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Determination of The pK and Transition Range of Cyanidin as an Acid-Base Indicator

By Umo, Anietie Ekpo

Determination of The pK and Transition Range of Cyanidin as an Acid-Base Indicator

Published: 23/07/2007

Tags: pK range, transition range, cyanidin, acid-base indicator

Size: 2.84MB

A Survey of Some Physicochemical Characteristics of Ekulu and Amia Rivers in Enugu State of Nigeria

By Nwajei, Godwin E

A Survey of Some Physicochemical Characteristics of Ekulu and Amia Rivers in Enugu State of Nigeria

Published: 05/02/1993

Size: 1.71MB

MODIFICATION OF COCONUT SHELL ACTIVATED CARBON WITH AN AZO LIGAND: 1, 2– DIHYDRO-1, 5- DIMETHYL-2 PHENYL-4- (E)–(2,3,4-TRIHYDROPHENYL)-3H-PYRAZOL-3-ONE (DDPTP) AND ITS POTENTIALS FOR THE REMO

By Anierobi, Peter Olisaemeka.

Modification of coconut (Cocos nucicera L.) shell activated carbon with an Azo ligand: 1, 2– dihydro-1,5-dimethyl-2-phenyl-4-(E)–(2,3,4-trihydrophenyl)-3H-pyrazol-3-one (DDPTP) and its potentials for the removal of Cd2+, Pb2+ and Ni2+ from polluted water samples were studied. It was activated chemically using CaCO3 as the activating agent. Proximate analysis on the coconut shell showed 8.7 % moisture content, 10.4 % volatile matter, 3.2 % ash content and 77.7 % fixed carbon. The developed adsorbent has bulk density of 0.46 g/cm3, pore volume of 8.0 x 10-3 cm3 and the conductivity was 37.9 µS/cm. Fourier Transform Infrared (FTIR) analysis showed that hydroxyl, carbonyl, amino and azo groups are present on the surface of the adsorbent. Scanning Electron Microscope (SEM) showed the micro-pores in the Modified Coconut Shell Activated Carbon (MCSAC) while Energy Dispersive X-ray Spectrum exposed carbon as the major quantitative element with 57 %. Batch adsorption was carried out and the results obtained showed that, MCSAC adsorbed Pb2+ (98 %), Cd2+ (80 %) and Ni2+ (92.2 %) ions more than un-modified coconut shell activated carbon which adsorbed Pb2+ (79 %), Cd2+ (60.2 %) and Ni2+ (73.6 %) ions from aqueous solutions. The quantity of the metal ions adsorbed increased with increase in initial concentrations, contact time, temperature of carbonization, the degree of treatment of adsorbent and pH for each metal. The percentage removal decreased with increase in particle sizes of the adsorbent. It also increased initially with increase in ligand amount but later decreased. Competitive adsorption of Pb2+, Cd2+ and Ni2+ on MCSAC from their mixed solution showed that the percentage removal of Ni2+ was highest with 80.35 % followed by Pb2+, 71.05 % and Cd2+, 45.10 %. The analysis of adsorption isotherm showed that, adsorption of Ni2+ followed Langmuir isotherm than Cd2+ and Pb2+; Ni2+ and Cd2+ followed Freunlich isotherm than Pb2+; Ni2+ and Pb2+ followed Temkin isotherm than Cd2+. Kinetic studies showed that the sorption of the metal ions can also be described by pseudo-first-order (Pb2+ and Ni2+), pseudo-second-order (Cd2+ and Ni2+) and intra-particle diffusion models for the three metals

Published: 19/07/2018

Tags: MODIFICATION OF COCONUT SHELL ACTIVATED CARBON WITH AN AZO LIGAND: 1, 2– DIHYDRO-1, 5- DIMETHYL-2 PHENYL-4- (E)–(2,3,4-TRIHYDROPHENYL)-3H-PYRAZOL-3-ONE (DDPTP) AND ITS POTENTIALS FOR THE REMOVAL OF Cd2+, Pb2+ and Ni2+ FROM POLLUTED WATER.

