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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

121 122 123 124 125

Zinc-Doped Titania Embedded on the Surface of Zirconia: A Potential Visible-Responsive Photocatalyst Material Azizia Alifi; Rian Kurniawan; Akhmad Syoufian
Indonesian Journal of Chemistry Vol 20, No 6 (2020)
Publisher : Universitas Gadjah Mada

The preparation and characterization of zirconia-supported titania with a zinc dopant had been studied. Zinc-doped titania was grown on the surface of zirconia by the sol-gel method. Various zinc contents and calcination temperatures were applied to investigate the zinc doping effect and crystal structure of the zirconia-titania composite. X-ray diffraction method, Fourier-transform infrared spectroscopy, and UV-Vis reflectance spectroscopy were performed to characterize the composite. The morphology of the composite was observed by using a scanning electron microscope, and its composition was analyzed by using energy dispersive spectroscopy. Among various zinc dopant contents and calcination temperatures investigated, doping with 5% zinc (Zn wt./Ti wt.) at 900 °C calcination shows the best result in response to visible light with a bandgap of 2.87 eV and absorption edge wavelength of 432.61 nm.

Effect of Microwave Pretreatment on Gaharu Essential Oil Using Hydrodistillation Method Nurhaslina Che Radzi; Filzah Anati Kasim
Indonesian Journal of Chemistry Vol 20, No 4 (2020)
Publisher : Universitas Gadjah Mada

Gaharu wood produces an expensive essential oil due to its fragrance and chemical compounds. Normally, the black color wood is used for the extraction of oil because it contains high resin. However, the cost of this resinous wood is very expensive. Therefore, in this study, the raw material with low resin content (identified by the white color of the wood) will be used for the extraction of oil. However, hydrodistillation alone will not produce satisfactory volume. Thus, pretreatment is needed to enhance the amount of essential oil. This paper aims to investigate the effect of microwave pretreatment on gaharu essential oil extraction using the hydrodistillation method for the lower grade wood. The gaharu wood was pre-treated with microwave irradiation power of 800 kW at three different durations which were 1, 2 and 3 min. Later, extraction was performed using the hydrodistillation method for 30 h. The chemical composition of the oil was analyzed using gas chromatography-mass spectrometry (GCMS). The results show that microwave pretreatment produced higher yield (0.0379 wt.%) of gaharu essential oil compared to the extraction of the non-pretreated wood (0.0286 wt.%) in which the increase was 24.55%. The three minutes pretreatment time produced the largest amount of oil (0.0877 wt.%). The outcomes of this study indicated the increase of chemical components of gaharu essential oils such as (+)-Epi-bicyclosesquiphellandrene, gurjunene, α-farnese, estragole, guaiene, valencene, spathulenol, α-cubebene and (-)-Spathulenol in the extraction of the pre-treated wood compared to the non-pretreated one.

Bioleaching Ability of Fungi Isolated from an Indonesian Sulfurous River Sediment Serafica Btari Christiyani Kusumaningrum; I Wayan Warmada; Wahyu Wilopo; Endah Retnaningrum
Indonesian Journal of Chemistry Vol 20, No 4 (2020)
Publisher : Universitas Gadjah Mada

The unique characteristics of sulfurous river sediment located in Ungaran, Indonesia, are a reservoir of novel fungi with manganese bioleaching properties. Fungi are known to produce metabolic organic acids that have a potential for the industrial application of leaching metal from the ores. This application has high advantages, including low cost, low energy, and creates minimal environmental damage. Therefore, this research was performed to analyze the manganese bioleaching activities of two fungal isolates (KA2B2 and KB4B) from Indonesian sulfurous river sediment on pyrolusite and determine their phenotypic characters. These activities were investigated in terms of changes in fungal biomass, soluble manganese concentration, pH reduction, and organic acid production during 16 days of leaching. Soluble manganese concentrations were measured by atomic absorption spectrometry (AAS), whereas organic acid concentrations were analyzed by high-performance liquid chromatography (HPLC). According to bioleaching investigations, KA2B2 strain was more efficient than KB4B1 strain in extracting manganese from 0.02 g/cm3 pyrolusite. It also produced higher levels of organic acids, such as oxalic acid and citric acid, than KB4B1 strain, proving that strain of KA2B2 could be used to extract manganese from pyrolusite. Based on the phenotypic characters, both strains were identified as genus Penicillium.

