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All Journal Natural Science: Journal of Science and Technology KOVALEN: Jurnal Riset Kimia Indonesian Journal of Chemistry

Erwin Abdul Rahim

Jurusan Kimia FMIPA Universitas Tadulako

Author-ID : 542598

Chemical Engineering, Chemistry & Bioengineering Chemistry Computer Science & IT

Published : 32 Documents Claim Missing Document

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Siklisasi Sitronelal Menggunakan Polimer Penyangga Katalis H2SO4 Berbahan Dasar Eugenol: Citronellal Cyclization Using Polymer Based-Eugenol Supported H2SO4 Catalyst Moh. Rifki Saputra; Erwin Abdul Rahim; Husain Sosidi; Ni Ketut Sumarni
KOVALEN: Jurnal Riset Kimia Vol. 7 No. 1 (2021): Edisi April
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2021.v7.i1.13660

Research on citronellal cyclization using a polymer based on eugenol supported H2SO4 catalyst has been carried out. The study aim was to determine the ratio of the addition of polymer based-eugenol supported H2SO4 catalyst used to produce the highest isopulegol. Citronellal cyclization was carried out using variations of catalyst concentration (1, 2, 3, 4, and 5%) and reaction time (30, 60, and 90 minutes). The results have obtained a yield of 50.67% found in the catalyst concentration of 1% and 90 minutes reflux time. From the results of GC-MS analysis, 29 compounds were read and among them isopulegol which was read at retention time 19.703 at peak 9 and peak area 4.76%. And the isopulegol results obtained are 11.34%.

Kualitas Minyak Ikan Lele Dumbo (Clarias gariepinus) Selama Penyimpanan dengan Penambahan Likopen Kasar dari Buah Tomat: Quality of Dumbo Catfish Oil (Clarias gariepinus) During Storage with The Additing of Crude Lycopene from Tomatoes Heince Andre Pua; Nurhaeni; Erwin Abdul Rahim; Prismawiryanti
KOVALEN: Jurnal Riset Kimia Vol. 7 No. 2 (2021): Edisi Agustus
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2021.v7.i2.13905

The quality of Dumbo Catfish (Clarias gariepinus) oil can be maintained during storage with the addition of crude lycopene in tomatoes as an antioxidant. The purpose of this study was to obtain the best ratio between crude lycopene in tomatoes and Dumbo catfish oil during storage. The study was conducted using a variable ratio of crude lycopene: Dumbo catfish oil with 4 treatment levels (6:40, 8:40, 10:40, and 12:40 (w/v)) and storage time variables of 1, 2, 3, and 4 weeks. Lycopene levels in Dumbo catfish oil were analyzed using a UV-Vis spectrophotometer, while the quality of Dumbo catfish oil during storage was determined through peroxide value analysis. The results showed that the best ratio of crude lycopene of tomatoes: Dumbo catfish oil was 12:40 at the third week of storage with lycopene content of 0.257 grams and the peroxide value of Dumbo catfish oil was 3.45 meq/kg or had met IFOS standards. Keywords: Crude lycopene, tomato fruit, dumbo catfish oil, peroxide value.

Pemanfaatan Selulosa dari Rumput Gajah (Pennisetum purpureum) pada Sintesis Karboksimetil Selulosa (CMC) : [Utilization of Cellulose from Pennisetum purpureum at The Synthesis of Carboxy Methyl Cellulose (CMC) Erwin Abdul Rahim; Grace Sita Turumi; Syaiful Bahri; Jusman; Syamsuddin
KOVALEN: Jurnal Riset Kimia Vol. 7 No. 2 (2021): Edisi Agustus
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2021.v7.i2.14227

Cellulose from Pennisetum purpureum has been used as the main ingredient in the synthesis of carboxymethyl cellulose (CMC). The purpose of CMC synthesis from the cellulose of Pennisetum purpureum is to obtain CMC compounds with the best degree of substitution (DS) value and the highest yield. The study was conducted using a completely randomized design with a factorial pattern consisting of two independent variables, namely the concentration of trichloroacetic acid (10%, 20%, and 30%) and reaction time (3 and 4 hours). The results showed that the CMC with the highest DS value (0.839) was obtained using 20% trichloroacetic acid with a reaction time of 3 hours. The highest CMC yield was 30.15% which was obtained using 30% trichloroacetic acid with a reaction time of 4 hours. Keywords: Pennisetum purpureum, carboxymethyl cellulose, substitution degree.

