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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

54 55 56 57 58

THE INTERACTION OF Co2+-AMMONIA MODELLING: THE COMPARATIVE STUDY BETWEEN AB INITIO AND ELECTRON CORRELATION METHODS Harno Dwi Pranowo; Foliatini Foliatini; Karna Wijaya
Indonesian Journal of Chemistry Vol 2, No 2 (2002)
Publisher : Universitas Gadjah Mada

Research on comparison between Hartree-Fock method and electron correlation methods as well as the effect of size of basis sets on representing interaction of Co2+-NH3 observed from complex energy parameters and optimum geometric parameters have been carried out.The first step is screening basis sets based on charge transfer effect and BSSE value. The selected basis set does not yield charge transfer at 1,4 Å < < 8 Å, and yield small BSSE value. Electron correlation methods used are Møller-Plesset order 2 (MP2), Møller-Plesset order 3 (MP3), Configuration Interaction, Doubles (CID), dan Configuration Interaction, Singles and Doubles (CISD) whereas the basis set used is the result of the screening. LANL2DZ ECP-6-31G* and LANL2DZ ECP-6-311++G(3df,3pd) basis sets are used with Unrestricted Hartree-Fock (UHF) and Møller-Plesset order 2 (MP2) methods to study the effect of size of basis sets.The result of the research showed that the best basis set is LANL2DZ ECP for Co2+ and 6-31G* for NH3. The application of electron correlation method and large basis set can increase the quality of interaction representation of Co2+- NH3. Møller-Plesset (MP) perturbation method gives larger contribution to correlation energy than Configuration Interaction (CI) method.

THEORETICAL STUDY OF SOLVENT EFFECTS AND NMR SHIELDING TENSORS OF DLPC M. Monajjemi; S. Afsharnezhad; M.R. Jaafari; S. Mirdamadi; H. Monajemi; S. Mollaamin
Indonesian Journal of Chemistry Vol 8, No 1 (2008)
Publisher : Universitas Gadjah Mada

The effect of the polarity of the environment on the conformation zwitterionic membrane dilauroyl phosphatidylcholine (DLPC) has been investigated with calculation at the Hatree-Fock level using the 6-31G* basis set with Onsager continuum solvation model. The ‘Gauge Including Atomic Orbital' (GIAO) approach is used to investigate Ab initio GIAO calculations of NMR chemical shielding tensors carried out within SCF-Hartree-Fock approximation are described. In order to compare the calculated chemical shifts with experimental ones, it is important to use consistent nuclear shielding for NMR reference compounds like TMS. Conformation of DLPC was evaluated with four different solvents with different dielectric constant (Water (ε = 78.39), Dimethyl Sulfoxide (ε = 46.7), Acetone (ε = 20.7) and Heptane (ε = 1.92). In concern with conformational energy, Water could be the most suitable solvent for DLPC. Moreover, as the polarity of the medium increase, the conformational stability of this molecule increases faster than that of DLPC in the gas phase. Consequently, the relative energy of DLPC also depends on the polarity of the environment. This subject was considered as well as the most variable in some dihedral angles degree and NMR isotropic shift were in the less dielectric constant (ε = 1.92). It could be in polar medium DLPC conformer becomes additionally stabilized by intermolecular ionic and hydrogen bond interactions with polar neighboring molecules. On the basis of this work it can be concluded that the effect of the polarity of the environment clearly are influenced on the isotropic values by geometry variation due to intermolecular motion in molecule.

