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Jaya Hardi
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KOVALEN: Jurnal Riset Kimia
Published by Universitas Tadulako
ISSN : -     EISSN : 24775398     DOI : https://doi.org/10.22487/kovalen
Core Subject : Science, Engineering,
Chemical Engineering, Chemistry & Bioengineering Chemistry
KOVALEN: Jurnal Riset Kimia is a peer-reviewed journal of chemistry published by the Tadulako University, Indonesia. This journal concern with publishing the original research articles, review articles, and the current issues related to chemistry. Publishing frequency 3 issues per year, in April, August, and December.
Arjuna Subject : Kimia(semua kategori) - Kimia (Lain-Lain)
Articles 320 Documents
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PENENTUAN SUHU DAN pH HIDROLISIS KITOSAN DARI CANGKANG KEONG SAWAH (Pila ampullacea) TERHADAP BERAT MOLEKUL HIDROLISATNYA Nurhaeni Nurhaeni; Angriani Sambali; Pasjan Satrimafitrah; Jusman Jusman
KOVALEN: Jurnal Riset Kimia Vol. 5 No. 1 (2019): Edisi April
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (815.085 KB) | DOI: 10.22487/kovalen.2019.v5.i1.11454

Abstract

Telah dilakukan penelitian tentang penentuan suhu dan pH hidrolisis kitosan dari cangkang keong sawah (Pila ampullacea) terhadap berat molekul hidrolisatnya dengan menggunakan enzim α-amilase. Penelitian ini bertujuan untuk menentukan suhu dan pH hidrolisis terbaik yang dapat menghasilkan hidrolisat kitosan dengan berat molekul yang rendah. Variasi suhu yang digunakan untuk menghidroisis kitosan dari keong sawah antara lain 300C, 400C, 500C, 600C dan 700C. Sedangkan pH hidrolisis yang diterapkan  untuk menghidrolisis kitosan dari cangkang keong sawah antara lain 4,5; 5,0; 5,5; 6,0 dan 6,5. Pengujian berat molekul hidrolisat kitosan dilakukan dengan menerapkan metode Mark-Houwink dan parameter yang diamati adalah berat molekul hidrolisat kitosan. Hasil penelitian menunjukan bahwa suhu optimum hidrolisis kitosan yaitu suhu 500C dan menurunkan berat molekul menjadi 14.488 g/mol. Sedangkan untuk pH optimum hidrolisis adalah pH 5,5 dan menurunkan berat molekul 12.850 g/mol.Kata Kunci : hidrolisat kitosan, cangkang keong sawah, enzim α-amilase
PENGGUNAAN KULIT UBI KAYU (Manihot utillisima Pohl) TERHADAP PENYERAPAN LOGAM Fe (III) PADA AIR PAYAU Delta Rinanda Duda; Syaiful Bahri; Jaya Hardi; Nov Irmawati Inda
KOVALEN: Jurnal Riset Kimia Vol. 5 No. 2 (2019): Edisi Agustus
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (380.243 KB) | DOI: 10.22487/kovalen.2019.v5.i2.11469

Abstract

The absorption of Fe (III) metal in brackish water in the Balaroa Village, West Palu District using Cassava peels (Manihot utillisima Pohl) has been carried out. The aim of this study is determining the lifetime of cassava peels (Manihot utillisima Pohl) on the absorption of Fe (III) ions in brackish water. The research was conducted in a simple purification water system. Brackish water was flowed through the simple purification water system containing Cassava peels (Manihot utillisima Pohl) with a volume of brackish water is 10 liters per day (measured flow rate) and been analyzed every 2 days using UV-Vis spectrophotometry for less than 1 month. The results of the study show that cassava peel could be used as biosorbent to absorb and reduce level of Fe (III) ions in brackish water for 2.821 months. The concentration of Fe (III) ions in brackish water in Balaroa Village, West Palu District is 1.666 ppm. Keywords : Fe (III) Ion, Biosorbent, Cassava Peel
PEMANFAATAN KARBON AKTIF AMPAS TAHU TERAKTIVASI NaCl SEBAGAI PENYERAP ZAT WARNA CONGO RED Sutomo Eka Putra; Khairuddin Khairuddin; Dwi Juli Puspitasari; Husain Sosidi
KOVALEN: Jurnal Riset Kimia Vol. 5 No. 1 (2019): Edisi April
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (301.116 KB) | DOI: 10.22487/kovalen.2019.v5.i1.11474

