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Item Comparative Determination of Heavy Metals in Flower farm and Road Side Soils Collected from Holeta by Using Flame Atomic Absorption Spectrophotometry(Addis Ababa University, 2023-06) Genet Mulugeta; Merid Tessema (PhD)In this study the concentration of heavy metals: Mn, Cu, Zn, Ni, Cd, Pb, Fe, Mg and Ca were determined in soil by flame atomic absorption spectrophotometry (FAAS). The soil samples were collected from a flower farm (Holeta) and from the roadside around the flower farm. After proper sample preparation, a 0.5 g of dried powdered soil sample was digested with 3ml of HNO3, 1ml of HCl at 240 0C for 2:45 hours and the concentration of the selected heavy metals were determined by flame atomic absorption spectrophotometry. The results showed that the soil samples in the two sampling areas contain high amount of iron and magnesium. As exception zinc being which is higher in the flower farm than on the road side, the mean metal concentration (mg/kg dry weight) in both soil samples are as follows: Fe (8807-9128) ˃ Mg (1023-1119) ˃ Mn (399-964) ˃ Ca (60-118) ˃ Zn (96.1-150.5) ˃ Cr (34- 48.54) ˃ Cu (30.5-35.6) ˃ Ni (21-33.43). A small amount of nickel was observed in both sample sites, while cadmium and lead were below the limit of detection. The detected metals in the present study were also compared with WHO recommended maximum permissible limit. Fe, Mg, Mn, Ca and Zn were above the WHO standard limit, but Cu, Ni and Cr were below the recommended permissible limit.At 95% confidence level between the two samples collected from the two sample sites the value obtained from ANOVA indicates that there is a significant difference among the mean concentrations of all the selected metals (P˂0.05).Item Determination of Metal Contents in Carrot and its Corresponding Soil of the Plant Cultivated in Akaki Kality Farms in Addis Ababa, Ethiopia by Flame Atomic Absorption Spectroscopy (FAAS)(Addis Ababa University, 2023-09-19) Seare G/micheal; Negussie Negash (PhD)The aim of this study is to determine the metal concentration of carrot and the corresponding soil sample collected from akaki kality farms in Addis Ababa, Ethiopia. Levels of selected metals (Fe, Cu, Ni, Zn, Pb and Cd) were determined using flame atomic absorption spectroscopy. After proper samples pre-treatment of washing, dried, crushed and homogenized, known weight of carrot sample was wet digested using 3:1 mL of HNO3, of HCl for 3:00 h at 300 oC and for soil sample 3:1 mL of HNO3 and of HCl and 1 mL for 3:00 hr at 300oC. Then using the optimized conditions sample preparation was made and levels of metals was determined by FAAS. The mean concentration range (mg/kg) of each metal in carrot were Zn (52.30)> Cu (25.3)> Pb (25.18) >Fe (23.94) > Cd (2.43), Ni was below the detection limit and in soil samples Zn (134.46) > Cu (71.45) > Pb (22.18) >Cd (4.02), respectively. Ni and Fe were below the detection limit. The result indicates that concentration of Cd, Zn, Cu, Fe, and Pb metals in carrot sample and Cd, Zn, Cu, and Pb metals in its soil is higher than the WHO guidelines. ANOVA indicated that there is significant difference between the mean concentration of Cd Cu, and Zn and the mean concentration of the metal Pb does not significantly differ between the samples means among carrot and soil samples at 95% confidence level, respectively. The accuracy of the optimized procedure was evaluated by analysing the digestion of the spiked samples with standard solution and the percentage recoveries varied from 93.5 % to 101.6%.Item Determination of Metal Contents in Carrot and its Corresponding Soil of the Plant Cultivated in Akaki Kality farms in Addis Ababa, Ethiopia by Flame Atomic Absorption Spectroscopy (FAAS)(Addis Ababa University, 2023-09-19) Seare G/micheal; Negussie Negash (PhD)The aim of this study is to determine the metal concentration of carrot and the corresponding soil sample collected from akaki kality farms in Addis Ababa, Ethiopia. Levels of selected metals (Fe, Cu, Ni, Zn, Pb and Cd) were determined using flame atomic absorption spectroscopy. After proper samples pre-treatment of washing, dried, crushed and homogenized, known weight of carrot sample was wet digested using 3:1 mL of HNO3, of HCl for 3:00 h at 300 oC and for soil sample 3:1 mL of HNO3 and of HCl and 1 mL for 3:00 hr at 300oC. Then using the optimized conditions sample preparation was made and levels of metals was determined by FAAS. The mean concentration range (mg/kg) of each metal in carrot were Zn (52.30)> Cu (25.3)> Pb (25.18) >Fe (23.94) > Cd (2.43), Ni was below the detection limit and in soil samples Zn (134.46) > Cu (71.45) > Pb (22.18) >Cd (4.02), respectively. Ni and Fe were below the detection limit. The result indicates that concentration of Cd, Zn, Cu, Fe, and Pb metals in carrot sample and Cd, Zn, Cu, and Pb metals in its soil is higher than the WHO guidelines. ANOVA indicated that there is significant difference between the mean concentration of Cd Cu, and Zn and the mean concentration of the metal Pb does not significantly differ between the samples means among carrot and soil samples at 95% confidence level, respectively. The accuracy of the optimized procedure was evaluated by analysing the digestion of the