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All Journal CAKRA KIMIA (Indonesian E-Journal of Applied Chemistry) Jurnal Kimia (Journal of Chemistry) Ecotrophic, Journal of Environmental Science Jurnal Ilmu Pendidikan Indonesia

I Made Siaka

Program Studi Kimia, FMIPA, Universitas Udayana, Bali, Indonesia

Author-ID : 2921974

Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Education Electrical & Electronics Engineering Environmental Science Mathematics Physics

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SPESIASI DAN BIOAVAILABILITS LOGAM BERAT Pb DAN Cu PADA SEDIMEN LAUT DI KAWASAN PANTAI CELUKAN BAWANG KABUPATEN BULELENG-BALI I Made Siaka
CAKRA KIMIA (Indonesian E-Journal of Applied Chemistry) Vol 5 No 2 (2017)
Publisher : Magister Program of Applied Chemistry, Udayana University, Bali-INDONESIA

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ABSTRAK: Karakteristik logam berat pada organisme dan sistem ekologis tidak dapat diterangkan hanya dengan mengetahui kandungan logam total dalam perairan, melainkan dengan penentuan bentuk geokimia atau spesies logam tersebut. Penelitian ini bertujuan untuk menentukan spesiasi dan bioavailabilitas logam berat Pb dan Cu pada sedimen di Kawasan Pantai Celukan Bawang Buleleng, Bali. Analisis logam total, spesiasi dan bioavailabilitas ditentukan dengan menerapkan metode digesti dan ekstraksi bertahap. Kandungan logam Pb dan Cu total dalam sedimen Pantai Celukan Bawang berturut-turut 17,2865-39,4533 mg/kg dan 12,9665-56,1346 mg/kg. Spesies logam Pb paling banyak berada sebagai fraksi resistant (29,75-67,10%), diikuti oleh fraksi tereduksi asam (22,45-31,67%), fraksi EFLE (easily, freely, leachable, exchangeable) dengan kisaran dari tidak terdeteksi (ND) hingga 29,33%, dan yang terendah berasosiasi dengan fraksi teroksidasi organik (ND-14,18%). Spesies logam Cu juga didominasi oleh fraksi resistant (80,52-90,22%), fraksi teroksidasi organik (4,81-17,20%) berada pada urutan ke dua, diikuti oleh fraksi EFLE (0,88-5,83%), dan terrendah adalah fraksi tereduksi asam (ND-1,14%). Bioavailabilitas logam Pb yang sertamerta bioavailabel berkisar ND-29,33% dan yang berpotensi bioavailabel adalah 33,35-42,78%, sedangkan logam Pb yang nonbioavailabel adalah 29,75-67,10%. Berbeda dengan Pb, logam Cu didominasi oleh bentuk non bioavailabel yaitu berkisar 80,52-90,22%, diikuti oleh Cu yang berpotensi bioavailabel, yaitu 5,95-16,61%, dan terkecil adalah Cu yang bersifat sertamerta bioavailabel (0,88-5,83%). ABSTRACT: The characteristics of heavy metals in organisms as well as on ecological systems cannot be explained by the only knowing total metal contents in sediments but also by determining the geochemical forms or the metal species in the sediments. This study aimed to determine the speciation and bioavailability of heavy metals, Pb and Cu in sediments of Celukan Bawang Beach area of Singaraja, Bali. The total metals, speciation and bioavailability analysis were determined by applying a digestion and sequential extraction methods. The total metal contents of Pb and Cu in the sediments were 17.2865-39.4533 mg/kg and 12.9665-56.1346 mg/kg, respectively. The species distribution of the metals in the sediments was as follows: species of Pb was dominated by the form of resistant fraction (29.75-61.10%), followed by reducible acid fraction (22.45-36.25%), EFLE fraction (easily, freely, leachable, exchangeable) ranging from undetectable (ND) to 29.33%, and the lowest percentage fraction was associated with the organic oxidizable phase (ND-14.18%). The resistant fraction was also the most dominant for Cu (80.52-90.22%), but the oxidizable fraction (4.81-17.20%) was found in the second level, followed by the EFLE fraction (0.88-5.83%), and the lowest was associated with reducible fraction (ND-1.14%). The readily bioavailable Pb ranged from 3.62 to 29.33% and potentially bioavailable Pb was 33.35-42.78%, nonbioavailable Pb was 29.75-61.10%. Different from Pb, Cu metal was dominant as non bioavailable metal (80.52-90.22%), but 0.88-5.83% of the Cu was readily bioavailable and 5.95-16.61% was potentially bioavailable.

