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All Journal Jurnal Ilmu Dasar BERKALA SAINSTEK EduChemia: Jurnal Kimia dan Pendidikan UNEJ e-Proceeding ALCHEMY Jurnal Penelitian Kimia PengabdianMu: Jurnal Ilmiah Pengabdian kepada Masyarakat JKPK (Jurnal Kimia dan Pendidikan Kimia) Indonesian Chimica Letters InSTEM
Yeni Maulidah Muflihah
Department Of Chemistry, Faculty Of Mathematics And Natural Sciences, University Of Jember
Agriculture, Biological Sciences & Forestry Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Control & Systems Engineering Economics, Econometrics & Finance Education Energy Environmental Science Law, Crime, Criminology & Criminal Justice Materials Science & Nanotechnology Mathematics Physics Public Health Social Sciences Other

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Spectrophotometric Analysis of Caffeine Content in Coffee Mistletoe (Dendrophthoe petandra L.) Apriliana, Gepsa; Indarti, Dwi; Muflihah, Yeni Maulidah
Indonesian Chimica Letters Vol. 2 No. 2 (2023)
Publisher : Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.19184/icl.v2i2.5606

Abstract

Caffeine, a well-known alkaloid presents in plants such as tea, coffee, and kola nuts, was thoroughly analyzed in coffee mistletoe. Our study successfully extracted caffeine using dichloromethane and chloroform, incorporating qualitative testing and robust method validation with a visible spectrophotometer. Notably, dichloromethane yielded the highest caffeine extract at 0.042 grams. The qualitative tests distinctly confirmed the presence of caffeine, evidenced by a color change with Parry's reagent and a maximum absorption wavelength of 273 nm. We also pinpointed the caffeine complex’s maximum wavelength at 640 nm, further validating our findings against a standard solution. Our method validation showed impressive linearity (r = 0.9974), with limits of detection at 1.81 ppm and quantitation at 6.02 ppm. The accuracy ranged between 90.0% and 97.5%, while the precision values were consistently around 98%. Additionally, we determined the water content of the coffee mistletoe leaf powder to be 8.733%. This comprehensive analysis establishes a strong foundation for the caffeine content in coffee mistletoe.
The Effect of Concentrated Seawater Salinity on Soybean Protein Coagulation in Tofu Production Rohmawati, Manis; Muflihah, Yeni Maulidah; Handayani, Wuryanti; Asnawati; Mulyono, Tri
Indonesian Chimica Letters Vol. 4 No. 1 (2025)
Publisher : Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.19184/icl.v4i1.5885

Abstract

Seawater, which has a salinity of 35 ‰, contains essential ions such as chloride, sodium, sulfate, magnesium, and calcium. These ions play a crucial role in the coagulation of proteins. Salt-based coagulants are among the oldest and most commonly used in tofu production. Additionally, several metal cations exhibit similar coagulating effects on soybean proteins. Tofu can be produced by adding salt coagulants, like calcium sulfate (commonly known as tofu stone) and seawater extract. The seawater extract was obtained from seawater through evaporation in three distinct ponds, with varying evaporation times that can lead to differences in salinity and density. In this experiment, we used coagulants from these three ponds, labeled A, B, and C. Coagulant C, derived from the pond with the longest evaporation time, has the highest salinity of 310 ‰ and a density of 1.220 g/cm³. The mass of the tofu produced shows a consistent pattern among coagulants A, B, and C: an initial increase followed by a decrease, which is influenced by the salting-out and salting-in processes. When used at a volume of 15 mL, Coagulant C yielded the highest mass at 179.426 grams and the lowest water content at 71.152%, demonstrating its effectiveness in protein coagulation.
Batch Injection Potentiometry Asam Aspartat, Asam Glutamat dan Arginin Menggunakan Elektroda Tungsten Oksida Yeni Maulidah Muflihah; Heny Masruroh; Zulfikar Zulfikar
ALCHEMY Jurnal Penelitian Kimia Vol 10, No 1 (2014): March
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (259.016 KB) | DOI: 10.20961/alchemy.10.1.18.1-10

