The extraction of Ni2+ and Pb2+ ions from aqueous medium using unmodified (ROSE) and the 4-aminophenol modified red onion skin extract (ROSEDS) has been successfully achieved. Cold solvent extraction technique using a 50:50 acetone/water ratio was used for extraction of the red onion skin at 125 µm mesh size. The metal concentrations were determined using Atomic Absorption Spectrometry technique. Optimum percentage removal of the metal ions was achieved at pH 6.26 for Ni2+ (89.40 % for ROSE and 97.60 % for ROSEDS) and pH 7.57 for Pb2+ (80.10 % for ROSE and 82.56 % for ROSEDS). Optimum adsorption capacities of ROSE and ROSEDS for Ni2+ were 6.30 mg/g and 7.10 mg/g respectively; while for Pb2+ ions, values obtained for ROSE and ROSEDS were 5.87 mg/g and 6.34 mg/g respectively. Varying adsorbents dosage at fixed metals ion concentration yielded optimum percentage removal of 89.90 % and 97.90 % for Ni2+, while 86.85 % and 90.80 % for Pb2+, using ROSE and ROSEDS, respectively. Adsorption capacities of the adsorbents varied inversely with adsorbent dosages. In general, 4-aminophenol modified red onion skin extract (ROSEDS) gave comparatively, better results for the extraction of Ni2+ and Pb2+ ions from aqueous medium; relative to the unmodified red onion skin extract (ROSE). Additionally, extraction of Ni2+ ions gave higher percentage removal values in both adsorbents when compared to extraction of Pb2+ ion under similar conditions. This result has been attributed to differences in their ionic radii.

Functional polymers has great importance in the field of electrochemical sensing and biosensors due to adaptable chemical, electrical, and structural features, functional polymers are a significant class of materials that have been extensively used to create electrochemical biosensors. Additionally, conducting polymers can be made nanostructured, functional group-grafted chemically, or combined with other functional materials, like nanoparticles, to significantly enhance the sensitivity, selectivity, stability, and reproducibility of the biosensor's response to a variety of bioanalytes. Since these biosensors offer benefits such being affordable and having a low detection limit, they are anticipated to play an increasingly important role in providing diagnostic information and monitoring therapy. Because of this, this article begins with a description of the electroanalytical techniques (amperometry, potentiometry, conductometry, impedometry, voltammetry) used in electrochemical biosensors, and then moves on to a review of recent developments in the use of conducting polymers in the identification of bioanalytes that led to the development of enzyme-based biosensors, immunosensors, DNA biosensors, and whole-cell biosensors.

The New ligand 5-methyl-2-(2-thienyl)-1,3-oxazole-4-carbaldehyde thiosemicarbazone (HL)(1) was synthesized. This ligand reacted with Co(II) and Ni(II) chloride in ratio 1:2 metal:ligand afforded two complexes, [Co(LH)]Cl2 (2) and [Ni(HL)2]Cl2 (3). The ligand and its metal (II) complexes have been characterized by spectroscopic techniques. The X-ray structural studies revealed that the free ligand exist in thione form and remain as neutral tridentate with NNS donor atoms in the tow complexes beside presence of uncoordinated chloride ions in the cavities of the crystal lattice of the complexes. One of these chlorides in complex (2) is hydrogen bonded to a proton of the amine of the ligand. While in complex (3) the chloride bonded to proton of imine (-N2H) of the ligand and the coordination environment has a distorted octahedral. The oxazole N and S atoms in the two complexes are cis to each other whereas the azomethine N atoms are trans coordinated. The ligand and its metal complexes were tested for their in vitro biological activity against six standard microorganisms: two Gram positive namely Bacillus subtilis and Micrococcus luteus, and one Gram negative bacteria Escherichia coli and three fungi: Saccharomyces cerevisiae (Baker’s yeast), Mucor spec., and Aspergillus niger, at a concentration 100µg/ml.

Tricyclic terpanes identified in two representative crude oils from the Central and Western Niger Delta (oil- RVAG and oil-DTIR, respectively) ranged from C19 to C29, including C24 tetracyclic terpane. Plot of the abundances of tricyclic terpanes show similarity in the distribution profile of the oil samples, characterized by the uncommon distribution of C20 and C21 tricyclic terpanes indicating both Niger Delta crude oils are derived from similar source organic matter. Ratios of C22/C21 and C24/C23 tricyclic terpanes indicate source rocks of the crude oil samples were deposited in a deltaic environment and derived from mixed marine/terrestrial organic matter. Additional, C26/C25 tricyclic terpanes, C24 tetracyclic/C23 tricyclic terpanes and C24 tetracyclic/C26 tricyclic terpanes indicate the crude oil samples are generated from shale source rocks derived from terrestrial organic matter, with oil-DTIR receiving a more terrestrial contribution, and marine facies, with oil-RVAG receiving a more marine contribution. Thermal maturity, determined from ratios of low to high molecular weight tricyclic terpanes, indicate the crude oil samples are mature with oil-RVAG more mature than oil-DTIR. The ratios of C19/C23 and C20/C23 tricyclic terpanes, which indicate high maturity of the crude oils, suggested terrestrial and marine source for oil-RVAG and oil-DTIR, respectively, contrasting with the relative abundances of tricyclic and tetracyclic terpanes. This implies the abundances of C19 and C20 tricyclic terpanes, particularly in crude oils at high maturity, as in the Niger Delta, has interfering effect on source interpretation and its ratios be used in combination with other parameters for evaluating Niger Delta crude oils.

In this study an effective method was developed to assay Bisoprolol fumarate in tablets dosage form. The chromatographic separation was achieved on Reprosil pure basic C18 analytical column. A mixture of acetonitrile + Potassium dihydrogen phosphate buffer (0.050 mol L-1) (30:70 V/V), pH 3.5 was used as the mobile phase, effluent flow rate monitored at 1.0 mL/min, and UV detection at 233 nm. In forced degradation studies, the effects of acid, base, oxidation, UV light and temperature which were investigated showed no interference in the peak of drug. The proposed method was validated in terms of specificity, linearity, robustness, precision and accuracy. The method was linear at concentrations ranging from 5µg/mL to 17.5µmg/mL, precise (intra- and inter-day relative standard deviations R.S.D. < 2 %), (r2 = 0.9995).