Size: 19.56MB

TOTAL ALKALOIDS, TOTAL TANNINS CONTENT AND ANTIULCER ASSAY OF FOUR SELECTED MEDICINAL PLANTS

By Abuekwu Priscillia Nwasi

The total alkaloid, tannins contents and antiulcer activity of the extracts from four selected medicinal plants were investigated. The total alkaloids content (TAC) was evaluated according to the chloride colometric method in which atropine was used as standard. While the total tannins content (TTC) was also determined using Folin Ciocalteau assay in which gallic acid was used as a standard. The antiulcer activity of the extracts was investigated using the ethanol induced model in wistar albino rats. Parameters such as gastric volume, pH and ulcer index were used as indicators for the antiulcerogenic activity of the extracts. The animals were orally treated with distilled water (Normal control group), ranitidine 5 mg/kg (standard control group), 0.5 mg/kg of ethanol (Negative control group) and 100,200 and 400 mg/kg of the extracts, 1 h before oral administration of absolute ethanol to induce gastric mucosal injury. The result showed that E. deightonii extract has the richest source of alkaloids and tannins (0.850 ± 0.001 mg AE/g and 0.133 ± 0.001 mg GAE/g respectively, while A. hispidum and P. staudtii has the least TAC and TTC (0.800 ± 0.001 mg AE/g) and (0.124 ± 0.001 mg GAE/g) respectively. The extract was considered safe with the LD50 greater than 5000 mg/kg for E. deightonii, 2154, 3808 and 2154 mg/kg for A. hispidum, P. staudtii and P. lunatus respectively. The extracts at dose levels of 100, 200 and 400 exhibited significant decrease *(P˂ 0.05) in the gastric volume, while the pH of the gastric juice was significant increase *(P˂ 0.05) in the ethanol induced model. The extracts showed minimum inhibition of gastric acid ranging from 16- 90%. The results showed that the methanol extracts of the selected plants possessed antiulcer as well as cytoprotective ability which could be attributed to the presence of the secondary metabolites.

Published: 19/12/2018

Tags: TOTAL ALKALOIDS, TOTAL TANNINS CONTENT AND ANTIULCER ASSAY OF FOUR SELECTED MEDICINAL PLANTS

Size: 1.40MB

SYNTHESIS, CHARACTERIZATION AND SOLVENT EXTRACTION STUDIES OF 3,5-BIS[(2-HYDROXY-BENZYLIDENE)-AMINO]-BENZOIC ACID AND ITS Co(II) AND Ni(II) COMPLEXES

By Umar, Abdullahi Yaro

3,5-Bis[(2-hydroxy-benzylidene)-amino]-benzoic acid (H2B) and its cobalt(II) and nickel(II) complexes were synthesized and characterized via: electronic, IR, 1H NMR and 13C NMR. Job’s continuous variation method was used to determine the mole ratio for both metal complexes. Solvent extraction studies were carried out on H2B in 5% DMF with its cobalt(II) and nickel(II) complexes using CHCl3 as organic solvent; with variable condition effects of equilibrium time, buffer pH, mineral acids, salting-out agents and complexing agents. IR spectral study indicates coordination through (N2O2) azomethine and protonated hydroxyl groups. Job’s continuous variation method showed a metal to ligand ratio, 1:1, for both metal complexes of H2¬B. Cobalt(II) complex of H2¬B showed quantitative extraction in pH range 5 – 7, while nickel(II) complex of H2B showed quantitative extraction in pH range 6 – 8. Nickel was successfully separated from cobalt by four-cycle extraction at 10-3 M HNO3 aqueous mixture of Ni(II) and Co(II) {10 µgcm-1 each} in 5% H2B/DMF using 0.05 M cyanide as masking agent and CHCl3 as organic solvent

Published: 14/07/2018

Tags: SYNTHESIS, CHARACTERIZATION AND SOLVENT EXTRACTION STUDIES OF 3,5-BIS[(2-HYDROXY-BENZYLIDENE)-AMINO]-BENZOIC ACID AND ITS Co(II) AND Ni(II) COMPLEXES

Size: 2.28MB

SYNTHESES, CHARACTERIZATION AND ANTIMICROBIAL ACTIVITIES OF ALKYNYLATED ANGULAR PHENOXAZINES AND ALKYNYLATED NAPHTHOQUINONES

