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All Journal JURNAL KIMIA SAINS DAN APLIKASI
Mohamad Rafi
Department of Chemistry, Faculty of Mathematics and Natural Sciences, IPB University, Bogor 16680|IPB University|Indonesia
Chemical Engineering, Chemistry & Bioengineering Chemistry Engineering

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Penentuan Kadar Fenolik Total dan Aktivitas Antioksidan Enam Tanaman Hias Mohamad Rafi; Tanti Yulianti Raga Pertiwi; Syaefudin Syaefudin
Jurnal Kimia Sains dan Aplikasi Vol 22, No 3 (2019): Volume 22 Issue 3 Year 2019
Publisher : Chemistry Department, Faculty of Sciences and Mathematics, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2554.67 KB) | DOI: 10.14710/jksa.22.3.79-84

Abstract

Total phenolic content and antioxidant activity from six Indonesian ornamental plants have been studied. Those plants are Yellow Allamanda (Allamanda cathartica L.), Bigleaf Hydrangea (Hydrangea macrophylla (Thunb.) Ser.), Crystal Anthurium (Anthurium crystallinum Linden & André), Kapok Bush (Aerva sanguinolenta (L.) Blume), Siamese Calypha (Acalypha siamensis Oliv. Ex Gage), and Wishbone Flower/Bluewings (Torenia fournieri Linden ex E. Fourn). Extraction was carried out by maceration using ethanol as the extracting solvent. Total phenolic content was determined by the Folin Ciocalteu method. Antioxidant activity was measured using the 2.2-diphenyl-1-picrylhydrazyl (DPPH), reducing power, and cupric ion reducing antioxidant capacity (CUPRAC) method. Based on the results obtained, Bigleaf Hydrangea has the highest yield and total phenolic content about 15.45% and 13.86 mg gallic acid/g dry powder respectively. Siamese Acalypha leaves have the highest antioxidant activity for all methods used namely DPPH, reducing power, and CUPRAC with a value of 180.45; 202,17; and 589.90 µmol trolox/g dry powder, respectively. This indicates that antioxidant activity is not only derived from phenolic compounds because Siamese Acalypha leaves which have lower total phenolic levels than Bigleaf Hydrangea leaves provide higher antioxidant capacity.
An Eco-Friendly Synthesis of Silver Nanoparticles Using Extract of Capsicum chinense Jacq. as A Bio-reducing Agent Boyfannie Ivan Putra; Hermin Sulistyarti; Rurini Retnowati; Mohamad Rafi
Jurnal Kimia Sains dan Aplikasi Vol 26, No 3 (2023): Volume 26 Issue 3 Year 2023
Publisher : Chemistry Department, Faculty of Sciences and Mathematics, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/jksa.26.3.101-108

Abstract

Silver nanoparticles (AgNPs) have become popular due to their unique properties that can be used as biosensors, composite fibers, semiconductor materials, and other medical applications. Green synthesis of AgNPs using natural reagents from plant extract offers advantages as an efficient and environmentally friendly technique by which the compounds from the extract perform as bio-reductor for silver ions and the capping agent for stabilizing the AgNPs. Therefore, the purpose of the study was to conduct the synthesis of AgNPs by utilizing an extract of Capsicum chinensie Jacq as the bioreductor. The effect of extract concentrations, duration of exposure to sunlight, and temperatures on AgNPs formation was studied to obtain the optimum synthesis condition. The biosynthesized AgNPs characteristics were analyzed using UV-Vis Spectrophotometry, FTIR, SEM, X-Ray Diffraction, and PSA. The results showed that the higher extract concentration produced smaller AgNPs. The synthesis under sunlight exposure showed more product of AgNPs compared to heating on a hot plate. The optimum conditions of biosynthesis of AgNPs were attained at the volume ratio of extract (20%) and AgNO3 (1mM) of 1:1 and duration of sunlight exposure of 90 min, resulting in AgNPs characterized with maximum wavelength 422 nm and average particle sizes of 67.94 nm.
Metabolite Profiling of Java Turmeric (Curcuma xanthoriza) Essential Oil with Different Harvest Times Mohamad Rafi; Dewi Anggraini Septaningsih; Rudi Heryanto
Jurnal Kimia Sains dan Aplikasi Vol 21, No 4 (2018): volume 21 Issue 4 Year 2018
Publisher : Chemistry Department, Faculty of Sciences and Mathematics, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2511.972 KB) | DOI: 10.14710/jksa.21.4.237-241

Abstract

Java turmeric (Curcuma xanthoriza) is one of the native plants from Indonesia. Java turmeric is known as a medicinal plant with a high content of volatile oils. In this study, we investigated the chemical profile of java turmeric essential oil obtained by hydrodistillation associated with different harvesting times of the rhizome (7, 9, and 11 months). The constituent of the essential oil was determined by using gas chromatography-mass spectrometer. About 19, 20 and 34 compounds were identified in 7, 9, and 11-month old java turmeric. Fifteen compounds were found in all samples namely β-elemene, zingiberene, γ-elemene, β-farnesene, α-curcumene, benzofuran, α-cedrene, epicurzerenone, ar-curcumene, germacrone, aromadendrene, α–longipene, trans-caryophilene, curcuphenol, and xanthorrhizol. This study showed the level of all compound detected in 7, 9, and 11 months old of java turmeric is different.
Optimization of Cadmium Removal Using Tetraethylene Glycol-Modified Silica-Based Adsorbent via Response Surface Methodology Roza Linda; Abdullah Abdullah; Afrianto Daud; Lisa Aprilia Indriyani; Henny Purwaningsih; Mohamad Rafi; Lee Wah Lim
Jurnal Kimia Sains dan Aplikasi Vol 27, No 3 (2024): Volume 27 Issue 3 Year 2024
Publisher : Chemistry Department, Faculty of Sciences and Mathematics, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/jksa.27.3.128-136

Abstract

In solid-phase extraction for preconcentration, silica (Si) is the most commonly used as an adsorbent. However, the selectivity and effectiveness of silica gel adsorption on metal ions are low, so it needs to be modified to improve the adsorption capability. The modification was done using reflux and oven heating in the modification silica with 3-glycidoxypropyl trimethoxysilane (GPTMS) and tetraethylene glycol (TEG). A central composite design batch process determined the optimum conditions for cadmium adsorption. TEG-modified silica was successfully synthesized and characterized using FTIR spectroscopy, SEM, and elemental analyzers. Peaks of C-H and epoxy on FTIR spectra showed that Si- GPTMS was formed. The increase of %C and %H from the first to the second step indicated that Si-TEG was successfully synthesized. There was no significant difference in silica particle morphology on SEM before and after modification. The reflux method gave a higher yield compared to the heating method. The constant stirring by the magnetic bar and solvent cycle in the reflux method catalyzed the reaction. This study found that at pH 7, 30 mg of adsorbent weight at 35°C and 22 minutes of contact time were optimum Cd2+ adsorption conditions. As the weight of the adsorbent increases, the adsorption capacity decreases. Contact time and temperature have no significant effect on Cd adsorption by Si-TEG.
Co-Authors Abdullah Abdullah Afrianto Daud Boyfannie Ivan Putra Henny Purwaningsih Hermin Sulistyarti Lee Wah Lim Lisa Aprilia Indriyani Roza Linda Rudi Heryanto Rurini Retnowati Septaningsih, Dewi Anggraini Tanti Yulianti Raga Pertiwi