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Department of Chemistry Faculty of Mathematics and Natural Sciences Universitas Andalas Kampus Universitas Andalas Limau Manih Padang 25163
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INDONESIA
Jurnal Riset Kimia
Published by Universitas Andalas
ISSN : 1978628X     EISSN : 24768960     DOI : -
Core Subject : Science,
Chemistry
Arjuna Subject : -
Articles 561 Documents
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Rapid Detection and Quantification of Gambir Adulteration Using ATR-FTIR Spectroscopy Coupled with Chemometric Analysis Satria, Dedi; Eranisa, Yenni; Arel, Afdhil
Jurnal Riset Kimia Vol. 16 No. 2 (2025): September
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v16i2.858

Abstract

Gambir (an extract from Uncaria gambir Roxb.) is a valuable Indonesian herbal product susceptible to adulteration for economic gain. In this study, we developed a rapid, non-destructive method to detect and quantify adulteration in gambir using Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy combined with chemometric analysis. In total, 32 gambir samples were prepared, including authentic gambir, samples adulterated with a fertilizer (SP36) at 0–50% w/w, quality control (pooled) samples, and a market sample of unknown purity. FTIR spectra (4000–600 cm−1) were collected. The spectral data were preprocessed and analyzed with PCA, SIMCA, and PLS-R. PCA revealed clear clustering of samples according to adulterant concentration, with the first two principal components capturing more than 99% of total variance. Chemometric classification models successfully distinguished authentic gambir from adulterated samples: SIMCA showed clear separation, with the 1% adulterant concentration sample clustering near authentic gambir, while the PLS-R calibration model achieved excellent linearity (R² ≈ 0.988) in predicting adulterant levels, with low RMSECV (≈ 0.0375) and a detection limit of ~0.54% adulterant concentration. When applied to a gambir sample obtained from the market, the PLS-R model indicated ~25% adulterant concentration. These results demonstrate that FTIR spectroscopy combined with multivariate analysis can effectively detect and quantify even low levels of adulterant concentration in gambir. This approach offers a fast and reliable tool for quality control and authentication of herbal products prone to adulteration.
The Novel of Chitosan-Hydroxyapatite of Chicken Eggshells Composite as Methylene Blue Adsorbent Arthika Putri, Nur; Ramadani, Kurnia; Chadijah, Sitti; Rasyid, Firnanelty
Jurnal Riset Kimia Vol. 17 No. 1 (2026): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v17i1.819

Abstract

High egg consumption in Indonesia, particularly in South Sulawesi, presents a significant opportunity to utilize eggshells as precursors for hydroxyapatite. This study aims to characterize hydroxyapatite derived from chicken eggshells and to evaluate the absorption properties of chitosan-hydroxyapatite composites for methylene blue removal. The precipitation method was used for hydroxyapatite synthesis, as it produces hydroxyapatite with a high level of purity and low contamination. X-ray diffraction (XRD) analysis revealed that eggshells contain approximately 30% CaCO₃. The XRD diffractogram of hydroxyapatite from eggshells showed a peak at 2θ = 31.94º. Fourier-transform infrared (FTIR) spectroscopy identified key functional groups in hydroxyapatite, including hydroxyl (-OH) at 3434 cm⁻¹, carbonate (-CO₃²⁻) at 1421 cm⁻¹, phosphate bending (-PO₄³⁻) at 565 cm⁻¹, and phosphate stretching (-PO₄³⁻) at 1035 cm⁻¹. The chitosan-hydroxyapatite (Cs-HAp) composite showed the incorporation of chitosan functional groups, including amine (-NH) at 1577 cm⁻¹ and methylene (-CH) at 2928 cm⁻¹. The chitosan-hydroxyapatite composite demonstrated effective removal of methylene blue dye, with an absorption efficiency of 96% at a Cs-HAp ratio of 2:2 within 180 minutes. Based on the high adsorption efficiency, the chitosan-hydroxyapatite composite shows great potential for absorbing methylene blue.
Dye-Sensitized Solar Cell (DSSC) with TiO2-Cu and Natural Pigmented Dye Hardeli, Hardeli; Sanjaya, Hary; Novita, Indri Panca; Luli, Rahmaneta; Yunita, Lasmi; Agdisti, Nurul Fadilah; Permatasari, Putri
Jurnal Riset Kimia Vol. 17 No. 1 (2026): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v17i1.821

