Browsing by Author "Kingsford-Adaboh, R."
Now showing 1 - 19 of 19
Results Per Page
Sort Options
Item Acceptor-donor-acceptor small molecules based on derivatives of 3,4-ethylenedioxythiophene for solution processed organic solar cells(Royal Society of Chemistry, 2016) Antwi, B.Y.; Taylor, R.G.D.; Cameron, J.; Owoare, R.B.; Kingsford-Adaboh, R.; Skabara, P.J.Three simple semiconducting acceptor-donor-acceptor (A-D-A) small molecules based on an electron-rich (3,4-ethylenedioxythiophene) EDOT central core have been synthesised (DIN-2TE, DRH-2TE, DECA-2TE) and characterised. Organic photovoltaic (OPV) devices incorporating these materials have been prepared and evaluated. The physical properties of the molecules were characterised by TGA, DSC, UV/vis spectroscopy and cyclic voltammetry. The optical HOMO-LUMO energy gaps of the molecules in the solid state were in the range 1.57-1.82 eV, and in solution 1.88-2.04 eV. Electrochemical HOMO-LUMO energy gaps determined by cyclic voltammetry were found to be in the range 1.97-2.31 eV. The addition of 1% 1,8-diiodooctane (DIO) to photoactive blends of the A-D-A molecules and PC71BM more than doubled the power conversion efficiency (PCE) in the case of DRH-2TE:PC71BM devices to 1.36%. © 2016 The Royal Society of Chemistry.Item Alpinumisoflavone(Acta Crystallographica, 2008-03) Harrison, K.E.J.J.; Tabuchi, Y.; Ishida, H.; Kingsford-Adaboh, R.Item Alpinumisoflavones(Acta Crystaltographics E Section E 4(64): 07-13, 2008) Kingsford-Adaboh, R.; Harrison, J. J. E. K.The title compound, C20H16O5, [systematic name: 5-hydroxy-7-(4-hydroxyphenyl)-2,2-dymethuyly-2H, 6H=benzol (1, 2-b:5, 4-b)] – dipyran-6-one], was obtained by demethylation of the biologically active related compound, 4-O methylaphinumiso-flavone. The molecular structure of the title compound is characterized by a fused tricyclic system that contains an approximately planar benzopyrone ring fragment. The six membered pyran ring adopts a half-chair conformation. Both ring systems show an out-of-plane twist. The dihedral angle between the mean plane of the benzopyrone system and the benzene ring is 54.29(3)o. The molecules are linked by O-H … hydrogen bonds, forming a molecular tape running along the b axis.Item Assessment of Gasoline Quality Marketed in Accra Metropolis, Ghana(University of Ghana, 2015-07) Ubeidalah, S. K.; Donkor, A. K.; Kingsford-Adaboh, R.; University of Ghana, College of Basic and Applied Sciences, School of Physical and Mathematical Sciences, Department of ChemistryPremium gasoline is often adulterated with cheaper products (adulterants) like domestic kerosene. Kerosene is more difficult to burn than gasoline and this result in the increase of tailpipe emissions and engine complexities. Having similar physical and chemical properties, the gasoline and kerosene cannot be distinguished easily leading to a complication in identification and quantification of the adulterant. Routine monitoring of gasoline at the pump has been pointed out as essential in the prevention of this adulteration and a number of possible methods have been reviewed as there is no standard method for the detection and quantification of kerosene in gasoline. Most of these methods are not utilized in developing countries like Ghana because they require either specialized laboratory, equipment or chemical hence their implementation involves huge financial budgets. A corollary of this is a need for cheaper and tailored method for monitoring kerosene adulteration in gasoline. This study monitored gasoline adulteration with domestic kerosene in Accra Metropolis by exploring the differences in their acidity levels as a “fingerprint”, determined by using an in-house, simple direct titration (SDT) method. Physicochemical properties of gasoline samples and other petroleum distillate fractions were studied after which simulation of gasoline adulteration with domestic kerosene was carried out and the acidity determined by the SDT method to obtain a calibration plot. The calibration standard was then utilized to estimate the amount of domestic kerosene (adulterant) present in 20 gasoline samples from some retail outlets in Accra Metropolis. Domestic kerosene in the range of 5 - 29% was found in 50% of the stations. This study therefore demonstrated that the method is feasible, cheaper, and does not require specialized laboratory or highly trained personnel to execute. Key standard quality parameters of the commercial gasolines were also determined and their compliance with local and international specifications was evaluated. However the gasoline available in Accra Metropolis was found not to conform to standard specifications for Europe, Japan and India. 