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Jurnal Akademika Kimia
Published by Universitas Tadulako
ISSN : 24775185     EISSN : 23026030     DOI : -
Core Subject : Science, Education,
Chemistry Education
Jurnal Akademika Kimia is an electronic open-access journal that aims to publish the latest research results in the area of chemistry education and pure chemistry from academicians, professionals, and other practitioners at all levels of chemistry education. The journal coverage includes the following: current trends of professional chemistry education, educational technology, teacher education, educational science, learning assessment, learning models and development of learning materials, as well as pure chemistry including organic chemistry, inorganic chemistry, analytical chemistry, physical chemistry, biochemistry and other chemistry fields such as environmental chemistry, that emphasis on a broad description of the general methods and processes for the synthesis, modification, and characterization of chemical materials.
Arjuna Subject : Kimia(semua kategori) - Kimia (Lain-Lain)
Articles 201 Documents
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Potential Antioxidant Activity in Octyl p - Methoxycinnamate (OPMC) Compound Synthesized by Sonochemical Method Indriyanti, Erwin; Adhityasmara, Dhimas; Praharsiwi, Masitoh S.; Wildan, Ahmad; Masduqi, Ahmad F.; Syukur, Mighfar; Mutiara, Erlita V.; Dinurrossifa, Rahmawati S.
Jurnal Akademika Kimia Vol. 12 No. 2 (2023)
Publisher : Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/j24775185.2023.v12.i2.pp100-107

Abstract

Octyl p - methoxycinnamate (OPMC) is a cinnamic acid derivative compound synthesized from p-methoxy cinnamic acid (PMCA) which is reacted with octanol in an acidic condition. OPMC has a substituted benzene group at the para position and conjugated at the carbonyl group. The method used to synthesize OPMC compounds is an esterification reaction with the help of ultrasonic waves at a sonication temperature of 60 0C for 4 hours. The synthesized compounds were then subjected to organoleptic tests, thin layer chromatography tests, solubility tests, melting point tests, FTIR - ATR, and GC - MS. The results showed that the OPMC results were in the form of fine white crystals. The qualitative test was carried out using thin-layer chromatography (TLC) showing an Rf value of 0.65 using n-hexane: ethyl acetate (4:1) eluent. OPMC synthesized is soluble in ethanol, methanol, chloroform, and ether and insoluble in water. The percentage yield of OPMC synthesized 55.72 % Melting point test with melting point apparatus showed that octyl p - methoxycinnamate started to melt at 50 0C. Analysis using FTIR - ATR showed 2919 and 2851 cm-1 (C - H alkyl) The absorption of the extended C=O ester group was at 1692 cm-1 close to the C=O ester (1712 cm-1). C=C group of alkenes and aromatics (1636, 1603, 1573, and 1510 cm-1). The stretching of the C-O ester group at wave number 1252 cm-1, Absorption for the stretching of the C-O ether group at wave number 1170 and 1167 cm-1. The wave number of 820 cm-1 indicates the presence of an aromatic group substituted at the para position. Tests with GC - MS found an abundance of compounds with 97.52 % base peak 290 m/z. Synthesized OPMC compounds have activity as a strong antioxidant with an IC50 value of 96.092 ppm.
Bioactive Compound Contents and Antioxidant Activity of Purified Red Sorghum Pericarp Extract by Membrane Ultrafiltration Process Afandy, Moh. A.; Sediawan, Wahyudi B.; Hidayat, Muslikhin; Susanti, Devi Y.; Sawali, Fikrah D. I.
Jurnal Akademika Kimia Vol. 12 No. 1 (2023)
Publisher : Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/j24775185.2023.v12.i1.pp13-19