PRODUKSI METIL OLEAT MELALUI REAKSI METANOLISIS MINYAK BIJI KELOR (Moringa oleifera Lam) Fatiah Riskah; Ahmad Ridhay; Mappiratu Mappiratu; Erwin Abdul Rahim
KOVALEN: Jurnal Riset Kimia Vol. 5 No. 1 (2019): Edisi April
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Telah dilakukan penelitian yang bertujuan untuk mendapatkan fraksi massa metil ester asam oleat tertinggi dari rasio minyak biji kelor/metanol (v/v) serta waktu reaksi dalam proses metanolisis minyak biji kelor serta komposisi dari metil ester asam oleat. Penelitian ini dilakukan dengan menggunakan Rancangan Acak Lengkap (RAL) dengan variasi rasio minyak biji kelor/metanol 1:3, 1:4, 1:5, 1:6 dan 1:7 (v/v) serta variasi waktu reaksi 30 menit, 60 menit, 90 menit, 120 menit dan 150 menit. Hasil yang diperoleh menunjukkan bahwa peningkatan rasio minyak biji kelor/metanol meningkatkan fraksi massa metil ester asam oleat dengan fraksi massa maksimum (72.61%) terdapat pada penggunaan rasio minyak biji kelor/metanol 1:7 (v/v). Demikian pula pada pengaruh waktu reaksi yang menunjukkan bahwa peningkatan waktu reaksi meningkatkan fraksi massa metil ester asam oleat dengan fraksi massa maksimum (78.75%) terdapat pada penggunaan waktu reaksi 150 menit. Berdasarkan hasil analisis GC-MS diperoleh senyawa dominan penyusun metil ester tersebut adalah metil oleat persentase sebesar 48.25%, kemudian metil stearat dengan persentase sebesar 7.67%, selanjutnya metil palmitat dengan persentase sebesar 5.14 dan senyawa yang belum diketahui secara pasti dengan persentase sebesar 38.94%Kata Kunci: Minyak biji kelor, metil oleat,metanolisis

Pembuatan Konsentrat Protein Ampas Tahu Menggunakan Garam Ammonium Sulfat: Manufacturing of Tofu Pulp Protein Concentrate Using Ammonium Sulphate Nurhaeni; Frischa Sari Kencana; Andi Tenri Ajeng; Khairuddin; Prismawiryanti; Syamsuddin; Dwi Juli Puspitasari; Indriani; Erwin Abdul Rahim
KOVALEN: Jurnal Riset Kimia Vol. 8 No. 1 (2022): April Edition
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2022.v8.i1.15844

Tofu pulp which generally becomes waste can be used as a source of protein concentrate. Protein concentrates from tofu pulp have been obtained at various ratios of tofu pulp: ammonium sulfate and ammonium sulfate salt concentration. The research was conducted to obtain the highest protein yield and content of tofu pulp protein concentrate. This study used a completely randomized design (CRD) with the independent variable being the ratio of tofu pulp filtrate: ammonium sulfate (1:2, 1:3, 1:4, 1:5, 1:6, and 1:7 (v/v)) and concentrations of ammonium sulfate (30, 40, 50, 60, 70, and 80%), while the dependent variables were the yield of protein concentrate and protein content. Production of protein concentrate used the salting-out method with ammonium sulfate salt. The ratio of tofu pulp: ammonium sulfate 70% obtained the best ratio of 1:5 with a yield of 41.6% and protein content of 84.58%. Tofu pulp as industrial waste can be a potential source of protein concentrate because it has a high protein content.

Antibacterial and Antioxidant Activities of Polyeugenol with High Molecular Weight Erwin Abdul Rahim; Nur Istiqomah; Gilang Almilda; Ahmad Ridhay; Ni Ketut Sumarni; Indriani Indriani
Indonesian Journal of Chemistry Vol 20, No 3 (2020)
Publisher : Universitas Gadjah Mada

