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Narsito Narsito

Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Sekip Utara, Yogyakarta 55281

Author-ID : 3957568

Chemical Engineering, Chemistry & Bioengineering Chemistry

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Articles

Physical Characteristics of Chitosan Based Film Modified With Silica and Polyethylene Glycol F. Widhi Mahatmanti; Nuryono Nuryono; Narsito Narsito
Indonesian Journal of Chemistry Vol 14, No 2 (2014)
Publisher : Universitas Gadjah Mada

Recently, development of film materials is focused on finding the films with high chemical and physical stabilities. Organic based material such as chitosan produces films with low physical stability, and hence addition of inorganic materials necessary. In this research, the effect of silica and polyethylene glycol (PEG) addition on the properties of chitosan based films has been investigated. Precursors used to produce films included chitosan with the deacetylation degree of 83% and sodium silicate solution as the silica source. A simple synthesis in a one-pot process was carried out by mixing 1%(w) of chitosan solution in 2%(v/v) acetate acid and sodium silicate solution (27% SiO2) in various composition ratios and casting the solution on a glass dish. The tensile strength and percentage of elongation decrease with increasing the silica content. The tensile strength tends to decline with addition of PEG, but the elongation percentage of the film increases. Hydrophilicity of the film decreases with the addition of silica and increases with the addition of PEG. The addition of silica and PEG does not change significantly the morphology of the film and functional groups indicating the domination of physical interaction among active sites in the film components.

INVESTIGATION ON THE MORPHOLOGY AND PROPERTIES OF AGGREGATE STRUCTURES OF NATURAL PHOSPHOLIPIDS IN AQUEOUS SYSTEM USING CRYO-TEM Dwi Hudiyanti; Tri Joko Raharjo; Narsito Narsito; Sri Noegrohati
Indonesian Journal of Chemistry Vol 12, No 1 (2012)
Publisher : Universitas Gadjah Mada

Cryogenic transmission electron microscopy (Cryo-TEM) was used to investigate the aggregates morphology and properties of candle tree (Aleurites moluccana) endosperm, sesame (Sesamum indicum L. syn.) seeds, and coconut (Cocos nucifera) endosperm phospholipids in dilute aqueous system. The micrographs showed that candle tree phospholipids formed planar bilayer and cluster of vesicles with lipid droplets, while coconut and sesame phospholipids formed well-defined unilamellar vesicles. The vesicles size could be as small as 50 nm in diameter. Coconut phospholipids also showed a good bending ability. Formation of clusters of vesicles was also found in coconut phospholipids dispersion, but this cluster was easily broken by extrusion through a small pore membrane.

SYNTHESIS AND CHARACTERIZATION OF MESOPOROUS ALUMINOSILICATES Al-MCM-41 AND INVESTIGATION OF ITS THERMAL, HYDROTHERMAL AND ACIDITY STABILITY Suyanta Suyanta; Narsito Narsito; Endang Tri Wahyuni; Triyono Triyono
Indonesian Journal of Chemistry Vol 10, No 1 (2010)
Publisher : Universitas Gadjah Mada

The synthesis and characterization of mesoporous aluminosilicates Al-MCM-41 and the investigation of its thermal, hydrothermal and acidity stability have been done. Al-MCM-41 were synthesized by hydrothermal method to the mixture of sodium silicate as Si source, aluminium hydroxide as Al source, sodium hydroxide as a solvent, and cethyltrimethylammoniumbromide (CTAB) as structure directing agent. The reaction were carried out in alkaline condition (pH = 10.2) at 383 K for about 24 h, followed by calcination at 723 K for about 10 h. The synthesized crystals were characterized using FTIR spectroscopy, X-ray diffraction and N2 fisisorption methods. The result showed that Al-MCM-41 sample with hexagonal structure was formed, it has a good in thermal and acid stability, but the structure disintegrated in an alkaline solution (pH = 10) and in boiled water.

IMMOBILIZATION OF PAPAIN ON CHITOSAN Sari Edi Cahyaningrum; Narsito Narsito; Sri Juari Santoso; Rudiana Agustini
Indonesian Journal of Chemistry Vol 8, No 3 (2008)
Publisher : Universitas Gadjah Mada

In this study, papain was immobilized on chitosan with Mg(II) cosslinked agent. Studies on free and immobilized papain systems for determination of optimum pH, optimum temperatur, thermal stability and reusability were carried out. The results showed that free papain had optimum pH 6.5 and optimum temperature 55 °C while the immobile papain hadoptimum pH 8 and optimum temperature 80 °C. The thermal stability of the immobilized papain, relative to that of the free papain, was markedly increased. The immobilized papain can be reused for at least six times.

ENCAPSULATION OF HORSERADISH PEROXIDASE-GLUCOSE OXIDASE (HRP-GOx) IN SILICA AQUAGEL SYNTHESIZED FROM RICE HULL ASH FOR ENZYMATIC REACTION OF GLUCOSE Nuryono Nuryono; Narsito Narsito; Endang Astuti
Indonesian Journal of Chemistry Vol 8, No 2 (2008)
Publisher : Universitas Gadjah Mada

In recent years, the sol-gel technique has attracted increasing interest as a unique approach to immobilize biomolecules for bioanalytical applications as well as biochemical and biophysical studies. In this research, encapsulation of Horseradish peroxidase-Glucose oxidase (HRP-GOx) enzymes in silica aquagel from rice hull ash by sol-gel process has been carried out. In addition, the effect of several parameters (weight ratio of HRP to GOx, pH, temperature, sodium ion concentration) on enzyme activity was studied, as well. Rice hull ash, which was produced by ashing at 700 °C, was extracted it's silika by NaOH solution 1 M at 100 °C for two hours to produce sodium silikate (Na2SiO3) solution. The Na2SiO3 solution with pH of 13 was added with a strong cation exchanger resin, to produce sol solution with the pH of 4. Encapsulation was emphasized by mixing sol solution and phosphate buffer pH 7 containing HRP-GOx solution at volume ratio of buffer to sol solution 1:5. The mixture was transferred into 96-microwell plate and was aged for 24 hours. Enzymatic reaction was carried out by adding chromogenic solution of phenol and 4-aminoantipyrine (4-AAP) and b-D-glucose solution (as substrate) into the microwell. Enzymatic activity was examined by measuring absorbance of product solution at 490 nm with ELISA reader. Result of enzymatic activity for encapsulated enzymes (SGE) was compared to that for free enzymes (EB). Results showed that at the investigated condition, HRP-GOx enzymes gave high activity at weight ratio of HRP to GOx 10:1 and pH 7 for both SGE and EB. Encapsulation caused the enzymes activity decrease to 53.0±0.2 %. However, SGE was observed to be more stable on pH and temperature changes than EB. Study on the effect of sodium concentration showed that the increase of sodium concentration from 0.10 to 0.37 M decreased the enzymatic activity to 56±0.2%. Reusability test showed that the synthesized SGE was reusable with activity decrease of 60% within 23 days.

Co-Authors Dwi Hudiyanti Endang Astuti Endang Tri Wahyuni F Widhi Mahatmanti Nuryono Nuryono Rudiana Agustini Sari Edi Cahyaningrum Sri Juari Santoso Sri Noegrohati Suyanta Suyanta Tri Joko Raharjo Triyono Triyono

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