By Ugwuona, Florence Oluchukwu

The synthesis of ten new alkynylated derivatives of angular phenoxazine and alkynylated naphthoquinone was thoroughly investigated. The first intermediate, 6-chloro-5H-benzo[a]phenoxazin-5-one was obtained by the condensation of 2-aminophenol with 2,3-dichloro-1,4- naphthoquinone in the presence of anhydrous sodium tricarbonate (IV) . Thereafter, the intermediate and 2,3-dichloro-1,4-naphthoquinone were each suggested to Sonogashira cross–coupling reaction under copper-, amine-, and solvent free conditions at 80 oC with five different terminal alkynes using PdCL2(PPh3)2 and tetrabutylammonium trihydrate (TBAF.3H2O) as the catalyst and ligand respectively to afford the alkynylated angular phenoxazines and alkynylated naphthoquinone derivatives in good to excellent yield . Structures of synthesized compounds were confirmed with Uv-visible, Fourier Transform – Infrared (FT-IR), 1H-NMR and 13C-NMR spectroscopy. The synthesized compounds were screened against five (5) micro-organisms viz: Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumonia, Escherichia coli 1 and Escherichia coli 12 using agar well diffusion technique. The results showed significant improvement in antimicrobial activities compared with gentamycin and ampicillin (standard drugs).

Published: 14/08/2018

Tags: SYNTHESES, CHARACTERIZATION AND ANTIMICROBIAL ACTIVITIES OF ALKYNYLATED ANGULAR PHENOXAZINES AND ALKYNYLATED NAPHTHOQUINONES

Size: 8.71MB

SYNTHESIS AND EVALUATION FOR BIOLOGICAL ACTIVITIES OF N-PYRIDIN-3-YL SUBSTITUTED [PHENYLSULPHONAMIDO] ACETAMIDE

By Ugwuja, Daniel Izuchukwu

In this study, a series of N-pyridin-3-yl substituted [phenylsulphonamido] acetamide has been synthesized. The reaction of phenylsulphonyl chloride with various amino acids in basic medium yielded phenylsulphonamido alkanoic acid which, on chlorination with thionyl chloride, gave acid chloride derivatives of phenylsulphonamido alkanoic acid in situ. The acid chloride derivatives on condensation with 3-aminopyridine gave corresponding acetamide in good to excellent yield. The compounds were characterized by FTIR, 1H-NMR and 13C-NMR and screened for antibacterial, antifugal and antioxidant activities. The result revealed that the compounds possess antibacterial activities.One the compounds, 2-[(phenylsulfonyl)amido]propanoic acid had better antibacterial activities than ciprofloxacin the reference drug while others are less active. All the compounds has less antifungal activities than ketokonazole the reference drug. 2-[(phenylsulfonyl)amido]propanoic acid had the best antioxidant properties of all the compounds.

Published: 14/11/2018

Tags: SYNTHESIS AND EVALUATION FOR BIOLOGICAL ACTIVITIES OF N-PYRIDIN-3-YL

Size: 509.24KB

KINETICS AND MECHANISMS OF THE REDOX REACTIONS OF µ-ADIPATO-DI (N,N/ BIS(SALICYLIDENE) ETHYLENEDIAMINATOIRON (III) [(Fe-Salen)2adi] WITH SOME THIOLS

