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Eti Rohaeti
Department of Chemistry, Faculty of Mathematics and Natural Science, IPB University, Bogor|IPB University|Indonesia;Tropical Biopharmaca Research Center, IPB University,Bogor|IPB University|Indonesia
Chemical Engineering, Chemistry & Bioengineering Chemistry Engineering

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Uric Acid Sensor Based on PEDOT:PSS Modified Screen-Printed Carbon Electrode Fabricated with a Simple Painting Technique Wulan Tri Wahyuni; Rudi Heryanto; Eti Rohaeti; Achmad Fauzi; Budi Riza Putra
Jurnal Kimia Sains dan Aplikasi Vol 24, No 2 (2021): Volume 24 Issue 2 Year 2021
Publisher : Chemistry Department, Faculty of Sciences and Mathematics, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (3442.057 KB) | DOI: 10.14710/jksa.24.2.43-50

Abstract

A screen-printed carbon electrode is a suitable electrode for electrochemical sensors due to its simplicity and portability. This study aimed to fabricate a screen-printed carbon electrode modified with poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (SPCE-PEDOT:PSS) to improve the electrochemical performance for uric acid detection. The SPCE was fabricated using a layer-by-layer painting process of conductive ink consisting of graphite as a conductive material, polystyrene as a polymeric binder, and dichloromethane solvent on a polyvinyl chloride paper substrate. The fabricated SPCE was then modified with PEDOT:PSS by a drop-casting method. The characterization of SPCE-PEDOT:PSS surface morphology was performed using the scanning electron microscopy technique. The SPCE-PEDOT:PSS provided an acceptable linearity (R2 = 0.9985, 0.9993, 0.9985), sensitivity (0.070, 0.015, 0.024 µA/µM), precision (%RSD = 2.70%, 2.89%, 2.40%), limit of detection (1.61 µM, 1.14 µM, 1.62 µM), and limit of quantitation (5.37 µM, 3.81 µM to 5.39 µM) in measurement of uric acid standard solution using cyclic voltammetry, amperometry, and differential pulse voltammetry techniques, respectively. The studies using SPCE-PEDOT:PSS indicated that the electrode could be applied in the electrochemical measurement of uric acid in the human urine sample.
Antibacterial Activity of Jojoba Seed residue and Its Possible Active Compound Irmanida Batubara; Arnold Patogi Siahaan; Eti Rohaeti; Ali Mahmoud Muddathir
Jurnal Kimia Sains dan Aplikasi Vol 25, No 6 (2022): Volume 25 Issue 6 Year 2022
Publisher : Chemistry Department, Faculty of Sciences and Mathematics, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (270.12 KB) | DOI: 10.14710/jksa.25.6.218-223

Abstract

Jojoba (Simmondsia chinensis) (Link) C.K. is a shrub plant widely used in cosmetics, especially jojoba oil. The residue will remain when producing jojoba oil and become waste. This study aimed to determine the antibacterial activity of Jojoba seed residue (JSR) and its possible active antibacterial compounds. JSR was collected from Sudan and extracted by maceration with n-hexane, ethyl acetate, and 70% ethanol. The antibacterial activity was determined with the microdilution method against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The 70% ethanol extract showed the value of MIC and MBC against E. coli, which was 7.8 mg/ml; meanwhile, against S. aureus was 3.9 mg/mL and 7.8 mg/mL, respectively. Fractionation of 70% ethanol extract using silica gel column chromatography with gradient elution produced ten fractions. Fraction 3 showed the MIC and MBC values in E. coli which were 3.1 mg/mL and 12 mg/ml, and in S. aureus, which were 3.1 mg/mL and 6.2 mg/mL. The fractionation continued to Fraction 3 using preparative thin layer chromatography to collect subfraction 3.2 at an Rf value of 0.76, actively based on contact autobiography against E. coli and S. aureus. Embelin was detected in Subfraction 3.2 using liquid chromatography-mass spectrometry (UHPLC-Q-Orbitrap HRMS) and suggested as the active antibacterial component in JSR.
Co-Authors Achmad Fauzi Ali Mahmoud Muddathir Arnold Patogi Siahaan Budi Riza Putra Irmanida Batubara Rudi Heryanto Wulan Tri Wahyuni