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Indonesian Journal of Chemistry

ijc
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Published by Universitas Gadjah Mada

ISSN : 14119420 EISSN : 24601578 DOI : -

Core Subject : Science, Engineering,

Chemical Engineering, Chemistry & Bioengineering Chemistry

Indonesian Journal of Chemistry is an International, peer-reviewed, open access journal that publishes original research articles, review articles, as well as short communication in all areas of chemistry including applied chemistry. The journal is accredited by The Ministry of Research, Technology and Higher Education (RISTEKDIKTI) No : 21/E/KPT/2018 (in First Rank) and indexed in Scopus since 2012. Since 2018 (Volume 18), Indonesian Journal of Chemistry publish four issues (numbers) annually (February, May, August and November).

Arjuna Subject : -

Articles 1,956 Documents

105 106 107 108 109

BALANOCARPOL AND AMPELOPSIN H, TWO OLIGORESVERATROLS FROM STEM BARK OF Hopea odorata (DIPTEROCARPACEAE) Sri Atun; Nurfina Aznam; Retno Arianingrum; Masatake Niwa
Indonesian Journal of Chemistry Vol 6, No 3 (2006)
Publisher : Universitas Gadjah Mada

Two oligoresveratrol, namely balanocarpol (2) and ampelopsin H (3) had been isolated from the steam bark of Hopea odorata (Dipterocarpaceae). The structures of these compounds were elucidated based on physical and spectroscopic data (MS, 1H and 13C NMR 1D and 2D). The activity of these compounds was evaluated against the 2-deoxyribose degradation induced by the hydroxyl radical generated via a Fenton-type reaction. The result showed that activity each compounds as radical hydroxyl scavenger of balanocarpol, and ampelopsin H with an IC50 1802.3 and 4840.0 μg/mL, respectively. Each compound showed low activity. Vitamin C (IC50 83.9 μg/mL) and butylated hydroxyl toluene (1328.0 μg/mL) were used as positif controls. These results suggest that oligoresveratrols from stem bark of H. odorata may be useful as potential sources of natural antioxidants.

THE EFFECT OF PECTIC SUBSTANCES, HEMICELLULOSE, LIGNIN AND CELLULOSE CONTENT TO THE PERCENTAGE OF BOUND IRON BY DIETARY FIBER MACROMOLECULES: ACIDITY AND LENGTH BOILING TIME VARIATION Leny Yuanita
Indonesian Journal of Chemistry Vol 6, No 3 (2006)
Publisher : Universitas Gadjah Mada

The aim of the study is to find the effect of dietary fiber components content to the percentage of bound iron by dietary fiber macromolecules at acidity and length of boiling time variation. Yard long bean super green variety as dietary fiber sources. The factorial design was applied at pH 4 and 7 with boiling time of 0 (raw), 5, 15, and 25 minutes; the content of dietary fiber components and percentage bound iron as dependent variables. Two way analysis of variance, least significant difference, and multiple regression analysis were applied. Significance level (α) = 5%.The results of the study reveal that acidity, length of boiling time, and its interaction have effect to the bound iron, but have no effect on pectic substances, hemicellulose and lignin. Decreasing pH and increasing boiling time will increase in cellulose, due to the formation of resistant starch. The content of dietary fiber components has no effect on percentage bound iron; pectic substances and hemicellulose have positif effect, while lignin and cellulose have negatif effect on percentage bound iron.

SYNTHESIS OF THIN FILM OF TiO2 ON GRAPHITE SUBSTRATE BY CHEMICAL BATH DEPOSITION Fitria Rahmawati; Sayekti Wahyuningsih; Pamularsih A.W
Indonesian Journal of Chemistry Vol 6, No 2 (2006)
Publisher : Universitas Gadjah Mada

Thin film of TiO2 on graphite substrat has been prepared by means of chemical bath deposition. Cetyltrimethylammonium Bromide served as linking agent of synthesized TiO2 to graphite substrate.The optical microscope and Scanning Electron Microscope (SEM) indicate that surfactant concentration affects the pore morphology of thin film Surface Area Analysis (SAA) of thin film indicated that the pore of thin film included in mesopore category. The anatase phase of TiO2 quantity arised as the surfactant concentration increase, gave high efficiency of induced photon conversion to current efficiency (% IPCE).