By Ugwuanyi Kenneth Okeke

The kinetics and mechanisms of the redox reactions of oxidant, -adipato-di(N,N/-bis(salicylidene)ethylenediaminatoiron(III),[(Fe-salen)2adi],hereafter denoted as Fe2adi, with the thiols L-cysteine (LSH), thiourea (USH), thioglycolicacid(GSH),2–mercaptobenzothiazole (BTSH) and benzylmercaptan (BSH) have been studied spectrophotometrically at 495 nm in aqueous perchloric acid, I=0.01mol dm-3 (NaClO4) and at 29 1oC. The stoichiometry of 1:1 was obtained for Fe2adi – LSH, Fe2adi – GSH and Fe2adi –BTSH systems while 1:2 was obtained for Fe2adi – USH and Fe2adi–BSH systems. Under pseudo – first order conditions of a large excess of the reductants, pseudo–first order rate constants increased with increase in concentrations of the thiols (LSH, USH, GSH and BTSH), but decrease in pseudo – first order rate constant was observed as the concentration of BSH increased. The second order rate constants k2 were fairly same for all the five systems with values. 0.009 0.003 dm3 mol-1 s-1, 0.063 0.01dm3 mol-1 s-1, 0.038 0.005 dm3 mol-1 s-1, 0.011 0.001 dm3 mol-1 s-1. and. 0.0015 0.0035 dm3 mol-1 s-1 for LSH, USH, GSH, BTSH and BSH respectively. The rates of reaction were directly dependent on acid concentrations for the five systems. The overall rate equation for the reactions can be given as [Fe2adi] [reductant] [ ] for Fe2adi–LSH, Fe2adi – GSH, and Fe2adi - BTSH systems where a and b are the intercept and slope respectively, [Fe2adi] [USH]2 for Fe2adi–USH, while the rate equation, was for Fe2adi –BSH system is [Fe2adi] [BSH] [ ]2. The values of a and b obtained for the reaction of Fe2adi with the thiols are given as LSH (a = 0.3 x 10-4 dm3mol-1 s-1 and b = 1.23 x 10-3 dm6 mol-2 s-1), USH (a=6.2x10-4 dm3mol-1s-1 and b = 6.4 x10-3 dm6mol-2s-1), GSH (a = 1.9 x 10-4 dm3mol-1s-1 and b = 8.18 x 10-2 dm6mol-2 s-1), BTSH (a = 0.51 x 10-5 dm3mol-1s-1 and b = 2.0 x 10-3 dm6mol-2s-1), BSH (b =8.0 x 10-3 dm6mol-2 s-1). The rates of reactions was observed to decrease with the increase in ionic strength of the medium for the five systems under study. Addition of magnesium and acetate ions in small amount did not affect the rates of reactions for the redox reactions of Fe2adi with LSH, USH, GSH and BTSH, but decrease in rates of reaction was observed for that of BSH. The rates of reaction were not affected by the decrease in dielectric constant D for the reaction of Fe2adi with LSH, GSH and BTSH but it was enhanced for USH and BSH under the same conditions. Furthermore, the activation parameters, H# and S# were also determined for the five systems; the values being 89.99kJmol-1 and -30195Jk-1 mol-1 for Fe2adi-LSH system, 20.68kJmol-1 and -197.60Jk-1mol-1 for Fe2adi-USH system, 27.38kJmol-1 and-303.48JK-1 mol-1 for Fe2adi-BTSH system and 12.83kJmol-1 and -313.82JK-1mol-1 for Fe2adi-BSH system. Michaelis-Menten plot of 1/kobs versus 1/[reductants] were linear with intercepts for the redox reactions of Fe2adi with LSH, GSH, BTSH, USH and BSH. On the basis of the results obtained above, the reactions have been proposed to follow the inner-sphere mechanism.

Published: 14/08/2018

Tags: KINETICS AND MECHANISMS OF THE REDOX REACTIONS OF µ-ADIPATO-DI (N,N/ BIS(SALICYLIDENE)

Size: 4.47MB

HEAVY METAL CONCENTRATIONS AND DEGRADATION EFFICIENCY OF TOTAL PETROLEUM HYDROCARBONS ON ENVIRONMENT IN IBENO LOCAL GOVERNMENT AREA, AKWA IBOM STATE, NIGERIA

