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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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Jurnal Riset Kimia
Published by Universitas Andalas
ISSN : 1978628X     EISSN : 24768960     DOI : -
Core Subject : Science,
Chemistry
Arjuna Subject : -
Articles 551 Documents
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PEMBUATAN DAN KARAKTERISASI KATALIS ZnO/KARBON AKTIF DENGAN METODE SOLID STATE DAN UJI AKTIFITAS KATALITIKNYA PADA DEGRADASI RHODAMIN B Upita Septiani; Ilona Bella; Syukri -
Jurnal Riset Kimia Vol. 7 No. 2 (2014): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v7i2.186

Abstract

 ABSTRACTComposite catalyst ZnO/Activated Carbon (ZnO/AC) had been synthesized successfully bysolid state method. Synthesis was done by varying the addition of activated carbon (AC) 2%,5%, and 10% ZnO mass. Composite catalyst were calcinated at 400oC and characterized byFTIR (Fourier Transform Infra Red), XRD (X-Ray Diffraction), SEM (Scanning ElectronMicroscopy). Based on the results of FTIR, absorption appeared in the region wave number1400-1600 cm-1, which indicated stretching of C=C was assumed come from AC. From theXRD results, it was known by the addition of AC, not overly change the crystallinity and crystalsize of ZnO, the crystal structure is hexagonal (wurtzite). SEM images showed AC preventedthe agglomeration of ZnO that would expand the surface area of ZnO and increased catalyticactivity of ZnO. For the results of the catalytic activity test, catalyst ZnO/AC was tested on thedegradation of Rhodamine B solution (10 ppm) by UV light irradiation, where the increasingnumber of trains the catalytic ability of ZnO also increased, it could be concluded that activatedcarbon can support to increase the role of ZnO in degrading Rhodamine B.Keywords: composite catalyst, ZnO, activated carbon, solid state, Rhodamine B
VALIDASI METODA PENENTUAN ANTIOKSIDAN TOTAL (DIHITUNG SEBAGAI ASAM SITRAT) DALAM SAMPEL JERUK SECARA SPEKTOFOTOMETRI DENGAN MENGGUNAKAN OKSIDATOR FeCl3 DAN PENGOMPLEKS ORTO-FENANTROLIN Yefrida -; Mega Ulfaningsih; Umiati Loekman
Jurnal Riset Kimia Vol. 7 No. 2 (2014): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v7i2.187

Abstract

ABSTRACTAntioxidant is a compound that can be used to obstruct species oxygen reactive, speciesnitrogen, and other free radicals so it can be used degenerative illnesses inhibition. Citric acid isa natural antioxidant that can be found in some kind of oranges. There are some methode thatusually used to determination the antioxidant, such as CUPRAC, DPPH, and FRAP. Objectiveof this research is studied about alternative method to determine total antioxidant that is countedas citric acid by using FeCl3 as an oxidator and o-phenantroline as a complexant reagent. Instudied of appropriateness of this method, validation has been done with parameter linearity,LoD, LoQ, SDR, and recovery with samples orange, kaffir lime, and lime. Base on the research,the regression equation is Y = 0,066 + 117.35 X and R2 = 0.990 with value of LoD is1.15x10-3M and LoQ is 3.86x10-3 M. The value of SDR and recovery in samples orange, kaffir lime, andlime are 1.64%, 0.53% 2.14%, and 100.47%, 93.58%, 93.78%, respectively. Base on validationmethod data, can be concluded that this method appropriate to be used to determination of totalantioxidant for samples orange, kaffir lime, and lime.Keywords : Antioxidant, Validation Method, Spectrophotometry
PEMANFAATAN ZEOLIT ALAM SEBAGAI MEDIA PENDUKUNG AMOBILISASI ENZIM α-AMILASE Upita Septiani; Agrina Lisma
Jurnal Riset Kimia Vol. 5 No. 1 (2011): September
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v5i1.188

Abstract

 ABSTRACT The utilization of natural zeolite as supporting media of α-amylase enzyme has been done. Natural zeolite which is activated with 3M HCl can remove impurities in the surface natural zeolite, uncover and widen the pores of the zeolite and activate functional groups to interact with α-amylase enzyme in the process of immobilization enzyme process. The mass of activated natural zeolite which is used as a material immobilized to get the optimal activity of α-amylase enzyme was 0.3 gram. Based on the measurement result of optimization of α-amylase enzyme were obtained optimum temperature of 35 oC, pH 5.6 and incubation time of 35 minutes with 0.04845 units/mL of the unit activity. And for α-amylase immobilized enzyme will be stable at the optimum temperature of 50 oC, pH 5.6 and incubation time of 45 minutes with 0.030 units/mL of the unit activity. SEM-EDX pattern shows the differences in surface morphology between natural zeolite and activated natural zeolites which contain α-amylase enzyme. A mobilization technique can increase the stability utilized in a α-amylase enzyme. Keywords : Zeolite, amobilization, α-amylase enzyme
SENYAWA FENOLIK DARI KULIT BATANG Garcinia cf. cymosa DAN UJI AKTIFITAS ANTIOKSIDAN Yuliar -; Yunazar Manjang; Syamsul A. Achmad; Sanusi Ibrahim
Jurnal Riset Kimia Vol. 5 No. 1 (2011): September
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v5i1.189