PEMBUATAN DAN KARAKTERISASI ARANG DARI BATANG TANAMAN GUMITIR (Tagetes erecta) PADA BERBAGAI SUHU DAN WAKTU PIROLISIS I Made Siaka; Ni Putu Diana Febriyanti; Emmy Sahara; I Made Sutha Negara
CAKRA KIMIA (Indonesian E-Journal of Applied Chemistry) Vol 4 No 2 (2016)
Publisher : Magister Program of Applied Chemistry, Udayana University, Bali-INDONESIA

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ABSTRAK: Telah dilakukan penelitian tentang pembuatan dan karakterisasi arang dari batang tanaman gumitir (Tagetes erecta) pada berbagai suhu dan waktu pirolisis. Penelitian ini dilakukan untuk memperoleh suhu dan waktu yang optimum dalam pembuatan arang serta mengetahui karakteristik arang yang dihasilkan pada suhu dan waktu optimumnya. Karakteristik arang mengacu pada SNI 06–3730-1995 dengan melakukan analisis terhadap kadar air, abu, volatile, dan karbon serta daya serapnya terhadap odine dan metilen biru. Suhu optimum pirolisis pembuatan arang adalah 300oC dengan karakteristik terbaik berupa rendemen, kadar air, volatile, abu, dan karbon berturut-turut sebesar 40,27 ±; 4,00 ± 0,00; 6,58 ± 0,07; 4,34 ± 1,22; dan 85,06%, serta daya serapnya terhadap iodin dan metilen biru sebesar 631,0935 ± 0,00 dan 131,34 ± 1,7 mg/g arang. Waktu pirolisis optimum adalah 90 menit dengan karakterisitik paling baik, yakni rendemen, kadar air, volatile, abu, dan karbon berturut-turut sebesar 42,30 ± 8,7; 2,00 ± 0,00; 2,87 ± 0,07; 9,68 ± 1,17; dan 85,44% serta daya serapnya terhadap iodin dan metilen biru sebesar 647,4642 ± 0,00 dan 136,20 ± 1,28 mg/g arang. Arang yang dihasilkan dari pirolisis pada suhu dan waktu optimum memiliki karakteristik yang sesuai dengan SNI 06-3730-1995 memiliki gugus fungsi O-H dan berupa karbon alifatik. ABSTRACT: This paper discusses the manufacture and characterization of carbon made from the stems of marigold (Tagetes erecta) at various temperatures and times of pyrolysis. This research aimed to obtain the optimum temperature and time of pyrolising in producing carbon, as well asto recognize the characteristics of the carbon produced. Characteristics of the carbon quality followed the Indonesian National Standard (SNI) 06-3730-1995 by analyzing the contents of water, volatile substances, ash, and carbon, as well as, the ability of the carbon in absorption capacities of iodine and methylene blue. The optimum pyrolysis temperature in producing carbon was 300oC with the best characteristics including result rendement, contents of water, volatile substances, ash, and carbon were 40,27 ± ; 4,00 ± 0,00; 6,58 ± 0,07; 4,34 ± 1,22, and 85,06%b/b respectively, as well as, the absorption capacities of iodine and methylene blue were 631,0935 ± 0,00 mg/g and 131,34 ± 1,7 mg/g respectively. The optimum time of pyrolysis in producing carbon was 90 minutes with the best characteristics including result rendement, contents of water, volatile substances, ash, and carbon were 42,30 ± 8,7; 2,00 ± 0,00; 2,87 ± 0,07; 9,68 ± 1,17; and 85,44% b/brespectively, as well as, the absorption capacities of iodine and methylene blue were 647,4642 ± 0,00and the 136,20 ± 1,28 mg/g respectively. The carbon produced from the optimum of pyrolysis temperature and time had characteristic in accordance with the SNI 06-3730-1995, it contained O-H functional group and it is in aliphatic structure.

