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Indonesian Chimica Letters
Published by Universitas Jember
ISSN : -     EISSN : 29646782     DOI : https://doi.org/10.19184/icl
Core Subject : Science,
Chemistry
ICL is an international peer-reviewed and open access journal that publishes scientific articles covering all branches of chemistry: organic chemistry, physical chemistry, inorganic chemistry, analytical chemistry, biochemistry, chemometry, and applied chemistry
Arjuna Subject : Kimia(semua kategori) - Kimia (Lain-Lain)
Articles 5 Documents
 1 
Search results for , issue "Vol. 2 No. 2 (2023)" : 5 Documents clear
Spectrophotometric Analysis of Caffeine Content in Coffee Mistletoe (Dendrophthoe petandra L.) Apriliana, Gepsa; Indarti, Dwi; Muflihah, Yeni Maulidah
Indonesian Chimica Letters Vol. 2 No. 2 (2023)
Publisher : Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.19184/icl.v2i2.5606

Abstract

Caffeine, a well-known alkaloid presents in plants such as tea, coffee, and kola nuts, was thoroughly analyzed in coffee mistletoe. Our study successfully extracted caffeine using dichloromethane and chloroform, incorporating qualitative testing and robust method validation with a visible spectrophotometer. Notably, dichloromethane yielded the highest caffeine extract at 0.042 grams. The qualitative tests distinctly confirmed the presence of caffeine, evidenced by a color change with Parry's reagent and a maximum absorption wavelength of 273 nm. We also pinpointed the caffeine complex’s maximum wavelength at 640 nm, further validating our findings against a standard solution. Our method validation showed impressive linearity (r = 0.9974), with limits of detection at 1.81 ppm and quantitation at 6.02 ppm. The accuracy ranged between 90.0% and 97.5%, while the precision values were consistently around 98%. Additionally, we determined the water content of the coffee mistletoe leaf powder to be 8.733%. This comprehensive analysis establishes a strong foundation for the caffeine content in coffee mistletoe.
Immobilization of Endo-Β-1,4-D-Xylanase using Alginate/Nanocellulose for Xylooligosaccharide Production Ratnadewi, Anak Agung Istri; Aprilia, Selvina Rizky; Piluharto, Bambang; Yulvia, Ana
Indonesian Chimica Letters Vol. 2 No. 2 (2023)
Publisher : Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.19184/icl.v2i2.5607

Abstract

Free endo-β-1,4-D-xylanase cannot be used more than once, so it needs to be modified by immobilizing the enzyme. Endo-β-1,4-D-xylanase was obtained from termite abdomen sources by isolation, ammonium sulfate purification, and dialysis methods. Endo-β-1,4-D-xylanase was immobilized with an alginate/nanocellulose matrix. This study aims to determine the activity, protein content, and repeated use of immobilized Endo-β-1,4-D-xylanase. This study used variations of Alginate/nanocellulose (0; 2.5; 5; 7.5; 10) %. Protein levels of Endo-β-1,4-D-xylanase were tested using the Bradford method and activity using the Miller method. The total protein bound to the immobilized Endo-β-1,4-D-xylanase was stated with the immobilized yield data. The immobilized yield with the composition of Alginate Nanocellulose (ANC) (0%) was 45.33% greater than the other compositions. Immobilized Endo-β-1,4-D-xylanase activity is efficient. ANC 5% produces an efficiency of 62.384% at the 12th hour, which is greater than the other ANC compositions.
Extraction of Aluminium (Al) Metal from Coal Fly Ash of PLTU-Paiton with NaOH Solvent Puspa, Aranca Nindya; Haryati, Tanti; Andarini, Novita
Indonesian Chimica Letters Vol. 2 No. 2 (2023)
Publisher : Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.19184/icl.v2i2.5616