By Udo Godwin James

Heavy metal concentrations and degradation efficiency of total petroleum hydrocarbons (TPHs) on environment in Ibeno Local Government Area, Akwa Ibom State, Nigeria was investigated. Experimental design method was adopted for this study. Fifteen composite samples each of soil, leaves of Telfairia occidentalis, sediment and water were collected in December 2012 and June 2013. The sediment and water samples were collected using corer and clean plastic bottles respectively. Soil and sediment samples were air dried, mechanically ground using mortar and pestle, and 2 mm mesh size obtained for further analysis. The soil and sediment samples (1.0 g) each were weighed into Kjeldahl flasks. Aqua regia (15 cm3) was added, swirled to mix and kept overnight. The flasks were heated on a hot plate to 50 oC for 30 min; temperature was later adjusted to 120 oC and heated continuously for 2 h. The mixture was cooled, and 0.2 M HNO3 (10 cm3) added. The resulting mixture was filtered with a Whatman no. 541 filter paper. The filtrate was transferred into a 50 cm3 standard flask and made up to the mark with 0.2 M HNO3. The leaves samples were washed with de-ionized water, dried to constant weight in an oven at 105 oC, pulverized and 2 mm mesh size obtained for further analysis. The ground leaves were digested with 1.0 cm3 concentrated HClO4, 5 cm3 concentrated HNO3 and 0.5 cm3 concentrated H2SO4 in 50 cm3 Kjeldahl flask. Each water sample (10 cm3) was digested with 2 cm3 concentrated HNO3. Concentrations of the heavy metals were determined using AAS Unicam 939 model. The soil samples (150 g) each were transferred into four (4) plastic buckets labeled A, B, C and D. Varying concentrations palm bunch ash (PBA) (0.0 g, 50.0 g), Tween 80 (50.0 g) and PBA + Tween 80 (25.0 g) each were added to A, B, C, and D, where A served as control. Portions (5 g each) of A, B, C and D were weighed into standard flasks, 25 cm3 of xylene added and shaken, NaCl (5 g) was added and left for 72 h. The liquid portion was decanted into a separatory funnel, corked and shaken. The xylene layer was transferred into 100 cm3 centrifuge tube containing 5 g of Na2SO4 and agitated for 15 min, the absorbance of the solution was measured at 425 nm and used for calculating concentrations of TPHs. Concentrations of TPHs were determined at 20 days intervals for 60 days. The data were analyzed on the basis of first order kinetic model InC = InCo- kt. Heavy metal concentrations (mg kg-1) during dry season were, soil: Fe (15.15 ± 5.91), Mn (10.36 ±3.18), Cd (0.23±0.31 ), V (0.17 ± 0.29), Ni (0.19 ± 0.05), leaves of Telfairia occidentalis: Mn (7.73 ± 3.06), Fe (5.93±1.28), V (0.16±0.26), Cd (0.21 ± 0.16), Ni (0.02 ± 0.01), sediment: Fe (22.18 ± 14.82), Mn (9.67±2.75), V (3.39±3.30), Ni (2.18±0.78), Cd (0.48 ± 0.75), and water: Mn (2.80±0.93), V (1.53±1.42), Ni (1.50 ± 1.53), Fe (0.86 ± 0.25), Cd (0.27±0.21), During wet season, soil: Fe (12.09±4.98), Mn (9.66 ± 2.18), Ni (0.05±0.03), V (0.04±0.01), Cd (0.04±0.02); leaves of Telfairia occidentalis: Mn (7.75±3.76), Fe (5.96±4.07), V (0.21±0.09), Cd (0.19±0.06), Ni (0.03±0.06), sediment: Fe (23.28±0.24), Mn (9.45±2.63), V (3.31±3.34), Ni (1.94±1.48), Cd (0.48±0.74), and water: Mn (3.13 ± 0.79),V (1.88 ±1.45), Ni (1.45 ±1.04), Fe(1.05 ± 0.25), Cd (0.10 ± 0.13), were obtained. The correlation coefficients were: V (0.556), Ni (0.376), Cd (-0.043), Pb (0.856), Mn (0.813), Co

Published: 14/07/2018

Tags: HEAVY METAL CONCENTRATIONS AND DEGRADATION EFFICIENCY OF TOTAL PETROLEUM HYDROCARBONS ON ENVIRONMENT

Size: 5.41MB

SYNTHESIS AND CHARACTERIZATION OF ZEOLITE AND ITS APPLICATION IN ADSORPTION OF NICKEL FROM AQUEOUS SOLUTION

By Orjioke, Nwakaego Marytheresa

The synthesis and characterization of zeolite and its application in adsorption of nickel from aqueous solution was investigated. Synthesis of zeolite was performed at 90 oC for 8 h. The size of the resulting crystals increased with an increase in the water content of the reaction mixture. The synthesized zeolite was characterized by Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) techniques. Crystal structure of the product was determined as zeolite X by XRD. The concentration of the nickel ion was determined using atomic absorption spectrophotometer (AA 320 – ON). Removal efficiency of nickel ion was dependent on the pH, contact time, adsorbent dosage and temperature. Batch adsorption studies conducted for the removal of nickel(II) ion at 25, 40 and 50 oC respectively showed that nickel ion adsorption increased with increase in temperature. The effect of adsorbent dosage of 0.5-4.5 g showed that there was an increase in the adsorption capacity when the adsorbent dose was increased from 2.0-4.0 g. The pH values were adjusted to 3.2, 4.3, 5.3, 6.7, 7.9 and 9.5 and it was evident from the result that at pH 5.3, uptake capacity of nickel(II) ion onto zeolite X was maximum. The effect of contact time at 10, 20, 30, 45, 60, 75 and 90 min was analysed and it was evident that adsorption of nickel was rapid in the first 40 min followed by a gradual increase until equilibrium was attained. Adsorption data was interpreted in terms of Langmuir and Freundlich isotherms. It was observed that the experimental data fitted better to Langmuir model with a correlation factor (R2) value of 0.993 compared to Freundlich with R2 value of 0.980. The kinetics rate were modelled using pseudo-first-order and pseudo-second-order models. The pseudo-second-order model explained the adsorption kinetics most effectively. The result showed that zeolite X was effective in the removal of Ni(II) ion from aqueous solution