35% did not conform to specification of Ghana Standard Authority (GSA) as well.Item Bis[(3-chlorobenzy]) 2-phenyl- propanediotate dehydrate(Acta Crystallographica section E 8(E66):02/68, 2010) Kingsford-Adaboh, R.; Harrison, J.J.E.K.; Gotoh, K.; Ishida, H.In the asymmetric unit of the title compound. 2C7H9CIN+… C2H2O22-2H2O, there are two crystallographically independent cations, one dianion and two water molecules. The dihedral angle between the two carboxylate groups of the dianion is 78.1 (2). In the crystal, the components are held together by N-H, O, O-H … O and C-H … O hydrogen bonds forming a layer parallel to the bc plane, with the bydrophilic and hydrophobic groups located I the inner and outer regions of the layers, respectively.Item Centrosymmetric structures of three substituted malonic acids(Journal of Chemical Crystallography 3(41): 306-311, 2010) Kingsford-Adaboh, R.; Harrison, J.J.E.K.; Ueda, S.; Gotoh, K.; Ishida, H.Crystal structures of 2-methylmalonic acid 2-ethlmalonic acid and 2-phenylmalonic acid, which are derivatives of malonic acid and have found usefulness in diagnostics and biochemical evaluations as markers and organic synthesis, are reported. 2-Methylmalonic acid and 2-ethylmalonic acid both crystallize in triclinic P-1 space group with cell parameters of a = 5.1033(7), b = 5.4231(7), c = 10.0887(14) , Ǎ = 88.074(4), = 89.999(5) and = 67.955()o for 2-methylmalonic acid, and a = 5.2073(4), b = 7.2258(6), c = 8.5655(6) Ǎ, a = 88.086(2), β = 75.307(2) and y = 85.904(3)o for 2-ethylmalonic acid, 2-phenylamlonic acid on the other hand crystallizes in monoclinic P21/c with cell parameters a = 8.6494(4), b = 5.48733(1(), c = 17.1706(6) Ǎ and β = 90.1068(17)o. The observed topology of the hydrogen bonding network is to a large extent dictated by the symmetrical substitution pattern with an open arrangement of hydrogen bonds. Each of the C=O double bonds in both 2-methylmalonic acid and 2-ethylmalonic acid in translationally offset, forming planarcentrosymmetric carboxy-dimmers. Molecules related by centre of inversion in spite of the constraints imposed by substituents are linked by O-H .. O hydrogen bonds. This results in the formation of paralled zig-zag chains running along the [101] direction. In 2-phenylmalonic acid, the zig-zag molecular residue is parallely stacked with successive catemers. These laterally displaced catemers are also coiled in a twofold twist on the screw axis (x, ½ + y, ½ - z) along the b-glide (x, ½ = y, ½ z) when viewed along the (101) plane.Item Crystal structure and in vitro antimicrobial activity studies of Robustic acid and other Alpinumisoflavones isolated from Millettia thonningii(Zeitschrift fur Kristallographie - Crystalline Materials, 2019-04) Harrison, J.J.E.K.; Ayine-Tora, M.D.; Appiagyei, B.; Mills-Robertson, F.C.; Asomaning, W.A.; Achel, D.G.; Ishida, H.; Kingsford-Adaboh, R.We report a systematic study of the antibacterial inhibitory potential of isoflavone natural products isolated from the seeds extracts of Millettia thonningii. In an effort to gain bond topological information which may have consequences for the observed bioactivities, the crystal structure of robustic acid was solved and refined using the independent atom as well as the invariom model, and the structures were compared. Robustic acid contains a fused tricyclic unit with a benzopyran moiety, with a phenylene ring substitution on the coumarin ring similar to the alpinumisoflavones isolated from this plant. At a minimum inhibitory concentration of ~1 mg/mL, alpinumisoflavone and robustic acid were found to be cytotoxic to Staphylococcus aureus (ATCC 25923) showing a zone of inhibition (ZOI) of ~9 mm. On the other hand, at ~2 mg/mL, these compounds were found to be bacteriostatic to a hospital isolate of Salmonella typhi with about 7 mm ZOI. Taken together, these compounds offer potential new avenues for targeting both Gram positive and negative