spiked samples with standard solution and the percentage recoveries varied from 93.5 % to 101.6%.Item Single-site Anisotropic Pair Potential Based on Spherical Harmonic Functions(Addis Ababa University, 1993-09) Awad, Mohamed; Zewdie, Habtamu (PhD)The main objective of this work is to model a less computationaly demanding flexible single-site anisotropic potential using genera li zed spherical harmonic functions. These functions have been used to expand the well depth, f(r,u"w.), and the range, o(r,~"w2)' parameters of the s hifted Lennard- Jones (LJ) potential. We have compared our potential with si te-si te LJ and single- si te Gay-Berne (GB ) potentials. The results are in better agreement with LJ site-site potential for all tested orientations. The computational time is comparable to that of GB potential. The new potential has the additional advantage of f lex i bili ty. By taking addi tional spherical harmonic terms any desired accuracy can be obtained. this model is that it can also cylindrically symmetric molecules. The important virtues of be used to model noncylindrically symmetric molecules.Item HPTLC method Development and Validation for Simultaneous Determination of Lamivudine and Tenofovir in Fixed Dose Combination Tablet(Addis Ababa University, 2009-06) Moges, Mesfin; Debela, Asfaw (Asst. Prof.)HPTLC-densitometry method was developed and validated for simultaneous determination of antiretroviral drugs tenofovir disoproxil fumarate and lamivudine in fixed dose combi nations. The method was based on HPTLC separation of the two drugs followed by densitometric measurements of their spots at 257 nm. Toluene-methanol (6:4, v/v) was used as mobile phase and HPTLC aluminum sheets of si lica gel 60 F254 as stationary phase and detection of the spots were made by observation under short wavelength (254 nm) UV li ght. The system was found to give compact spot for lamivudine (Rr= 0.32 ± 0.02) and tenofovir disoproxil fumarate (Rr = 0.57 ± 0.02). The method was validated for precision, accuracy and robustness. The linear regression analysis data for the calibration plots showed good linear relationship with r2 = 0.998 in the concentration range 100-900 ng/spot for tenofovir disoproxil fumarate and linear relationship with r2 = 0.994 in the concentration range 200-800 ng/spot for lamivudine. The mean value of determination coefficient, slope and intercept were 0.998 ± 0.0012 and 0.994 ± 0.002, 4.80 ± 0.076 and 8. 12 ± 0.21 , 232.80 ± 36.21 and 478.16 ± 72.85 for tenofovir disoproxil fumarate and lamivudine, respectively. The intra-day and inter-day precision was less than 3% relative standard deviation (RSO <3%). The LOO and LOQ were 24.89 and 75.40 ng/spot for tenofovir disoproxil fumarate and 29.60 and 89.72 for lamivudine, respectively. The percentage assay of tenofovir disoproxil fumarate and lamivudine was found 98.63 ± 2. 17 and 100.93 ± 1.32, respectively. The described method has the advantage of being rapid, simple and inexpensive. No chromatographic interferences between the excipients and active ingredients were found. The method therefore could be applied for routine quality control analysis of lamivudine and tenofovir di soproxil flUllarate in fixed dose combination tablet. Key words: Lamivudine; Tenofovir Oisoproxil Fumarate; HPTLC-Oensitometty; Method validationItem Hoptly Method Development and Validation for Simultaneous Determination of Lamivudine and Tenofovir in Fixed Dose Combination Tablet(Addis Ababa University, 2009-06) Moges, Mesfin; Debela, Asfaw (PhD)Lamivudine and tenofovir disoproxil fumarate are antiretroviral drugs available in a fixed dose combination tablet. They are nucleoside analogues and an increasingly important member of antiretroviral drugs. HPTLC-densitometry method was developed and validated for simultaneous determination of antiretroviral drugs tenofovir disoproxil fumarate and lamivudine in fixed dose combi nations. The method was based on HPTLC separation of the two drugs followed by densitometric measurements of their spots at 257 nm. Toluene-methanol (6:4, v/v) was used as mobile phase and HPTLC aluminum sheets of si lica gel 60 F254 as stationary phase and detection of the spots were made by observation under short wavelength (254 nm) UV li ght. The system was found to give compact spot for lamivudine (Rr= 0.32 ± 0.02) and tenofovir disoproxil fumarate (Rr = 0.57 ± 0.02). The method was validated for precision, accuracy and robustness. The linear regression analysis data for the calibration plots showed good linear relationship with r2 = 0.998 in the concentration range 100-900 ng/spot for tenofovir disoproxil fumarate and linear relationship with r2 = 0.994 in the concentration range 200-800 ng/spot for lamivudine. The mean value of determination coefficient, slope and intercept were 0.998 ± 0.0012 and 0.994 ± 0.002, 4.80 ± 0.076 and 8. 12 ± 0.21 , 232.80 ± 36.21 and 478.16 ± 72.85 for tenofovir disoproxil fumarate and lamivudine, respectively. The intra-day and inter-day precision was less than 3% relative standard deviation (RSO <3%). The LOO and LOQ were 24.89 and 75.40 ng/spot for tenofovir disoproxil fumarate and 29.60 and 89.72 for lamivudine, respectively. The percentage assay of tenofovir disoproxil fumarate and lamivudine was found 98.63 ± 2. 