Indian Journal of Ch e mistry Vol. 44A, March 2005 , pp. 469-475 Volumetric and viscometric studies of glycine in binary aqueous solutions of sucrose at different temperatures Amalendu Pal * & Suresh Kumar Departme nt of Chemistry. Kurukshetra University, Kurukshetra 1 36 11 9, 1ndia Emai l: pa l chem @sify.com Recei ved I September 2003; revis ed 5 January 2004 Densiti es and visco sities of glyc in e have been mea sured at 288. 15, 298 .15 and 308.15 K in aqueous sucrose soluti ons ranging fr om 5 to 25 ma ss o/o of sucro se. The visco sity data ha ve been ana lyzed using the J ones-Do le equatio n. Apparent molar volumes, limiting partial molar volume and relative viscos it y have been eva luated from th e de nsity and vi scos ity data. Tra nsfer volumes and limiting partial molar expansibi lities have also been ca lc ul ated from the te mperature dependen ce of limiting partial molar volumes . Th e res ults have been discu ssed in terms of solut e-so lute and solute-solvent interactions and the stru ctural chan ges of the solut es in solutions. IPC Code: lnt.CI 7 GO IN Study of the vo lumetr ic an d transport properties of sucrose in water and in aqueous so lutions of amino acids are very useful to obtain information abo ut various typ es of interactions in so luti on. Consequently, the characteri zation of these interactions can ass ist tn und erstanding the thermodynamic stability of proteins an d their unfolding behavior. Al so, the interactions of amino acids wi th water molecules in aq ueous soluti ons of sucrose and the temperature dependence of these interactions play a vi tal ro le in understanding the nature of action of bioactive molecules and/or the thermodynamic behavior of biochemical process in the body sy stem. In fact, there are ex tensive volumetric and thermochemical property st udi es of amino acids in aq ueo us 1 · 6 or non-aqueous 7 · 8 solutions but very few in aqueous sucrose solutions 9 . We report here in the partial molar volumes, limiting partial molar vo lumes, transfer volumes at infinite dilution, and the infinite dilution partial molar expansibilities of glycine in aqueous sucrose solutions at various temperatures. We al so report here the viscosi ty data in o rd er to compute va lu es of viscosity 8-coefficients. Such data are expected to hi ghli ght the rol e of glycine in presence of aq ueous sucrose so luti on and it s influence with temperature. Materials and Methods Analytical reagent grade glyc in e was recry sta lli zed twice from ethanol-water mixtures. The mate ri al was used after dry in g at 100°C for 6 h and then under vacuum over silica gel at room temperature for a minimum of 24 h. Sucrose (A . R.) was dried under vacuum at 50°C and kept over P 2 0 5 in a vacuum desiccator for a minimum of 48 h at room temperature before use. Water used in these ex periments was deio ni zed and di still ed, and was degassed prior to making solution s. Solutions of sucrose were prepared by ma ss in the range 5-25 % by 5% increments with a precision of ±I x l 0-4 g on a Dh ona balance (Ind ia , model 200 D). Solutions of glycine were made by mass on the molality concentration scale. Uncertainties in solution concentration were esti mated at ±2x l0- 5 mol kg- 1 in calculation s. All solutions were used within 12 h after preparation to minimize decomposition due to bacterial contamination. Solution density was measured usin g a s in gle stem pyknometer having a total volume of 8 cm 3 and an internal diameter of the capillary of abo ut 0.1 em. The deta il s pertai ning to calibration, exper imen tal set-up and operational procedure have been previously descr ib ed 10 . An average of triplicate measu rements were taken into account. Sufficient care was taken to avoid any air bubble entrapme nt. The reproducibi lity in th e density measureme nt s was better than ±3x I o- 2 kg m- 3 . Viscosity was measured by means of a suspen ded level Ubbelohde viscometer with a flow time of abo ut 330 s for distilled water at 298 . 15 K. The flow times were measured with a stop watch capable of registering time accurate to ±0.1 s. An average of three or four sets of flow times for each fluid was taken for the purpose of the calculation of