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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 1,981 Documents

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1D AND 2D NMR STUDIES OF 2–(2–(BENZYLOXY)–3–METHOXYPHENYL)–1H–BENZIMIDAZOLE Mohammed Hadi Al–Douh; Shafida Abd Hamid; Hasnah Osman
Indonesian Journal of Chemistry Vol 7, No 2 (2007)
Publisher : Universitas Gadjah Mada

The reaction of Benzyl o-vanillin 1 and o-phenylene diamine 2 in dichloromethane produced new benzimidazole, 3. The complete assignments of 3 were made using 1D and 2D NMR including COSY, HMQC and HMBC NMR in CDCl3 and acetone-d6. The coupling constants J are reported in Hertz, and the differences in the peak splittings using both solvents are discussed.

INTEGRATED GAS-LIQUID SEPARATOR-REACTOR FOR DETERMINATION Sn(II) AT TRACE LEVELS IN SOLUTION A. Sentosa Panggabean; M. Bachri Amran; Buchari Buchari; Subur P. Pasaribu
Indonesian Journal of Chemistry Vol 10, No 1 (2010)
Publisher : Universitas Gadjah Mada

The determination of Sn(II) ion at trace levels using integrated gas-liquid separator-reactor with hydride generation-quartz furnace atomic absorption spectrophotometer (HG-QFAAS) has been done. This modified gas-liquid separator at various sizes was able to increase sensitivity in the determination of Sn(II) in solution. The acid reagent mixing techniques, sample and reductant optimally occurs in a coil reaction before they are going to the gas-liquid separators. The optimum conditions of parameter measurement in the determination of Sn ion with HG method are influenced by type and concentration of acid, and the concentration of reductant has been evaluated. This optimum parameters can increase of analytical performance simultantly, which is shown by detection limit 3.74 mg L-1 for 100 mL injection volume (3.74 pg Sn). The accuracy of measurement shown by the % recovery of the Sn determination in natural water sample at > 95%, indicate this technique is good to be applied for tin analysis at picogram level.

OPTIMATION OF THE INCUBATION TIME FOR ENZYMATIC PRODUCTION OF COCONUT OIL USING THE FRUIT’S LATEX OF Carica papaya L M Chasani; Sri Sutji S
Indonesian Journal of Chemistry Vol 3, No 1 (2003)
Publisher : Universitas Gadjah Mada

Optimisations of incubation time of the enzymatic coconut oil extraction using Carica papaya's latex have been done. These researches were performed based on completed randomised design with varying incubation time (12, 24, 36 and 48 hours) and 3 % inoculums. Experimental data covered of yield, refractive index, water content, acid number, iodine number and organoleptic parameters and then analysed using t-test and regression analysis. The result showed that coconut oil produced by enzymatic reaction had good quality especially in iodine number parameter compared with conventional extraction. From the statistical analysis, the product by 24 hours incubation had the highest yield and best quality.

SQUARE WAVE CATHODIC STRIPPING VOLTAMMETRY ADSORPTIVE FOR NICKEL AND COBALT ANALYSIS Saryati Saryati; Sumardjo Sumardjo
Indonesian Journal of Chemistry Vol 6, No 2 (2006)
Publisher : Universitas Gadjah Mada

The adsorptive stripping voltammetric determination of Ni and Co based on adsorption of the Ni/Co and dimethylglioxime (DMG) complex on a hanging mercury drop electrode is studied. The reduction current of the adsorbed DMG complex is measured by square wave cathodic stripping voltammetry method. The effect of various parameters such as ligand concentration, pH of supporting electrolytic, adsorption potential and adsorption time on the current peak of Ni and Co voltammogram were studied. Optimum condition of this method are supporting electrolyte pH 9, DMG concentration 5×10 -4 M, adsorption potential -0.7 V vs Ag/AgCl and adsorption time 180 second. A linier relationship between the current peak and Ni or Co concentration was obtained in the range 5 - 30 ng/mL and the detection limit 0.6 ng/ml for both Ni and Co. The recovery of Ni and Co were 98.11-104.17% using standard biological materials with RSD 2.59 - 10.37%. Based on ";t"; test can be conclude that the result are nearly equal to the standard reference material.