EXTRACTION OF COPPER ELECTROLYTICALLY BY USING SOLID MIXTURE OF CuFeS2 AND CaCO3 (CHALCOPYCA) AS ANODE Agus Kuncaka; Eko Sugiharto; Yasinta Endah Nastiti
Indonesian Journal of Chemistry Vol 5, No 3 (2005)
Publisher : Universitas Gadjah Mada

Study on a new road of copper electroextraction to make use the solid mixture of CuFeS2 and CaCO3 as anode has been done. The aim of these research was to determine reaction kinetic and faradic efficiency of anodic copper dissolution and catodic copper precipitation. A solid mixture of CuFeS2 and CaCO3 at weight ratio 9:1 was functioned as anode. Electrolysis was carried out at 1.5 mA by varying times of 30,60,120, and 240 minutes in Na2SO4 0.5 M + H2SO4 0.01 M electrolyte. The quantity of copper at the electrolyte and cathode was analyzed by Atomic Absorption Spectrophotometer (AAS). The result of these research showed that copper was deposited in the cathode simultaneously with anodic dissolution. The kinetic of copper dissolution follow zero order with rate constant of 5.10-6 mg/second. The faradic efficiency of copper dissolution and precipitation for those various time respectively were 17.31%; 14.00%; 11,16%; 62.31%; and 1.60%; 8.61%; 7.59%; 60.63%.

ELECTROCHEMICAL SYNTHEZIS AND CHARACTERIZATION OF POLYPYRROLE FOR DODECYLSULFATE SENSOR MEMBRANE Abdul Haris Watoni; Suryo Gandasasmita; Indra Noviandri; Buchari Buchari
Indonesian Journal of Chemistry Vol 7, No 3 (2007)
Publisher : Universitas Gadjah Mada

A conducting polymer, polypyrrole, has been electrochemically synthesized from pyrrole monomer using cyclic voltammetry technique in aqueous solution in the presence of HDS dopant and KNO3 supporting electrolyte. The polymer was deposited on the surface of an Au-wire and the modified electrode obtained was then used as dodecylsulfate (DS-) ion sensor electrode. The best performance PPy-DS modified-Au electrode conditioned in the air system without HDS or SDS solution gave linear potential response for the concentration range of 1.0 x 10-5 - 1.0 x 10-3 M, sensitivity of 54.5 mV/decade, detection limit of 1.0 x 10-5 M, and response time of 23 - 30 second. The electrode showed good selectivity towards other anions, therefore can be used to determine SDS concentration in real samples system without any change of the samples matrix.

FORMULA ESTABLISHMENT OF COLORLESS Pb(II) COMPLEX WITH N-BENZOYL-N-PHENYL HYDROXYLAMINE (BPA) USING ATOMIC ABSORPTION SPECTROSCOPY Dhananjay B Sarode; Sopan T Ingle; Sanjay B Attarde
Indonesian Journal of Chemistry Vol 12, No 1 (2012)
Publisher : Universitas Gadjah Mada

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.

DISTRIBUTION OF URANIUM IN WATER OF GRESIK COASTAL WATERS June Mellawati
Indonesian Journal of Chemistry Vol 9, No 2 (2009)
Publisher : Universitas Gadjah Mada

Determination of uranium in water sample at Gresik coastal waters around Gresik industrial area have been carrid out. The purpose of research is to find the distribution of uranium at the coastal where the phosphate industry standing and potencially to contribute uranium pollutant to the waters. The measurement of uranium was pasive of Gamma Spectrometry, and uranium was measured as 234Th (uranium daughters) on 92.80 and 1001.03 keV gamma energies. Sea water sample was taken up by water pump sampler as a vertical mixing. The sample was sampling on the highest tide and lowest ebb, at the east season (March-August) west season (September-February). The concentration of 238U on higher tide of the west season are range between 0.0016-0.0128 Bq/l, while on lowest ebb of the east season are 0,0013-0,0877 Bq/l. There was significantly different (α= 5%) of uranium concentration in water between two seasons (east and west) in tide and ebb respectively. According to Quality Standard from Dirjen BATAN No.293/Dj/VII/1995 (radioactivity on environment), the concentration of 238U in water obtained from coastal around phosphate industry are still lower than that of recomended values (10.000 Bq/l).