STUDY ON EFFECT OF pH AND METAL CONCENTRATION ON THE SYNTHESIS OF DIMENSIONALLY STABLE ANODE GAPHITE/La2O3-ZrO2 AND GAPHITE/RuO2-TiO2 Suyanta Suyanta; Agus Kuncaka
Indonesian Journal of Chemistry Vol 6, No 2 (2006)
Publisher : Universitas Gadjah Mada

The objective of this research is to study the effect of pH and metal concentration toward the mass of metal oxides coated on gaphite in the synthesis of dimensionally stable anode (DSA) gaphite/La2O3-ZrO2 and gaphite/RuO2-TiO2. The synthesis of those DSA was done by thermal decomposition technique. The solution containing metal ion to be coated (as its oxides) on the gaphite, followed by heating. Those spraying and heating were repeated up to ten times, so that it was expected that all of gaphite surface was covered by the metal oxides. It was concluded that the mass of metal oxides coated on the gaphite was affected by the pH and concentration of metals in the solutian to be sprayed. Treatment by using solution at pH of 4 and 6 produced more in mass of metal oxides mixture than using solution of 1 and 2 on pHs. DSA gaphite/La2O3-ZrO2 produced by treatment using solution of 4 and 6 on pHs contained more in mass of La2O3 than of ZrO2; meanwhile DSA gaphite/RuO2-TiO2 produced in this research (for all of treatment) contained more in mass of RuO2 than of TiO2.

A NOVEL METHOD OF THE HYDRIDE SEPARATION FOR THE DETERMINATION OF ARSENIC AND ANTIMONY BY AAS Ganden Supriyanto; Jürgen Simon
Indonesian Journal of Chemistry Vol 6, No 2 (2006)
Publisher : Universitas Gadjah Mada

A novel method is proposed for the hydride separation when determinining of arsenic and antimony by AAS. A chromatomembrane cell was used as preconcentration-, extraction- and separation-manifold instead of the U-tube phase separator, which is normally fitted in continuous flow vapour systems generating conventionaly the hydrides. The absorbances of the hydrides produced were measured by an atomic absorption spectrophotometer at 193.7 nm and 217.6 nm. Under optimized analytical conditions, the calibration plot for arsenic was linear from 50 to 500 ng.mL-1 (r2 = 0.9982). The precision for three subsequent measurements of 500 ng.mL-1 arsenic gave rise to a relative standard deviation of 0.4%. The detection limit was 15 ng.mL-1, which is much lower compared with that of the conventional hydride system (2000 ng.mL-1). A similar result was observed in case of antimony: the detection limit was 8 ng.mL-1 when the proposed method was applied. Consequently, the sensitivity of the novel method surpasses systems with conventional hydride generation, i.e. the precision and the acuracy increase whereas the standard deviation and the detection limit decrease. The proposed method was applied in pharmacheutial analysis and the certified As-content of a commercial product was very sufficiently confirmed.

INVESTIGATION OF DISSOLVED SULPHATE IN VARIOUS GEOTHERMAL FIELDS OF SUMATRA USING OXYGEN AND SULPHUR ISOTOPES E. Ristin Pujiindiyati; Zainal Abidin
Indonesian Journal of Chemistry Vol 6, No 2 (2006)
Publisher : Universitas Gadjah Mada

There are at least 30 high temperature systems; eleven active volcanoes, five degassing volcanoes and one caldera volcano controlled by Sumatra Fault Zone over a length of 1700 km. To understand this geothermal field system, some information about geochemistry including isotope composition in its fluid is needed. Sulphur-34 and oxygen-18 isotopes in dissolved sulphate pair have been used to determine the origin of acidic fluid of sulphate and to evaluate the process involved. The fluids from eight hot springs, two fumaroles, four deep wells and crater have been collected in along Sumatra geothermal fields. Sulphur-34 (d 34S (SO4), 0/00 CDT) and oxygen-18 (d 18O (SO4), 0/00 SMOW) in sulphate is analyzed according to Robinson-Kusakabe and Rafter method, respectively. The d 34S (SO4) values from Sibayak wells are more enriched of 16.8 0/00 to 18.2 0/0 that may indicate the dissolution of anhydrite minerals or isotope partitioning in hydration of SO2. The d 34S (SO4) values from two fumaroles (Pusuk Bukit - North Sumatra and Rantau Dadap - South Sumatra) are at depleted value of -0.150/00 and 1.80/00, those are close to d 34S from magmatic sulphur. In general, the d 34S (SO4) of springs spread in a wide range of 5.250/00 to14.20/00 and show a mixing process between atmospheric sulphate and sulphate from deep wells. The d 18O (SO4) from wells exhibits depleted value around -3.60/00 suggesting that 87.5% of sulphate oxygen is derived from groundwater oxygen and 12.5% is derived from atmospheric molecular oxygen in sulphide oxidation reaction. In the other hand, hot springs (except Semurup), crater and fumaroles have enriched value of d 18O (SO4). These enriched values suggest that a higher percentage of atmospherically derived oxygen compared to those from the depth.