PHOTODEGRADATION AND ANTIOXIDANT ACTIVITY OF CHLOROPHYLL a FROM SPIRULINA (Spirulina sp.) POWDER Rebecca Christiana; Hari Kristopo; Leenawaty Limantara
Indonesian Journal of Chemistry Vol 8, No 2 (2008)
Publisher : Universitas Gadjah Mada

Research on chlorophyll a from Spirulina (Spirulina sp.) powder has been done in order to determine chlorophyll a content, to compare degradation pattern and kinetics degradation of chlorophyll a and crude extract as well as to investigate the difference of antioxidant activity of chlorophyll a with or without irradiation. Chlorophyll a content in spirulina powder was calculated by using Porra's equation. Irradiation and recovery ability of chlorophyll a were measured by using volpi light (Intralux 6100) equipped with daylight filter. The antioxidant activity of chlorophyll a was determined by using DPPH method. The results showed that chlorophyll a content was 2.886 μg/g dry weight. Chlorophyll a has the higher stability than crude extract against 60 minutes irradiation at room temperature. Kinetics degradation of chlorophyll a was based on second order while crude extract based on first order. Chlorophyll a and crude extract have recovery ability. The results also showed that antioxidant activity of chlorophyll a was increased after 60 minutes of irradiation.

THE INFLUENCE OF STRONG AND WEAK ACID UPON AGGREGATION AND PHEOPHYTINIZATION OF CHLOROPHYLL A AND B Lia Kusmita; Leenawaty Limantara
Indonesian Journal of Chemistry Vol 9, No 1 (2009)
Publisher : Universitas Gadjah Mada

Chlorophyll is green pigment that can be found in plant chloroplast. Higher plants usually have two kinds of chlorophylls, chlorophyll a and b. These green pigments are easily degraded by temperature, light intensity, oxygen, acid, and water. Water causes aggregation of chlorophyll, while acid causes pheophytinization of chlorophyll. Aggregation and pheophytinization process of chlorophyll are influenced by solvents. This study was conducted to observe the spectral difference of aggregated chlorophyll in acetone and methanol upon pheophytinization by strong (HCl) and weak acid (CH3COOH), in comparison to the non-aggregated chlorophyll. Observation of spectral pattern was carried out using double beam spectrophotometer CARY 50 at 350-1100 nm. The result shows that pheophytinization of chlorophyll a and b causes hypsochromic shift, particularly at Soret band. There are new peak formations in Qx region, specifically at 506 and 535 nm for pheophytinized-chlorophyll a, and at 371, 435, 526 and 599 nm for pheophytinized-chlorophyll b.

STUDY ON THE RATE OF REDUCTION OF Cr(VI) TO Cr(III) BY HUMIC ACID USING CONTINUM MULTICOMPONENT MODEL Uripto Trisno Santoso; Herdiansyah Herdiansyah; Wega Trisunaryanti; Sri Juari Santosa
Indonesian Journal of Chemistry Vol 4, No 1 (2004)
Publisher : Universitas Gadjah Mada