17 and 100.93 ± 1.32, respectively. The described method has the advantage of being rapid, simple and inexpensive. No chromatographic interferences between the excipients and active ingredients were found. The method therefore could be applied for routine quality control analysis of lamivudine and tenofovir di soproxil flUllarate in fixed dose combination tablet. Key words: Lamivudine; Tenofovir Oisoproxil Fumarate; HPTLC-Oensitometty; Method validationItem Newly Developed Methods for the Determination of Selected Pharmaceuticals in Water and Vegetable Samples by HPLC and their Removal(Addis Ababa University, 2021-06-22) Tegegne, Bisratewongel; Zewge, Feleke (PhD)Pharmaceutical consumptions are now increasing worldwide as it is essential to treat and prevent health issues but at the end of the day, they end up in the environment as a persistent pollutant. However, very little research has been carried out in Africa and there is no study in Ethiopia concerning method development and quantitative analysis of pharmaceuticals in the environment. This research work is aimed to develop analytical methods for the determination of selected pharmaceuticals from water and vegetable samples and it also presents their removal. An effective liquid chromatography for the determination of thirteen pharmaceuticals (metformin, amoxicillin, chloroquine, theophylline, trimethoprim, caffeine, norfloxacin, ciprofloxacin, acetylsalicylic acid, doxycycline hyclate, metronidazole, albendazole and cloxacillin) was developed and validated. Kromasil C18 column, gradient elution with aqueous formic acid (0.1%), methanol and acetonitrile, a UV absorption wavelength of 250 nm and a mobile phase flow rate of 1 mL/min over a 22 min run time was optimized for complete separation. The method was validated and results for: linearity, precision, sensitivity, accuracy, specificity, suitability and method robustness were obtained and met the ICH guidelines. Using the validated chromatographic conditions, solid-phase extraction (SPE) for the extraction of 13 pharmaceutical compounds in water samples was developed. Different types of SPE sorbent, sample solution pH, type of elution solvent, sample load volume and addition of EDTA were evaluated. The LOD and LOQ of the optimized method were in the range 0.1 - 0.8 μg/L and 0.2 - 2.6 μg/L, respectively. The proposed method was applied for water samples from Addis Ababa, Ethiopia. Trimethoprim concentration of 7.8(1.1) μg/L, caffeine 3.2(0.4) μg/L, albendazole 2.1(0.1) μg/L and norfloxacin 65% for 70% of the compounds and the rest were found in > 55%. Amoxicillin was not detected in all sampling points and caffeine was found in high concentration. The concentration ranged from not detected to 48.8 μg/L. QuEChERS sample preparation was optimized for five selected pharmaceuticals and a combination of d-SPE sorbent, MgSO4, PSA, C18 and DE (clean-up sorbent), methanol (extraction solvent), MgSO4 with NaCl (extraction salt) and 5 min extraction time were obtained. The method was successfully applied to different vegetable samples collected from Addis Ababa, Ethiopia and Johannesburg, South Africa (carrot, cabbage and lettuce) and none of the target analytes were found in the sample investigated. The matrix effect study on vegetable samples collected was found to be very high that suppressed the signal during analysis. For selective removal of pharmaceuticals, molecularly imprinted polymer (MIP) was synthesized and optimized for albendazole, ciprofloxacin, norfloxacin and venlafaxine in an aqueous solution. The polymer was characterized by FT-IR, TGA, XRD, SEM and BET. MIP mass 50 mg, sample pH of 9 and adsorption time of 20 min and 1 mL mixture of formic acid in water and methanol as elution solvent was optimized. The adsorption experimental data fitted with the Freundlich isotherm model and the pseudo-second-order kinetic model best fitted which implied adsorption through chemisorption. MIP reusability was demonstrated for six repeated cycles without significant loss in performance. Lastly, the efficiency of Moringa oleifera (seed cake, seed husk and water-soluble protein) was studied for removal of nine pharmaceuticals. The adsorbent was characterized by FT-IR, SEM and points zero charge. Sample solution pH of 5, a contact time of 80 min and 0.5 mg/L initial concentration of the analyte were optimized. Adsorption on the Moringa adsorbent was well defined by Freundlich adsorption isotherm model and the pseudo-second-order kinetic model. The results obtained showed that the use of this plant can be considered as one of the most promising, and low-cost adsorbents for the removal of pharmaceuticals.Item Phytochemical Studies of Cyperus Esculentus Carissa Spinarum Melilotus Officinalis Rhus Glutinosa and Rhus Natalensis(Addis Ababa University, 2021-09-12) Assefa, Melaku; Ele, Estifanos (PhD); Mammo, Wendimagegn (Professor)In this study, the essential oils obtained from the rhizomes of Cyperus esculentus L. and the roots of Carissa spinarum Linn. together with medicinal smoke obtained from burnt roots of Carissa spinarum were analyzed by GC-MS. The major components of the essential oil of Cyperus esculentus were pinocarveol (11.42%), humulene epoxide II (10.18%), caryophyllene oxide (9.38%) and β-pinene (8.95%). On