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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).

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Articles 1,956 Documents

115 116 117 118 119

Determination of Total Phenolic Content and NIR-Chemometrics Classification Model of Queen and Local Varieties of Soursop (Annonamuricata L.) Leaf Powder Lestyo Wulandari; Mellda Kusuma Candra Dewi; Nia Kristiningrum; Yashinta Nirmala Siswanti
Indonesian Journal of Chemistry Vol 20, No 3 (2020)
Publisher : Universitas Gadjah Mada

The leaves of soursop (Annonamuricata L.) are commonly used for health because of their antioxidant activity from its highest phytochemical content, namely phenolic compound, which is influenced by the varieties of this plant. In Indonesia, there are two soursop varieties, namely ‘queen’ and ‘local’ varieties which are difficult to determine morphologically. The aim of this study was to determine the total phenolic content of soursop leaves of both varieties and to establish a classification model of NIR spectroscopy combined with chemometrics for the identification of the varieties of soursop leaves. After the soursop leaves were dried and grinded, they were then scanned to obtain the spectra of NIR spectroscopy. NIR spectras were combined with chemometrics to classify the varieties of the soursop. The classification models used were Linear Discriminant Analysis (LDA), Support Vector Machines (SVM) and Soft Independent Modelling of Class Analogies (SIMCA). Total phenolic content of the soursop leaves was determined by UV-Vis spectroscopy using Folin-Ciocalteau reagent and gallic acid as reference. The result showed that the local variety had higher total phenolic content than the queen variety. NIR spectroscopy combined with chemometrics was able to classify the varieties of soursop leaves with 100% accuracy using LDA and SVM.

Electrochemical Removal of Copper Ions Using Coconut Shell Activated Carbon Nur Azza Azyan Muin; Hawaiah Imam Maarof; Nur Alwani Ali Bashah; Nor Aida Zubir; Rasyidah Alrozi; Norhaslinda Nasuha
Indonesian Journal of Chemistry Vol 20, No 3 (2020)
Publisher : Universitas Gadjah Mada

In this work, coconut shell activated carbon (CSAC) electrode was evaluated to remove copper ion via electrochemical processes. CSAC electrode and graphite were applied as the cathode and the anode, respectively. The reusability of the electrode, the effects of initial pH, applied voltage and initial concentration were studied. The electrochemical process was carried out for 3 h of treatment time, and the electrodes (anode and cathode) were separated by 1 cm. The results revealed that CSAC is proven as a reusable electrode to remove copper ion, up to 99% of removal efficiency from an initial concentration of 50 ppm after it had been used three times. From the observation, the removal efficiency was optimum at an initial pH of 4.33 (without any initial pH adjustment). The applied voltage at 8 V showed a higher removal efficiency of copper ion compared to at 5 V.

Assessment of the Level and Health Risk of Fluoride and Heavy Metals in Commercial Toothpastes in Bangladesh Chanchal Chayan Paul; Md. Abu Shamim Khan; Probir Kumar Sarkar; Abdul Hakim; Md. Waliullah; Bablu Hira Mandal
Indonesian Journal of Chemistry Vol 20, No 1 (2020)
Publisher : Universitas Gadjah Mada

Toothpaste is one of the daily essentials, and good quality control practices over it are very important to protect the oral public health from adverse effects. The current study aimed to assess the concentration of fluoride and heavy metals, physicochemical properties in ten different toothpaste samples in Bangladesh, followed by related health risk analysis. pH, moisture content, F–, As, Cu, Pb contents were measured by membrane electrode, thermogravimetric, SPADNS, HG-AAS, flame-AAS methods, respectively. The results were compared to the specification of the packet and Bangladesh Standard and Testing Institute (BSTI) standard. The physicochemical properties well-matched the formulation standard values. The moisture content was 27.18 ± 2.20 to 52.10 ± 5.01%, with 50% of the samples in permissible limit but the pH of all the samples (6.40-8.60) was within the standard limit. Available F–, Cu, Pb, and As content ranged from 803–1617, 2.78–13.10, 0.27–2.12, and 0.027–0.637 mg/Kg, respectively. F– content in 80% toothpaste did not meet the packet specification and was higher than BSTI standard, though heavy metals were within the BSTI limit. Hazard quotient (HQ) and HI (Hazard Index) analysis revealed that toothpaste safe from heavy metal related to health risk.