bacteria and could be useful as chemical probes for understanding these pathogens in an effort to overcome drug resistance.Item Crystal structure of 4'-O-methylalpinumisoflavone at 90K(Crystal Research and Technology, 2006-07) Kingsford-Adaboh, R.; Ahiano, E.; Dittrich, B.; Okamoto, H.; Kimura, M.; Ishida, H.4'-O-Methylalpinumisoflavone crystals which hitherto had been difficult to crystallize for X-ray diffraction analyses have been obtained from a demethylated product of O, O- dimethylalpinumisoflavone. The structural and conformational features of the crystal measured at 90 K are reported and compared with previously reported work of O,O-dimethylalpinumisoflavone and 5-O-methyl-4'-O-(3-methyl-but-2-en-1-yl) alpinumiso-flavone. Each of these compounds is characterized by a six membered ring that is further fused to a benzopyrone isoflavone moiety resulting in a tricyclic ring system. This six membered ring shows a half-chair conformation in all the molecules studied, with the ring in the title compound showing the least Cremer-Pople puckering amplitude Q and shorter inter and intramolecular contacts. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA,.Item Crystal structure of three solvated alphinumisoflavones(Struct. Chem. 2(20): 203-211, 2008) Kingsford-Adaboh, R.; Harrison, J. J. E. K.Single crystals of alphinumisoflavone, C20H16O5, (systematic name: 5-hydroxy-7- (4 hydroxyphenyl)-2, 2-dimethly-2H, 6Hbenzo [1, 2-b: 5, 4-b’] solvated with water, methanol, and ethanol, have been obtained. The incorporation of the solvent molecules into the crystal structure creates a new short inter-molecular O-H … O and C-H … O contacts between the alphinumisolavone moiety and its solvate molecule. The temperatures at which the solvated molecules lose their solvent molecules are 53, 54, and 65 oC for water, methanol, and ethanol, respectively. The observed temperatures at which the solvates efflorescence are reflective of the progressive increase in mass of the solvates from water to ethno lint he series. The benzopyrone moiety shows the usual planar conformation with the pyran ring deformed into a half-chair conformer as seen previously in the other analogues compounds with puckering pharameters [A], 0.2656(8), 0.3703), and 0.3957(9), respectively, for the water, ethanol, and methanol solvates. These are higher than the non-solvated alpinumisoflaovone compound previously studies. The size of a substituent group proximal to the keto group has a more pronounced effect on the degree of pickering than substation on the terminal phenyl ring. The attached phenyl ring shows consistent out-of-plane twist from the mean plane of the benzopyrone system as the observed previously for this class of compounds. The observed dihedral angles are 30.26(3), 37.75(3), and 3400(3)o, respectively, for the water, methanol, and ethanol solvates.Item Crystal structure of three solvated Alpinumisoflavones(Structural Chemistry, 2009-04) Harrison, J.J.E.K.; Tabuchi, Y.; Ishida, H.; Kingsford-Adaboh, R.Single crystals of alpinumisoflavone, C20H16O 5, {systematic name: 5-hydroxy-7-(4 hydroxyphenyl)-2, 2-dimethyl-2H, 6H-benzo [1, 2-b: 5, 4-b′]-dipyran-6-one}, solvated with water, methanol, and ethanol, have been obtained. The incorporation of the solvent molecules into the crystal structure creates a new short inter-molecular O- H•••O and C-H•••O contacts between the alpinumisoflavone moiety and its solvate molecule. The temperatures at which the solvated molecules lose their solvent molecules are 53, 54, and 65 °C for water, methanol, and ethanol, respectively. The observed temperatures at which the solvates efflorescence are reflective of the progressive increase in mass of the solvates from water to ethanol in the series. The benzopyrone moiety shows the usual planar conformation with the pyran ring deformed into a half-chair conformer as seen previously in the other analogous compounds with puckering parameters [Å], 0.2656(8), 0.3703(8), and 0.3957(9), respectively, for the water, ethanol, and methanol solvates. These are higher than the non-solvated alpinumisoflavone compound previously studied. The size of a substituent group proximal to the keto group has a more pronounced effect on the degree of puckering than substitution on the terminal phenyl ring. The attached phenyl ring shows