KANDUNGAN LOGAM Pb DAN Cu DALAM TANAMAN BAYAM DAN BIOAVAILABILITASNYA DALAM TANAH PERTANIAN DENGAN PEMBERIAN PUPUK NPK Ni Made Dwita Prasetyawati; I Made Siaka; Wiwik Susanah Rita
CAKRA KIMIA (Indonesian E-Journal of Applied Chemistry) Vol 9 No 2 (2021): Cakra Kimia (Indonesian E-Journal of Applied Chemistry)
Publisher : Graduate Program of Applied Chemistry, Udayana University, Bali-INDONESIA

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ABSTRAK: Pencemaran logam berat pada tanah pertanian akibat penggunaan pupuk anorganik seperti pupuk NPK dapat berdampak pada kandungan logam berat dalam tanaman hasil pertanian. Penelitian ini bertujuan untuk mengetahui kandungan logam Pb dan Cu dalam tanaman bayam dan tingkat bioavailabilitas logam tersebut dalam tanah pertanian dengan pemberian pupuk NPK. Metode yang diterapkan pada penelitian ini adalah digesti basah untuk menetapkan logam berat total dan ekstraksi bertahap untuk spesiasi dan menentukan bioavailabilitas logam berat tersebut. Kuantifikasi Pb dan Cu dilakukan dengan menggunakan alat Atomic Absorption Spectrofotometer (AAS) dengan metode kurva kalibrasi dan adisi standar. Pada penelitian ini ditemukan bahwa kandungan logam Pb dan Cu pada tanaman bayam mengalami peningkatan berturut-turut dari 59,7617 dan 14,0713 mg/kg untuk tanaman tanpa pupuk NPK menjadi 80,2736 dan 21,5550 mg/kg pada tanaman dengan pemberian pupuk NPK. Penggunaan pupuk NPK pada tanah pertanian juga dapat meningkatkan logam yang bioavailable sebesar 0,83% untuk Pb dan 2,70% untuk Cu. Dengan demikian, pemberian pupuk NPK pada tanah pertanian dapat menyebabkan peningkatan bioavailabilitas Pb dan Cu dalam tanah dan kandungannya dalam tanaman bayam. ABSTRACT: Heavy metal contamination in agricultural soil due to the use of inorganic fertilizers such as NPK fertilizer could have an impact on heavy metal content in agricultural products. This study aimed to determine the metal content of Pb and Cu in spinach and the level of bioavailability of these metals in agricultural soils treated with NPK fertilizer. The methods applied in this study were wet digestion and sequential extraction for determining the total metals of Pb and Cu, as well as the bioavailability of these metals. The measurement and quantification of the metals were performed by the use of an Atomic Absorption Spectrophotometer (AAS) with applying calibration curve and standard addition techniques. In this study, it was found that the metal contents of Pb and Cu in spinach plants increased from 59,7617 and 14,0713 mg/kg, respectively for plants without NPK fertilizer to 80,2736 and 21,5550 mg/kg in plants with NPK fertilizer application. The use of NPK fertilizer on agricultural soils could also increase the bioavailable metal by 0,83% for Pb and 2,70% for Cu. Therefore, the application of NPK fertilizer to the agricultural soils could increase the bioavailability of Pb and Cu in the soil and their content in the spinach plants.