Published: 14/10/2018

Tags: SYNTHESIS AND CHARACTERIZATION OF ZEOLITE AND ITS APPLICATION IN ADSORPTION OF NICKEL FROM AQUEOUS SOLUTION

Size: 2.29MB

PHYTOCHEMICAL QUANTIFICATION, ANTIOXIDANT AND ANTIMICROBIAL ACTIVITIES OF ROOT EXTRACTS OF DENNETTIA TRIPETALA AND MILICIA EXCELSA

By Oparanozie Tochukwu I.

The roots of Dennettia tripetala and Milicia excelsa were analyzed for the presence of phytochemicals. Five different solvents, which include methanol, ethanol, ethyl acetate, butanol and water, were used for the extraction of the phytochemicals.The root of Dennettia tripetala contained alkaloids, terpenoids, flavonoids, saponins, phenols, steroids and glycosides in varying degrees of abundance in the different solvents with tannins not detected in all the solvents. Milicia excelsa contained all the phytochemicals in Dennettia tripetala, in addition to tannins, in different degrees of abundance in the various solvents. The root of Dennettia tripetala contained 1.83 % alkaloids, 3.64 % flavonoids, 1.41 % saponins, 0.67 %phenols, 0.36 % steroids and 0.08 % glycosides whereas that of Milicia excelsa contained 2.19 %alkaloids, 6.40 % flavonoids, 0.87 % saponins, 0.34 % phenols, 0.36 % tannins, 0.15 % steroids and 0.09 % glycosides. Results of the Principal Component Analysis (PCA) of the phytochemicals revealed that, in Dennettia tripetala, there was strong positive correlation between alkaloids and glycosides (0.995)and also phenols and saponins (1.000) while the strong negative correlations were between alkaloids and flavonoids (-0.980), flavonoids and glycosides (-0.956), phenols and steroids (-1.000) and also saponins and steroids (-1.000). In Milicia excelsa, the strong positive correlations were between alkaloids and flavonoids (0.908), phenols and saponins, glycosides (0.866) and also steroids and tannins (1.000) whereas the strong negative correlations were between phenols and steroids (-0.866), saponins and tannins, steroids (-1.000) as well as tannins and phenols (-0.866). An assay of the antioxidant potentials of various extracts of both plants, using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method, revealed that the ethanolic extracts of Dennettia tripetala and Milicia excelsa as well as the methanolic extract of Dennettia tripetala showed high percent inhibition ranging from 83.34 to 89.75 at 0.01 mg/mL of the extracts; results which showed to be better than standard ascorbic acid (67.89) at the same concentration. Other extracts of both plants, at higher concentrations, gave percent inhibitions ranging from 35.80 for the butanolic extract of Milicia excelsa at 0.025 mg/mL to 95.96 for the methanolic extract of the same plant at 0.5 mg/mL. A comparison of the half maximal inhibitory concentration (IC50) values of the extracts showed that ethyl acetate extracts of both plants had the best IC50 values at 0.014 and 0.150 for Dennettia tripetala and Milicia excelsa respectively which were better than ascorbic acid standard whose IC50 value was 1.060. All the other extracts of both plants also had IC50 values better than ascorbic acid except for ethanol in both plants and methanol in Milicia excelsa. The extracts were tested for antimicrobial activity against a gram positive cocci, staphylococcus aureus, and a gram negative rod, klebsiella sp. The results revealed that the ethanolic extract of Dennettia tripetala and the butanolic extracts of both plants showed activity against the test organisms at two concentrations, 400 mg/mL and 200 mg/mL, with the inhibition zone diameters (IZD) ranging from 8.2 mm to 12.0 mm and 6.5 mm to 14.0 mm for the ethanolic and butanolic extracts respectively. The minimum inhibitory concentration (MIC) of the extracts ranged from 41.5 mg/mL to 48.3 mg/mL for the ethanolic extracts and 164.8 mg/mL to 111.7 mg/mL for the butanolic extracts. The presence of these secondary metabolites in varying and substantial amounts in the roots of the plants as well as the antioxidant and antimicrobial potentials of the roots of the plants lends scientific credence to the ethnomedicinal use of these plants parts for the treatment of various diseases