consistent out-of-plane twist from the mean plane of the benzopyrone system as observed previously for this class of compounds. The observed dihedral angles are 30.26(3), 37.75(3), and 34.00(3)°, respectively, for the water, methanol, and ethanol solvates. © 2009 Springer Science+Business Media, LLC.Item The crystal structures of O,O-Dimethylalpinumisoflavone and 5-O-Methyl-4′-O-(3-methyl-but-2-en-1-yl)alpinumisoflavone(Crystal Research and Technology, 2001-01) Kingsford-Adaboh, R.; Osei-Fosu, P.; Asomaning, W.A.; Weber, M.; Luger, P.The petrol extract of the rootbark of Milletia Thonningii obtained by column chromatography afforded sixteen different crystalline samples to be isolated. The crystal structures of two of these compounds, O,O-Dimethylalpinumisoflavone (I) and 5-O-Methyl-4′-O-(3-methyl-but-2-en-1-yl)alpinumisoflavone (II) are being reported here. (II) has two independent molecules in the asymmetric unit and differs from (I) in a longer side chain attached to C(15) of the phenyl ring. The structural features of the three molecules in the title compounds are reported and compared. The derivatives, being subject of this article are the first reported crystal structures where the isoflavone fragment is fused to a further six membered ring that results in a tricyclic ring system. The benzopyrone fragments are planar. The dihedral angles between the benzopyrone fragment and the phenyl ring being 55.38(6)° for (I) and 44.75(15)°/44.64(15)° for the respective independent molecules of (II) are within the range of values observed for similar structures.Item DL-Arginine monohydrate at 100 K(Acta Crystallographica, Section C: Crystal Structure Communications, 2000-11) Kingsford-Adaboh, R.; Grosche, M.; Dittrich, B.; Luger, P.In the title compound, C6H14N4O2·H2O, the α-amino group is neutral. The molecular side chain including the guanidinium group is not fully extended, having a near gauche-gauche conformation [χ3 = 59.0 (1)°; χ4 = 72.8 (1)°]. The network of hydrogen bonds stabilizing the crystal lattice includes those formed between the deprotonated and negatively charged α-carboxylate groups and the positively charged amino groups of the guanidinium group of neighbouring molecules. N-H···O double bond C and water-mediated N-H···O hydrogen bonds link individual molecules to produce pairs of spiral motifs laterally connected by N-H···O and C-H···O hydrogen bonds.Item In search of new leads: A closer look at the therapeutic potential of the constituents of millettia thonningii, Millettia pachycarpa and their structural analogues(International Journal of Pharmacy and Pharmaceutical Sciences, 2011-01) Harrison, J.J.E.K.; Dankyi, E.; Kingsford-Adaboh, R.; Ishida, H.This review discusses the potential applications of isoflavonoids from Millettia thonningii and M. pachycarpa in developing new pharmaceutical agents based on folkloric anecdotes and evidences from pharmacological and biochemical assays and to encourage further research into their pharmacological applications. Millettia thonningii is a deciduous plant indigenous to tropical West Africa, M. pachycarpa, is a climbing shrub indigenous to South-East Asia and other species have been used in folk-medicine for the treatment of inflammatory diseases, chronic diseases and several pathogenic diseases. Scientific research has implicated several prenylated isoflavonoids as being useful antioxidants and used in the management of radical-mediated diseases such as cancer, diabetes, ischemic heart diseases, Alzheimer's and Parkinson's diseases etc. Chemical investigations into these plants have revealed that they contain several isoflavonoids which bear structural resemblance to some of the isoflavonoids already in allopathic medical usage. Plants continue to maintain their historical stead as a store house of important drug candidates and source of new "leads" for synthetic modifications to improve activity through optimization of pharmacodynamic and pharmacokinetic properties. Natural products have also been found useful in specific pharmacological probes, a potential which is grossly underestimated. The alpinumisoflavones which have been isolated from the Millettia thonningii have shown high toxicities to the brine shrimp while isolates from M. pachycarpa have also shown anti-estrogenic and anticancer