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All Journal Indonesian Journal of Chemical Science and Technology EINSTEIN (E-JOURNAL)
S, Abd Hakim
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Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Control & Systems Engineering Earth & Planetary Sciences Electrical & Electronics Engineering Energy Materials Science & Nanotechnology Mechanical Engineering Physics

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ENHANCEMENT OF SENSITIVITY, DETECTION RANGE, AND DETECTION LIMIT USING GA METHOD POTENTIOMETRIC BIOSENSOR WITH UREASE ENZYME IMMOBILIZATION TECHNIQUE ON PVA Sibarani, Willi Firmando; S, Abd Hakim
EINSTEIN (e-Journal) Vol. 12 No. 3 (2024): EINSTEIN (e-Journal)
Publisher : Universitas Negeri Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24114/ein.v12i3.48873

Abstract

This study aims to increase the sensitivity range of the width of the UV-Vis absorbance peak with Glutaraldehyde (GA) crosslinking and useful to determine the level of urea in the urine. The potentiometer cell consists of an indicator electrode and a reference electrode. The indicator electrode is denoted PVA-Enzyme/GA/PVC-KTpCIPB, meaning PVA-Enzim as the first layer, GA as the second layer and PVC-KTpCIPB as the third layer. Biosensor with urease enzyme immobilization technique analyzed variations of urea 10-7-10-1 M. The potentiometric method of the biosensor detects signal and voltage (potentiometer cell). The signals that were analyzed for signal variables were symmetrical up and down signals of 2000 signals/second. Voltage was carried out by linear curve analysis, the results of linear curve analysis were the range of detection from a concentration of 10-4-10-2 M with cross-linked GA which increased the absorbance, the detection limit was 10-4 M, the sensitivity was 46.67 mV/ war reversibly and R squared (R2) which is 0.9839 is close to linear.
Influence of Citric, Acetic, and Ascorbic Acids on the Solubility of Paracetamol Ramadhan, Dwi Sapri; Wardana, Dian; Fahmi, Jaman; Safitri, Wulan Dwi; Aulia, Amanda; purba, Gracia; Manalu, Anrian Haholongan; Damanik, Angelica; Tambunan, Ida Mariati; Zubir, Moondra; S, Abd Hakim
Indonesian Journal of Chemical Science and Technology (IJCST) Vol. 8 No. 2 (2025): JULY 2025
Publisher : Universitas Negeri Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24114/ijcst.v8i2.68730

Abstract

This study examined the influence of citric, acetic, and ascorbic acids on the solubility of paracetamol, an analgesic with inherently low aqueous solubility. Paracetamol tablets were dissolved in different concentrations of organic acid solutions, and dissolution times were visually monitored. The most rapid dissolution occurred in 30% acetic acid solution (190 seconds), followed by the citric–acetic acid mixture. Increasing paracetamol mass extended dissolution time, with saturation reached at 3.5 g. Enhanced solubility was attributed to hydrogen bonding interactions between organic acids and paracetamol molecules. Compared with complex techniques such as solid dispersions or co-amorphous systems, this acid-assisted approach is simple, low-cost, and requires no specialized equipment. These findings highlight the role of weak organic acids as practical solubility enhancers and suggest a promising strategy to improve paracetamol bioavailability and therapeutic effectiveness.
Exploring the Redox Reaction Potential of Local Fruits: Galvani Cell Trials Based on Areca nut (Areca catechu), Rimbang (Solanum torvum), and Bangkok starfruit (Averrhoa carambola) Fahmi, Jaman; Ramadhan, Dwi Sapri; Wardana, Dian; Safitri, Wulan Dwi; Mendrofa, Bulan Susanti; Br Nadeak, Stephani Bintang N.; ayumi, Sheilla Maliza; Nasution, Dhea Ananda; Zubir, Moondra; S, Abd Hakim
Indonesian Journal of Chemical Science and Technology (IJCST) Vol. 8 No. 2 (2025): JULY 2025
Publisher : Universitas Negeri Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24114/ijcst.v8i2.68731

Abstract

This research aims to explore the potential of three fruits, such as areca nut (Areca catechu), rimbang (Solanum torvum), and star fruit (Averrhoa carambola), as a natural electrolyte source in generating electricity through a simple Galvani cell test. The research method includes making Galvani cells using fruit pieces as electrolyte media, measuring the voltage and current produced, and testing the ability to light an LED as an indicator of electrical output. The measurement results showed that areca nuts produced the highest voltage and current compared to rimbang and star fruit, demonstrating its effectiveness as a natural electrolyte. This finding indicates that local fruits have the potential to be an environmentally friendly electrochemical energy source material that can be applied in education and simple technology. This research opens opportunities for further development in utilizing local biological resources for electrochemical applications.
Sustainable Candle Production from Waste Cooking Oil and Waste Lubricating Oil Wardana, Dian; Ramadhan, Dwi Sapri; Fahmi, Jaman; Safitri, Wulan Dwi; Damanik, Wicha Rosari; Simamora, Astuty Evalina; Sigalingging, Olivia Gina Ananta; Manullang, Okto Panca; Rahmadyani, Zaskia; Zubir, Moondra; S, Abd Hakim
Indonesian Journal of Chemical Science and Technology (IJCST) Vol. 8 No. 2 (2025): JULY 2025
Publisher : Universitas Negeri Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24114/ijcst.v8i2.68733

Abstract

This study investigates the potential utilization of waste cooking oil and used lubricant oil as raw materials for candle production. These waste materials, often regarded as environmental pollutants, contain fats and hydrocarbons that can be converted into value-added products. The manufacturing process involved filtration, heating, and the incorporation of additives such as paraffin wax to enhance quality and stability, followed by molding. The resulting candles demonstrated acceptable physical properties, including melting points and burning times comparable to standard requirements. However, noticeable differences in color and odor were observed when compared to commercial candles. Despite these limitations, the valorization of waste cooking oil and used lubricant oil presents an environmentally friendly and cost-effective alternative, contributing to the development of sustainable products. Further research is recommended to optimize the blending ratios and additive compositions in order to improve the overall performance of the candles
Co-Authors Aulia, Amanda ayumi, Sheilla Maliza Br Nadeak, Stephani Bintang N. Damanik, Angelica Damanik, Wicha Rosari Fahmi, Jaman Manalu, Anrian Haholongan Manullang, Okto Panca Mendrofa, Bulan Susanti Nasution, Dhea Ananda purba, Gracia Rahmadyani, Zaskia Ramadhan, Dwi Sapri Safitri, Wulan Dwi Sibarani, Willi Firmando Sigalingging, Olivia Gina Ananta Simamora, Astuty Evalina Tambunan, Ida Mariati Wardana, Dian Zubir, Moondra