This study was aimed to prepare polyeugenol with high molecular weight and to evaluate its antibacterial and antioxidant activities. First, polyeugenol was synthesized from eugenol in the presence of H2SO4-CH3COOH (4:1) as catalyst. The synthesized polyeugenol was weighed by using viscometer, revealing its high molecular weight of (7.76–21.9) × 105 g/mol. Furthermore, the antibacterial activity of the polyeugenol was conducted against Staphylococcus aureus and Escherichia coli bacteria. It was conducted by applying well diffusion method at 1, 2, 3, 4 and 5% concentrations to observe inhibition zones, in which the tests showed that the antibacterial activity of the polyeugenol against S. aureus were 17.42, 17.76, 18.79, 21.42 and 22.55 mm, while those against E. coli were 15.87, 17.23, 17.56, 18.24 and 19.21 mm, respectively. In short, these results indicated a strong antibacterial activity. Then, tests on antioxidant activity against free radical DPPH (2,2-diphenyl-1-pycrylhydrazyl) gave the IC50 value of 80.47 µg/mL, indicating a strong antioxidant activity. Therefore, the polymer synthesized in this work has a high potential to be applied in various biomedical applications.

Synthesis of Soluble Novel Polyacetylenes Containing Carbamate and Eugenol Moieties Erwin Abdul Rahim
Indonesian Journal of Chemistry Vol 20, No 4 (2020)
Publisher : Universitas Gadjah Mada

This study was aimed to synthesize a series of novel polyacetylenes containing carbamate and eugenol moieties. The polymerization of 1-(3,4-dimethoxyphenyl) propane-2-yl prop-2-ynylcarbamate (1), 1-(3,4-dimethoxyphenyl)propane-2-yl 3-ethynyl phenylcarbamate (2), 1-(3,4-dimethoxyphenyl)propane-2-yl 4-ethynylphenylcarbamate (3), (2S)-1-(3,4-dimethoxyphenyl)propane-2-yl 2-((prop-2ynyloxy)carbonylamino)propanoate (4) in the presence of (nbd)Rh+[ɳ6-C6H5B–(C6H5)3] as catalyst have successfully produced corresponding polyacetylenes [poly(1)–poly(4)] in high yield. The molecular weight of the synthesized polyacetylenes ranged between 13,900–18,400 g/mol. In particular, the molecular weight of poly(1) could be increased by the addition of menthol. Practically, these polymers were found to have a stable helical structure and soluble in common organic solvents.

Aktivitas Antibakteri Ekstrak Kulit Batang Tumbuhan Johar (Senna siamea Lam) pada Berbagai Polaritas Pelarut : Antibacterial Activity of Johar (Senna siamea Lam) Stem Bark Extract on Various Solvent Polarities Djumidar; Abd. Rahman Razak; Ahmad Ridhay; Ni Ketut Sumarni; Syamsuddin; Jusman; Nurhaeni; Erwin Abdul Rahim
KOVALEN: Jurnal Riset Kimia Vol. 8 No. 2 (2022): August Edition
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2022.v8.i2.15970

Johar plant is a type of plant from the Fabaceae family which is widely used in traditional medicine such as malaria, itching and diabetes medicine. This study aims to determine the antibacterial activity of Johar stem bark extract with different levels of solvent polarity on the growth of Staphylococcus aureus and Escherichia coli bacteria and to determine the active compound class by TLC-Bioautography. The extraction of active compounds used a multilevel maceration method starting with n-hexane (non polar), followed by ethyl acetate (semi-polar) and ethanol (polar) solvents. Antibacterial activity testing was carried out by diffusion well method with a concentration variant of 25% and 50%. The results showed that n-hexane, ethyl acetate, and ethanol extract had antibacterial activity against the two test bacteria. Ethyl acetate and ethanol extract from Johar stem bark at a concentration of 50% were classified as very strong antibacterials with inhibition zone diameters against S. aureus, which were 22.02±0.84 mm and 20.16±0.23 mm, respectively. The results of the TLC-Bioautography test showed that the three test extracts had strong antibacterial activity against S. aureus and E. coli. In the n-hexane extract with n-hexane: ethyl acetate (9:1) eluent using Lieberman-Burchard spray reagent, it was suspected that triterpenoid compounds were present. In ethyl acetate extract with n-hexane: ethyl acetate (6:4) eluent and ethanol extract with chloroform: methanol (8:2) eluent using FeCl3 1% spray reagent, it was suspected that the tannin compound was present in both extracts.