Synthesis of Zinc Oxide Nanoparticles for Oil Upgrading and Wax Deposition Control: Effect of Calcination Temperature Siti Nurliyana Che Mohamed Hussein; Fatin Syahirah Mohamed Fuad; Marina Ismail
Indonesian Journal of Chemistry Vol 20, No 4 (2020)
Publisher : Universitas Gadjah Mada

In this study, ZnO nanoparticles were synthesized using a sol-gel method for oil upgrading and wax deposition control. The synthesized ZnO nanoparticles were used to measure viscosity and wax deposition in the heavy crude oil and to investigate the effectiveness of the nanoparticles in the reduction of viscosity and wax deposition control of the heavy crude oil. This study investigated the effect of calcination temperature on ZnO nanoparticles during synthesis towards viscosity reduction and wax deposition control. ZnO nanoparticles were calcined at different temperatures ranging from 300 to 900 °C. The calcined ZnO nanoparticles were characterized using X-ray diffraction (XRD), Field Emission Scanning Electron microscope (FESEM), and Energy-dispersive X-ray spectroscopy (EDX) for its structure, size, shape, and morphology. The characterization results showed a hexagonal wurtzite structure of ZnO nanoparticles. The physical properties and rheology of heavy crude oil were characterized by using Electronic Rheometer and cold finger method to analyze the viscosity, shear rate, and wax deposition of the heavy crude oil for performance study. Decreased in crystallite size from 15.59 to 12.84 nm was observed with increasing calcination temperature from 300 to 400 °C, and a further increase of calcination temperature from 400 to 900 °C, the crystallite size increased from 12.84 to 41.58 nm. The degree viscosity reduction (DVR %) of heavy crude oil was observed to increase by 41.7%, with decreasing ZnO nanoparticles size from 30.11 nm to 12.84 nm. The optimum calcination temperature was 400 °C. Wax deposition decreases by 32.40% after the addition of ZnO nanoparticles into heavy crude oil.

Isolation and Antibacterial Activity by in vitro and in silico Approach of 6-Deoxyjacareubin Compound from Garcinia latissima Miq. Fruit Neneng Siti Silfi Ambarwati; Berna Elya; Amarila Malik; Yuditya Artha; Islamudin Ahmad; Azminah Azminah; Muhammad Hanafi; Hanita Omar
Indonesian Journal of Chemistry Vol 20, No 4 (2020)
Publisher : Universitas Gadjah Mada

The previous research showed that the fraction C from active extract of Garcinia latissima Miq. fruit was active against Bacillus subtilis. This study aims to isolate and identify the active compound as an antibacterial agent from the fraction C. Fraction C was purified by recrystallization using chloroform and n-hexane solvents and then isolated using preparative-thin layer chromatography-silica gel 60 GF254 to give a yellow compound. The antibacterial activity was determined using microdilution with thiazolyl blue tetrazolium bromide indicator against B. subtilis American Type Culture Collection 6633. The isolate was identified using UV-Vis, IR, MS, Proton Nuclear Magnetic Resonance (1H-NMR) and carbon NMR (13C-NMR), and NMR-2D techniques including HMQC and HMBC. Based on the spectroscopic analysis and literature review, the compound was identified as 6-deoxyjacareubin, which is a new compound from Garcinia latissima Miq. The 6-deoxyjacareubin showed antibacterial activity with MIC value of 156.25 ppm and was categorized as a weak antibacterial agent because the MIC value was more than 100 ppm. According to in silico approach to the docking study, 6-deoxyjacareubin showed similar hydrophobic interaction with several amino acid residues including C2565, C2589, G2484, U2590, and U5588 between a native ligand.

Chemical Literacy: Performance of First Year Chemistry Students on Chemical Kinetics Muntholib Muntholib; Suhadi Ibnu; Sri Rahayu; Fauziatul Fajaroh; Sentot Kusairi; Bambang Kuswandi
Indonesian Journal of Chemistry Vol 20, No 2 (2020)
Publisher : Universitas Gadjah Mada

This study aims to (1) develop and validate a multiple choice chemical literacy test instrument (MC-CLTI) on chemical kinetics and (2) conduct a small survey on chemical literacy of first year chemistry students. The development of the instrument involved expert consultation and judgment, validation and two times pilot studies. The first pilot study involved 119 first year chemistry students while the second pilot study involved 197 second year chemistry students. The final form of MC-CLTI consists of 30 valid and reliable items (Cronbach's Alpha coefficient = 0.744). The survey showed that the average score of respondents' chemical literacy was 63.24. This score is in the range of the average scores reported by several previous studies.

Study of the Synthesis of Zirconia Powder from Zircon Sand obtained from Zircon Minerals Malaysia by Caustic Fusion Method Istikamah Subuki; Mimi Fazzlinda Mohsin; Muhammad Hussain Ismail; Fazira Suriani Mohamed Fadzil
Indonesian Journal of Chemistry Vol 20, No 4 (2020)
Publisher : Universitas Gadjah Mada

The zircon powder from Zircon Minerals Malaysia is a pure premium grade zircon sand milled 1.5 µm that contain ZrSiO4, ZrO2, HfO2, SiO2, Al2O3, TiO2, and Fe2O3. The monoclinic zirconia powders were synthesized from the zircon sand of Zircon Minerals Malaysia, by caustic fusion method at calcination temperatures between 500 °C to 800 °C. The as-synthesized zirconia was characterized through X-Ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric and differential thermal analysis (TG-DTA), and X-Ray fluorescence (XRF) techniques. The XRD results show two monoclinic phases of microcrystalline zirconia. Zirconia that was calcined at 600 °C obtained the highest value of ZrO2, which was 54.48%; followed by zirconia calcined at 700 °C, 800 °C, and 500 °C, which obtained the ZrO2 values of 53.58%, 52.41%, and 51.53%, respectively, based on the XRF analysis. As-synthesized zirconia showed monoclinic phases where the surface areas were 0.0635 m2/g, 0.135 m2/g, 0.0268 m2/g, and 0.0288 m2/g, for zirconia calcined at temperatures of 500 °C, 600 °C, 700 °C, and 800 °C, respectively. The surface structure of the powder that had been calcined at 600 C showed similarities with the commercial zirconia. The similarities of the synthesized zirconia and commercial zirconia showed that the zirconia powder could be synthesized using zircon sand by caustic fusion method, even though the content of zirconia was lower compared to that of the commercial zirconia powder.