Published: 01/04/2015

Tags: PHYTOCHEMICAL QUANTIFICATION, ANTIOXIDANT AND ANTIMICROBIAL ACTIVITIES OF ROOT EXTRACTS OF DENNETTIA TRIPETALA AND MILICIA EXCELSA

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KINETICS AND MECHANISMS OF THE ELECTRON TRANSFER REACTIONS OF THE µ-OXO- BRIDGED IRON(III) COMPLEX, Na4[(FeEDTA)2O].12H2O WITH SOME THIOLS

By Ezennodebe, Grace

The kinetics and mechanisms of the redox reactions of µ-oxo-bridged iron(III) complex ion Na4[(FeEDTA)2 O].12H2O denoted as Fe2 O4+, with the thiols-2-mercaptobenzothiazole(MBSH), 2- mercaptophenol(PhSH), 2-mercaptoacetic acid (MSH), and l-cysteine (RSH) have been investigated in aqueous perchloric acid medium at [H+]=1×10-4 mol dm-,3,I=0.05mol dm-3(NaClO4) and at T =27.0±0.1oC. The reactions were monitored under pseudo-first order condition .The rate of reaction was first-order in reductant and oxidant for all the systems giving overall second –order reactions. The inorganic and organic products of the reaction between Fe2O4+ -MBSH, PhSH, MSH and RSH and oxidants were found to be Fe(II) ions and disulphides respectively. The stoichiometries of Fe2O4+ -MBSH, PhSH, MSH, and RSH was determined by mole ratio method and was found to be 1:2 for all the systems. The reactions of the thiols (MBSH.PhSH,MSH and RSH) had an inverse dependence on hydrogen ion concentration ,and so the general rate law can be given as follows
d[Fe2O4+] = (a + b) [H+]-1) [Fe2O4+] [reductant]

Changes in ionic strength of the reaction medium had a negative effect on the rate of reaction of Fe2O4+ - MBSH and RSH and positive effect in the reaction of Fe2O4+ - PhSH and MSH. Reduction of Fe2O4+ by MBSH, PhSH, MSh and RSH showed no dependence on dielectric constant because decrease of dielectric constant did not change kobs. CH3COO-,/NO3-/Cl-/SO42-/K+ and Mg2+,were used to determine the effect of catalysis on Fe2O4+-MBSH,PhSH,MSH and RSH reactions and there was decrease in catalysis. The effect of temperature on the rate of reduction of Fe2O4+ with reductants was studied and was found to have negative entropy which confirmed the formation of binuclear complexes at the activated complex. The results of the study indicate that the reactions of Fe2O4+ and thiols probably occur by the outer-sphere mechanism

Published: 14/02/2018

Tags: KINETICS AND MECHANISMS OF THE ELECTRON TRANSFER REACTIONS OF THE µ-OXO- BRIDGED IRON(III) COMPLEX, Na4[(FeEDTA)2O].12H2O WITH SOME THIOLS

Size: 1.14MB

EVALUATION OF THE QUALITY ASSURANCE OF FIVE BRANDS AMOXICILLIN TRIHYDRATE CAPSULES SOLD IN THE OPEN DRUG MARKET AT NSUKKA