properties. Information obtained from crystal structural studies of these alpinumisoflavonoids coupled with their molecular and electronic distribution properties can further our understanding of their therapeutic potential and their observed bioactivities. The alpinumisoflavones are characterized by a fused tricyclic ring system which contains nearly coplanar benzopyrone ring fragments and a puckered six membered pyran ring that adopts a half-chair conformation with inter and intra molecular O-H....O and C-H...O contacts. A phenyl ring attached to the benzopyrone moiety shows out of plane twist with various degrees of torsion depending on the substitution on the phenyl ring.Item Invariom structure refinement, electrostatic potential and toxicity of 4-O-methylalpinumisoflavone, O,O-dimethylalpinumisoflavone and 5-O-methyl-4-O-(3-methylbut-2-en-1-yl)alpinumisoflavone(Acta Crystallographica Section B: Structural Science, 2006-10) Kingsford-Adaboh, R.; Dittrich, B.; Hübschle, C.B.; Gbewonyo, W.S.K.; Okamoto, H.; Kimura, M.; Ishida, H.The accurate X-ray single-crystal structures of the isoflavone compounds 4-O-methylalpinumisoflavone, O,O-dimethylalpinumisoflavone and 5-O-methyl-4-O-(3-methylbut-2-en-1yl)alpinumisoflavone {alpinumisoflavone = 5-hydroxy-7-(4-hydroxyphenyl)-2,2-dimethyl-2H,6H-benzo[1,2-b:5,4-b′] -dipyran-6-one} from data sets measured at cryogenic temperature have been obtained from invariom modelling using theoretically predicted Hansen and Coppens multipole-model form factors, which describe the aspherical electron density distribution. Molecular dipole moments and electrostatic potentials obtained from invariom modelling are discussed and compared with results from ab initio theoretical calculations. All three studied compounds are solvent extracts of root bark or seed powder of Millettia thonningii (leguminosae), a plant molluscicide and cercaricide used in Franco West Africa as medication against various diseases. The compounds' toxicities to brine shrimp have been determined and their different potencies tentatively related to conformation differences, intramolecular contacts, dipole moments and electrostatic potential features. © 2006 International Union of Crystallography Printed in Great Britain - all rights reserved.Item Mechano synthesis of co-crystals of Sulfamethoxazole and 8-Hydroxy-7-Iodoquinoline-5-Sulfonic acid based on Green Chemistry principles(Science and Development, 2017) Quashie, A.; Kingsford-Adaboh, R.; Gadzekpo, V.P.Y.Co-crystals have been used to produce new drugs and to improve the physical properties of drugs. Some disease causing germs have developed resistance to newer drugs, hence there is a general trend to take ‘old’ but efficacious drugs, improve their properties and use them to treat the conditions. This study used mechano-synthesis to produce a co-crystal of two active pharmaceutical ingredients (API), Sulfamethoxazole and 8-hdroxy-7-iodoquinoline-5-sulfonic acid (Ferron), based on Green Chemistry principles. The two APIs were combined by mixing, grinding and kneading. The resulting co-crystals were characterized using analytical methods such as spectroscopy, thermal analysis and diffractometry. In-Silico techniques based on computer modelling using Gaussian 09 and VEDA 4 software were used to interpret the vibrational spectrum of the co-crystals. The study found that kneading gave the highest yield compared to mixing and grinding. The study also confirmed that a combination of the analytical methods was necessary to characterize a co-crystal. Co-crystals of Sulfamethoxazole and 8-Hydroxy-7-Iodoquinoline- 5-Sulfonic acid can therefore be formed by kneading, implying that the production of the co-crystals can be done using a process that reduces pollution by the minimal use of solvents. Another implication is that Sulfamethoxazole, whose use has been minimised because of problems such as allergic reactions from patients, can be looked at again and used to produce ‘polydrugs’ which can be used to manage conditions at relatively cheaper costs.Item Pesticide Contamination of Fruits and Vegetables - A Market-Basket Survey from Selected Regions in Ghana(University of Ghana, 2013-06) Asiedu, E.; Kingsford-Adaboh, R.; Klake, R.A market- basket survey was carried out with the aim of determining the concentration levels of