Abstract

 ABSTRACT A Phenolic compound was isolated from the bark of Garcinia cf. cymosa. Isolation methods were used are maseration, fractionation, and chromatography. Structure determination was done using spectroscopy methods including IR, H-NMR, C-NMR, DEPT, COSY, HMQC, and HMBC. The result showed that the isolated compound is (-)epicatechin. Antioxidant activity of isolated compound was determined by DPPH method. Isolated compound has antioxidant activity which has IC50 = 41,8 ppm. Keywords : Phenolic, (-)epicatechin, Garcinia cf. cymosa, DPPH
PRODUKSI GLUKOSA DARI BATANG KELAPA SAWIT MELALUI PROSES HIDROLISIS SECARA ENZIMATIS MENGGUNAKAN AMILASE TERMOSTABIL Yetti Marlida; Mirzah -; Syukri Arief; Khoirul Amru
Jurnal Riset Kimia Vol. 7 No. 2 (2014): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v7i2.190

Abstract

ABSTRACTThis study aimed to explore the optimization of the concentration of oil palm trunks andthermostable amylase enzyme preformance produce highest sugar (glucose total and reducingsugars) as well as the degree of polymerization. The design used in this study was a completelyrandomized design (CRD) factorial using 2 factors: factor A which consists of four levels ofamylase enzyme that A1: 250 units / kg, A2: 500 units / kg, A3: 750 units / kg and A4: 1000 units/ kg. Factor B is the concentration of oil palm trunk yitu B1: 20% (200 g / 1 liter) B2: 40% (400g / 1 liter) and B3: 60% (600 g / 1 liter) were repeated 3 times. The results showed that there is ahighly significant interaction (P <0.01) in the levels of amylase enzyme (factor A) with theconcentration of oil palm trunks (factor B) on reducing sugar, siqnificantly interaction (P <0.05)on total sugars and degree of polymerization (DP) . This research can be concluded that the besttreatment at a concentration of 60% oil palm trunks and levels 250 unit/kg of an enzymeconcentration that produces of total sugars 7.86 mg/ml, reducing sugar 15.69 mg /ml and degreeof polymerization 0.50Keywords : amilase, total gula, gula pereduksi, derajat polimerisasi.
ANALISIS SEDIMEN SEKITAR KERAMBA JARING APUNG DI PERAIRAN DANAU MANINJAU TERHADAP KANDUNGAN LOGAM BERAT Fe, Cu, Pb dan Cd Yulizar Yusuf; Umiati Lukman; Fitra Rahmi
Jurnal Riset Kimia Vol. 5 No. 1 (2011): September
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v5i1.191

Abstract

 ABSTRAK Penelitian tentang penentuan kandungan logam berat Fe, Cu, Pb, dan Cd dalam sedimen di sekitar keramba jaring apung di perairan danau Maninjau telah dilakukan. Sampel sedimen diambil pada 7 titik di lokasi dimana terdapat keramba jaring apung. Selanjutnya sampel didestruksi dengan HNO3 dan H2O2, kemudian kandungan logam diukur dengan menggunakan Spektrofotometer Serapan Atom (SSA). Dari hasil analisis sampel sedimen danau Maninjau diperoleh kandungan logam Fe berkisar antara 772,77 – 946,78 mg/kg, logam Cu berkisar antara 447,92 – 531,44 mg/kg, logam Pb berkisar antara 356,81 – 483,47 mg/kg dan logam Cd berkisar antara 249,68 – 318,95 mg/kg. Hasil yang didapat menunjukkan bahwa keempat logam telah melampaui ambang batas yang telah ditetapkan oleh Roseau National d Observation. Keywords: Logam berat, sedimen,dekstruksi
THE OPTIMATION SIMULTANEUOS DETERMINATION OF LEAD(II) AND CADMIUM(II) BY ADSORPTIVE STRIPPING VOLTAMMETRY (ADSV) Deswati -; Hamzar Suyani; Umiati Loekman; Nilam Sari
Jurnal Riset Kimia Vol. 5 No. 2 (2012): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v5i2.198

