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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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Morphological Effect on Swelling Behaviour of Carboxymethyl Cellulose–Maleic Acid Hydrogel Modified with Kombucha Bacterial Cellulose Siahaan, Tanty N.; Basuki, Basuki; Siregar, Amir H.; Muthawali, Dede I.
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.pp86-91

Abstract

The incorporation of bacterial cellulose from kombucha tea in carboxymethyl cellulose / maleic acid (CMC / MA) hydrogels has been successfully conducted. This study aims to analyze the relationship between the pores on the surface of the hydrogel with their water-absorbing ability. Bacterial cellulose from kombucha (KBC) was confirmed by the spectrum of OH, C-O-C, and C-OH functional groups with FT - IR analysis. Filler KBC was added to CMC / MA hydrogel with variations in the concentration of 2, 4, 6, and 8 % wt. The CMC / MA / KBC hydrogels were characterized by swelling test, degree of crosslinking, FTIR, and SEM. The swelling results showed that hydrogels with 2 % KBC produced the best water absorbing ability up to 172 %, water absorption decreased with the increase of KBC concentrations. Furthermore, SEM image results showed that the addition of KBC affects the morphological shape and pore size of the hydrogel. Meanwhile, FTIR analysis showed that there were no major changes in the functional groups of hydrogels.
Determination of Secondary Metabolites and Antioxidant Activity of Robusta Coffee Bean Ethanol Extract by UV-Vis Spectrophotometry Tandi, Joni; Riani, Ni P. I.; Handayani, Tien W.; Kanan, Maria
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.pp58-64

Abstract

Robusta coffee beans (Coffea canephora Pierre ex.A.Froehner) have antioxidant, antidiabetic, and antihypertensive effects and can prevent coronary heart disease. This study aims to determine the compound content and total levels of secondary metabolites and to determine the antioxidant activity of robusta coffee bean extract. UV-Vis spectrophotometer was used to determine the total levels of secondary metabolites and antioxidant assay using DPPH reagent. The results obtained for the positive qualitative test contain secondary metabolites of alkaloids, flavonoids, saponins, and tannins and do not contain steroid compounds while for the quantitative test, the total alkaloid content is 0.1973% w/w (caffeine equivalent), flavonoids are 1.2106% w/w (equivalent to quercetin), saponins 0.536% w/w (equivalent to sapogenins), tannins at 9.7103% w/w (equivalent to tannic acid). The IC50 result for the antioxidant activity of the ethanolic extract of robusta coffee beans is 55.16 µg/mL which is included in the category of strong antioxidants.
Antioxidant Activity Test of Ethanolic Extract of Tempuyung Leaves (Sonchus Arvensis L.) Based on Linoleic - Thiocyanic Method Suprijono, Agus; Sulistiani, Dian; Purwadi, Sarosa
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.pp116-122

Abstract

Free radicals chemically have free electrons, free radicals tend to take electrons from other molecules, which then give rise to abnormal compounds. Antioxidants are substances that can delay or prevent free radical oxidation reactions in lipid oxidation. Tempuyung leaves contain flavonoids which can act as antioxidants. This research aims to determine the antioxidant activity of the ethanol extract of tempuyung leaves using the linoleic-thiocyanate method and to determine the total phenolic and total flavonoid content using the Folin-Chiocalteu reagent method. The results showed that the ethanol extract of tempuyung leaf extract had antioxidant activity. Percentage of antioxidant activity of 10 % extract = 82.91 %, 5 % extract = 70.07 %, 1 % extract = 57.70 %, Vitamin E 1 % = 70.2 1%. Total phenolic content of 10% extract = 0.48 %, 5 % extract = 0.25 % and 1 % extract = 0.04 %. The total flavonoid content of the extract is 10 % = 0.14 %, 5 % extract = 0.07 %, and 1 % extract = 0.02 %. Pearson correlation test showed that phenolic and flavonoid compounds greatly influenced the antioxidant activity of the ethanol extract of tempuyung leaves.
Performance of The Composite Electrode of Reduced Graphene Oxide Palm Oil Shell - Zinc Oxide (rGOCKS - ZnO) as a Chemical Oxygen Demand (COD) Sensor by Photoelectrocatalysis Azis, Thamrin; Muzakkari, Muhammad Z.; Nurdin, Muh.; Maulidiyah, Maulidiyah; Muslia, Wa O.; Bijang, Catherina M.; Tahril, Tahril
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.pp123-131