pesticides, in lettuce, garden eggs, pineapple and mango from some selected regions in Ghana and to assess the potential health risk associated with exposure to the pesticide residues from fruits and vegetables consumption. A total of 192 fresh samples of fruits and vegetables were randomly collected under normal purchase conditions from 12 major towns and cities in the three regions of Ghana. The samples were extracted and analyzed for organophosphates, synthetic pyrethroids and organochlorine pesticides. The percentage of samples of fruits and vegetables with pesticide residues in Lettuce, Garden eggs, Pineapple and Mango were 52%, 40%, 45%, 48% respectively and concentrations of pesticides did not vary significantly in samples as well as the sampling areas (p>0.05) even though there were differences in residual concentrations of pesticides . The differences in residual concentrations of pesticides could be due to different agricultural practices adopted by farmers and also accessibility of the pesticides. The average residue concentrations range from 0.01-0.45 mg/kg, 0.01-0.30 mg/kg and 0.01- 1.27 mg/kg for organophospates, synthetic pyrethroids and organochlorine pesticides respectively. Lindane, chlorpyrifos and cypermethrin were the most frequent organochlorine, organophosphate and synthetic pyrethroid pesticides respectively while lettuce was the most frequently contaminated sample. Comparing the concentration levels of organochlorine pesticides residue with the maximum residue limits (MRLs) adopted by the FAO/WHO Codex Alimentarious Commission shows that some of the fruits and vegetables sold on Ghanaian markets are contaminated even though the levels are generally low. Health risk analysis indicates that heptachlor in particular may be of public concern since its concentration levels exceeded the reference dose in all the four different types of samples analyzed indicating a great potential for systemic toxicity to consumers in Ghana.Item Speciation of Inorganic Antimony in Polyethylene Terephthalate (Pet) Bottled Water Using Hydride Generation Atomic Absorption Spectrophotometry (HG-AAS)(University Of Ghana, 2015-07) Ali, M.; Carboo, D.; Kingsford-Adaboh, R.; University of Ghana, College of Basic and Applied Sciences, School of Physical and Mathematical Sciences, Department of ChemistryAntimony (Sb) is a regulated drinking water contaminant that has been found to leach from polyethylene terephthalate (PET) plastic containers into the waters stored in them. The common inorganic species of antimony in water are Sb(III) and Sb(V), with the former being more toxic and the latter being more soluble. In order to assess the extent to which waters stored in PET bottles are contaminated with inorganic Sb and to further examine the effect of typical storage conditions on migration rates, speciation analysis of inorganic Sb using hydride generation atomic absorption spectrophotometry (HG-AAS) was undertaken on selected PET plastic bottled waters marketed in the Greater Accra Region of Ghana. Six brands of PET plastic bottled waters were obtained at source on the day of packaging, and analyses undertaken on samples of the waters stored in the plastic containers at intervals of four weeks for twelve weeks, under three carefully chosen storage conditions distinctive of bottled water usage. Selected physicochemical properties of samples of the waters stored in the plastic containers and total Sb of samples of the plastic containers were also determined to discover the effect of some physical properties and certain major ions, and the influence of the different quality PET plastic types on Sb migration respectively. The study revealed amounts of total Sb in the PET plastic containers of the 6 brands ranging from 123.46 mg/kg to 146.45 mg/kg. The selected physicochemical properties of the waters stored in the PET plastic containers considered were pH (6.78 – 7.43), Ca2+ (1.61 – 12.39 mg/L), Mg2+ (1.00 – 4.96 mg/L), HCO3− (6.18 – 55.41 mg/L) and TDS (8.70 – 70.40 mg/L)). PET bottled waters of 5 out of the 6 brands contained Sb (initial total Sb ranging from 1.11 – 14.65 μg/L) before storage. Total Sb concentrations of the waters stored in the plastic containers were observed to increase with storage time under all the three storage conditions for all the brands