STRUCTURE ELUCIDATION OF BIOACTIVE ALKALOID COMPOUNDS ISOLATED FROM SPONGE Petrosia sp COLLECTED FROM BUNAKEN BAY MENADO Gemini Alam; Puji Astuti; Subagus Wahyuono; Dinar Sari; Mark T Hamman
Indonesian Journal of Chemistry Vol 5, No 2 (2005)
Publisher : Universitas Gadjah Mada

Two alkaloid compounds have been isolated from sponge Petrosia sp collected from Bunaken Bay Menado. These compounds have been found to inhibit several human cancer cell proliferation in vitro. Structure elucidation is needed to further characterize these bioactive compounds. The structure is determined by analyzing Ultra Violet (UV), Infra Red (IR), Mass Spectra (MS) and Nuclear Magnetic Resonance (NMR) spectra. Based on spectroscopic data, Thin Layer Chromatography (TLC) co-chromatograph with authentic samples and comparison with reported data the two compounds were identified as Manzamine A and 8-OH Manzamine A, respectively.

CONFORMATIONAL EQUILIBRIUM AND SPECTROSCOPIC PROPERTIES OF CALIX[4]ARENE: THEORETICAL STUDY USING AB INITIO METHOD Hanggara Sudrajat; Ria Armunanto
Indonesian Journal of Chemistry Vol 8, No 3 (2008)
Publisher : Universitas Gadjah Mada

Molecular structures were optimized for the calix[4]arene by ab initio method at the Hartree-Fock level of theory using LANL2DZ and 6-311G basis sets. Conformational equilibrium of four calix[4]arene conformers are reported. The results are compared with experiment, force field, and semiempirical molecular orbital calculations. General trends in relative stabilities of calix[4]arene decrease in following order: cone > partial-cone > 1,2-alternate > 1,3-alternate. The most stable conformer is the cone conformer that is stabilized by an array of four hydrogen bonds and these results agree with the reported experimental observations. All structures were analyzed using theoretical IR, UV-Vis, and 1H NMR spectra attributed to the conformational equilibrium at the Hartree-Fock level of theory using LANL2DZ basis set.

CHEMICAL STABILITY AND ADSORPTION SELECTIVITY ON Cd2+ IONIC IMPRINTED Nannochloropsis sp MATERIAL WITH SILICA MATRIX FROM TETRAETHYL ORTHOSILICATE Buhani Buhani; Suharso Suharso; Liza Aprilia
Indonesian Journal of Chemistry Vol 12, No 1 (2012)
Publisher : Universitas Gadjah Mada

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 > 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+ < Cd2+/Zn2+ < Cd2+/Cu2+ < Cd2+/Ni2+ for each α at metal ionic ratio of 1:1; 0.887; 20.180; 28.053; 33.417, respectively.

DEVELOPMENT OF FLOW INJECTION METHOD FOR ONLINE DETERMINATION OF THIOCYANATE BASED ON OXIDATION BY PERMANGANATE Hermin Sulistyarti; Spas D. Kolev; Stephanie Lim
Indonesian Journal of Chemistry Vol 10, No 2 (2010)
Publisher : Universitas Gadjah Mada

The importance of developing method for thiocyanate becomes obvious, because thiocyanate can inhibit iodine uptake of thyroid gland leading to mumps disease. In this work, thiocyanate is oxidized by permanganate in the acid donor stream to cyanide, which is directly converted to hydrogen cyanide. Then, hydrogen cyanide diffuses through a Teflon membrane into acceptor stream containing nickel(II) in ammoniacal buffer to form tetracyanonickelate(II) which is detected spectrophotometrically at 267 nm. Analytical figures of merit were linear up to 50 mg L-1 for thiocyanate, with RSD of 1.34%, and detection limit of 0.07 mg L-1, respectively. Interfering anions were eliminated under stoichiometric amount of permanganate and sample throughput was 20 h-1. The method was validated for determining thiocyanate samples from synthetic and gold process waters with satisfactory results.

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