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Jurnal Riset Kimia
Published by Universitas Andalas
ISSN : 1978628X     EISSN : 24768960     DOI : -
Core Subject : Science,
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Articles 6 Documents
Search results for , issue "Vol. 10 No. 2 (2019): September" : 6 Documents clear
Identifikasi Senyawa Metabolit Sekunder, Uji Antimikroba dan Antioksidan Ekstrak Akar Gantung Hornstedtia Scyphifera Var. Fusiformis Holttum (Sijangkang) Adlis Santoni; Mai Efdi; Akmel Suhada
Jurnal Riset Kimia Vol. 10 No. 2 (2019): September
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v10i2.264

Abstract

Hornstedtia scyphifera var. fusiformis Holttum is endemic plant of Zingiberaceae family that distributed in Sumatera. Hornstedtia scyphifera var. fusiformis Holttum contained some secondary metabolite such as phenolic, saponin, triterpenoid and alkaloid. The biological activity of methanol, ethyl acetate, and n-hexane extracts from Hornstedtia scyphifera var. fusiformis Holttum suspended roots was tested for antibacterial and antioxydant activity. Antioxidant activity was analized by DPPH method. The antibacterial activity  was tested by used disk difussion method againts Staphylococcus aureus bacteria (gram-positive bacteria) and Escherichia coli (gram-negative bacteria). Almost all of Hornstedtia scyphifera var. fusiformis Holttum suspended roots extract were given antibacterial activity, nonetheless the biggest inhibition zone of Escherichia coli that was inhibited by n-hexane and ethyl acetate extracts which have inhibtion zone 10 mm at  concentration 500 mg/L and also againts Staphylococcus aureus, the biggest inhibition by ethyl acetate and n-hexane extracts which have inhibition zone 10.30 mm at concentration 500 mg/L. Among all extracts tested, methanol extract of the possessed moderate free radical scavenging activity with IC50 = 51.89 mg/L.
Sintesis Senyawa Aurivillius Lapis Empat PbBi4Ti4O15 dan PbBi3NdTi4O15 dengan Metode Lelehan Campuran Garam NaCl-KCl dan Karakterisasi Struktur Gita Rachmad Wibowo; Emriadi Emriadi; Zulhadjri Zulhadjri
Jurnal Riset Kimia Vol. 10 No. 2 (2019): September
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v10i2.307

Abstract

Four-layered Aurivillius phases PbBi4Ti4O15doped with Nd3+ with formula PbBi3NdTi4O15 were synthesized by molten-salt technique using NaCl and KCl (1:1 molar ratio) as the flux. Precursors were weighed stoichiometrycally and grinded with salts mixture in 1:7 ratio (product : salts mixture) until homogenous. The samples were heated at temperature 600oC, 700oC, 800oC, and 900oC for 5 hours for each temperature. The products were characterized by X-ray diffractometer (XRD), Scanning Electron Microscope (SEM) and LCR-meter. XRD data were refined by Rietica program using Le Bail technique. Refinement results showed the best structure as the A21am of space group for both samples. Surface analysis for each samples morphology is the plate-like by SEM characterization. Dielectric constants measured at room temperature show that the sample doped Nd3+ has lower value than sample without containing Nd3+ cation.
Pengaruh Pemberian Variasi pH terhadap Produksi Trigliserida Total dan Komposisi Asam Lemak dari Chlorella Vulgaris Air Tawar Rahmadani Wulandari; Abdi Dharma; Syafrizayanti Syafrizayanti
Jurnal Riset Kimia Vol. 10 No. 2 (2019): September
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v10i2.316