By Onunze Emmanuel Chukwudi Sunday

The active drug content and weight uniformity of five brands (A – E) of Amoxicillin Trihydrate capsules in Nsukka open drug market were evaluated to ascertain their quality assurance using UV visible spectroscopy and gravimetry. This study has shown that all the brands analyzed showed significant variations with respect to active drug content determination for the three brands B, D and E. Using United State Pharmacopoeia (USP) and British Pharmacopoeia (BP) specifications of 90 – 110 %, the values obtained were B – (413.525 mg), D – (440.325 mg), E – (414.100 mg). These values were within the general drug acceptance limit of 80 – 110 % but failed the antibiotic amoxicillin trihydrates USP and BP specifications with acceptable limit of 90 – 110 % determined at 266 nm. The percentage mean content of all the brands (A – E) were 77.64, 82.80, 74.24, 88.07 and 82.82. All the brands passed the weight uniformity test with coefficient of variation CV value range of ± 0 – 5 % for capsules more than 250 mg according to USP and BP specifications. However, with the result obtained, the consequences are that it poses a serious threat to the health of the entire people of West Africa sub regions that depend on these drugs for therapeutical response. As all the drugs assayed were below the acceptance limit requirement of antibiotic amoxicillin trihydrate and thus, can lead to serious health implications such as drug resistance, cardiac failure, etc. Drug regulatory bodies should be at alert and they should conduct strict routine check on all the NAFDAC satisfied companies as all the drugs analyzed compromise their quality because of profit reasons.

Published: 14/05/2018

Tags: EVALUATION OF THE QUALITY ASSURANCE OF FIVE BRANDS AMOXICILLIN TRIHYDRATE CAPSULES SOLD IN THE OPEN DRUG MARKET AT NSUKKA

Size: 335.97KB

PRODUCTION, OPTIMIZATION AND APPLICATION OF PRINTING INK FROM WASTE CARBON SOURCES

By Oko-udu, Chijioke Okpara

Production of carbon black from novel sources like spent automobile tyre, anthracite coal, furnace soot and graphite rod and subsequent use in the production of offset printing inks has been investigated. Carbon black from these sources were obtained by pyrolysis of shredded spent tyre and coal samples at 750-900oC in an electrical furnace, isolation of furnace carbon black and graphite rod from dry cell, drying and pulverization of the resulting samples. Acid demineralization of the samples for 24hr followed with distilled water rinsing and oven drying at 110oC for 12 hr were also carried out before sieving. The production of offset printing ink from the synthesized carbon black samples each of particles

Published: 14/02/2018

Tags: PRODUCTION, OPTIMIZATION AND APPLICATION OF PRINTING INK FROM WASTE CARBON SOURCES

Size: 9.68MB

FABRICATION AND CHARACTERIZATION OF ZEOLITES AND ITS APPLICATION IN HEAVY METAL CAPTURE

By Okorie Amaka Juliet

Zeolite crystals were synthesized by mixing sodium silicate and sodium aluminate to obtain aluminosilicate gel which was further treated hydrothermally to obtain the final product. The zeolite crystals were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD result identified the synthesized crystals as zeolite z; additional evidence was provided by the SEM images which showed that the zeolite crystals were disc-shaped and the particle sizes ranged between 13.4 – 53.6 µm. batch adsorption studies using the synthetic zeolite showed efficient removal of chromium (III) ion from aqueous solution. The atomic absorption spectroscopy (AAS) result which gave the final metal ion concentration indicated that the rate of adsorption increased with increase in the mass of adsorbent (zeolite) and decrease in particle size of the zeolite crystals. In the course of treatment, different quantities of zeolite ranging from 0.5 – 2.5 g were used; also different concentrations of Cr (III) ion (10, 15, 20, 25, 30 ppm) were used to determine the extent of adsorption. The percentage adsorption increased from 55.75 – 96.6 % and decreased from 98 -88.3 % respectively in each case. As the pH values were adjusted between 1 – 11, percentage adsorption increased from 55 – 97 % with a sharp increase at pH 7. While in the case of the zeolite samples with different particle sizes, the percentage adsorption reduced from 98.9 -70 % as particle sizes increased from 13.4 – 53.6 µm. The high percentage adsorption of the zeolite samples suggests that zeolites are good adsorbents for the removal of Cr from aqueous solutions. Also the batch experiment conducted showed that the adsorption pattern followed the Langmuir and Freundlich isotherm models with correlation factors (R2) values of 0.997 and 0.963 respectively.

Published: 14/08/2018

Tags: FABRICATION AND CHARACTERIZATION OF ZEOLITES AND ITS APPLICATION IN HEAVY METAL CAPTURE

Size: 2.12MB