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Ridhay, A., Noor, A., Soekamto, N. H., Harlim, T., & Altena, I. van. (2012). A STIGMASTEROL GLYCOSIDE FROM THE ROOT WOOD OF Melochia Umbellata (Houtt) Stapf var. degrabrata K. Indonesian Journal of Chemistry, 12(1), 100–103.
Abstract: A stigmasterol glycoside (stigmast-5,22-dien-3-O-β-D-glucopyranoside) has been isolated from the chloroform fraction of root wood of Melochia umbellata (Houtt) Stapf var. degrabrata K. The compound structure was determined on spectroscopic evidences including IR, 1D and 2D NMR and compared to previous data. The isolate was also active against Aspergillus niger.
Keywords: Aspergillus niger, Melochia umbellata, root wood, stigmasterol glycoside
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Buhani, B., Suharso, S., & Aprilia, L. (2012). CHEMICAL STABILITY AND ADSORPTION SELECTIVITY ON Cd 2+ IONIC IMPRINTED Nannochloropsis sp MATERIAL WITH SILICA MATRIX FROM TETRAETHYL ORTHOSILICATE. Indonesian Journal of Chemistry, 12(1), 94–99.
Abstract: Chemical stability, reusability, and adsorption selectivity of Cd2+ ionic imprinted Nannochloropsis sp with silica matrix (Cd(II)-IIP) from precursor tetraethyl orthosilicate (TEOS) have been studied through adsorption experiment series with batch method. Nannochloropsis sp (Cd(II)-IIP) material was characterized with an infrared spectrophotometer (IR) to identify the functional groups in this material and identification of metal ion concentration was analyzed with an atomic absorption spectrophotometer (AAS). Chemical stability was determined in solution media of acid, neutral, and base. Adsorption selectivity was obtained with determination of selectivity coefficient (α) of Cd2+ ion toward its ionic pair such as Ag+, Zn2+, Cu2+, and Ni2+ ions. Nannochloropsis sp Cd(II)-IIP material is very stable in acid media and lack stable in base media as well as it can be reused for extraction 4 cycles with adsorption capacity value \textgreater 95% using eluent of 0.1 M Na2EDTA. Selectivity of Cd(II)-IIP material upon Cd2+ ion is higher than non imprinted polymer (NIP) and it increases with these orders; Cd2+/Ag+ \textless Cd2+/Zn2+ \textless Cd2+/Cu2+ \textless Cd2+/Ni2+ for each α at metal ionic ratio of 1:1; 0.887; 20.180; 28.053; 33.417, respectively.
Keywords: adsorption selectivity, ionic imprinted, Nannochloropsis sp
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Widjajakusuma, E. C., Villa, A., & Stock, G. (2012). Effect Of The Ion Treatment On An Rna Hairpin: Molecular Dynamics Study. Indonesian Journal of Chemistry, 12(1), 1–11.
Abstract: Molecular dynamics has been employed to study the effect of ion treatment on the stability of 14-nucleotide RNA hairpin of Coxsackievirus B3. Three AMBER force fields were used: AMBER94, AMBER98, and AMBER99, which showed no significant structural difference of the hairpin. Thereafter, we applied two different long-range electrostatic treatments that were reaction field and PME methods, and calculated the distribution of ions around the hairpin. Although the structural stabilities of the MD simulations using both methods were similar in 0.14 M Na+, ion environment around the hairpin was notably different. In particular, structural stabilition of the hairpin with increasing ion concentration and with ion Mg2+ cannot be accommodated by simulations using reaction field method. Furthermore, the MD simulations using PME method suggested the strong similarity in structural and dynamical properties of the hairpin with 0.14 M Na+, 0.50 M Na+, 1,03 M Na+, and 0.08 M Mg2+ concentrations. However, the simulations revealed different ion occupations of Na+ and Mg2+.
Keywords: Coxsackievirus B3, ion treatment, md simulations, RNA hairpin
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Sarode, D. B., Ingle, S. T., & Attarde, S. B. (2012). FORMULA ESTABLISHMENT OF COLORLESS Pb(II) COMPLEX WITH N-BENZOYL-N-PHENYL HYDROXYLAMINE (BPA) USING ATOMIC ABSORPTION SPECTROSCOPY. Indonesian Journal of Chemistry, 12(1), 12–19.
Abstract: A new method for determination of stoichiometry of colorless complexes by using atomic absorption spectrophotometric technique in continuous variation method and slope ratio method was described here. This method can be used in same manner as that of mole ratio method and slope ratio method. In this method atomic absorption spectroscopy was used instead of UV-Vis spectrophotometry. Atomic absorption spectrophotometric technique is superior to UV-Vis spectrophotometry as it can be applied to colorless soluble complexes. Pb(II) and n-benzoyl-n-phenyl hydroxylamine react to form colorless complex at pH 6.5, which can be easily determined by this method. It was found that Pb(II) forms 1:2 complex with n-benzoyl-n-phenyl hydroxylamine and is quantitatively extracted back to aqueous solution for AAS analysis.
Keywords: continuous variation method, n-benzoyl-n-phenyl hydroxylamine, Pb(II), slope ratio method, Stoichiometric ratio of complex ions
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Santoso, U. T., Nurmasari, R., Umaningrum, D., Santosa, S. J., Rusdiarso, B., & Siswanta, D. (2012). Immobilization Of Humic Acid Onto Chitosan Using Tosylation Method With 1,4-Butanediol As A Spacer Arm. Indonesian Journal of Chemistry, 12(1), 35–42.
Abstract: Immobilization of humic acid (HA) onto chitosan using tosylation method with 1,4-butanediol as a spacer arm has been evaluated. Chitosan was phthaloylated selectively using phthalic anhydride in dimethylformamide as solvent with addition of 5% water (v/v) as cosolvent prior to be tosylated. N-phthaloyl-chitosan and HA were tosylated using tosyl chloride in excess and triethylamine as catalyst at temperature \textless 10 °C for 12 h. The 6-O-tosyl-N-phthaloyl-chitosan was reacted with 1,4-butanediol in order to obtain a spacer arm attached chitosan. The 6-O-butanol-N-phthaloyl-chitosan was activated by reacting with tosyl chloride. For evaluation on immobilization of HA on chitosan with and without spacer arm, 6-O-tosylbutane-N-phthaloyl-chitosan was reacted with HA and the 6-O-tosyl-N-phthaloyl-chitosan was reacted with HA. The HA immobilized onto chitosan was characterized by XRD and FTIR spectrophotometric method. The result showed that HA can be immobilized covalently onto chitosan after attaching 1,4-butanediol as spacer arm onto 6-O-tosyl-N-phthaloyl-chitosan and activating the product with tosyl chloride, but HA cannot be reacted directly onto 6-O-tosyl-N-phthaloyl-chitosan.
Keywords: chitosan, humic acid, immobilization, spacer arm, tosylation
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