Abstract

Chlorella vulgaris is a microalgae that has high lipid content and potential as raw material for biofuel production. This study aims are to determine the effect of pH on growth, lipid production and fatty acid composition of C. vulgaris by using Growmore 32-10-10 fertilizer as a culture medium. Microalgae were cultured in medium Growmore 32-10-10 for 10 days. Afterward, pH of medium was varied into pH 5, 7, 8.2 and 9 and continued cultivate for 3 days. C. vulgaris cultured at pH 8.2 which is a control pH reached optimum growths. The GC-MS analysis for lipid productivity of C. vulgaris was 0.5020 g/L/day and 0.2902 g/L/day for microalgae grew at pH 8.2 and 9, respectively. Cultures at pH 8.2 and 9 produce methyl hexadecanoate, methyl 9-octadecanoate, methyl octadecanoate, methyl 9,12-octadecadienoate, methyl 9,11-octadecadienoate. Additional fatty acid methyl nonadecanoate was also found in C. vulgaris grew at pH 9. The low and high pH stress of C. vulgaris culture medium did not affect culture growth but altered lipid production and fatty acid composition.
Penentuan Kadar Karbohidrat pada Biji Cempedak Hutan (Artocarpus champeden Lour.) dengan Metoda Tembaga-Iodometri Neri Fadjria; Zulfisa Zulfisa; Arfiandi Arfiandi; Indah Yolandari
Jurnal Riset Kimia Vol. 10 No. 2 (2019): September
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v10i2.327

Abstract

Forest Cempedak Seeds (Artocarpus champeden Lour.) Are types of seeds that are underutilized by humans. Forest Cempedak Seed Flour has nutritional content of carbohydrates, fats, and proteins that can be processed as ingredients for food. This study aims to determine the carbohydrate content of Forest Cempedak Seeds (Artocarpus champeden Lour.) Conducted by the Copper-Iodometric method using a luff schoorl reagent. From the research that has been carried out obtained levels of carbohydrates in Cempedak Seeds (Artocarpus champeden Lour.) of 38.016%. 
Perbandingan Efektivitas Dekolorisasi Fotokatalitik Metilen Biru dan Metil Jingga menggunakan Semikonduktor ZnO pada Variasi pH Annisa M. Dewi; Wahyu B. Widayatno; Yuly Kusumawati
Jurnal Riset Kimia Vol. 10 No. 2 (2019): September
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v10i2.328

Abstract

The comparison of photocatalytic decolorization of Methylene Blue and Methyl Orange using ZnO Semiconductor under UV-LED radiation has been studied at varied pH. ZnO have been synthesized using co-precipitation method. The Scanning Electron Microscopy (SEM) result showed that the synthesized ZnO has a hexagonal structure with the particle size range 0.125 to 0.5 µm. The BET isotherm characterization showed the synthesized ZnO has a specific surface area (SBET), mesoporous volume and micropore volume of 60.20 m2/g, 0.541 cm3/g and 0.02 cm3/g, respectively. The observation of the effect of pH to the photocatalytic activity showed that the highest removal percentage occurred at pH 9 with the value of 95.64% for methylene blue and occurred at pH 3 with the value of 6.236% for methyl orange. 
Kajian Kualitas Air Tanah Ditinjau dari Parameter pH, Nilai COD dan BOD pada Desa Teluk Nilap Kecamatan Kubu Babussalam Rokan Hilir Provinsi Riau Arief Yandra Putra; Putri Ade Rahma Yulia
Jurnal Riset Kimia Vol. 10 No. 2 (2019): September
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v10i2.337

Abstract

Based on a preliminary study that has been carried out, Teluk Nilap Village, Kubu Babussalam District, Rokan Hilir was affected by the disposal of waste from oil company. The waste partly seeps into the residents' water sources which are used for domestic activities. It was because the location of the water sources close to the location of the waste oil disposal. The sampling technique in this study used the observation point technique (pumping test). Sampling refers to the point of waste oil flow (upstream, middle, downstream) and dug well water taken randomly (random sampling). The results showed pH values ranged from 2.8 to 6.6; BOD values range from 0.42 to 141.1 mg / L; COD values range from 20 to 291 mg / L. Ground water quality at some point in Teluk Nilap Village exceeded quality standard limits allowed and included in heavy pollution category.

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