Synthesis, Structural and Optical Characterization of Titanium Dioxide Doped by (Ce, Yb) Dedicated to Photonic Conversion Zobair El Afia; Mohamed Youssef Messous; Mohamed Cherkaoui; Mounia Tahri
Indonesian Journal of Chemistry Vol 20, No 1 (2020)
Publisher : Universitas Gadjah Mada

The synthesis of TiO2 co-doped by (Ce, Yb) rare earth couple has been realized. This couple of rare earth can convert a high-energy photon to two low energy photons to enhance the energy efficiency of silicon solar cells. The undoped, 2% Ce doped- and (2% Ce, 4% Yb) Codoped- Titanium oxide were prepared by the co-precipitation method. The Infrared spectroscopy FTIR-ATR analysis indicates a continuous visible absorption in the 750–400 cm–1 region, confirming the formation of a titanium-oxygen bond. The X-Ray Diffraction characterization showed the dominance of the rutile crystalline phase with the presence of anatase one and the calculated crystallite size is between 7 to 13 nm. The X-Ray Fluorescence confirms the insertion of the dopants while the Inductively Coupled Plasma Mass Spectrometry ICP-MS showed the ratio 2 between Ce and Yb concentration. The thermogravimetric analysis indicated that Ce/Yb doped titanium was thermally stable. The absorption in the UV-visible (200 and 1000 nm) has been improved proportionally with the dopants.

Catalytic and Thermal Cracking of Bio-Oil from Oil-Palm Empty Fruit Bunches, in Batch Reactor Santiyo Wibowo; Lisna Efiyanti; Gustan Pari
Indonesian Journal of Chemistry Vol 20, No 5 (2020)
Publisher : Universitas Gadjah Mada

The world’s potency of fossil-derived petroleum fuels has declined steadily, while its consumption continues to rise ominously. Therefore, several countries have started to develop renewable fuels like bio-oil from biomass. Relevantly, the aim of this research was to explore the technical feasibility of upgrading the qualities of crude bio-oil (CBO) produced from the pyrolysis on oil-palm empty fruit bunches (OPEFB) using Ni/NZA catalyst in a batch reactor. The natural zeolite (NZ) was activated by HCL 6 N and NH4Cl (obtained sample NZA). Supporting Ni onto NZA was conducted with an impregnation method using a salt precursor of Ni(NO3)2·6H2O followed by calcination with a temperature of 500 °C. Catalyst characterization includes determining the site of TO4 (T = Si or Al) in zeolites, acidity, crystallinity, and catalyst morphology. Cracking reaction of CBO was carried out in batch reactor in varied temperatures of 250 and 300 °C with the variation of catalyst weight of 0, 4, 6, and 8% toward CBO. Several analyses of the liquid product such as product yield, specific gravity, pH, viscosity, calorific value, and chemical compound were conducted. The results showed that acidification and Ni loading on zeolite samples increased their acidity. The optimum CBO’s cracking condition was judged to be the temperature of 300 °C with 6% Ni/NZA catalyst use, whereby the fuel yield reached 26.42% and dominated by particular compounds comprising phenol, octanoic acid, and alkane hydrocarbons. Under such conditions, the characteristics of fuel were pH 3.54, specific gravity 0.995, viscosity 14.3 cSt, and calorific value 30.85 MJ/kg.

Preparation, Characterization and Study of the Photodecolorization of Mixed-Ligand Binuclear Co(II) Complex of Schiff Base by ZnO Suhad Kareem Abass; Jassim Abbas Al-Hilfi; Sawsan Khudhair Abbas; Luma Majeed Ahmed
Indonesian Journal of Chemistry Vol 20, No 2 (2020)
Publisher : Universitas Gadjah Mada

In this work, a new mixed-ligand binuclear Co(II) complex of Schiff base was prepared. Moreover, the characterization of this prepared complex was performed by measurement of melting points, UV-Vis spectra, FT-IR spectra, and magnetic susceptibility measurements, and later compared with metal and ligand solutions. It has been discovered that the Schiff bases with Co(II) ion forms a binuclear complex with a stoichiometry of molar ratio 1:2 from “metal:ligand”. The photodecolorization of this complex was done under UV light for ZnO's suspension solution. The results of this photodecolorization showed that the greatest efficiency was obtained with the use of ZnO dose of 300 mg/100 mL and at an initial pH of 7. The decolorization activation energy for this complex is a small value of 11.289 kJ mol–1. Additionally, the thermodynamic study for this reaction is non-spontaneous, endothermic and less random.

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