Abstract

Dye-Sensitized Solar Cells (DSSC) are solar cells that use dye as a sensitizer. Titanium dioxide (TiO2) is a semiconductor that is frequently used in DSSC. However, the effectiveness of TiO2 can decrease due to electron and hole recombination. In this study, copper metal (Cu) was electrodeposited onto the TiO2 layer, where Cu plays a role in forming a barrier layer to reduce electron recombination. Anthocyanins are natural dyes with a broad light spectrum that can be used as a photon absorber in the DSSC. Anthocyanins in this study were extracted from red grape skin (Vitis Vinifera), jengkol skin (Pithecellobium jiringa), senduduk fruit (Melastoma malabathricum L), and mangosteen peel (Garcinia Mangostana L). To create a more stable organic dye, the dye is co-pigmented with salicylic acid. The XRD characterization of the layers revealed a diffraction pattern indicating the presence of anatase-phased and size reduction on TiO2-Cu layers. As a result, the DSSC performance increased. SEM-EDS analysis was performed to determine surface morphology and identify Cu metal. FTIR analysis of dyes revealed the presence of specific anthocyanin groups. The UV-Vis characterization revealed the effect of co-pigmentation on the dye absorption area. The highest DSSC performance with TiO2-Cu coating and co-pigmented dye was achieved in the DSSC by electrodepositing Cu on the TiO2 layer while using grape skin as a dye source.
Detection of Clove Essential Oil Purity Using a Combination of Chemometric Models with UV-Vis Spectrophotometry Wijaya, Triyadi Hendra; Rehana, Rehana; Endriastuti, Nialiana Endah; Suryoputri, Masita Wulandari; Defa, Ines Naila
Jurnal Riset Kimia Vol. 17 No. 1 (2026): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v17i1.846

Abstract

Clove Essential Oil (CEO) has extensive benefits for health, cosmetics, and food. Low extraction yield (<1%) causes relatively high production costs. This becomes an opportunity for deliberate adulteration to gain greater business profits. This study developed a combination of UV-Vis spectrophotometry with chemometrics to separate pure CEO and adulterated CEO. The adulterants used included Corn Oil (CO) and Olive Oil (OO) at several adulteration levels to see their spectrum and absorption profiles using UV-Vis spectrophotometry. The data were analyzed using PCA and HCA chemometric techniques through R Studio 4.3.3 software. The results of UV-Vis spectrophotometry measurements on CEO adulteration showed similarities in the spectrum profiles of pure CEO and adulterated CEO. Data analysis with PCA can separate pure CEO from adultered CEO with a percentage of cumulative variance of the resulting spectrum of 98.2%. The more similar the composition of a particular oil in a sample, the closer the position of the sample to the oil on the score plot of PCA. HCA analysis can cluster pure CEO separately from adultered CEO. Cluster I in the dendogram consists of samples with large CO concentrations, while samples with large CEO and OO concentrations will be included in Cluster II. The combination of UV-Vis spectrophotometry and chemometrics can be used as a method to separate pure CEO from adultered CEO.
Synthesis of Copper Oxide from HKUST-1 and Its Applications for Removal of Congo Red Maulidah, Izzah; Patah, Aep
Jurnal Riset Kimia Vol. 17 No. 1 (2026): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v17i1.822

Abstract

This study presents research findings on the synthesis and characterization of HKUST-1 and derived-copper oxide materials, with significant practical implications. The HKUST-1 was synthesized using the solvothermal method at 100 °C for 10 hours using copper nitrate trihydrate (Cu(NO3)2∙3H2O) as the metal ion and trimesic acid as the ligand. The various copper oxides, CuO (air), Cu/Cu2O/C (Ar), and CuO (Ar/O2) were produced through pyrolysis from HKUST-1 at 600 °C for 8 hours. X-ray Diffraction (XRD) analysis confirmed the characteristic peaks of HKUST-1 and the other copper oxides. Pyrolysis under argon yielded a Cu/Cu2O/C (Ar) mixture instead of CuO. Fourier Transform Infrared (FTIR) spectroscopy showed consistent absorption bands while Scanning Electron Microscopy (SEM) revealed that HKUST-1 and derived HKUST-1 copper oxides had an octahedral crystal morphology. UV-DRS analysis demonstrated that CuO derived HKUST-1 exhibited smaller band gap as compared to the pure CuO sample. Adsorption tests with a 50 ppm Congo Red (CR) solution showed that all materials reached optimal adsorption at 60 minutes, with Cu/Cu2O/C (Ar) achieving the highest capacity of 95,52 mg/g. In photocatalysis tests, CuO (Ar/O2) removed 53% of contaminants, outperforming commercial CuO at 29%. The Cu/Cu2O/C (Ar) composite demonstrated the highest removal rate at 99%, indicating its potential for practical applications.
Regioselective Synthesis of 5-Nitronaphtalene-1,4-dione Derivatives in Various Solvents and Their Characterization Narwanti, Iin; Warsi, Warsi; Sethy, Bidyadhar
Jurnal Riset Kimia Vol. 17 No. 1 (2026): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v17i1.837