The objective of this study is to develop a rate equation for reduction of Cr(VI) by humic acid (HA) using a continuum multicomponent model. HA was extracted from peat soil samples in Gambut Subdistrict, South Kalimantan. Parameters influencing the rate of reduction, i.e., medium acidity ([H+]), as well as initial humic acid concentrations ([HA]o) and initial Cr(VI) concentrations ([Cr(VI)]o) were critically evaluated. Experiments were performed in triplicate tests. Aliquots of stock solution containing 100 mg/L HA were equilibrated for 24 h at pH 1.5, 2.05, 3.2, 5.6, and 6.5 before being spiked with 0.02 mM of Cr(VI). [Cr(VI)] was determined by 1,5-diphenylcarbazide spectrometric method. A similar set of rate experiments was conducted at a fixed pH of 1.5 and an [Cr(VI)]o of 0.02 mM and with [HA]o of 25, 50, 75, 100, 150, 200, and 250 mg/L. A third set of batch experiment was performed at pH 1.5, an [HA]o of 100 mg/L, and [Cr(VI)]o 0.01, 0.02, 0.05, 0.10, and 0.20 mM. The results showed that the rate of reduction cannot be adequately modeled by either a simple first- or second- order rate equation. A continum multicomponent model adequately describes the effect of solution parameters on the rates of Cr(VI) reduction.

BALANOCARPOL AND HEIMIOL A, TWO RESVERATROLS DIMER FROM STEM BARK Hopea mengarawan (Dipterocarpaceae) Sri Atun; Nurfina Aznam; Retno Arianingrum; Masatake Niwa
Indonesian Journal of Chemistry Vol 6, No 1 (2006)
Publisher : Universitas Gadjah Mada

Isolation and structure elucidation of two resveratrols dimer, namely balanocarpol (1) and heimiol A (2) from stem bark of Hopea mengarawan had been done. The isolation of those compounds was carried out by chromatographic method and structure elucidation was performed by interpretation of spectroscopic data, including UV, IR, 1H and 13C NMR 1D and 2D, and FABMS.

ANTIMALARIAL COMPOUNDS FROM ENDOPHYTIC FUNGI OF BROTOWALI (Tinaspora crispa L) Elfita Elfita; Muharni Muharni; Munawar Munawar; Leni Legasari; Darwati Darwati
Indonesian Journal of Chemistry Vol 11, No 1 (2011)
Publisher : Universitas Gadjah Mada

The term endophytic refers to a bacteria or a fungi microorganism that colonizes interior organs of plants, but does not have pathogenic effects on its host. In their symbiotic association, the host plant protects and feeds the endophytic, which ";in return"; produces bioactive metabolites to enhance the growth and compotitiveness of the host and to protect it from herbivores and plant pathogens. Plants with ethnobotanical history, for example brotowali (Tinaspora crispa L), are likely candidates to find bioactive compounds. Two alkaloids have been isolated from endophytic fungi of brotowali. The molecular structures of the isolated compounds were determined based on spectroscopic data, including UV, IR, NMR 1D and 2D spectrum. The compounds were determined as: 7- hydroxy-3,4,5-trimethyl-6-on-2,3,4,6-tetrahydroisoquinoline-8-carboxylic acid (1) and 2,5-dihydroxy-1-(hydroxymethyl)pyridin-4-on (2). The compound has antimalarial activity against Plasmodium falciparum 3D7, with IC50 values 0,129 µM and 0,127 µM.

PREPARATION AND CATALYTIC ACTIVITY FOR ISOPROPYL BENZENE CRACKING OF Co, Mo AND Co/Mo-Al2O3-PILLARED MONTMORILLONITE CATALYSTS Hasanudin Hasanudin; Karna Wijaya; Budi Santoso
Indonesian Journal of Chemistry Vol 9, No 2 (2009)
Publisher : Universitas Gadjah Mada

It has been prepared Co, Mo and Co/Mo-Al2O3-pillared montmorillonite catalysts using montmorillonite clay as raw material. The structure and porosity of the catalysts were determined using N2 adsorption-desorption and FT-IR spectroscopy analysis methods. Isopropyl benzene cracking using these catalysts were used to test the catalytic activity and performance of Co, Mo and Co/Mo-Al2O3-pillared montmorillonites. Characterization results showed that pillarization resulted in the increase of the total pore volume and specific surface area of the clay. Meanwhile, transition metals (Co, Mo and Co/Mo) loaded on Al2O3-pillared monmorillonites could increase the catalytic activity of the catalysts for isopropyl benzene cracking significantly.

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