Abstract

Telah dilakukan penelitian mengenai pemanfaatan karbon aktif ampas tahu teraktivasi NaCl sebagai penyerap zat warna Congo Red. Penelitian ini bertujuan untuk mengetahui kemampuan karbon aktif ampas tahu teraktivasi NaCl dalam menyerap zat warna Congo Red . Penelitian ini menggunakan rancangan acak lengkap dengan tiga variabel bebas yaitu konsentrasi aktivator, waktu kontak dan pH sedangkan variabel terikat yaitu persentase Congo Red yang terjerap. Hasil penelitian menunjukkan  penyerapan terbaik diperoleh pada karbon aktif  ampas tahu teraktivasi NaCl 3M dengan waktu kontak optimum selama 60 menit pada kondisi pH 2. Dari penelitian ini diketahui bahwa limbah ampas tahu dapat dimanfaatkan menjadi karbon aktif.Kata kunci:  Karbon Aktif, Ampas Tahu, Zat Warna Congo Red, Adsorpsi
UJI AKTIVITAS ANTIBAKTERI EKSTRAK n-HEKSAN, ETIL ASETAT DAN ETANOL KULIT BATANG KAYU EBONI (Diospyros celebica Bakh.) MENGGUNAKAN METODE DIFUSI Ni Luh Sumitriasih; Ahmad Ridhay; Indriani
KOVALEN: Jurnal Riset Kimia Vol. 5 No. 3 (2019): Edisi Desember
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (446.37 KB) | DOI: 10.22487/kovalen.2019.v5.i3.11540

Abstract

A study was conducted on the antibacterial activity test on n-hexane, ethyl acetate, and ethanol extracts of ebony bark (Diospyros celebica Bakh.) using a diffusion method. The purpose of this research is to know the antibacterial activity of ebony bark against Staphylococcus aureus and Escherichia coli bacteria using n-hexane, ethyl acetate dan ethanol. The method of extraction used in this research was maceration method with three polarity levels of solvent. The antibacterial activity test was performed by diffusion-well test. The results showed that ethyl acetate extract gave the highest inhibition of 26.14 mm in gram-positive bacteria (Staphylococcus aureus) and ethanol extract of 25.97 mm in gram-negative bacteria (Escherichia coli). Keywords: Ebony (Diospyros celebica. Bakh), Tree Bark, Inhibitory, Antibacterial
ANALISIS KADAR SERAT DAN KADAR PROTEIN SERTA PENGARUH WAKTU SIMPAN TERHADAP SEREAL BERBASIS TEPUNG AMPAS KELAPA DAN TEPUNG TEMPE Fitrianingsih Mozin; Nurhaeni; Ahmad Ridhay
KOVALEN: Jurnal Riset Kimia Vol. 5 No. 3 (2019): Edisi Desember
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (545.164 KB) | DOI: 10.22487/kovalen.2019.v5.i3.11579

Abstract

Research on dissolved protein and crude fiber flour based on coconut pulp and tempe flour has been performed. This study aims to determine the effect of shelf time on levels of dissolved protein and crude fiber flour-based cereal coconut pulp and tempeh flour. Cereals were made from coconut pulp flour and tempe flour as the main ingredients and the ratio of the ingredients was varied to 25:75; 50:50; and 75:25. The ratio of 25:75 produced the highest dissolved protein level of 3.88% and the 75:25 ratio produced the highest crude fiber of 21.96%. Keywords: Coconut pulp flour, tempe flour, dissolved protein, crude fiber
EKSTRAKSI PEKTIN PADA KULIT BUAH KLUWIH (Artocarpus camansi Blanko) PADA BERBAGAI SUHU DAN KONSENTRASI ASAM SITRAT Reski Putriani Demsi; Ruslan Ruslan; Erwin Abdul Rahim; Hardi Ys
KOVALEN: Jurnal Riset Kimia Vol. 5 No. 1 (2019): Edisi April
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (664.678 KB) | DOI: 10.22487/kovalen.2019.v5.i1.11591

Abstract

Telah dilakukan penelitian tentang ekstraksi pektin pada kulit buah kluwih (Artocarpus camansi Blanko) pada berbagai suhu dan konsentrasi asam sitrat. Penelitian ini bertujuan untuk mengetahui konsentrasi dan suhu ekstraksi yang menghasilkan pektin dari kulit buah kluwih (Artocarpus camasni Blanko) dengan rendemen tinggi. Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) dengan empat variasi suhu (90 oC, 100 oC, 110 oC dan 120 oC) dan empat variasi konsentrasi (5%, 7%, 9%, dan 11%), dengan menggunakan metode ekstraksi meserasi. Hasil penelitian ini menunjukan rendeman tertinggi didapatkan pada konsentrasi 9% sebesar 35,65% dan suhu 90 oC  sebesar 40,69%. karakteristik terhadap pektin adalah kadar metoksil 8,12 %, kadar galakturonat 41,88 %.Kata Kunci : Ekstraksi pektin, kadar metoksil, kadar galakturonat
EKSTRAKSI DAN KARAKTERISASI KARAGENAN KASAR RUMPUT LAUT Eucheuma cottoni Asri jaya; Ni Ketut Sumarni; Ahmad Ridhay
KOVALEN: Jurnal Riset Kimia Vol. 5 No. 2 (2019): Edisi Agustus
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (582.07 KB) | DOI: 10.22487/kovalen.2019.v5.i2.11598