Abstract

Regioselective synthesis is a crucial strategy in the development of bioactive molecules, as regioisomers may exhibit distinctly different biological activities. Heterocyclic naphthoquinones are a promising class of bioactive scaffolds with potential anticancer properties that might be influenced by their regiochemical configuration. This study aimed to investigate the regioselective synthesis of 5-nitronaphthalene-1,4-dione with an amine using various solvents and to characterize the target compounds. The synthesis was initiated with the nitration of 2,3-dichloronaphthalene-1,4-dione using a mixture of HNO3/H2SO4, generating compound 2 in a moderate yield. Next, compound 2 was subsequently reacted with N, N-dimethylethane-1,2-diamine under alkaline conditions at ambient temperature, affording two regioisomeric target compounds (compounds 4 and 5). The characterization confirmed the successful synthesis of compounds 4 and 5, with findings indicating that aprotic solvents facilitated the formation of compound 4, while protic solvents slightly favored the formation of compound 5. In conclusion, the results reveal that the solvent governs regioselective synthesis of 5-nitronaphthalene-1,4-dione derivatives, providing a basis for controlling substitution patterns in these scaffolds. Further, the successful synthesis and isolation of regioisomerically pure compounds establishes a foundation for further exploration of their biological activities.
Green Synthesis, Characterization, and Antibacterial Activity of Copper Oxide Nanoparticles (CuO NPs) Using Papaya Leaf (Carica papaya L.) Extract as a Capping Agent Pangestutia, Citra Pramestiardhiani; Nazriati, Nazriati
Jurnal Riset Kimia Vol. 17 No. 1 (2026): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v17i1.866

Abstract

The existence of pathogenic bacteria remains a serious problem in various fields. Prolonged use of conventional antibiotics can cause bacterial resistance; therefore, a safe and effective antibacterial alternative, such as copper oxide nanoparticles (CuO NPs), is needed. This research uses a green synthesis method that is environmentally friendly. This study aims to synthesize CuO nanoparticles using papaya leaf extract (Carica papaya L.) as a stabilizing or capping agent because it contains secondary metabolite compounds that play a role in stabilizing and preventing nanoparticle agglomeration. Variations in the volume of extract added to the precursor were conducted to determine the optimal volume for the formation of CuO nanoparticles. The successful synthesis of CuO nanoparticles was demonstrated by XRD peaks in accordance with JCPDS standard No. 45-0937 and the appearance of characteristic CuO absorption peaks. The results showed that increasing the volume of extract led to an increase in crystal and particle size. The optimal extract volume produces smaller CuO nanoparticles, which increase the surface area and widen the band gap. These effects enhance Cu²⁺ release and ROS generation, leading to improved antibacterial activity. The optimal extract volume for CuO nanoparticle formation was 6.25 mL, as it provided the most favorable balance between particle growth and stability. The antibacterial test using the disc diffusion method showed that antibacterial activity increased at the optimum extract volume but decreased when the extract addition was too high. This study shows that papaya leaf extract is effective as an agent in the synthesis of CuO NPs and provides potential antibacterial activity.
Determination of Optimum Extraction Conditions for Antioxidant Capacity from White Turmeric Rhizome (Curcuma zedoaria (Christm.) Roscoe) Using Response Surface Methodology El Firsti, Nurjannah; Yefrida; Refilda
Jurnal Riset Kimia Vol. 17 No. 1 (2026): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v17i1.872