the other hand, the essential oil obtained from the roots of Carissa spinarum was predominantly 2- hydroxyacetophenone (16, 82.97%). The dominant components of the n-hexane- and MeOH-soluble fractions of the smoke derived from the roots of Carissa spinarum were found to be 2,6-dimethoxyphenol, 2-methoxyphenol and 2-hydroxyacetophenone. The radical scavenging activities of the EtOAc extract of the rhizomes of Cyperus esculentus, the MeOH-soluble fraction of the smoke derived from the roots of Carissa spinarum, the MeOH extract of the seeds of Melilotus officinalis and the EtOAc extracts of the fresh leaves of Rhus glutinosa and Rhus natalensis were also evaluated using the diphenylpicrylhydrazyl (DPPH) method. The smoke derived from the roots of Carissa spinarum and the MeOH-soluble fraction of the seeds of M. officinalis showed 88.48 ± 0.31% and 26.35 ± 0.54% DPPH inhibition at concentration of 50.00 μg/mL, respectively. On the other hand, the EtOAc-soluble fractions of the rhizomes of Cyperus esculentus and III the leaves of R. glutinosa and R. natalensis reduced DPPH radical by 24.53 ± 0.36%, 94.89 ± 0.10% and 94.94 ± 0.29% at 50.00 μg/mL, respectively. At the same concentration, standard ascorbic acid (a known antioxidant) scavenged the DPPH radical by 96.29 ± 0.06%. The seed fatty acid composition of M. officinalis was determined in this study by GC-MS analysis. Hence, the n-hexane extract of the seeds of M. officinalis unveiled twelve compounds with a combined area percentage of 98.33%, the major constituents being (9Z,12Z)-octadecadienoic acid (20.22%, 366.08 ppm), 14-methylpentadecanoic acid (19.52%, 353.45 ppm) and (9E)-octadecenoic acid (15.94%, 288.66 ppm). Four sesquiterpenes, namely, caryophyllene oxide (113), cyperotundone (12), corymbolone (114) and tricyclohumuladiol (115), were also isolated from the EtOAc extract of the rhizomes of Cyperus esculentus. Furthermore, two compounds, namely, cis-coumaric acid- 2-O-β-glucopyranoside (cis-melilotoside, 116) and 1,2-benzopyrone (coumarin, 65), were isolated from the MeOH extract of the seeds of M. officinalis. Twelve compounds, namely, pentacosanol (119), acacetin (120), kaempferol (38), rhusflavanone (121), rhusflavone (122), avicularin (123), quercetin (1), myricetin (2), quercitrin (124), shikimic acid (125), hyperoside (126), and myricetin-3-O-β-galactopyranoside (127) were obtained from R. glutinosa leaves and three compounds, namely, quercetin (1), guaijaverin (131) and vitexin (132) were isolated and characterized from the leaves R. natalensis. Spectroscopic techniques such as NMR, UV-Vis, FTIR, HRESIMS and single X-ray crystallography were used to characterize the isolated compounds.Item Phytochemical Investigation and Antioxidant Analysis of Seeds and Aerial Parts of Coriander (Coriandrum Sativum L.) Cultivated in Ethiopia(Addis Ababa University, 2021-08-31) Assefa, Mekides; Ele, Estifanos (PhD)In this study essential oils extracted from coriander seed and aerial parts of the samples collected from Sululta, Jimma and Wolaita Sodo were analyzed using GC-MS. Similarly, fatty acids from the coriander seeds were extracted and analyzed in their methyl ester form. The antioxidant activities of the crude extracts of coriander aerial parts were evaluated using a UV-Vis spectrophotometer. The optimum time for extraction of essential oil was determined to be 5 h. The concentration of each fatty acid component was evaluated based on an external standard prepared from linoleic acid ethyl ester. From the analyzed data, the sample collected from Sululta showed the highest number of compounds and a higher amount of Petroselinic acid (107.53 μg/mL) compared to Wolaita Sodo (41.12 μg/mL) and Jimma (20.41μg/mL). In this study, 18.24-22.37% linoleic acid (omega-6) was determined. The P/S index values were calculated for all oil and found to be between 1.69 and 2.39. The total number of compounds identified in the essential oils extracted from seeds collected from Jimma, Sululta and Wolaita Sodo were 7, 9 and 15 with combined percent areas of 99.64, 75.14 and 96.68, respectively. The essential oils were dominated by linalool, which accounts for 36.72%-88.50% of the total amount. From the aerial parts of the plants collected from Jimma, Wolaita Sodo and Sululta, 45, 21 and 19 different compounds were identified, respectively. Decanal and (E)-2-decenal were the major components of the essential oils. The crude methanol extract of coriander aerial parts from all three sample areas showed good radical scavenging activities with values ranging from 91.091% to 92.295% at a concentration of 500 μg/mL.Item Development of Choline Chloride Modified Glassy Carbon Electrode for the Determination of Pentachlorophenol(Addis Ababa University, 2021-07-19) Berhe, Meron; Negash, Negussie (PhD)A simple, sensitive electrochemical sensor was developed for the determination of pentachlorophenol (PCP) using low cost and environmental friendly choline chloride (ChCl) modified glassy carbon electrode (GCE). The structural and electrocatalytic activities of the electrodes were characterized using Fourier transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The covalent attachment of ChCl on to GCE results in a stable positively charged choline chloride modified glassy carbon electrode (ChCl/GCE) with large effective surface area. The ChCl/GCE also showed a remarkable improvement for the oxidation activity of PCP, which results in enhancement in the current response compared to the bare GCE. Under optimum conditions, the square wave voltammetric current of PCP was proportional to its concentration in the linear range of 9 ×10 −9 to 1 ×10 −5 mol L−1 with a detection limit 4.45×10 −9 mol L−1 (S/N=3). The developed method was more sensitive and simple as compared with the literature reports. Additionally, it is also successfully applied for the determination of PCP in three different water samples collected from the river around the industrial area, the tap water and effluents from the pulp and paper industry.Item Determination of Selected Heavy Metals in Little Akaki Waste Water by Using Graphite Furnace Atomic Absorption Spectroscopy (GFAAS)(Addis Ababa University, 2021-06-06) Melese, Gashaw; Tessema, Merid (PhD)In this study, river water samples taken from three different locations along the course of the Little Akaki and Entoto River in Addis Ababa were analyzed to determine potentially toxic trace element concentrations. The mean concentrations of toxic heavy metals in Little Akaki and Entoto River in (μg/L); for Zn (124 ± 2.2, 108 ± 1.3), Cr (3.51 ± 0.05, 0.74 ± 0.13), Cu (10.3 ± 1.1, 10.1 ± 0.27) , Pb (15.7 ± 0.76, 3.42 ± 0.07), Co (13.3 ± 0.34, 3.32 ± 0.11) , Cd (5.41 ± 0.21 , 0.435 ± 0.049), As (5.58 ± 0.32 , 1.20 ± 0.043), and Hg (0.0564 ± 0.0123, BDL), respectively. A strong positive correlation was observed between several of the trace elements indicating common sources. The concentrations of Cd, Co and Pb in Little Akaki River exceeded the permissible limits of the Ethiopian, European Community and WHO for drinking water quality guidelines. The pollution of the river water is increasing alarmingly and poses serious threat to human health. Many of the concentrations were higher than previously reported. It is, thus, necessary to take serious and essential measures from the concerned bodies. Adoption of adequate measures to remove the heavy metal load from the industrial waste water and upgrading of sewage treatment plants are suggested to avoid further deterioration of the river water quality.Item Phytochemical Studies on Premna Schimperi Engl (Lamiaceae)(Addis Ababa University, 2021-09-20) Nasir, Mohammedamin; Ele, Estifanos (PhD); Mammo, Wendimagegn (Professor)In this study, attempts were made to isolate secondary metabolites from the solvent extracts of the dried leaves of Premna schimperi Engl. The essential oil obtained by hydrodistillation of the dried leaves of P. schimperi was also analyzed by GC-MS. A total of six compounds were isolated from the solvent extracts, of which ent-8,12α-epidioxy-12-hydroxylabda-9(11),13-dien-15-oic acid -lactone (71), 3,5,5'-trihydroxy-6,7,3',4'-tetramethoxyflavone (157) and 3,5,7,5'-tetrahydroxy-6,3',4'-trimethoxyflavone (158) were isolated from the chloroform extract, while a straight chain primary alcohol (165) was isolated from the petroleum ether extract, and luteolin (159) and p-hydroxycinnamic acid (164) were isolated from the ethyl acetate portion of the methanol extract. Per acetylation of compound 157 using acetic anhydride and pyridine gave triacetate 157-Ac. The GC-MS analysis of the essential oil revealed 36 compounds, of which the major compositions were caryophyllene (9), caryophyllene oxide (10), terpinen-4-ol (33), -curcumene (166), eugenol (167), -sesquiphellandrene (168), -gurjunene (169), 2-isopropyl-5-methyl-9-methylene-bicyclo[4.4.0]dec-1-ene (170), -eudesmol (171). The antioxidant activities of the MeOH extract of the leaves of P. schimperi and compound 71 were assessed using the DPPH radical scavenging assay. The MeOH extract reduced the stable DPPH radical by 95.3% whereas compound 71 reduced the stable DPPH radical by 62.2% at 100 μg/mL, which suggested that they are potential radical scavengers.Item Simultaneous Determination of Ampicillin Sodium and Sulbactam Sodium in Binary Mixtures and Commercial Dosage Forms using Chemometrics Assisted Spectrophotometric Techniques(Addis Ababa University, 2009-06) Mamo, Zelalem; Maaboud, Abdel (Prof.)The binary mixture of ampicillin sodium and sulbactam sodium is officially analyzed by HPLC but they can not be simultaneously determined by the normal spectrophotometric techniques since their absorption spectra have a strong degree of overlapping. This study applied four Chemometrics-a ssisted spectrophotometric techniques for the simultaneous determination of the two drugs without undergoing any physical separation: derivative spectrophotometry, derivative ratio technique, class ical least square techniques and principal component regression techniques. The derivative spectrophotomet ric t echniques could not be successful since the overlapping absorption spectra of the two drugs could not be resolved from each other by this t echnique. The derivative ratio technique showed a better result since it has separated the two spectra to a better extent. The technique determi ned ampicil lin in t he mixture by using sulbactam sodium as a divisor at 251 nm, 252nm & 253nm. The amount of sulbactam sodium was also determined using ampicillin sodium as a divisor at 205nm, 222nm & 245nm. The