VALIDASI METODE ANALISIS BAHAN KIMIA OBAT PARASETAMOL DAN FENILBUTASON PADA PRODUK OBAT TRADISIONAL DENGAN HPTLC-SPEKTROFOTODENSITOMETRI I Putu Ngurah Apri Susilawan; I Made Siaka; I Made Oka Adi Parwata
CAKRA KIMIA (Indonesian E-Journal of Applied Chemistry) Vol 7 No 1 (2019): Volume 7, Nomor 1, 2019
Publisher : Magister Program of Applied Chemistry, Udayana University, Bali-INDONESIA

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Tujuan dari penelitian ini adalah untuk melakukan validasi metode analisis secara simultan bahan kimia obat parasetamol dan fenilbutason yang terdapat pada produk obat tradisional dengan menggunakan high performance thin layer chromatography (HPTLC)-spektrofotodensitometri. Validasi ini dilakukan dengan menentukan spesifitas, linieritas, presisi dan akurasi pengukuran. Spesifitas ditentukan dengan membandingkan profil analit dalam larutan baku, sampel dan spike. Selanjutnya, noda yang telah terpisah secara kromatografi lapis tipis discan menggunakan spektrofotodensitometer. Linieritas, batas deteksi (limit of detection, LoD), batas kuantitasi (limit of quantitation, LoQ) ditentukan dengan konsentrasi 25 – 700 ng/spot untuk parasetamol sementara 75 – 2100 ng/spot untuk fenilbutason. Presisi dan akurasi dilakukan dengan menambahkan baku campuran ke dalam larutan uji menggunakan satu konsentrasi dengan 6 kali pengulangan. Hasil validasi metode analisis parasetamol dan fenilbutason pada produk obat tradisional dengan HPTLC-Spektrofotodensitometri menunjukkan metode ini valid dengan spesifisitas, linieritas, batas deteksi, batas kuantitasi, presisi dan akurasi yang memenuhi persyaratan. The aim of this study was to validate the simultaneous analysis method of paracetamol and phenylbutazone contained in traditional drugs using high performance thin layer chromatography(HPTLC)-Spectrophotodensitometry. The validation was carried out by determination of the specificity, linierity, limit of detection (LoD) and limit of quantitation (LoQ), precision and accuracy. The specificity was determined by comparing the profile of analytes in standart solution, sample solutions, and spike. Further, the seperated spots on thin layer chromatograms were scanned using spectrophotodensitometry. The liniarity, LoD and LoQ were determined using 25 – 700 ng/spot of paracetamol concentrations while 75 – 2100 ng/spot of phenylbutazone concentrations. The precision and accuracy were determined by adding a centain concentration of the chemicals into sample solutions with 6 time of repetitions. The results showed that the simultaneous analysis method of paracetamol and phenylbutazone contained in traditional drug products with HPTLC- Spectrodensitometry is valid since the specificity, linearity, LoD and LoQ, and precision and accuracy of the analysis meet the requirements.

PEMANFAATAN ARANG AKTIF DARI BATANG TANAMAN GUMITIR (Tagetes erecta) SEBAGAI ADSORBEN LOGAM BERAT Pb(II) DAN Cd(II) DENGAN AKTIVATOR NaOH I Made Siaka; Putu Dona Oka Putri; I Wayan Suarsa
CAKRA KIMIA (Indonesian E-Journal of Applied Chemistry) Vol 5 No 2 (2017)
Publisher : Magister Program of Applied Chemistry, Udayana University, Bali-INDONESIA

