the FTO substrates. Impedance spectroscopy of the fabricated cells was also carried out

Aldimine derivatives as photosensitizers for dye-sensitized solar cells

Five aldimine derivatives were prepared by condensation of the appropriate amine with salicylaldehyde (m1-m4) and 4-aminobenzoic acid with 2-thiophene carboxaldehyde (m5). A molar ratio of 1: 1 was used and the mixture was refluxed in ethanol for 2 h to obtain the corresponding aldimine derivative. These derivatives were used as photosensitizers for dye-sensitized solar cells (DSSCs). The best performance was obtained for the DSSC sensitized with 2-(2-hydroxybenzylideneamino) benzoic acid, for which a short-circuit current of 2.86 mA/cm^ 2, an open-circuit voltage of 0.562 V, and an efficiency of 0.575% were obtained.Five aldimine derivatives were prepared by condensation of the appropriate amine with salicylaldehyde (m1-m4) and 4-aminobenzoic acid with 2-thiophene carboxaldehyde (m5). A molar ratio of 1: 1 was used and the mixture was refluxed in ethanol for 2 h to obtain the corresponding aldimine derivative. These derivatives were used as photosensitizers for dye-sensitized solar cells (DSSCs). The best performance was obtained for the DSSC sensitized with 2-(2-hydroxybenzylideneamino) benzoic acid, for which a short-circuit current of 2.86 mA/cm^ 2, an open-circuit voltage of 0.562 V, and an efficiency of 0.575% were obtained