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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

103 104 105 106 107

ISOLATION AND PURIFICATION OF LIPASE FROM COCOA BEANS (Theobroma cacao. L.) OF CLONE PBC 159 Ratna Agung Samsumaharto
Indonesian Journal of Chemistry Vol 8, No 1 (2008)
Publisher : Universitas Gadjah Mada

Lipase (triacylglycerol acylhydrolase, EC 3.1.1.3) was extracted and purified from acetone dry powder of cocoa (Theobroma cacao. L.) of clone PBC 159 extract. The Lipase from AcDP of cocoa beans was used for purification using 40-60 and 60-80% ammonium sulphate precipitation. The resulted indicated 44.73 and 60.51-fold purification with 26.74 and 33.31% recovery lipase activity (yield), respectively. The crude lipase enzyme from both precipitation were eluted, producing a single peak after applying through Sephacryl S-200 chromatography. The purified enzyme had a uniform specific activity throughout the final chromatography peak. The results from SDS-PAGE analysis showed that the molecular weight of the lipase enzyme was in between 45-66 kDa.

INHIBITION OF HUMAN LOW-DENSITY LIPOPROTEINS OXIDATION BY Hibiscus radiatus CUV. CALYCES EXTRACT Hernawan Hernawan
Indonesian Journal of Chemistry Vol 8, No 1 (2008)
Publisher : Universitas Gadjah Mada

Hibiscus radiatus Cuv calyces extracts rich in polyphenols was screened for their potential to inhibit oxidation of human low-density lipoproteins-cholesterol (LDL-C) in vitro. The inhibition of LDL-C oxidation (antioxidant activity) was determined by measuring the formation of conjugated dienes and thiobarbituric acid reagent substances (TBARS). LDL-C oxidation was carried out in the presence of H. radiatus Cuv calyces extract (20 and 50 μM). CuSO4 (10 μM) was used as the oxidation initiator and butylated hydroxytoluene (BHT) at 50 μM was used as standard antioxidant. The protective effect of H. radiatus Cuv. calyces extract toward human low-density lipoproteins, complex lipid system was demonstrated by significant increase lag time (> 103 min), diminished of the propagation rate (44 %), and diminution of conjugated dienes formation 59.42 % (50 μM) compared to control.

A REVISIT OF PECHMANN REACTION UNDER MICROWAVE RADIATION Fauzia Anjum Chattha; Saeed Ahmed Nagra; Munawar Ali Munawar
Indonesian Journal of Chemistry Vol 8, No 1 (2008)
Publisher : Universitas Gadjah Mada

A series of coumarins have been prepared by the Pechmann reaction of different phenols with ethyl acetoactate as well as malic acid using catalytic amount of sulfuric acid under microwave irradiation for few seconds.

PURIFICATION AND CHARACTERIZATION OF POLY-HYDROXYBUTYRATE (PHB) IN CUPRIAVIDUS NECATOR Sergio Leon De Rooy; Endang Tri Wahyuni; Wiratni Wiratni; Siti Syamsiah; Jamil Ismail
Indonesian Journal of Chemistry Vol 7, No 3 (2007)
Publisher : Universitas Gadjah Mada

Purification and characterization of biodegradable plastic namely Polyhydroxybutyrate (PHB) in Cupriavidus necator have been carried out. C. necator was grown on a Ramsay medium with fixed substrate conditions and optimized for time. Stepwise purification of PHB was carried out, by using hydrogen peroxide and chloroform. The effect of temperature, time, and hydrogen peroxide concentration on the purification were also evaluated. The extracted PHB was studied with XRD, FTIR and 1H-NMR and 13C-NMR to determine its structure and purity. Yield and crystallinity were also studied with HPLC and XRD, respectively. The results of the research showed that higher concentrations of hydrogen peroxide gave better yields, whereas higher temperatures and longer lysis times led to different results. Higher crystallinity was observed when purification temperatures were elevated, but higher hydrogen peroxide concentration and longer extraction time gave varying crystallinity. The highest yield ca 66.10 % DCW was reached by purification using H2O2 20 %, at 100 oC for 2 h. The results of TGA analysis indicated that the purity of the PHB obtained was about 75 % and by using DSC, it was found that the PHB showed good thermal properties.