Abstract

The role of free radicals in oxidative stress poses risks to cells and tissues. The effect of stress and tissue oxidation damage leads to loss of structure and, ultimately, tissue necrosis. Antioxidants quell free radicals and stabilize them. White turmeric (Curcuma zedoaria (Christm.) Roscoe) rhizome, another natural source used in traditional medicine, is said to have some potential as an antioxidant. The current study sought to investigate methods used in devising the optimization of antioxidant extraction from white turmeric using the decoction method. The main factors considered were temperature, extraction time, and sample-to-solvent ratio. The DPPH assay measured at 522 nm provided the readings for antioxidant activity. The initial OFAT approach used to devise the experiment tested and confirmed those optimal conditions of extraction (80 ˚C, 50 minutes, and 1:25 g/mL). These optimal conditions were tested in the central composite design within RSM. The confirmation of optimal conditions within RSM was (84 ˚C, 51 minutes, 1:25 g/mL). The extraction of 1.3963 mg AAE/g FW and the predicted value of 1.3450 mg AAE/g FW. These findings validate the extraction efficiency in RSM and demonstrate the antioxidant potential of white turmeric in the pharmaceutical industry.
Optimalization of Holes Variation to Improve the Performance of Catalytic Converter from Waste Pulp and Rice Husk Ash Jahro, Iis Siti; Zubir, Moondra; Faradilla, Putri; Jasmidi, Jasmidi; Nursanni, Banu
Jurnal Riset Kimia Vol. 17 No. 1 (2026): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v17i1.857

Abstract

The agricultural wastes in the form of rice husk ash, manufacturing solid wastes consisting of pulp grits, dregs, and biosludge as well as motor vehicle exhaust gases containing carbon monoxide, hydrocarbons and carbon dioxide are pollutants that endanger humans and other living things. In fact, the mineral content in pulp solid waste and rice husk ash can be converted into catalytic converters that absorb and convert pollutants from vehicle flue gases so that the amount released into the air is decreased. Therefore, the use of catalytic converters in motor vehicle exhaust is one of the solutions to reduce the air pollution. The ratio of zeolite weight from rice husk ash to pulp solid waste and the number of holes in the catalytic converter are important factors that can affect the performance and mechanical properties of the catalytic converter. The catalytic converter with a zeolite weight ratio of rice husk ash to pulp solid waste at 4:5 and a number of holes at 8 has an absorption power of carbon monoxide (CO), hydrocarbon (HC) and carbon dioxide (CO2) gases of about 54.83; 71.19 and 36.95%, respectively, with a conversion power indicated by an increasing oxygen content in the flue gas by 23.81%.
Biocatalytic Performance and Dosage-Dependent Behavior of Fruit Peel–Derived Eco-Enzymes in Organic Matter Removal from Simulated Lake Water Pramana Putra, Aldho; Komala, Puti Sri; Nur, Ansiha
Jurnal Riset Kimia Vol. 17 No. 1 (2026): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v17i1.936

Abstract

The increasing organic pollution in lake water systems due to continuous domestic wastewater discharge presents significant environmental challenges, particularly in urban areas. This study investigates the biocatalytic performance and dosage-dependent behavior of fruit peel–derived eco-enzymes in removing organic matter from simulated lake water under laboratory-scale batch conditions. Eco-enzymes were produced from banana, pineapple, papaya, watermelon, and orange peels, including a mixed formulation, produced through a three-month anaerobic fermentation process. The products were characterized based on physicochemical properties and enzymatic activities, including amylase, protease, and lipase, to evaluate their biocatalytic potential. Batch experiments were conducted using eco-enzyme dosages of 5%, 10%, and 15%, with continuous monitoring of chemical oxygen demand (COD) and biochemical oxygen demand (BOD) over 12 days until steady-state conditions were achieved. The results showed that eco-enzymes exhibited significant biocatalytic activity, promoting enzymatic hydrolysis and degradation of complex organic compounds into simpler biodegradable forms. Treatment performance was strongly influenced by dosage, where the 5% concentration achieved the highest removal efficiencies, with maximum reductions of 71.7% for COD and 74.6% for BOD, while higher dosages reduced performance due to additional organic loading. Statistical analysis using one-way ANOVA confirmed that eco-enzyme dosage significantly affected treatment performance, with highly significant differences for COD removal (F = 262.348; p < 0.05) and significant differences for BOD removal (F = 7.410; p < 0.05). Furthermore, first-order kinetic analysis revealed that the 5% dosage produced the highest reaction rate constants, with the papaya-based eco-enzyme achieving k values of 0.105 day⁻¹ for COD and 0.114 day⁻¹ for BOD, indicating faster organic matter degradation compared to other treatments. In contrast, higher dosages (10% and 15%) resulted in negative removal efficiencies, reflecting process inhibition due to excessive organic loading and preventing valid kinetic interpretation. These findings demonstrate the dual role of eco-enzymes as both biocatalytic agents and contributors to organic loading, highlighting the importance of dosage optimization supported by both statistical and kinetic approaches in sustainable lake water remediation systems.

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