Abstract

Fly ash, a solid waste product from the coal combustion process at the Paiton PLTU, contains 14.52-23.78% alumina (Al2O3). This can be extracted using NaOH for further utilization. The Al(OH)3 precipitate was obtained using a 4 M HCl solution with pH variations of 6 and 6.5. Meanwhile, Al metal was obtained using a reduction temperature variation of 600-700°C with an interval of 50°C using Mg metal reductant for 2.5 hours. The aluminum metal obtained was subjected to qualitative analysis by UV-Vis spectrophotometer and quantitative analysis by XRF and AAS. The Al(OH)3 precipitate obtained at a pH of 6.001 weighed 1.581 grams, with a yield of 61.83%, while at a pH of 6.500 it weighed 1.688 grams, with a yield of 66.02%. Applying a specific reagent for Al metal, alizarin, to qualitative analysis resulted in a maximum wavelength of 495 nm. A quantitative analysis was conducted utilizing the atomic absorption spectrophotometer (AAS) at a wavelength of 309.3 nm. The alumina content in fly ash was determined to be 14.52%, with an Al metal yield of 8.67% at a pH of 6 and 9.01% at a pH of 6.5, at an optimal reduction temperature of 650°C.
The Influence of Cellulose Acetate Concentration for Ultrafiltration Membranes Apriliasari, Yekti; Indarti, Dwi; Oktavianawati, Ika; Piluharto, Bambang
Indonesian Chimica Letters Vol. 2 No. 2 (2023)
Publisher : Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.19184/icl.v2i2.5618

Abstract

Separation process using a membrane is a common method used in many fields. The objective of this research is to find out the influence of polymer concentration on the physical properties and performance of cellulose acetate as an ultrafiltration membrane. The cellulose acetate membrane is made by phase inversion technique. This technique is carried at by dissolving cellulose acetate in a range of concentration (18%, 19%, 20%, 21%, and 22%) in the solvent (acetone/DMSO = 15%/60%) and DMP as additives (3% mL). Then the mixtures homogenized and added PEG400 for 10% of cellulose acetate concentration (% w/w), strired ± 12 hours left in place until the buble disappeared. Then the dope solution is printed the glass plate, evaporated for 3 minutes, and immersed in a coagulation bath containing 5% acetone. The results suggest that the greater the concentration of cellulose acetate membrane increase the number density while the swelling degree decrease. The performance of the membrane showed that the greater concentration of cellulose acetate will water of flux the membrane decrease and rejection coefficient increase. Cellulose acetate membrane by varying the concentration of 21% and 22% included in the classification of ultrafiltration membranes for rejection coefficient value (90,37% and 91,43%) 90% may rejection by a membrane.
Development of C-Pd electrode as a working electrode in the detection of dissolved oxygen by cyclic voltammetry Setiawan, Mohamad Bayu; Mulyono, Tri; Siswoyo
Indonesian Chimica Letters Vol. 2 No. 2 (2023)
Publisher : Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.19184/icl.v2i2.5644

Abstract

Dissolved oxygen in water is vital in supporting life, so it becomes one of the parameters of water quality and makes dissolved oxygen measurement very important. This study attempts to develop an electrode based on carbon-palladium alloy material (C-Pd) to be used as a voltammetric detector of dissolved oxygen in water. The formation of the alloy is carried out by electrodeposition using the cyclic voltammetry technique. The effect of HCl concentration in the palladium electrodeposition process is studied to obtain the optimum HCl concentration. The resulting C-Pd electrode is then tested for its performance in measuring dissolved oxygen. It is carried out by cyclic voltammetry in NaOH electrolyte solution, Ag/AgCl reference electrode, and Pt counter electrode. Before standard solutions and samples are measured, the NaOH concentration is optimized first to obtain the best oxygen reduction conditions on the Pd surface. The results of oxygen measurements with the C-Pd electrode are compared with those from a commercial DO meter. The results showed that palladium electrodeposition on the carbon surface was optimum in 0.5 M HCl solution, and the optimum dissolved oxygen reduction process used 0.1 M NaOH electrolyte solution. The results of the C-Pd electrode performance test showed a decrease in sensitivity in the form of a calibration curve slope value of -703.77 nA/ppm on the first day, -558.36 nA/ppm on the second day, and -417.81 nA/ppm on the third day. A comparison of measurement results between the C-Pd electrode and a commercial DO sensor showed a significant difference. Despite the less-than-optimal results, this study shows the potential for palladium to be used as an electrode in an electrochemical oxygen sensor as an alternative electrode material besides precious metals.

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