Abstract

Sorghum plants contain bioactive compounds such as phenolic compounds and proanthocyanidins. The presence of these compounds is extremely valuable for use as antioxidants in health care. This study aims to determine the total phenolic content, total proanthocyanidin content, and antioxidant activity of purified red sorghum extract using the ultrafiltration membrane method with different transmembrane pressure. At pressures of 8, 9, and 10 Bar, an ultrafiltration process was carried out using a polyethersulfone (PES) membrane with a molecular weight cut-off size of 10 kDa. The total phenolic content was determined using the Folin-Ciocalteu method and identified using UV-Vis spectrophotometry at 760 nm. Total proanthocyanidin content was measured using the acid-butanol method and then analyzed using UV-Vis spectrophotometry at 550 nm. The DPPH (2,2-diphenyl-2-picrylhydrazyl) method will be used to determine the antioxidant activity of purified red sorghum extract. The results of the measurements show that the higher the transmembrane pressure, the higher the concentration of phenolic and proanthocyanidins content, and that the purified red sorghum extract has a high antioxidant value (IC50 = 66.852 ppm).
Learning Difficulties and Students' Ability Level During Pandemic Covid-19 on the Subject of Thermochemistry Agustina, Rizza R. T.; Afadil, Afadil; Rahmawati, Sitti; Tiwow, Vanny M. A.
Jurnal Akademika Kimia Vol. 12 No. 1 (2023)
Publisher : Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/j24775185.2023.v12.i1.pp26-31

Abstract

This study aims to identify learning difficulties learning experienced by students on the subject thermochemistry in class XI IPA SMA Negeri 8 Palu during the Covid-19 pandemic for the 2021 / 2022 school year. The instruments used in this study are thermochemistry tests, questionnaires, and interviews. The result showed students’ difficulties in the subject thermochemistry in class XI IPA was 60 %, the highest difficulty of students is found in the thermochemistry test of calculating the heat of the type of compound, calculating enthalpy changes, and formulating steps and hypotheses of an experiment. The difficulty is indicated by the low level of student comprehension of 54 %, medium 43 %, and high 3 % with an average of 30%. Furthermore, the difficulty of students in participating in chemistry learning during the Covid-19 pandemic is technical difficulties with a percentage of 65.92 %, difficulties in implementing learning with a percentage 0f 65.44 %, and external difficulties (environment and parents) with a percentage of 52.92 %. based on these results, the learning difficulties experienced by students during chemistry learning thermochemistry subjects during the Covid-19 pandemic include students often being constrained by signals and quotas to access materials on the internet and do not have student handbooks to study at home, difficulty understanding chemistry concepts because teacher explanations are elusive, students are not active in participating in learning because chemistry learning during the pandemic is not interesting, can’t afford chemistry books and quotas also parents don’t provide motivation and students are often lazy to do assignments because no one helps with doing. The result of this study indicates that the level of students' difficulties learning about thermochemistry is a quite high category with a low level of student ability and students agree that it is difficult to study chemistry during the pandemic Covid-19.
Cross-Sectional Survey : The Influence of Various Teacher Backgrounds on West Kalimantan Chemistry TPACK Teachers Permasari, Ninda; Nahadi, Nahadi; Hernani, Hernani
Jurnal Akademika Kimia Vol. 12 No. 1 (2023)
Publisher : Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/j24775185.2023.v12.i1.pp1-12

Abstract

This study aims to examine teachers' perceptions of their Technological Pedagogical and Content Knowledge (TPACK) about age, gender, length of teaching, work location, teacher status, teacher education, and certification programs. This study used a cross-sectional survey method used in non-experimental quantitative research. The population in this study were all chemistry teachers in West Kalimantan using a purposive sampling technique obtain 70 to respondents from 14 districts. The survey consisted of 28 statement items and distributed questionnaires via Google form to chemistry teachers. Chemistry teachers rated themselves on a 5-point scale. All domains of the TPACK framework demonstrated valid and reliable instruments on Pearson's correlation values and Cronbach's Alpha Kruskal Wallis non-parametric test, Pearson's correlation was performed to analyze the data. Significant differences can be seen in the CK domain when viewed from gender differences with a p for CK of 0.044, so there is a significant difference between the gender of women (Mean = 4.08 SD = 0.416) and men (Mean = 4.32 SD = 0.470). Location of work affects the teacher's TCK and TPACK because there is a significant difference when viewed from the p namely the TCK and TPACK of 0.036 and 0.025. Perceptions of teachers' TPACK abilities were greater for teachers in cities than in villages in both the TCK domain (Mean = 3.58; 3.82 SD = 0.430; 0.466) and TPACK (Mean = 3.63; 3.91 SD = 0.483; 0.554).
Analysis of the Levels of Ethanol Extract Flavonoid Compounds in Cocor Bebek (Kalanchoe Pinnata) Leaves using UV - Vis Spectrophotometer Tisman, Ulfana; Supriadi, Supriadi
Jurnal Akademika Kimia Vol. 12 No. 1 (2023)
Publisher : Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/j24775185.2023.v12.i1.pp65-70