MICELLE-MEDIATED EXTRACTION AS A TOOL FOR SEPARATION AND PRECONCENTRATION IN COPPER ANALYSIS F. Ahmadia; A. Khanmohammadi; A. Malekpour
Indonesian Journal of Chemistry Vol 7, No 3 (2007)
Publisher : Universitas Gadjah Mada

A cloud point extraction method was presented for preconcentration of copper in various samples. After complexation with 4-Amino-2,3-dimethyl-1-phenyl-3-pyrazoline-5-one (ADPP) or N-Benzoyl-N-phenylhydroxylamine (BPA) in water, analyte ions are quantitatively extracted to the phase rich in Triton X-114 after centrifugation. 2.0 mol L-1 HNO3 solution in methanol was added to the surfactant-rich phase prior to its analysis by flame atomic absorption spectrometry (FAAS). The adopted concentrations for ADPP, Triton X-114, HNO3 and parameters such as bath temperature, centrifuge rate and time were optimized. Detection limits (3SDb/m) of 1.3 and 1.9 ng mL-1 for ADPP and BPA along with enrichment factors of 30 and 38 for ADPP and BPA were achieved. The high efficiency of cloud point extraction to carry out the determination of analyte in complex matrices was demonstrated. The proposed method was applied to the analysis of biological, industrial, natural and wastewater, soil and blood samples.

THE EFFECT OF IRRADIATION DOSE AND AMMONIA CONCENTRATION ON THE APPLICATION OF ELECTRON BEAM FOR TREATMENT GASES POLLUTION OF SO2AND NOX Erizal Erizal
Indonesian Journal of Chemistry Vol 7, No 3 (2007)
Publisher : Universitas Gadjah Mada

The application of electron beam for treatment gases pollution of SO2 and NOx has been studied. The simulated SO2 and NOx gases stream produced from diesel fuel burning boiler were flown into electron beam chamber. Irradiation was conducted using 1000 keV electron beam machine at the dose up to 8.8 kGy, while water vapour and the ammonia gas with variation concentration flew into the system during irradiation. The concentrations of the gases change were observed during processes. After evaluation, it was found that by increasing irradiation dose, the concentration of SO2 and NOx gases removal increases. The efficiency of gases removal may reach 98 % for SO2 and 88 % for NOX at a dose of 8.8 kGy. By increasing ammonia concentration, the efficiency gas removal increases. Besides, by-products from the irradiation yield were sulfate and nitrate salt compound which are possible to be used as a fertilizer.

STABILITY OF BETACYANIN PIGMENTS FROM RED PURPLE PITAYA FRUIT (Hylocereus polyrhizus) : INFLUENCE OF PH, TEMPERATURE, METAL IONS AND ASCORBIC ACID Tang, C.S Tang, C.S; Norziah M.H Norziah M.H
Indonesian Journal of Chemistry Vol 7, No 3 (2007)
Publisher : Universitas Gadjah Mada

Betacyanin pigments from red-purple pitaya fruit (Hylocereus polyrhizus) could be an attractive source of red colourant for food application. This paper presents results on the extraction of betacyanin pigments from pitaya fruits grown locally in Malaysia. Both the flesh of the fruit and its mesocarp were investigated and it was found that the flesh had higher pigment contents compared to its peel component. The concentration of betacyanins expressed as betanin equivalents per 100 g of flesh and peel were 10.1 ± 0.6 mg and 6.7 ± 0.2 mg, respectively when 80% methanol was used. The stability of betacyanin pigments were investigated at different pH, temperature and in presence of different concentrations of metal ions (Cu2+ and Fe2+) and ascorbic acid. The results showed that the pigment was most stable at pH range between 5 and 6. However, it forfeited its stability to the heat induced at elevated temperatures. Metal ions (Cu2+ and Fe2+) proved to be capable of accelerating betacyanin degradation, with Cu2+ exhibiting the greatest effect. By contrast, supplementation with ascorbic acid could enhance the pigment stability against the detrimental effects caused by pH, temperature and metal ions. Nevertheless, if the concentration of ascorbic acid exceeds 0.7 %, it may change its role from pigment stabilizer to become a pro-oxidant.