Abstract

The preparation of reduced graphene oxide composite electrodes from palm shells (rGOCKS-ZnO) as a chemical oxygen demand (COD) sensor by photoelectrocatalysis has been successfully carried out. The preparation of rGOPS - ZnO electrodes by thermal reduction method and modified Hummer. The XRD results showed several peaks of rGOCKS - ZnO namely 23.287 º, 26.781 °, 29.889 °, 32.468 °, 35.109 °, 37.14 °, 39.822 °, 43.559 °, 47.927 °, and 48.537 °. SEM-EDX analysis reveals the surface of graphene sheets containing aggregates in the shape of small particles attached to graphene sheets. The results of the EDX analysis consisted of C 67.82 %, O. 19.2 %, Zn. 7.85 % and 5.13 % impurity. The CV and LSV tests showed that the rGOAK - ZnO electrode with a variation of 1 gram: 0.3 gram had a good response to the oxidation process under visible light. The profile tests of these organic dyes (methylene blue) in concentrations of 0.5 ppm, 1.0 ppm, 2.0 ppm, and 3.0 ppm were applied by Multi Pulse Amperometry (MPA). The performance of the rGOPS - ZnO electrode has been in determining the value of COD by photo electrocatalytic good sensitivity, linearity, limit of detection, repeatability, and service life. The COD value was determined using the rGOPS - ZnO electrode and obtained 2.97897 mg/LO2 close to the theoretical value.
Synthesis of Silver Nanoparticles using Gandaria Seeds Bioreductor Bijang, Catherina M.; Hasanela, Nurani; Joris, Shielda N.; Fransina, Eirene G.; Tahril, Tahril; Azis, Thamrin; Tehuayo, Ahmadin
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.pp142-148

Abstract

The silver nanoparticles (NPP) are synthesized with the chemical reduction method by using a water extract bioreductor of gandaria seed (Bouea macrophylla G.) which acts as a reducing precursor, in this case, AgNO3 Ag+ is reduced to AgO. The concentration of AgNO3 is made between 0.5 mm and 1 mm. The characteristic of NPP is unstable, so a modification is needed with and without the addition of PVA 1 %. The process of NPP shaping is monitored by observing the uptaken of UV - Vis when the color changes occur. The high NPP concentration of AgNO3 has higher absorbance and is wider if compared to the lower AgNO3 concentration. The result of this research based on the absorbance value and the wavelength showed the NPP synthesized without the addition of PVA 1 % (b/v) is wider. The addition of PVA 1 % (b/v) provides better stability and maintains the absorbance of spectrum changes from day to day. The maximum uptaken of UV-Vis from NPP AgNO3 0.5 mm by using green synthesis and 1 mm without adding PVA are 0.946 and 0.980, respectively. However, NPP with the addition of PVA has 0.968 and 0.978 absorbance. The best concentration of NPP produced was 1 mm AgNO3.
SPF Activity Sunscreen Spray Gel Ethanol Extract of Cinnamon Bark (Cinnamomum burmanii Ness. BI, Syn) Sari, Wulan K.; Kristantri, Rika S.; Pebriani, Tris H.
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.pp132-141

Abstract

This cinnamon bark contains cinnamaldehyde, which is a secondary metabolite compound derived from aldehydes, including the polyphenolic group, which activity as a sunscreen and antioxidant by absorbing UV rays, so it can protect the skin from direct sun exposure (sunscreen). The study aimed to determine whether there was an effect of the concentration of the ethanol extract of cinnamon bark (Cinnamomum burmanii Ness. BI, Syn) on the physical characteristics and SPF value of spray gel preparations and to determine the concentration of the ethanol extract of cinnamon bark that produced spray gel with physical characteristics and SPF value. best. The study was conducted by extracting cinnamon bark by the maceration method using 96 % ethanol for 3 days. The extract obtained was then subjected to phytochemical screening TLC and then applied to a spray gel preparation with concentrations of FI (10 %), FII (15 %), and FIII (20 %), followed by testing the activity of sunscreen using the UV-Vis spectrophotometry method. The results of phytochemical screening and TLC on the ethanol extract of cinnamon bark showed positive results for containing flavonoids, alkaloids, tannins, steroids, and antioxidants. The statistical test results showed that there was a difference with a sig value of 0.05. It was concluded that the ethanol extract of cinnamon bark affected pH, viscosity, spreadability, stickiness, drying time, and SPF value. The formula that gave the best physical characteristics and SPF value was found in the concentration of sunscreen spray gel: the ethanol extract of cinnamon bark with a concentration of FIII (20 %).
Analysis of Calcium (Ca) and Potassium (K) Contents in Tin Fruits (Ficus carica Linn) Hamzah, Abdul; Aminah, Sitti; Said, Irwan; Nurmayanti, Yuli
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.pp52-57