Abstract

  Cocor bebek is a plant that is easy to cultivate in Indonesia. This cocor bebek contains chemical compounds such as steroids, alkaloids, glycosides, tannins, and flavonoids which have antioxidant properties. Research on the analysis of flavonoid levels in the leaves of cocor bebek (kalanchoe pinnata) has been carried out using the UV-Vis spectrophotometric method. This research aims to determine the levels of flavonoids in the ethanol extract of cocor bebek leaves. The extract of chemical content in cocor bebek leaves was carried out by maceration method using 70 % ethanol. The flavonoid content of the sample extract was measured by measuring the absorption at wavelengths of 510 nm and 700 nm. The results obtained in the qualitative test showed that the cocor bebek leaf extract was positive for flavonoids which were characterized by a change in color from brownish red to green. The results of the quantitative test showed that the flavonoid content in the cocor bebek leaf extract was 0.321 mg/100 g.
Impact of the Concentration Ethylenediamine on Optical Properties of Carbon Dots from Jengkol Peel (Archinendron pauciflorum) Prayugo, Aniza S.; Marpongahtun, Marpongahtun; Gea, Saharman
Jurnal Akademika Kimia Vol. 12 No. 1 (2023)
Publisher : Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/j24775185.2023.v12.i1.pp20-25

Abstract

Carbon dots (CDs) are a new member of fluorescent nano carbons that have attracted attention because of their potential applications derived from their optical, chemical, and electrical properties. CDs from jengkol peel via the solvothermal method at 200 oC for 7 h with the addition of ethylenediamine (EDA) as a heteroatom dopant have been successfully carried out. This study aims to determine the effect of concentration EDA on the optical properties of CDs for the possible reason. The results revealed that the CDs solution has fluorescence properties; that bluish-green glow can be observed under ultraviolet radiation (365 nm). The UV - Vis absorption peaks did not depend on the CDs concentration, but the absorbance intensity decreased with increasing EDA concentration. The best fluorescence properties were possessed by 10 % EDA in CDs which produced λex/λem of 370 nm/518 nm, respectively, with a quantum yield of 42 %. The FTIR spectra of all samples showed that the CDs surface had functional groups such as carboxylic acids, hydroxyl, and amines. The obtained CDs have the potential to be used as heavy metal ion detectors, bioimaging, and antibacterial agents.
Synthesis of Fluorescent Carbon Dots from Soybean Residuals Using Hydrothermal Method Ayu, Dinda G.; Gea, Saharman; Andriayani, Andriayani; Goei, Ronn
Jurnal Akademika Kimia Vol. 12 No. 2 (2023)
Publisher : Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/j24775185.2023.v12.i2.pp71-77

Abstract

Soybean residuals are biowaste composed of carbon chains and amine groups bounded in peptide linkages. The component was identified through FTIR analysis which showed the vibration of the diamide bond (N=C=N) at wave number 2132cm-1. Owing to the existence of these components, soybean has the potential to be used as a precursor to synthesize carbon nano-material, such as Carbon Dots (C - Dots). In this study, the synthesis of C - Dots material from soybean residuals was carried out using the facile hydrothermal method at a temperature of 200 oC for 6 hours. Afterward, the as-synthesized C - Dots were analyzed for their optical property, structure, and morphology. Based on the analysis of the UV - Vis and photoluminescent spectra, C - Dots exhibited absorbance peaks of 292 nm and 301 nm in the UV light region, and fluorescence emission peaks of 468 nm, with blue luminescence characteristics. The observation was supported by the morphological analysis using the HR - TEM, C - Dots exist in a spherical shape with an average particle size of 3.467 nm and a lattice distance of 0.363 nm. Besides, the C - Dots exhibited a good quantum yield of 28.15 %. From the results of the analysis, it is known that the synthesis of C - Dots material has been successfully carried out with particle size < 10 nm.
Degradation of Natural Rubber as Asphalt Mixes Modifier using UV-Ozone Light Ritonga, Irene I. C.; Tamrin, Tamrin; Marpongahtun, Marpongahtun
Jurnal Akademika Kimia Vol. 12 No. 2 (2023)
Publisher : Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/j24775185.2023.v12.i2.pp78-85