of PET plastic bottled waters. Sb(III) and Sb(V) of the waters stored in the plastic containers were observed to increase with storage time, with the latter in higher amounts in solution under all the three storage conditions. Waters stored in plastic containers exposed to harsh conditions of the weather like high air temperatures (average temperature for 12 weeks: 23.0ºC in the morning and 39.5ºC in the afternoon) and sunlight outdoors registered the highest Sb concentrations. In conclusion, PET bottled waters marketed in the Greater Accra region were not found to be contaminated with Sb leaching from their packaging PET plastic containers within the one year limited time of expiry using WHO MCL. Notwithstanding that, harsh weather conditions outdoors is most likely to contribute to the rapid migration of the metalloid (Sb) from the plastic containers, making the bottled water unwholesome before its due expiry time is reached.Item Synthesis and crystal structure studies of three n-phenylphthalimide derivatives(Journal of Chemical Crystallography, 2013-03) Rauf, M.K.; Badshah, A.; Kingsford-Adaboh, R.; Harrison, J.J.E.K.; Ishida, H.The three N-phenylphthalimide derivatives, 2-(3,4-dichlorophenyl) isoindoline-1,3-dione (I), 2-(2,4-dichlorophenyl)isoindoline-1,3-dione (II) and 2-(2,4,5-trichlorophenyl)isoindoline-1,3-dione (III), were synthesized by the condensation of equimolar amounts of phthalic anhydride and 3,4-dichloroaniline, 2,4-dichloroaniline, 2,4,5-trichloroaniline, respectively, under acetic acid reflux and their structures determined by a combination of elemental analysis, FT-IR, 1H & 13C-NMR spectroscopy and single crystal X-ray diffraction studies. Compounds I and II crystallize in a monoclinic crystal system (space group P21/c) with cell parameters of a = 5.7414(2), b = 8.0917(6), c = 26.077(1) Å and β = 99.4709(12) o for compound I, and a = 12.7133(9), b = 13.4328(9), c = 7.2603(5) Å and β = 93.210 (2)o for compound II. On the other hand, compound III crystallizes in a tetragonal crystal system (space group I4 1/a) with a = 13.4607(9) and c = 30.100(2) Å. The phthalimide moieties of these compounds are essentially planar, while the chloro-substituted phenyl ring of each compound shows consistent twist from the phthalimide plane with dihedral angles of 61.02(3), 69.09(3) and 85.78(5)o, respectively, for I, II and III. In the crystal structures of these compounds, a few weak C-H···O interactions form double-tape structures of centrosymmetric dimers of graph-set notation R 2 2 (10) for I and III, and an inversion dimer of graph-set motif R 2 2 (14) for II. In addition, some short contacts of C···C, C···O and Cl·· ·Cl are observed for I, II and III, respectively. © 2013 Springer Science+Business Media New York.Item Validation of QuEChERS method for the determination of 36 pesticide residues in fruits and vegetables from Ghana, using gas chromatography with electron capture and pulsed flame photometric detectors(Journal of Environmental Science and Health - Part B Pesticides, Food Contaminants, and Agricultural Wastes, 2015-06) Donkor, A.; Osei-Fosu, P.; Nyarko, S.; Kingsford-Adaboh, R.; Dubey, B.; Asante, I.In this study, “Quick, Easy, Cheap, Effective, Rugged and Safe” ‘QuEChERS’ method was modified for the determination of 36 pesticides fortified at (0.01–1.0) mg kg−1 in three vegetables and a fruit (lettuce, carrot, tomatoes and pineapples respectively) from Ghana. The method involved extraction with acetonitrile, phase separation with primary secondary amine and magnesium sulfate; the final injection solution was reconstituted in ethyl acetate. Organochlorine and synthetic pyrethroids residues were detected with electron capture detector whereas organophosphorus, pulsed flame photometric detector was used. The recoveries at different concentration levels (0.01, 0.1 and 1.0 mg kg−1) were in the range of 83% and 93% with relative standard deviation ranging from 2% to 10% (n = 5) and the coefficient of determination (R2) was greater than 0.99 for all the 36 pesticides. The method was successfully tested on 120 real samples from Accra markets and this proved to be useful for monitoring purposes particularly in laboratories that have no gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry. © 2015, Copyright © Taylor & Francis Group, LLC.