CLS and PCR methods were found to be capable of separating and hence determining the two drugs simultaneously better than the oth er t echniques as ca n be seen from the recovery res ults. The recovery results by all techniques were acceptable and very close to the results obtained by the officia l method and t herefore the techn ique can equivalently be used for the simultaneous determination of the studied drugs. Key words: Chemometrics, Spectrophotometry, Ampicillin sodium, Sulbactam sodium.Item Flame Atomic Absorption Spectrophotometric Determination of some Selected Minerals in Multivitamin Pharmaceutical Dosage forms Marketed in Ethiopia(Addis Ababa University, 2009-12) Mengistu, Mequanent; Ahmed, Adnan( Prof,)Six commercial brands of multivitamins with multimineral marketed in Ethiopia were analyzed for their macro Ca (II), Mg (II) and K (I)) and micro Cr (III and VI)) elemental quantitation , prior to analysis samples were digested in Kjeldahl apparatus with 10 ml analytical grade of o concentrated (67-70) HNO) % w/v and 5 ml of 30% H20 2 w/v healed at a temperature of 150 C in order to remove all the organic matters of multivitamin until a clear solution was obtained. Each sample solution was quantitative ly transferred to 100 ml volumetric flask and adjusted to the mark with deionized water. The calibration curve was linear in the range of 0.001 Ilg/mL to 0.0225 Ilg/mL for magnesium (TI), 0.01 Ilg/mL to 3.00 Ilg/mL of calcium (II), 0.01 Ilg/mL to 1.5 Ilg/ml of potassium (I) and 0.05Ilg/ml to 3.00 Ilg/mL of total clU'omium (III and VI).The correlation coefficients for all standard metallic solutions of Ca (II), Mg (II), K (I) and total Cr . (III and VI) in the linear range of r > 0.998. The precision were evaluated in an inter-day and intera-day determination of magnesium (II) and calcium (II) in Maxamine forte tablets, the RSD and RSE were lower than 2% and the recoveries were carried out and found to be between 98% and 101.0 I % that ascertains good precision of the method. Thus, F AAS was found to be simple to operate, sensitive, precise alld suitable for quantitative determination of metal ions in multivitamin with multimineral preparations and could be useful in a routine work. Key words: FAAS, Wet digestion, Elemental analys is, Multivitamins with multiminerals dosage formsItem Determination of Heavy Metal (Cr, Cd, Pb, Ni) Concentration in Paint Industry Effluent in Addis Ababa Ethiopia by Flame Atomic Absorption Spectroscopy (FAAS)(Addis Ababa University, 2021-11-23) Hailemichael, Million; Tessema, Merid (PhD)Heavy metals pollution is a major problem in both developed and developing countries. In Ethiopia, the wastewater in most of the paint industries is not treated properly, but instead is fed directly into rivers. Recently, there are more paint industries in Ethiopia, polluting the environment and posing public risk from the release of untreated waste. This industrial sewage pollutes the nearby bodies of water and affects the growth of vegetation. These toxic heavy metals, when released into the aquatic environment, enter the food chain and cause various health problems in humans. This research work deals with the determination of toxic heavy metals in industrial effluents from four paint industries. The overall results indicate a high concentration of heavy metals in the effluents samples from four different paint industries.The study reveals that the Kadisco and Abay paint industries were the major contributors of toxic heavy metals, particularly Cr, Cd, Pb, and Ni in the surrounding. The paint industry in Addis Ababa contributes to the pollution of the river water. Major contributors include the Nefas silk paint factory which released 5.602 mg/L toxic cadmium, the Kadiscopaint factory which released 1.781 mg/L chromium and an average of 0.8101 mg/L lead. The paint factory Abay released an average value of 4.261 mg/L nickel. All indicated values were above the permissible limit value of the ES EPA and the WHO.Item Removal of Hexavalent Chromium by Adsorption Using Stem Extract Material from Water Hyacinth(Addis Ababa University, 2021-07-27) Mekonen, Nibret; Mehretie, Solomon (PhD)Environmental pollution is one of the public issues for both developed and developing countries due to population growth, industrialization, urbanization and economic development. Toxic heavy metals are the most common inorganic pollutants to the environment. Chromium is one of the toxic heavy metal identified by world health organization (WHO) as major public health concern. This study focus on the removal of hexavalent chromium (Cr(VI)) on a stem extract material from water hyacinth. The physicochemical properties like crude fat, crude protein, crude fiber, moisture and ash contents of the adsorbent material were investigated. The effects of various variables such as initial concentration of Cr(VI), contact time, adsorbent dosage and pH, which influence the adsorption process were studied using UV-visible spectrophotometer. The optimum conditions were found to be 5.0 mg for adsorbent dose, and 240 and 210 min for contact times in the unmodified (SEMWH) and modified (SEMWH-AN) adsorbent materials, respectively. The adsorption capacities were found to be of 31.82 for SEMWH and 35.64 mg/g for SEMWH-AN adsorbents. In addition, maximum removal percentages of Cr(VI) were 96.0% and 99.9% for the aforementioned adsorbents, respectively. The experimental results show that the adsorption of Cr(VI) on adsorbents follow Langmuir isotherm model and obey pseudo-second-order kineticsItem An Investigation of the Flavonoids of Berbera (millpttia ferruqinea)(Addis Ababa University, 1988-06) Bekele, Amha; Dajen, Ermias (PhD)Mi ~letti a f-?rr ;~~~in~a (Hcc:--'!s-:) BAK .. : ·:>ca.l:y known as Berbera is a pla~t ~~ ~ ·~~ic to ~thi0?:a. P":1ytochemi c~!l.l ir-:ve.