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All Journal POSITRON Komunikasi Fisika Indonesia Spektra: Jurnal Fisika dan Aplikasinya Unri Conference Series: Community Engagement Journal of Technomaterial Physics Science, Technology, and Communication Journal
Rini, Ari Sulistyo
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Aerospace Engineering Humanities Astronomy Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Earth & Planetary Sciences Electrical & Electronics Engineering Energy Engineering Materials Science & Nanotechnology Physics

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Journal : POSITRON

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Quantitative Caffeine Analysis in Robusta Coffee Utilizing Amperometric Biosensing Technology Rosandi, Vira Annisa; Umar, Lazuardi; Setiadi, Rahmondia Nanda; Rini, Ari Sulistyo; Erwin, Erwin; Yanuar, Yanuar; Linda, Tetty Marta
POSITRON Vol 13, No 2 (2023): Vol. 13 No. 2 Edition
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam, Univetsitas Tanjungpura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26418/positron.v13i2.70008

Abstract

Consuming caffeine in inappropriate amounts can disrupt various aspects, especially health. Controlling intake by knowing the caffeine levels in coffee is necessary to reduce the potential negative impacts. This research focuses on the detection of caffeine in Robusta coffee at two different concentrations (1:10 and 1:20 g/mL) and its relationship with yeast metabolism. An amperometric biosensor with a transimpedance amplifier to measure caffeine levels is used which has the advantages of sensitivity, cost-effectiveness, real time monitoring, biocompatibility, and reliable measurements. The data were statistically analyzed using ANOVA and visualized using Principal Component Analysis (PCA). The results revealed a concentration -dependent decrease in biosensor readings as caffeine levels increased (0.1, 0.5, 1, 1.5, and 2 mM), indicating caffeine's ability to inhibit yeast oxygen consumption and oxygen-dependent metabolic processes. The sensitivity of the biosensor in detecting caffeine is 36.66 mV/mM. PCA uncovered complex patterns, relationships, and variations within the caffeine data. PC1 and PC2, the first two principal components, collectively explained 86.3% of the data's variance. Eigenvalues for both PCs were greater than 1, highlighting their significance in understanding the dataset's complexity. This research enhances our understanding of caffeine content in Robusta coffee and its effects on yeast metabolism, providing valuable insights for the coffee industry. This use of yeast biosensors offers efficiency, and adaptability that make that biosensor valuable in a variety of scientific and industrial contexts.
Biosynthesis of Zinc Oxide Powder Using Sandoricum koetjape Peel Extract at Various Annealing Temperature Rini, Ari Sulistyo; Hidayanti, Nurul; Rati, Yolanda
POSITRON Vol 11, No 2 (2021): Vol. 11 No. 2 Edition
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam, Univetsitas Tanjungpura

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (487.835 KB) | DOI: 10.26418/positron.v11i2.49699

Abstract

Zinc oxide (ZnO) synthesized with natural reductants has attracted the attention of researchers because it is environmentally friendly and non-toxic. In this study, ZnO was prepared using Sandoricum koetjape (S. koetjape) peel extract. An aqueous extract of S. koetjape peel was used as biological reduction agent for the synthesis of ZnO from zinc nitrate hexahydrate. The ZnO powder obtained was annealed at different temperatures i.e, 300°C, 400°C, and 500°C for 1 hour. Structural, morphological, optical properties, and functional groups of samples were analyzed using X-Ray Diffraction, Scanning Electron Microscopy, UV-Vis Spectroscopy, and Fourier Transform Infrared Spectroscopy, respectively. The X-ray diffraction pattern shows that pure hexagonal wurtzite structure of ZnO particles can be achieved after annealing. The crystal size has also increased with increasing annealing temperature. SEM photo demonstrates the transformation of ZnO particle from spherical to microflower due to annealing. The widest absorption peaks in the UV-Vis spectrum was occurred after annealing at 500°C. The bandgap energy of ZnO increases after annealing from 3.08 eV to 3.20 eV. The FT-IR analysis confirms O-H functional group from extract has been decomposed due to the annealing process. Based on this study, biosynthesized ZnO using Sandoricum koetjape peel extract requires annealing process to improve the purity, enhance the light absorbance and change the microstructure of ZnO.
Co-Authors Agrina, Agrina Aminnurdin, Dikri Asrinaldo, Brian Noval Asyana, Vepy Awitdrus Awitdrus, Awitdrus dedi irawan Defrianto Defrianto Erwin Erwin Fadhali, Mohammed Hidayanti, Nurul Kasri, Anshori Lazuardi Umar Manalu, Wesly Arianto Noferdi, Muhammad Deri Rabiah Rabiah Rabin, Mohammed Fisal Rahmi Dewi Rahmondia N. Setiadi Rakhmawati Farma Rati, Yolanda Rosandi, Vira Annisa Saktioto Saktioto Simatupang, Mediniah Putri Soerbakti, Yan Sofia Anita Tengku Emrinaldi Tetty Marta Linda Yanuar Hamzah Yanuar Yanuar, Yanuar Yupapin, Preecha