Abstract

The elastic properties of natural rubber are indispensable in improving the physical properties of asphalt mixtures. However, the long natural rubber molecule chains make it difficult to modify with other polymeric materials, so it needs to be degraded. In this study, the authors succeeded in degrading natural rubber using a combination of UV light and ozone with the addition of an H2O2 initiator; from the FTIR data, it appears that there are peaks indicating vibrations of the C=O and –OH groups indicating that natural rubber chain termination has occurred. The addition of natural rubber to asphalt was carried out with several variations, namely 8; 10; 12; 14; 16 % (to asphalt content), from the results of the softening point and ductility test of the asphalt mixture explained that the addition of 12 % natural rubber was the most optimum mixture. This result explains that efforts to degrade natural rubber using the UV - ozone combination method can increase the optimum insertion of natural rubber into asphalt mixtures by up to 100 % from previous studies.
Effect of Avocado Leaves Extract on Creatinin and Urea Levels in Rats Induced NaCl and Prednison Najwa, Hilya U.; Elisa, Novi; Puspitaningrum, Ika; Anggraeny , Ebta N.; Sundoro, Aries K.
Jurnal Akademika Kimia Vol. 12 No. 2 (2023)
Publisher : Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/j24775185.2023.v12.i2.pp108-115

Abstract

Creatinine and urea are metabolic waste substances excreted by the kidneys. Kidneys excrete metabolic waste substances. Renal dysfunction is associated with the increased level of creatinine and urea in the blood. The ethanolic extract of avocado leaves (Persea americana Mill.) contains flavonoid compounds, alkaloids, tannins, saponins, and steroids which act as antioxidants and antihypertensive. It is known to reduce creatinine and urea levels in the blood. The animal model was divided into five groups: normal control, negative control (CMC - Na 0.5 %), and avocado leaves ethanolic extract group with doses of 75, 150, and 250 mg/kg BW rats. All groups except the normal control group were induced by oral administration of NaCl solution 2 % and prednisone suspension 1.5 mg/kg BW rats for 21 days and following treatment by oral administration for 7 days based on its group. Flavonoid compounds of avocado leave ethanolic extract identified as 5,7-di-OH-dihydroflavonol. Results show Kruskal - Wallis test between groups (p < 0.05) is significantly different. Concluded that administration of avocado leaves ethanol extract at doses of 75, 150, and 250 mg/kg BW rats might reduce creatinine levels, while avocado leaves ethanol extract at a dose of 250 mg/kg BW rats could reduce urea levels.
Analysis of Water-Soluble Vitamin Change in Tomato (S.lycopersicum) Due to Ozonolysis of Imidacloprid Degradation Treatment by Using Spectrometry and HPLC Method Donanita, Tysa; Safni, Safni; Suryati , Suryati
Jurnal Akademika Kimia Vol. 12 No. 2 (2023)
Publisher : Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/j24775185.2023.v12.i2.pp92-99

Abstract

In this study, the effect of imidacloprid degradation on the reduction of water-soluble vitamins in tomatoes was observed, such as ascorbic acid, pyridoxine, niacin, and thiamine. Analysis was carried out using a spectrophotometer and high-performance liquid chromatography. The degradation method with ozone water for 15 minutes showed a better result than the ozonolysis method because the decrease in levels of water-soluble vitamins is smaller. The percentage decrease of each water-soluble vitamin in the ozone water method is ascorbic acid by 17.103 %, pyridoxine by 6.723 %, niacin by 2.781 %, and thiamine by 0.333 %. Ozone water methods also produce a high percentage of degradation which is 90.56 %.

Page 15 of 21 | Total Record : 201

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