Cobalt Doping on Zirconium Titanate as a Potential Photocatalyst with Visible-Light-Response Emilya Faridatul Sulaikhah; Rian Kurniawan; Mokhammad Fajar Pradipta; Wega Trisunaryanti; Akhmad Syoufian
Indonesian Journal of Chemistry Vol 20, No 4 (2020)
Publisher : Universitas Gadjah Mada

Synthesis of cobalt-doped zirconium titanate (Co-doped ZrTiO4) as a potential photocatalyst with visible-light-response had been conducted. Materials used in this research were titanium tetraisopropoxide (TTIP) as a precursor of TiO2, ZrO2 as another semiconductor for coupling, and CoSO4·7H2O as the source of cobalt dopant. The composite was prepared by the sol-gel method with various cobalt contents and calcination temperatures. Composites with various Co dopant contents (0, 1, 3, 5, 7, and 9% (Co wt./Ti wt.)) were calcined at 500 °C for 4 h. In addition, the composite with 5% of dopant content was calcined at 700 and 900 °C to observe the influence of calcination temperature. All samples were characterized by using X-ray powder diffraction method (XRD), Fourier-transform infrared spectroscopy (FTIR), specular reflectance UV-Vis spectroscopy (SRUV), and scanning electron microscopy equipped with X-ray energy dispersive spectroscopy (SEM-EDS). Co-doped ZrTiO4 with the lowest bandgap (2.94 eV) was achieved in a sample containing 3% of cobalt content calcined at 500 °C.

Kinetic study of HTPB (Hydroxyl Terminated Polybutadiene) Synthesis Using Infrared Spectroscopy Heri Budi Wibowo; Widhi Cahya Dharmawan; Ratih Sanggra Murti Wibowo; Adi Yulianto
Indonesian Journal of Chemistry Vol 20, No 4 (2020)
Publisher : Universitas Gadjah Mada

A kinetic study of HTPB synthesis by radical polymerization of butadiene with hydrogen peroxide initiator was conducted using infrared spectroscopy. HTPB conversion was determined based on the conjunction termination rate constant, and all polymerization kinetics were evaluated to identify the constant. All polymerization steps (decomposition, initiation, propagation, conjunction, and proportional termination) can be evaluated based on polymer conversion and functionality from data provided by infrared spectroscopy. The investigation variables included the initial molar ratio of initiator to monomer (H2O2/butadiene) and the reaction temperature. These steps were assumed as the first-order reactions, giving constant reaction rates of kd, ka, kp, kt, ktc, and ktd. The reaction rates obtained for these constants were 4.2 × 10–5 sec–1, 8.9 × 10–4, 7.7 × 103, 8.5 × 107, 3.2 × 107 and 5.3 × 107 L mol–1 sec–1, respectively, with activation energy of 7608, 14188, 2247, 105, 87 and 135 kJ mol–1, respectively. The determining step of the reaction rate was identified as the initiation reaction. HTPB conversion can be measured if all polymerization kinetics constants have been evaluated.

Synthesis, Characterization, and Stability Evaluation of β-Carotene Encapsulated in Starch-Chitosan/Tripolyphosphate Matrices Agnes Dyah Novitasari Lestari; Dwi Siswanta; Ronny Martien; Mudasir Mudasir
Indonesian Journal of Chemistry Vol 20, No 4 (2020)
Publisher : Universitas Gadjah Mada

This study aims to investigate the synthesis and characterization of β-carotene encapsulated in the blending matrices of starch (native and hydrolyzed starch)-chitosan/TPP (tripolyphosphate) by examining the effects of starch-to-chitosan weight ratio, β-carotene addition level, and TPP addition level on the encapsulation efficiency (EE) and loading capacity (LC); and to evaluate their storage stability. The encapsulation was done by the dropwise addition of ethanolic β-carotene dispersion into the blending matrices. The results of XRD analysis show that the encapsulation process significantly decreases the crystallinity of the starches, chitosan, and β-carotene. Scanning electron microscope (SEM) images reveal that the encapsulation products form irregular lumps. The EE and LC tend to increase with the increase in polymer fraction of matrices and β-carotene addition level, and with the decrease in TPP addition level. The addition of chitosan and the replacement of native starch by hydrolyzed starch tend to increase storage stability of β-carotene encapsulated in the starch matrix because chitosan can act as a good film-forming and antioxidant, while hydrolyzed starch contains amylose amylopectin with a short chain which is better in film-forming ability. These results promote the use of the hydrolyzed starch-chitosan/TPP as a matrix to enhance the stability β-carotene via encapsulations.

pH Dependence on Colorimetric Detection of Hg2+ by Histidine-Functionalized Gold Nanoparticles Dewi Eviane; Dwi Siswanta; Sri Juari Santosa
Indonesian Journal of Chemistry Vol 20, No 4 (2020)
Publisher : Universitas Gadjah Mada

In this study, we successfully developed gold nanoparticles capped with histidine (His-AuNPs) for Hg2+ detection using trisodium citrate as the reducing agent. The optimum pH for the detection of Hg2+ by His-AuNPs was 12. The addition of Hg2+ to the His-AuNPs caused the color change from red to black-blue, which is readily detectable by the naked eye. This color change is followed by a decrease in the intensity of the primary Surface Plasmon Resonance (SPR) peak at a wavelength (λ) of 525 nm and an increase in the secondary peak at λ = 650 nm. His-AuNPs effectively detected Hg2+ with limits of detection and quantitation of 1.77 µM and 5.89 µM, respectively. His-AuNPs exhibited good performance for the detection of Hg2+ in waste water collected from a steel industrial facility in Banten Province, with a recovery and a percent relative standard deviation of 115% and 1.02%, respectively.