=t'::7a+_ic-:1 of t~·;,:: st.eI:l-!:H:1!.-}-: cf ·.:.~:ls I.J :a.!it r-es:..tlted in the isolativ~'" ':. f 2C Gl1mp-;".u'.dz ,)f w~ic~: :--.:ne b -;J.ve b~~ :1 s-~nel-ated on t~e remaini~g 0~~ C0~~0~~d . ~e c~oracter izec ("ompounds are 4-hyG.!"'oxy: o:-'.chocar;· in (4'5) . 4 I hydroxyis01o:1chccdr'pir'..(47 ) ~ fle:1'icnappa::5!'1-B(48) , calopogoniurn isofl avone-B(49). i s oj arna i ci!'1 (5 G) jamaicird511. ichthynone( 52j a:-.d 5-methoxy durn: il one (53) . Three of the i501 ated compounds a ppea ;~ to be nove 1 ar.d are ide::.t i f ied as 5-rr.et:,,)x)' d~.lr!U.i llo.:lc (5. 6--c.imethoxy-3 ' .41- met~y 1 enedioxy-2 ~ .2: I -di met~y: ~'{ra.~ ::,. [5 " ,6 " : 7 .8 ~ isc.flavo: 1e:. iS0jamo.icin (3··-m.eth0Xy·-~·.5-~nt?tr:ylen '?d:oxy- 2 1 : .2 1 1- dimethylpyrano [5 1' ,6 1 1: 7.81 150: ~avcne1 a:1G.. 4 : - ~yd.':"oxyi.s G-- :or:ch.:)car-pin(4' -hydrc.xy-2: I, 21 '-di:netr.y:pyt'"a~ .... :) {5:' .6 t ::7 .81 flavar.one) .Item Determination of Selected Metals in Pumpkin Peel Flesh and Seed Samples from three Different Areas in Ethiopia by Microwave Plasma Atomic Emission Spectrometry(Addis Ababa University, 2021-07-23) Yetesha, Abeb; Yohannes, Weldegebriel (PhD)In this study the level of selected metals (Na, Mg, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Cd) and health risk assessment of heavy metals (Mn, Ni, Cu, Zn, Cr, Cd) in pumpkin peel, flesh and seed were determined using microwave plasma-atomic emission spectrometry. Samples were collected from three different parts of Ethiopia (Woliso, Oromiya Region; Minjar Shenkora, Amhara Region and Arbaminch, South Nations and Nationality People Region). A 0.5 g dried and powdered samples were wet acid digested (69% HNO3 and 30% H2O2) in three stages for each sample by microwave digester with optimized conditions. The calibration curves were linear with correlation coefficient (R2) value ranging from 0.996 to 0.9999 which indicates a very good linearity of curves. The calculated percentage recovery for different parts of pumpkin samples digestion method were found in the range 90-106% for peel; 92-110% for flesh and 90-108% for seed which are within the acceptable range for all metals, indicating the efficiency of the optimized procedure. The results show the mean concentration of studied metals in pumpkin peel sample from three areas were K (27806), Ca (5268), Mg (4716), Fe (157), Na (167), Mn (28.9), Zn (24.2), Cu (8.14), Ni (3.79), Cr (0.28), Cd (0.24) mg/kg. The average concentration of metals determined in pumpkin flesh were K (29531), Ca (3191), Mg (848), Fe (111), Na (63.1), Cu (15.1), Mn (9.63), Zn (10.6), Ni (2.14), Cd (0.46) and Cr (0.36) mg/kg. Pumpkin seed average metal concentration from the three sites were K (10667), Mg (4668), Ca (2919), Fe (225), Na (171), Zn (67.8), Mn (33.4), Cu (10.8), Ni (3.44), Cd (1.39) and Cr (0.69) mg/kg. The concentration levels of K, Cr, Fe, Ni, Cu and Cd obtained are higher than daily recommended values of guidelines (FAO/WHO, 2015). All calculated values of HQ from three sites were less than the permissible limit (1.0). This indicates no adverse non carcinogenic health risk due to consumption of the pumpkin from selected areas. The HI for pumpkin flesh from three areas were found to be less than unity, with HI values = 0.54, 0.42, 0.54 for Woliso, Minjar Shenkora and Arbaminch, respectively. HI values from pumpkin seed were = 0.73, 0.61 and 0.62 from Woliso, Minjar Shenkora and Arbaminch, respectively. HI values from pumpkin edible part in all selected areas are less than one and thus have no adverse health impact on consumers. This indicates ingestion of pumpkin from selected areas is safe from non-carcinogenic risk. The total cancer risk (TCR) due to the consumption of pumpkin flesh and seed through Cr and Cd from all sampling areas are between 1.1 x 10-4 to 1.8 x 10-4 which is approximately equal to the maximum limit value of 1 x 10−4 indicating the non-risk of exposure to cancer due to the consumption of pumpkin from the selected areas. ANOVA result shows that for most of the determined metals there was a significant variation within and between sample sites which could be ascribed to different factors such as maturity of the pumpkin when collected, type of soil, the level of traditional fertilizer (dung), level of different wastes from household. The Pearson correlation coefficients of most metals from three sites have shown strong relationship. Pearson correlation coefficient between metal concentrations of pumpkin peel sample was a perfect positive relationship (+1 correlation value) between Na/Ni, Mg/Cr, Mg/Cd, Cr/Cd; a perfect negative relationship is observed between K/Fe; pumpkin flesh samples have a perfect positive relationship between K/Cu and Fe/Ni (r = +1). The perfect positive correlation is detected in between Na/Fe, Mg/Mn and a negative perfect correlation is in between Mg/Cd and Ca/Cr from the pumpkin seed samples.Item Investigation of Solvent Effects on Carbonyl Stretching Vibrational Frequency of Camphor(Addis Ababa University, 2021-08-30) Fituma, Abiyot; Redi, Mesfin (PhD)Solvent effects on the carbonyl stretching vibrational frequency of Camphor were investigated. The solvents were chosen to cover wide polarity range and include carbon tetrachloride,2-propanol, methanol, and acetonitrile. For protonic and aprotonic solvents two distinct behaviors were observed. In non-protonic or aprotonic solvent there seems little or negligible polarity dependent shift was observed. The situation is different for protonic solvent where strong blue shift was obtained. These facts could be attributed to the low dipole moment of the chromophore (in aprotonic solvents) and hydrogen bonding with solvent molecules. The broadness in protonic solvents compared to that in aprotonic solvents support the suggestion made earlier and indicate the Band I is due to mainly hydrogen bonding. Similarly, the solvent dependence of Band II analyzed. Generally, a bathochromic shift was observed though the peak in acetonitrile appears at higher frequency than both protonic solvents. Additional shoulder peak of absorption was observed in methanol and propanol solvents. What is striking was that the shoulder is approximately same as that found in CCl4 solution. This may be due to complex (hydrogen bonding) between the carbon of carbonyl and oxygen of the alcohols.Item Disposable Screen Printed Carbon Electrode Based Electrochemical Sensors for the Determination of Brucine Chloramphenicol Niclosamide and Nicotine(Addis Ababa University, 2021-09-23) Hailu, Tesfu; Tessema, Merid (PhD)In this study, various types of simple, scalable and low cost chemically modified electrodes were successfully developed for the sensitive and selective determination of niclosamide (NA), chloramphenicol (CAP), Nicotine (NIC) and Brucine (BRU). First, a simple and fast efficient activation of pristine bare screen printed carbon electrode (SPCE) was performed by linear sweep voltammetry using KOH solution and was used for the determination of NA and CAP. The activated-SPCE was characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), electroactive surface area (ESA), Fourier transform infrared spectrometry (FTIR) and scanning electron microscope (SEM). The cyclic and square wave voltammetric (SWV) studies of NA in 30% DMF Britton-Robinson buffer (BRB) solution pH of 7.5 showed an electrocatalytic effects towards NA, which resulted in a higher current response and a negative shift in the peak potential at the activated-SPCE compared to the bare SPCE. Under the optimized conditions, a linear calibration curve was obtained using SWV in the range of 0.06 to 50 μM with a limit of detection and a limit of quantification of 0.0051 μM and 0.017 μM, respectively. Next, the same electrode material was used for the determination of CAP using SWV. The CV and SWV studies of CAP in 0.10 M phosphate buffer solution (PBS) pH 6.5 showed an electrocatalytic effect towards CAP, which resulted in a higher current response and a negative shift in the peak potential. The activated-electrode exhibited linear SWV responses towards the determination of CAP in the range of 0.05-100 μM with a limit of detection and a limit of quantification 0.02 and 0.067 μM, respectively. To the activated-SPCE, para-aminobenzene sulfonic acid (p-ABSA) was grafted electrochemically and SEM, EIS, CV, FTIR, and ultraviolet–visible spectroscopy (UV-Vis) were used for the characterization of the electrografted SPCE. The CV and EIS studies of the modified electrode showed that it has lower conductivity however; the grafted electrode has better electrocatalytic performance towards nicotine determination in BRB solution pH 8.0. The p-ABSA grafted SPCE exhibited excellent SWV responses towards NIC determination in the linear range of 0.5-300 μM with a limit of detection and a limit of quantification of 0.35 μM and 1.14 μM, respectively. Lastly, a new SPCE was prepared by electropolymerization of 3,4-Ethylenedioxythiophene (EDOT) on the surface of the p-ABSA grafted SPCE. The electrode was characterized by SEM, CV, ESA, EIS, FTIR and UV-Vis, and the formation of a highly conductive surface was confirmed by CV, ESA and EIS studies. The polymer film modified SPCE was used for the determination of brucine (BRU). A significant enhancement in the peak current response for BRU was observed at the modified electrode compared to the unmodified electrode. The modified electrode demonstrated excellent SWV responses for the determination of BRU in the linear range of 0.03-5.0 μM with a limit of detection and a limit of quantification 0.012 μM and 0.042 μM, respectively. Generally, all the developed sensors were validated successfully for real sample analysis in pharmaceutical formulation and human urine samples with good recovery results. The proposed sensors also displayed good repeatability, reproducibility, long-term stability and selectivity towards potential interferents and are promising materials for the electrochemical sensing of these compounds in real samples.