Asian Journal of Applied Chemistry Research

Swampy agricultural soils could be contaminated as a result of accumulation of heavy metals through emission from industrial areas, mines tailings, metal wastes, gasoline, paints, fertilizers, manure, sewage sludge, pesticide, waste water irrigation, coal combustion residue, spillage of petrochemicals and atmospheric deposition. This study aimed at evaluating the carcinogenic and non-carcinogenic risk of the study area using X-Ray fluoroscopy. The results shows that, mean concentration level in the area was in decreasing order Ni(525) > Cu(515.9) > Zn(367.6) > Cr(336.6) > Cd(260.9) > Pb(219.5) > As(18.9). The Hazard Quotient (HQ) was all recorded to be low except ingestion adult which is higher than unity. The Hazard Index (HI) was also recorded to be 2.3 a value greater than one (>>1). This makes non-carcinogenic effects significant to the population and poses serious effects in the area under study. The total excess life cancer risk were found to be (5.0 x 10^-2), a value greater than that of U.S (1.0x10^-4 to 1.0x10^-6) and above that of South Africa (5.0x10^-6). This implies that there is a probability that one person in 1,000 may be affected. Regular monitoring and evaluation of the soils and the crops cultivated at the sample locations is recommended.

Aims: Two spectrophotometric methods were developed and validated for the determination of sofosbuvir in presence of its alkaline degradate.

Study Design: Ratio difference and ratio derivative methods were assisted for determination of sofosbuvir in presence of its alkaline degradate, laboratory-prepared mixtures and in tablet dosage forms.

Place and Duration of Study: Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy (Girls), Al - Azhar University, between December 2019 and January 2020.

Methodology: Two analytical methods were achieved and validated for the quantitative determination of Sofosbuvir in presence of its alkaline degradate. The first method was ratio difference (RD) method, where the UV absorption spectra of different concentrations of sofosbuvir were divided by the spectrum of a certain concentration (15 µg mL^-1) as a devisor of its alkaline degradate to get the ratio difference spectra. Afterwards, the peak amplitudes difference between 253.7 and 243.5 nm were measured. The second method was the ratio derivative (¹DR) method, where the first derivative of the ratio spectra (¹DR) was obtained and its amplitude was measured at 247 and 268 nm. Good linearity was obtained over the concentration range of 3-15 µg mL^-1 for the proposed methods. The proposed procedures were adopted for the selective determination of intact Sofosbuvir in presence of up to 80% of its degradation product. Sofosbuvir was exposed to different conditions as alkaline, acidic and oxidative degradation.

Results: The proposed methods were developed and validated with good linearity range of 3-15 µg mL^-1 for both methods, and also with good accuracy and precision. And the obtained results were statistically compared to those obtained by the reported method.

Conclusion: Sofosbuvir was successfully determined by the proposed ratio difference and ratio derivative methods in bulk powder, laboratory prepared mixtures and tablet dosage form with good accuracy and precision. The methods were validated according to ICH guidelines. The results obtained were compared with those of the reported method and were found to be in good agreement.

Bread loaves and bread ingredients (wheat flours, salt, sugar, yeast and water) were randomly sampled from ten bakeries within Akure metropolis of south western Nigeria and analysed to determine their safety levels for human consumption with respect to trace metal contents. The trace metals (Cu, Zn, Mn, Cr, Cd and Pb) were analysed in the samples using flame atomic absorption spectrophotometer. Results obtained revealed that toxic trace metals such as Cr, Cd and Pb were not detected in any of the samples. However, the levels of essential trace metals such as Cu, Zn and Mn had range of values in mg/kg: (0.039 – 0.091), (0.837 – 3.310) and (0.035 – 3.148); (0.056 – 0.091), (0.034 – 2.755) and (0.054 – 1.054) in the wheat flours and bread samples analysed respectively. This study revealed that the bread ingredients and loaves of bread sampled contained essential trace metals at levels that could not threaten the health of consumers over prolonged regular consumption.