Sintesis dan Karakterisasi Polivinil Alkohol (PVA) Terlapis Polieugenol: Synthesis And Characterization of Polyvinyl Alcohol (PVA) Coated with Polyeugenol Rahim, Erwin Abdul; Ridhay, Ahmad; Sitti Nur Halizah; Indriani; Sosidi, Husain; Khairuddin; Inda, Nov Irmawati; Nurakhirawati; Mirzan, Moh.; Amar, Aini Auliana
KOVALEN: Jurnal Riset Kimia Vol. 10 No. 1 (2024): April Edition
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2024.v10.i1.17088

A study has been conducted on materials containing polyvinyl alcohol (PVA) coated with poly eugenol. This research aims to explore the synthesis process and properties of PVA coated with poly eugenol. Characterization of PVA includes tensile strength measurement and surface observation using SEM. Additionally, the antioxidant activity of PVA was also tested using the DPPH method. In this study, PVA films were obtained by dissolving PVA in a water solvent. The characterization results indicate that the tensile strength ranges from 25.56 to 271.10 Mpa, elongation reaches 315.20 to 320%, and the young modulus ranges from 4.05 to 6.27 Mpa. Surface observation with SEM shows a smooth surface without pores. The antioxidant activity test shows IC50 values ranging from 84.11 to 175.37 ppm.

Speciation and Bioavailability of Heavy Metals Pb and Cd in Palu Bay Sediments after the Earthquake and Tsunami Sosidi, Husain; Khairuddin; Ruslan; Abustiana, Rahma Lolita; Ramli, Aksar; Rahim, Erwin Abdul
KOVALEN: Jurnal Riset Kimia Vol. 11 No. 1 (2025): August Edition
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2025.v11.i1.17671

Major disturbances to seafloor morphology and input of terrestrial material due to the earthquake- tsunami in Palu City in 2018 have the potential to alter the chemical form (speciation), bioavailability, and flux of lead (Pb) and cadmium (Cd) in Palu Bay sediments. This study was conducted to analyze the speciation of Cd2+ ions and Pb2+ ions and determine the concentration of elusion ions using Diffusive Gradient in Thin Film (DGT). In this study, two methods were carried out, namely the fractionation method and the DGT method. The results showed that the analysis of ion speciation at 3 locations using the fractionation method obtained the highest concentration of Cd2+ ions of 1.4492 mg/L at location 1 and the highest concentration of Pb2+ ions of 0.0200 mg/L at location 3. The results of ion analysis at 3 locations using the DGT method obtained the highest elution yield concentration of Cd2+ ions of 0.0225 mg/L at location 1 and the highest elution yield concentration of Pb2+ ions of 0.0155 mg/L at location 3. This study shows that the presence of heavy metals Pb and Cd in Palu Bay sediments after the earthquake-tsunami is still detected with varying concentrations between locations. The fractionation method is able to describe the distribution of metal speciation in sediments, while the DGT method provides information on labile fractions that are more relevant to bioavailability. The combination of these two methods is important for understanding the potential risk of heavy metals to Palu Bay aquatic ecosystems and can be used as a basis for post-disaster environmental monitoring and management efforts.

Co-Authors A. Risman Abd. Rahman Razak Abustiana, Rahma Lolita achmad rihday Ahmad Kamal Ahmad Ridhay Aini Auliana Amar Andi Nursyafinah Andi Tenri Ajeng Dina Apriana Putri Husni Dini Safitri Djumidar Dwi Juli Puspitasari Dwi Juli Pusptasari Fadhillah Fadhillah Fatiah Riskah Fisty Sumangkut Frischa Sari Kencana Gilang Almilda Grace Sita Turumi Hardi Ys Hardi Ys. Heince Andre Pua Husain Sosidi Indriani Indriani Indriani Indriani Indriani Indriani Irmawati Inda, Nov Jaya Hardi Jusman, Jusman Khairuddin - Khairuddin Khairuddin Laksono Trisnantoro Lindawati, Eka Mappiratu Mappiratu Megmerio Soro Misba Anggriani Moh. Mirzan Moh. Mirzan Moh. Rifki Saputra Muh. Hajir S. Lasapo Musafira Musafira Musafira Musafira Musafira Musafira Ni Ketut Sumarni Nov Irmawati Inda Nur Istiqomah Nurakhirawati Nurhaeni Nurhaeni Nurhaeni Nurhaeni Nurhaeni Nurhaeni Nurhaeni Nurhaeni Prismawiryanti Prismawiryanti Ramli, Aksar Reflin Yuliana Reski Putriani Demsi Ripdayana Ripdayana Rismawati Sikanna Ruslan Ruslan Ruslan Sitti Ainun Hikmah Sitti Nur Halizah Sulfitri Suardi Sumarni Syaiful Bahri Syaiful Bahri Syamsuddin Syamsuddin Syamsuddin Yanti, Wilda

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