Abstract

The presence of aspartic acid, glutamic acid and arginine in solution can be detected by potentiometric method using tungsten oxide electrode in a batch system. Characterization of tungsten oxide electrode used include linear range, limit of detection, sensitivity and reproducibility. Buffer type and concentration effect also studied to optimize the measurement results. Optimum conditions for detecting arginine was at pH 6.0 with a phosphate buffer concentration of 0.5 x 10-3 M. Correlation coefficient was obtained for 0.9864, the detection limit of 5.24 x 10-6 M, sensitivity 16.1 mV/decade with reproducibility 0 –7 %. Glutamic acid has a correlation coefficient of 0.9789, the detection limit of 3.80 x 10-6 M, the sensitivity of 9.2 mV/decade and reproducibility of 0 – 6 %. Aspartic acid has a correlation coefficient of 0.9949, the detection limit of 7.76 x 10-6 M, sensitivity of 13.4 mV/decade and reproducibility of 0 – 5 %.
The Effect of Testing Chamber on the Response Patterns of an array of Gas Sensor in Sensing Robusta Coffee Aroma from Bangsalsari and Sidomulyo, Jember Asnawati, Asnawati; Siswoyo, Siswoyo; Ningsih, Febiola Silvia; Ainiyah, Qurotul; Zulfikar, Zulfikar; Mulyono, Tri; Muflihah, Yeni Maulidah
JKPK (Jurnal Kimia dan Pendidikan Kimia) Vol 8, No 1 (2023): JKPK (Jurnal Kimia dan Pendidikan Kimia)
Publisher : Program Studi Pendidikan Kimia FKIP Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/jkpk.v8i1.68520

Abstract

The gas sensor performance can be improved by optimizing the testing chamber design, including volume, shape, gas inlet/outlet positions, and sensor array. We studied the effect of chamber design on the gas sensor's response patterns characteristics in differentiating Robusta coffee aroma from Sidomulyo, and Bangsalsari, Jember. Hemisphere and cylindrical chambers, with three variations for each model, and a ring chamber, were used as model chambers. Eight types of gas sensors (MQ-135, MQ-136, MQ-2, MQ-3, MQ-6, MQ-7, MQ-8, and MQ-9) were used in the sensor array system to examine the gas sensor instrument performance. The resulting responses were analyzed using the reproducibility, response time, and principal component analysis (PCA) test. The result shows that the reproducibility value for all hemisphere chamber models, cylindrical chamber model-1, and ring chamber indicated an excellent sensor performance (%RSD<20%). Meanwhile, the cylindrical chambers model-2 and 3 resulted in %RSD>20%, indicating the low performance of the gas sensor. Among all variations, hemisphere chamber model-1, a hemisphere chamber with the inlet position lower than the outlet gas position, has the best performance due to the shortest response time, high-intensity signal, and performing ability to distinguish the response patterns characteristics of Robusta coffee aroma from Sidomulyo and Bangsalsari, Jember, Indonesia. In this study, we found that changing the testing chamber design, volume, and inlet/outlet position resulting different gas sensor responses to the coffee aroma. The proposed instrument can distinguish the coffee aroma from a different origin.
Co-Authors Adiwinata, I Nyoman Ainiyah, Qurotul Amiyati, Dewi Rara Apriliana, Gepsa Ardyanti, Zona Salsabila Asnawati Asnawati Asnawati Asnawati Asnawati Azhar, Adella Rahani Bambang Piluharto Denny Trias Utomo, Denny Trias Diah Ayu Nur Sholehah Dwi Indarti Fitriyah, Azhaara Raihanah 'Urfatul Hanafi, Mustika Intan Sahifah Heny Masruroh Heny Masruroh, Heny Jamala, Tipta Kholifa, Mulik Kiki Puji Setianingrum Muhammad Farhan Mulyono, Tri Nabila, Cinta Rivani Ningsih, Febiola Silvia Ningsih, Fitriyah Novita Andarini Qurrota Ayun Rayhan, Nevanda Shaquille Rohmawati, Manis Saputri, Nora Dwi Sartikasari, Mindarti Siswoyo Siswoyo Siswoyo Siswoyo Syahrulita, Dita Crisma Tamami, Akfani Jahval Tanti Haryati Tri Mulyono Tri Mulyono Vania, Amanda Wuryanti Handayani Yudi Aris Sulistiyo, Yudi Aris Zein, Inayatul Aulia Rizka Zulfikar Zulfikar