The corrosion inhibition characteristics of Chrysophyllum cainto cotyledon aqueous extract was studied for the corrosion of pipeline steel in 0.5 M HCl using gravimetric technique. The corrosion surface morphology and corrosion surface film were studied using Scanning electron microscope and Fourier transform infrared spectroscopy respectively. The results obtained showed Chrysophyllum cainto aqueous extract as a good corrosion inhibitors of pipeline steel corrosion in acidic environment, recording an average corrosion inhibition efficiency above 90% at 303 K. The Scanning electron micrograph showed a smoother corrosion surface morphology in the presence of the extract while the Fourier transform infrared spectroscopic data showed the corrosion inhibition mechanism to be through adsorption.

For the first time, this study aimed to determine the chemical composition and the antibacterial activity of Melaleuca quinquenervia leaf essential oils from Senegal. Ten samples of leaves from M. quinquenervia were collected on two Senegal localities. The essential oils were obtained by hydrodistillation and analyzed by GC/FID and GC/MS. The oil yields ofdried leaves ranged 1.65 to 3.74%. Oilsamples were dominated by 1,8-cineole (24.6-49.3%), viridiflorol (14.9-35.7%), a-terpineol (6.3-12.7%), a-pinene (5.0-11.5%) and limonene (3.7-7.3%). The antibacterial activity was evaluated using a paper disc diffusion method. The essential oil exhibited excellent activity against S. aureus, moderate activity against E. coli and E. faecalis and no activity against P. aeruginosa.

The study focused on the investigation of the effectiveness of the pericarp of monkey kola (Cola lepidota) biomass (CLPB) in the removal of toluene from aqueous system. X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM) and phytochemical screening methods were used for characterizing the biosorbent. The effects of contact time, pH, and concentration on biosorption process were studied.

The phytochemical screening showed the presence of alkaloids, flavonoids, tannins, carbohydrate, saponins and steroids. Carboxylic, alkene and alcohol groups were found to be the principal functional groups. The highest percentage removal was 99.63% at toluene initial concentration of 40 mg/L and 98.30% at pH 8. The contact time 30 minutes gave better removal efficiency of 99.89%. Among the biosorption isotherm models tested (Langmuir, Freundlich, Dubinin Radushkevich and Temkin, respectively), the Langmuir model equation gave a better fit of the equilibrium data with a correlation coefficient (R²) of 0.99. The equilibrium data was tested with pseudo-first order and pseudo-second order models and pseudo-second order model (R² = 0.99) fitted more than the pseudo-first order model (R² = 0.85). This study has revealed that Cola lepidota is a potential biosorbent for the removal of toluene from aqueous medium under the operating conditions of contact time of 30 minutes, pH of 8 and initial concentration of 40 mg/g.

Cetyltrimethylammonium bromide (CTAB) – modified and unmodified sodium bentonite were both used for the competitive adsorption of m-xylene and toluene from their aqueous solution. Infrared spectroscopy (IR) and expansion tests (adsorption capacity and Foster swelling) measurement were performed in order to evaluate the performance of the adsorbents. The FT-IR results indicated that the quaternary ammonium salts (CTAB) were intercalated between the layers of the sodium bentonite clay. The Foster swelling test results indicated that the affinity of CTAB was more in the treated clay for all other organic compounds tested. The result showed that modified sodium bentonite swelled more than the unmodified and the order of the swelling factor is; m- xylene > toluene > gasoline > diesel > kerosene > water. However, when the assay was performed under agitation, it yielded higher swelling capacity. The modified clay exhibited very high capacity of adsorption compare to unmodified samples. The m-xylene and toluene uptake follows a pseudo second order kinetics mechanism, suggesting that the rate determining step of adsorption involves the two adsorbates competitively adsorbed on the adsorbent sites. Therefore this organo-modified bentonite can be used for the removal of organics from polluted aqueous effluents.