Abstract

Research on extraction and characterization of crude carrageenan from seaweed (eucheuma cottoni) has been carried out. The research aims to determine the optimum extraction time and temperature of crude carrageenan extract from seaweed (eucheuma cottoni). Crude Carrageenan was extracted from seaweed (eucheuma cottoni) by dissolving crushed seaweed in 8% KOH with variation of extraction times are 1 hour, 1.5 hours, 2 hours, 2.5 hours and 3 hours, and temperatures are 50, 70, 90, 110 and 130oC. The results were analyzed using a Completely Randomized Design (CRD). The results show that the optimum extraction time in producing the best quality of crude carrageenan is 2 hours at 50oC with percentage is 78.4%, viscosity is 9.155 cP, sulphate content is 3.102% and gel strength is 7 g. Keywords : eucheuma cottoni seaweed, crude carrageenan, characterization
POTENSI ANTIOKSIDAN METABOLIT SEKUNDER FRAKSI ETIL ASETAT DARI KULIT BATANG EBONI (Diospyros celebica Bakh.) Vivi Sasmita; Ahmad Ridhay; Hardi Ys
KOVALEN: Jurnal Riset Kimia Vol. 5 No. 2 (2019): Edisi Agustus
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (676.081 KB) | DOI: 10.22487/kovalen.2019.v5.i2.11642

Abstract

Research on the antioxidant potential of the secondary metabolite compound, ethyl acetate from ebony bark (Diospyros celebica Bakh.) has been conducted. This study aims to characterize and determine the antioxidant activity of secondary metabolites of ethyl acetate fraction from ebony bark. Ethyl acetate extract was fractionated using Liquid Vacum Chromatography (KVC) and Gravity Column Chromatography (KKG). The isolated compounds were characterized using UV-Vis and IR spectrophotometers. Data on maximum absorption of λmax 273 nm from UV-Vis analysis showed the presence of chromophore phenol. IR spectral data showed several specific peaks, among others, at wave number (ʋ) of 3425.58 cm-1 indicating the presence of –OH group, C-H aliphatic bond at ʋ of 2924.09 cm-1 and 2854.65 cm-1, and the peak at ʋ of 1604.77 -1465.90 cm-1 and 3078.39 cm-1 indicated the aromatic group, reinforcing the assumption that the isolates produced were phenolic compounds. IC50 value of 75.47 µg/mL from antioxidant activity testing showed that the isolates obtained were antioxidant compounds with strong antioxidant categories. Keywords: antioxidant, Diospyros, ebony, phenolic, isolation
PEMBUATAN Carboxymethyl cellulose (CMC) DARI PELEPAH NANAS (Ananas cosmosus Merr.) Ripdayana Ripdayana; Ahmad Ridhay; Erwin Abdul Rahim
KOVALEN: Jurnal Riset Kimia Vol. 5 No. 2 (2019): Edisi Agustus
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (419.223 KB) | DOI: 10.22487/kovalen.2019.v5.i2.11654

Abstract

A research about production of Carboxymethyl cellulose (CMC) from pineapple midrib (Ananas cosmosus Merr.) has been conducted. This research aims to determine the best cellulose ratio with sodium monochloro acetate and the best reaction time to the substitution degree of carboxymethyl cellulose from pineapple midrib fibers. This study used a Completely Randomized Design method with two independent variables, i.e. variations in the weight of sodium monochloroacetate (2.5 grams, 3 grams, 3.5 grams, 4 grams, and 4.5 grams) and variations in reaction time (1 hour, 2 hours, 3 hours, 4 hours , and 5 hours), each treatment was done duplo using 20 treatment units. The result of the study showed that the best ratio of sodium monochloroacetate to cellulose which produced carboxymethyl cellulose from pineapple midribs was 2.5: 2.5 with substitution degree value of 1.93 and optimum reaction time which produced carboxymethyl cellulose from pineapple midribs was 1 hour with substitution degree of 2.38. Keywords: Carboxymethyl cellulose, Pineapple midrib
PENGARUH pH PADA PEMANFAATAN CAMPURAN KITOSAN – DITIZON SEBAGAI ADSORBEN ION KALSIUM (Ca2+) Reni Seprianti; Syaiful Bahri; Musafira Musafira
KOVALEN: Jurnal Riset Kimia Vol. 4 No. 2 (2018): Edisi Agustus
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (612.851 KB) | DOI: 10.22487/kovalen.2018.v4.i2.11737

Abstract

Telah dilakukan penelitian tentang pengaruh pH pada pemanfaatan campuran kitosan-ditizon sebagai adsorben ion kalsium (Ca2+). Penelitian ini bertujuan untuk menentukan pH terbaik pada pemanfaatan campuran kitosan-ditizon, kitosan dan ditizon sebagai adsorben ion Ca2+. Penelitian menggunakan rancangan acak lengkap (RAL) dengan 5 variasi pH (4; 5; 6; 7 dan 8). Setiap perlakuan dilakukan sebanyak dua kali sehingga diperoleh 30 unit percobaan. Persentase penyerapan terbaik menggunakan kitosan adalah sebesar 83,21% pada pH 7. Sedangkan bila menggunakan ditizon diperoleh persentase sebesar 89,73% pada pH 6. Penggunaan campuran kitosan-ditizon diperoleh persentase sebesar 93,73% pada pH 7.Kata Kunci: Kitosan, Ditizon, Kalsium, pH, Adsorpsi

Page 10 of 32 | Total Record : 320

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