TWO ALKYLATED FLAVONOID ISOLATED FROM THE STEM OF THE FERN Chingia sakayensis (Zeiller) Holtt Suyatno Suyatno; Sri Hidayati Syarief; Nurul Hidajati; Kuniyoshi Shimizu
Indonesian Journal of Chemistry Vol 7, No 3 (2007)
Publisher : Universitas Gadjah Mada

Two known alkylated flavonoid namely matteucinol dan matteucinol-7-O-b-D-glucoside was isolated for the first time from the fern Chingia sakayensis (Zeiller) Holtt's stem. Their structures were elucidated on the basis of spectroscopic evidence and by comparation with those reported data in literature.

SYNTHESIS AND CHARACTERIZATION OF CdS IN DIOL VANILIN LIQUID CRYSTAL MONOMER H. L. Lee; M. Abu Bakar; J. Ismail; A.M. Issam
Indonesian Journal of Chemistry Vol 7, No 2 (2007)
Publisher : Universitas Gadjah Mada

Nanocomposites comprising diol-vanilin and cadmium sulfide (CdS) has been synthesized via chemical precipitation method in ethanol at refluxed temperature (160 oC) for 12 hours. CdCl2. 2.5H2O and thiourea as cadmium and sulfide precursors respectively were employed. Diol vanilin is a thermotropic liquid crystal monomer which exhibits enantiotropic nematic metaphase texture when observed under polarizing microscope and confirmed by DSC thermal stability study. A series of different mass composition of diol vanilin and CdS nanocomposites ranging from 0.1:1.0 till 1.0:1.0(w/w) were prepared and characterized using XRD, TEM, SEM-EDX, POM and DSC. The X-ray diffraction pattern (XRD) showed broad peaks due to the formation of cubic CdS nanoparticles in diol vanilin matrix. The nanocomposites at low mass composition of CdS still maintained their nematic phase. However, the liquid crystal property was affected when the mass composition of CdS in nanocomposite was increased and the liquid crystal characteristic vanished when the mass composition was at 0.6:1.0.

MONTE CARLO SIMULATION OF I-, Br-, AND Cl- IN WATER USING AB INITIO PAIR POTENSIAL FUNCTIONS Harno Dwi Pranowo
Indonesian Journal of Chemistry Vol 7, No 2 (2007)
Publisher : Universitas Gadjah Mada

Monte Carlo simulations were performed for I-, Br- and Cl-, in water using ab initio pair potential. The systems consisting of one anion in 215 solvent molecules have been simulated at 298 K. Anion-water pair potentials have been newly developed based on ab initio calculations of split valence basis set plus polarization quality. The structure of the solvated ion is discussed in terms of radial distribution functions, coordination number and pair potential distribution. Structural properties were investigated by means of radial distribution functions and their running integration numbers, leading for the first solvation shell to an average 12.60 H2O around I- with I--O distance of 3.74 Å and I--H distance of 2.86 Å, 11.84 H2O around Br- with Br--O distance of 3.40 Å and Br--H distance of 2.42 Å, and 10.68 H2O around Cl- with Cl--O distance of 3.20 Å and Cl--H distance of 2.24 Å, respectively. The structure of the water-anion complexes are agreed with dipole orientation. Pair energy distribution of hydrated anions showed that the pair interaction energy are increase from I-, Cl-, to Br-, namely, -6.28, -9.98 and -13.67 kcal/mol, respectively. The coordination number distribution analysis for the first solvation shell of the all hydrated anions indicated a high exchange rate for the first solvation shell ligands.

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