CAPILLARY ELECTROPHORETIC ANALYSIS OF LOW-MOLECULAR-MASS OF CA SPECIES IN PHLOEM SAP OF Ricinus communis L. Noor Fitri; Björn Thiele; Klaus Günther; Buchari Buchari
Indonesian Journal of Chemistry Vol 6, No 2 (2006)
Publisher : Universitas Gadjah Mada

A capillary electrophoretic (CE) analysis with ultra-violet (UV) detection was performed for further separation of low-molecular-mass (LMM) calcium species in phloem sap of Ricinus communis L. Two different background electrolytes (BGE) were used for the separation; these are (1) hydrogen phosphate/dihydrogen phosphate buffer containing cetyltrimethylammonium bromide (CTAB) as an electro-osmotic flow (EOF) modifier, and (2) boric acid buffer containing CTAB. Various parameters affecting the analysis, including the composition and pH of the BGE were systematically studied. The sensitivity, resolution, baseline noise, migration time of the species peaks, and reproducibility of the method were evaluated under optimised condition. At least 13 UV-active species were optimally separated within about ten minutes. The optimised measurement condition was also achieved using 10 mM hydrogen phosphate/10 mM dihydrogen phosphate containing 0.5 mM CTAB at pH 8.0 as BGE, and by applying voltage of ‑20 kV and temperature of 14°C. Evidently, the analytical method was successfully used for the separation of LMM calcium species in phloem sap of R. communis L.

THE INFLUENCE OF CONVERSION MODEL CHOICE FOR EROSION RATE ESTIMATION AND THE SENSITIVITY OF THE RESULTS TO CHANGES IN THE MODEL PARAMETER Nita Suhartini
Indonesian Journal of Chemistry Vol 6, No 2 (2006)
Publisher : Universitas Gadjah Mada

A study of soil erosion rates had been done on a slightly and long slope of cultivated area in Ciawi - Bogor, using 137Cs technique. The objective of the present study was to evaluate the applicability of the 137Cs technique in obtaining spatially distributed information of soil redistribution at small catchment. This paper reports the result of the choice of conversion model for erosion rate estimates and the sensitive of the changes in the model parameter. For this purpose, small site was selected, namely landuse I (LU-I). The top of a slope was chosen as a reference site. The erosion/deposit rate of individual sampling points was estimated using the conversion models, namely Proportional Model (PM), Mass Balance Model 1 (MBM1) and Mass Balance Model 2 (MBM2). A comparison of the conversion models showed that the lowest value is obtained by the PM. The MBM1 gave values closer to MBM2, but MBM2 gave a reliable values. In this study, a sensitivity analysis suggest that the conversion models are sensitive to changes in parameters that depend on the site conditions, but insensitive to changes in parameters that interact to the onset of 137Cs fallout input.

RADIATION GRAFTING OF STYRENE ONTO PTFE FILM Yohan Yohan; Rifaid M. Nur; Lilik Hendrajaya; E. S. Siradj
Indonesian Journal of Chemistry Vol 6, No 1 (2006)
Publisher : Universitas Gadjah Mada

Radiation grafting of styrene monomer onto poly(tetrafluoroethylene) (PTFE) film has been investigated. This research is emphasized on the conditioning of PTFE film. It was irradiated by γ-ray radiation at various irradiation dose from 2.5 - 12.5 kGy with dose rate 1.9 kGy/hour. Irradiated copolymer was then grafted by styrene monomer under various conditions. The results showed that degree of grafting increased by increasing irradiation dose, solvent concentration, temperature and time of grafting. The optimum condition of radiation grafting relatively was obtained at irradiation dose of 10 kGy, 2-propanol solvent, styrene concentration of 40 volume%, temperature and time of grafting of 70 oC and 6 hours each.

THE INFLUENCE OF pH TOWARDS MULTIPLE METAL ION ADSORPTION OF Cu(II), Zn(II), Mn(II), AND Fe(II) ON HUMIC ACID Buhani Buhani; Suharso Suharso
Indonesian Journal of Chemistry Vol 6, No 1 (2006)
Publisher : Universitas Gadjah Mada

Multiple metal ions adsorption of Cu(II), Zn(II), Mn(II) and Fe(II) on humic acid with a batch method has been carried out at pH interaction of 3, 5, and 6. Concentration of metal ions in solution before and after interaction was analyzed with Atomic Absorption Spectrophotometer (AAS). Result showed that adsorption multiple metal ions of Cu(II), Zn(II), Mn(II), and Fe(II) on humic acid is optimum at pH 5. Adsorption energies of the multiple metal ions Cu(II), Zn(II), Mn(II), and Fe(II) on humic acid at pH 3, 5, and 6 are around 35.0 - 37.6 kJ/mole. In general, capacity of competition adsorption of the multiple metal ions has an order as follows; Cu(II) < Fe(II) < Zn(II) < Mn(II).

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