Study of the Mechanical Properties of Natural Rubber Composites with Synthetic Rubber Using Used Cooking Oil as a Softener Nasruddin Nasruddin; Tri Susanto
Indonesian Journal of Chemistry Vol 20, No 5 (2020)
Publisher : Universitas Gadjah Mada

This research aims to study the mechanical properties of natural rubber composites with nitrile butadiene rubber and ethylene propylene diene monomer rubber. Composite fillers consisted of kaolin, and softener using used cooking oil. The study was carried out by the method of mastication, vulcanization, and maturation of the compound into rubber vulcanizates. The vulcanization and mastication process is carried out in the open mill. The maturation of the compound into rubber vulcanizates from the results of mastication and vulcanization was carried out using semi-automatic heat press and press at a temperature of 130 °C ± 2 °C for 17 min. Based on data from testing the mechanical properties of five samples from five formulas, the mechanical properties of composite rubber are affected by the ratio of natural rubber, synthetic rubber, kaolin, and used cooking oil as a softener. The difference in the results of vulcanizates rubber testing of natural rubber composites with synthetic rubber is not only influenced by the ratio of the composite, but also by the degree of cross-linking between the material molecules.

Pharmacokinetic Study and Incurred Sample Stability of Esomeprazole in Dried Blood Spot Sample Using High Performance Liquid Chromatography-Photodiode Array Yahdiana Harahap; Anja Tamabri; Vicha Vicha; Herman Suryadi; Sunarsih Sunarsih; Callista Andinie Mulyadi
Indonesian Journal of Chemistry Vol 20, No 5 (2020)
Publisher : Universitas Gadjah Mada

In the past years, Esomeprazole (EMP) was analyzed in human plasma samples, which still has stability issues; thus, the new biosampling technique known as Dried Blood Spot (DBS) might solve the issue. This research aims to evaluate the incurred sample stability of esomeprazole in dried blood spot using high performance liquid chromatography-photodiode array with lansoprazole as an internal standard. The analytical separation was performed on a C-18 column (Waters, Sunfire™ 5 μm; 250 × 4.6 mm) at 40 °C. The mobile phase used was acetonitrile–phosphate buffer pH 7.6 (40:60% v/v) with a flow rate of 1.00 mL/min; and was detected at 300 nm. The analyte was extracted from dried blood spot by methanol. Incurred sample stability was evaluated from 6 healthy subjects on day 0, 7, 14, and 28, respectively. This method was linear in the range concentration of 70–1400 ng/mL with r > 0.98. Pharmacokinetic study shows that the average of AUC0–t of EMP in the DBS sample was 1765.41 ngh/mL. The highest percent difference value of esomeprazole’s incurred samples stability on day 7, 14, and 28 from 6 healthy subjects were 9.81%. This result fulfilled the acceptance criteria, which is the percent difference should not be greater than 20%, and 67% of total samples have to fulfill the criteria. The incurred sample stability result showed that esomeprazole was stable in the DBS sample at least until 28 days with the highest value of percent difference is 9.81%.

Synthesis 1,1-Dibutoxybutane from Single Reagent of n-Butanol Using Cr/Activated Carbon Catalyst Iip Izul Falah; Mokhammad Fajar Pradipta; Alvan Luthfi Rinaldi; Wega Trisunaryanti
Indonesian Journal of Chemistry Vol 20, No 5 (2020)
Publisher : Universitas Gadjah Mada

Synthesis of 1,1-dibutoxybutane from the single reagent of n-butanol using Cr/Activated Carbon (Cr/AC) as a catalyst has been done. The aims of this research were to evaluate the effect of temperature, amount of catalyst, and alcohol flow rate towards the yield of 1,1-dibutoxybutane. Activated carbon (AC) was prepared by activating coconut shell carbon at 650 °C in the atmosphere of H2 at a flow rate of 15 mL/min for 4 h, and then it was washed using acetone in a Soxhlet for 15 rounds, washed 3 times by 1.0 M HCl, and finally, it was sieved at 60–80 mesh. Metal content was analyzed using atomic absorption spectroscopy (AAS) of Na, Ca, and Fe. The AC was impregnated with Cr(VI) solution and reduced with H2 at 650 °C. The acidity of Cr/AC catalyst was determined by the adsorption of ammonia vapor. Optimization of n-butanol conversion to 1,1-dibutoxybutane using Cr/AC catalyst was conducted in an oven using variations of temperature of 450, 500, and 550 °C, catalyst amount of 5, 10, and 15 g, under an alcohol flow rate of 0.10, 0.50, and 0.90 mL/min. The conversions of 1,1-dibutoxybutane were analyzed by GC-MS and 1H-NMR. The results showed that after washing by acetone and 1.0 M HCl, the content of metals in the AC was significantly decreased. The AC and Cr/AC showed acidity of 2.49 and 8.27 mmol/g, respectively. The highest product of 1,1-dibutoxybutane (53.42%) was reached at 450 °C using 5 g catalyst of Cr/AC under the alcohol flow rate of 0.10 mL/min.

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