http://nopr.niscair.res.in/handle/123456789/9005 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/9499 Title: Steam distillation of lemon grass (<i style="">Cymbopogon </i>spp.) <br/> <br/>Authors: Koul, V K; Gandotra, B M; Koul, Suman; Ghosh, S; Tikoo, C L; Gupta, A K <br/> <br/>Abstract: A simple first order kinetic model has been developed for steam distillation of lemongrass (Cymbopogon spp.). This rate model was tested on pilot scale, steam distillation units, with lemon grass batches of 70 to 1000 kg. For intimate contact of lemongrass and steam, two improved direct steam spargers were provided in these units. It is observed, that, the loose packing of plant material inside distillation still and steam injection rate, increases the oil yield. Straight line behaviour with intercept on time axis of the above rate model explains, that, oil production inside the distillation unit is not instantaneous, but some time is required for wetting of grass for the diffusion and osmosis of oil. <br/> <br/>Page(s): 135-139 http://nopr.niscair.res.in/handle/123456789/9498 Title: Metal complexation on functionalised polymer supports–An adsorption/complexation phenomenon <br/> <br/>Authors: Chettiar, K Sivadasan; Sreekumar, K <br/> <br/>Abstract: The present study is aimed at preparing polymer metal complexes of Co(II) and Cu(II) under controlled conditions of concentration, time, temperature and pH The complexes are derived from DVB crosslinked polystyrene and poly(hydroxyethyl methacrylate) supported thiosemicarbazone-transition metal interaction. Crosslinked polymer ligand beads with definite porosity can adsorb metal ions. The question whether metal complexation is a case of adsorption and coordination, is investigated. Kinetics and thermodynamics of adsorption of metal ions on the polymeric ligand with proper surface structures is determined. The equilibrium metal intake by 10 and 15% crosslinked resins at constant temperature was utilised to construct Langmuir and Freundlich adsorption isotherms. The influence of temperature on the extent of adsorption was studied by plotting isotherms at different temperatures and calculating different thermodynamic parameters. <br/> <br/>Page(s): 59-66 http://nopr.niscair.res.in/handle/123456789/9497 Title: Determination of ranitidine using potassium iodate and dichlorofluorescein <br/> <br/>Authors: Basavaiah, K; Nagegowda, P <br/> <br/>Abstract: Two methods for determining ranitidine hydrochloride (RNH) in pure drug and in formulations using potassium iodate and dichlorofuorescein are described. Titrimetry involves the oxidation of RNH by a known excess of potassium iodate in acidic conditions followed by iodometric determination of surplus iodate. In spectrophotometry also, the drug is oxidized by a large excess of iodate and the iodine released is oxidized to ICl₂^- in the presence of chloride ions, and is used to iodinate 2,7-dichlorofluorescein dye and the amount of iodinated dye is measured. Reaction conditions of both methods have been optimized. In titrimetry, the reaction stoichiometry has been established and the reaction scheme of the spectrophotometric method is given. Titrimetry is applicable over 1-16 mg range. In spectrophotometry, the system obeys Beer’s law for 5-50 <img src='/image/spc_char/micro.gif' border=0>g mL^-1. The molar absorptivity and Sandell sensitivity were calculated to be 3.88×10³ L Mol^-1 cm^-1 and 5.72 ng cm^-2, respectively. The calculated limits of detection and quantification were 2.14 and 7.15 <img src='/image/spc_char/micro.gif' border=0>g mL^-1, respectively. The proposed methods were applied successfully to the determination of RNH in pharmaceutical preparations with recoveries in the range of 98.28 ± 0.88 to 103 ± 1.96% (titrimetry) and 99.46 ± 1.88 to 102.58 ± 0.73% (spectrophotometry). The reliability of the assay was established by parallel determination by an established procedure and by recovery studies using standard–addition technique. <br/> <br/>Page(s): 11-16 http://nopr.niscair.res.in/handle/123456789/9496 Title: Assay of tylosin using sodium metaperiodate as an oxidant <br/> <br/>Authors: Prasad, A V S S; Rao, P S N H Ramachandra; Sastry, C S P <br/> <br/>Abstract: Simple and sensitive spectrophotometric methods (M₁ and M₂) based on the oxidation of tylosin (TS) with excess of sodium metaperiodate and estimating either the amount of periodate consumed (with celestine blue (CB) in the presence of Te(IV), M₁) or product formed (iodate with <i style="">p</i>-N-methylaminophenol sulphate–sulphanilamide (PMAP-SA, M₂) have been described. Beer’s law limits, precision and accuracy of the methods are checked by the UV reference method. The methods are found to be suitable for the assay of tylosin. The recovery range is 99.02 to 100.96%. <br/> <br/>Page(s): 7-10