Abstract

Tin Fruits (Ficus carica Linn) are typical Middle Eastern plants that have been cultivated in Indonesia. Tin fruits are rich in minerals, especially calcium and potassium. In addition, they also contain benzaldehyde which is beneficial against cancer cells. This study aimed to determine the concentrations of calcium and potassium contained in tin fruits. Determination of calcium and potassium contents using an atomic absorption spectrophotometer (AAS). The results showed an analysis of the water content of the sample obtained was 89.065 %, ash content was 1.0165 % and biomass content was 9.9185 %. While the analysis of calcium contents at a wavelength of 422.7 nm and potassium at a wavelength of 766.5 nm respectively obtained that an average yield of calcium was 354.97 mg/100g and 752.68 mg/100g for potassium. The results of this study are expected to be able to attract the interest of the community to cultivate tin fruits, especially in Central Sulawesi.
Application of Discovery Learning Model to Improve Student Science Process Skills in Colloid Material on Senior High School Lationo, Mahdayanti; Mustapa, Kasmudin
Jurnal Akademika Kimia Vol. 12 No. 3 (2023)
Publisher : Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/j24775185.2023.v12.i3.pp149-153

Abstract

This study aimed to describe the improvement of students' science skills by applying the discovery learning model to the colloid material of class XI IPA SMA Negeri 1 Ampibabo. The research method used was pre-experiment with one group pretest-posttest. The sample in this study consisted of students from class XI IPA as experimental class 1, which was planned for 30 students, and class XI IPA B as class experiment 2, which meant 30 students. The instrument used was a science skills test, student activity observation sheets measured using six aspects, namely, observation, asking questions, hypothesizing, classification, interpreting data, and communicating) and student response questionnaires. The results of the study were obtained from the science skills test scores, the pretest, and the hottest of the two classes; namely, the average pretest score for class XI IPA A was 11.66 % and class XI IPA B was 13.3 %, while the average posttest score was 11.66 %. Obtained from class XI IPA B of 75.48% and class XI IPA B of 75.97 % The results of the analysis of the six aspects of science process skills of students in class XI IPA A obtained an average of 75.52 % and class XI IPA B was obtained an average of 78.64 %. Based on the study results, it can be ignored that the application of discovery learning models can improve students' skills in colloid material in class XI IPA SMA Negeri 1 Ampibabo. This can be seen from the proportion of the average student response, which is 90.61 % strongly agree with the discovery learning model.
Study of Ethanol Extract of Karamunting (Rhodomyrtus tomentosa (Aiton) Hassk) as Acid-Base Bioindicator wiwit, Wiwit; W. M Diah, Anang
Jurnal Akademika Kimia Vol. 12 No. 3 (2023)
Publisher : Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/j24775185.2023.v12.i3.pp154-159

Abstract

Karamunting or Rhodomyrtus tomentosa (Aiton) Hassk is a fruit that contains anthocyanins. This study aimed to determine the potential of the ethanol extract of this fruit as an acid-base bioindicator. Karamuting fruit was macerated using three solvents (n-hexane, ethyl acetate, and ethanol) for 24 hours. The extract of the karamunting fruit was tested as indicators in acid-base solutions and buffer solutions and compared with phenolphthalein and methyl orange for acid-base titrations, namely: Strong acids with strong bases, weak acids with strong bases and weak bases with strong acids. The results showed that the ethanol extract of karamunting fruit was brown, in strong acids was red, in strong bases was dark green, in weak acids was pink, and in weak bases was light green. Furthermore, the kara munting fruit indicator extract buffer solution gave four groups of colour changes, namely, at pH 1, it was red; at pH 2 to 6, it was pink; at pH 7 to pH 10, it was light green; and at pH 11 to 12, it was dark green. The ethanol extract of karamunting fruit can be used as an acid-base indicator because it gives equivalent results to comparative indicators, namely phenolphthalein and methyl orange.
Antioxidant Activity Test of (Acalypha indica L) Extract Nursafitri, Nursafitri; Santoso, Tri
Jurnal Akademika Kimia Vol. 12 No. 3 (2023)
Publisher : Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/j24775185.2023.v12.i3.pp176-181

Abstract

The antioxidant activity test of Acalypha indica L has been carried out. This study aimed to determine the IC50 value of the Acalypha indica L extract. The radical concentration of 2,2-diphenyl-1-picrylhydrazyl (DPPH) after adding Acalypha indica L extract was determined using a UV-Vis spectrophotometer. The concentration variations used in Acalypha indica L extract were 15.48 ppm, 30.96 ppm, 46.44 ppm, and 61.92 ppm. The results showed that the IC50 value of Acalypha indica L extract was 41,259 ppm, while the IC50 value of vitamin C as a comparison was 50.626 ppm. Based on the IC50 value data above, it can be seen that the antioxidant of Acalypha indica L extract is robust compared to vitamin C.

Page 16 of 21 | Total Record : 201

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