Abstract

A selective and sensitive adsorptive stripping voltammetric (AdSV) method for simultaneous determination of lead(II) and cadmium(II) were proposed. The aim of this study was to get the optimum condition for simultaneuos determination of lead(II) and cadmium(II). The parameters were studied such as: variation of accumulation potential, accumulation time, pH, and variation ofcalcon concentration. In this case, the optimum conditions were reached at accumulation potential –0.7 V, accumulation time 80 s, concentration of 0.12 mM calcon, and pH 7.0. At the optimumconditions the relative standard deviation were 2.90% and 1.46% for Pb(II) and Cd(II) respectively for eight replicates (n = 8) measurements. The method was applied for the direct determination of Pb(II) and Cd(II) in sea water around Bungus, Padang City. Concentration Pb(II) and Cd(II) insample were 9.918 μg/L – 27.320 μg/L for Pb(II) and 7.997 μg/L - 32.521 μg/L for Cd(II), with recovery of 99.48%, and 103.28 for Pb(II), and Cd(II) respectively.
PEMECAHAN (SPLITTING) MOLEKUL AIR MENJADI GAS H2DAN O2 MELALUI PROSES FOTOVOLTAIK Dini Fatmi; Admin Alif; Hamzar Suyani
Jurnal Riset Kimia Vol. 5 No. 2 (2012): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v5i2.209

Abstract

One method to overcome the scarcity of alternative sources of energy on earth is through the development of photovoltaic cells. This method used a solar energy to electrical energy transformation. In this research, breaking (splitting) of water molecules into H2 and O2 gas by the photovoltaic process uses electrodes CuO/C with Na2SO4 electrolyte. In this process used 2 photovoltaic cells as electricity producing and U-shaped electrolysis cell for solver (splitting) of water molecule produce H2 and O2 gas. CuO electrode (anode) is made through the burning of copper rod in a furnace at temperature 400 oC with a variety of combustion 1, 3, 4 times each lasting for 1 hs, while the cathode in the form of carbon rods obtained from 2B pencil. The optimum conditions for Na2SO4 electrolyte concentration is 0.8 N and for CuO electrodes with 3x burning. Optimum efficiency photovoltaic process was 2.66%. H2 and O2 gas volume obtained near stoichiometric ratio is 2 : 1.
PENGGUNAAN FRONTIER ORBITAL MOLEKUL SEBAGAI DESKRIPTOR PADA ANALISIS HUBUNGAN KUANTITATIF STRUKTUR AKTIVITAS (HKSA) TOKSIK SENYAWA KHLOROFENOL - Emdeniz
Jurnal Riset Kimia Vol. 5 No. 2 (2012): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v5i2.211

Abstract

Quantitative structure-activity relationship (QSAR) methods have been applied to prediction of the toxicity of certain chemical compound. In this research a QSAR descriptor used frontier molecular orbital (LUMO energy (EL), HOMO energy (EH), and band gap (ΔE) and its derivatives were obtained from density functional theory (DFT) (chemical hardness (η) chemical potential (μ) or absolute electronegativity (χ) and global electrophicility indeks (ω)). Frontier molecular orbital (EL and EH) was calculated by ab initio quantum methods. This research found the correlation between the experimental ecotoxicological data of chlorophenols and toxicity prediction were calculated based on the best QSAR equation model of all equation model which have been studied. The best QSAR equation model using parameter LUMO energy (EL), and global electrophilicity index (ω) as descriptor on QSAR toxic of chlorophenol compounds against Bacilus sp TL81 is - log IC50 = 11,022 - 1,767 EL - 5,687 ω, and it has the coefficient of determination (R2) = 0,581 and standard deviation (SD) = 0,6111.
OPTIMASI TRANSPOR Cu(II) DENGAN APDC SEBAGAI ZAT PEMBAWA MELALUI TEKNIK MEMBRAN CAIR FASA RUAH - Imelda; Zaharasmi Kahar; Maria Simarmata; Djufri Mustafa
Jurnal Riset Kimia Vol. 5 No. 2 (2012): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v5i2.212

Abstract

The transport of Cu(II) with Ammonium Pyrrolidine Dithiocarbamate(APDC) as carrier through bulk liquid membrane had been researched. The measurement was performed to source phase and feed phase by using Atomic Absorption Spectrophotometer toward λmaks 324.7 nm. The result of the research showed the optimum condition to separate 20 ppm of Cu(II) was at pH 4 of source phase, concentration of APDC was 1 : 30, stirring time was 2 hours, and the stirring velocity was 300 rpm with the percentage of Cu(II) transport to feed phase was 97,06% and percentage of remains Cu(II) was 0%.

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