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ABSTRAK : Limbah batang gumitir mengandung selulosa cukup tinggi, sehingga dapat dimanfaatkan sebagai bahan dasar pembuatan arang. Arang yang dihasilkan tersebut dapat digunakan sebagai adsorben. Kualitas adsorben dapat ditingkatkan melalui proses aktivasi. Penelitian ini bertujuan untuk mengetahui perbedaan karakteristik antara arang tanpa pemanasan dengan yang dipanaskan sebelum diaktivasi dengan NaOH dan menentukan gugus fungsi, situs aktif, serta mengetahui waktu kontak dan pH optimum dalam adsorpsi Pb(II) dan Cd(II). Metode metilen biru digunakan untuk analisis luas permukaan, spektroskopi FTIR dan AAS digunakan untuk analisis gugus fungsi dan konsentrasi logam berat. Arang tanpa pemanasan sebelum aktivasi (KA1) memiliki karakteristik (kadar air, zat mudah menguap, abu total, dan karbon terikat) terbaik dan memenuhi baku mutu sesuai dengan standar SNI 06-3730-1995. Arang aktif KA1 juga memiliki luas permukaan dan bilangan iodin paling tinggi yaitu 1816,16 m2/g dan 1227,21 mg/g. Hasil identifikasi FTIR menunjukkan bahwa arang aktif KA1 mengandung gugus fungsi OH, COOH, C=O, dan CH3 dengan jumlah situs aktifnya sebesar 17,14x1020 molekul/g. Waktu dan pH optimum adsorpsi terhadap logam berat adalah 120 menit pada pH 5 untuk Pb(II) dan 60 menit pada pH 7 untuk Cd(II). Kata kunci :Gumitir, arang aktif, adsorben, logam berat ABSTRACT : Marigold stem wastes contain high enough cellulose, so it can be utilized as the basic material of making active carbon. The carbon produced can be used as an adsorbent. The quality of the adsorbent can be improved through the activation process. The aim of this study was to determine the characteristic differences between carbon without heating and heated before being activated with NaOH, as well as, to determine functional group, active site, and the optimum of contact time and pH in adsorption of Pb and Cd. The methylene blue method was used for analysing surface area, spectroscopy of FTIR and AAS was used for analysing functional groups and heavy metal concentrations. The carbon without preheating of activation (KA1) had the best characteristics (including, moisture content, volatile matter, total ash, and carbon bonded) and meets the quality standard in accordance with SNI 06-3730-1995 standard. The active carbon of KA1 also had the highest surface area and iodine number of 1816,16 m2/g and 1227,21 mg/g, respectively. Spectra of FTIR indicated that the active carbon of KA1 contained functional groups of OH, COOH, C=O, and CH3 with the number of active sites of 17.14x1020 molecules/g. The optimum time and pH of adsorption to the heavy metals was 120 minutes at pH 5 for Pb(II) and 60 minutes at pH 7 for Cd(II).

KANDUNGAN LOGAM Cu DAN Zn DALAM TANAH DAN PUPUK SERTA BIOAVAILABILITASNYA DALAM TANAH PERTANIAN DI DAERAH BEDUGUL I Putu Meda Parmiko; I Made Siaka; Putu Suarya
Jurnal Kimia (Journal of Chemistry) Vol. 8, No. 1 Januari 2014
Publisher : Program Studi Kimia, FMIPA, Universitas Udayana (Program of Study in Chemistry, Faculty of Mathematics and Natural Sciences, Udayana University), Bali, Indonesia

This research was carried out to determine the total metal concentrations of Cu and Zn in soil and inorganic fertilizer, as well as their bioavailabilities in the soil agricultural of Bedugul area. This study aims to determine the total metals and bioavailability of Cu and Zn in agricultural land in Bedugul. Analysis of the heavy metal contents of Cu and Zn in soil samples was started with the process of digestion the samples in a mixture of HNO3 and HCl (3:1) with an ultrasonic bath for 45 minutes at 60°C, followed by heating on a hotplate for 45 minutes at 140oC. Total metal concentrations of Cu and Zn in solutions resulted from digestion, extraction, and fertilizer samples were analyzed using Atomic Absorption Spectroscopy (AAS). The concentrations of Cu and Zn were calculated using a standard calibration method. Bioavailabilities of Cu and Zn were determined by comparing the results of a single extraction with HCl and EDTA to the total metal concentrations. The results obtained from 3 types of soil samples which were analyzed for determination of total Cu and Zn concentrations, showed that the highest Cu content was found in the land planted with tomatoes vegetables, 49.6437 mg/kg, while the highest total Zn contained in the land of carrot, i.e. 137,1457 mg/kg. TSP fertilizer contained Cu and Zn 29.3143 mg/kg and 186,2156 mg/kg respectively, whereas NPK fertilizer contained 16.9527 mg/kg of Cu and 168,3549 mg/kg of Zn. The percentage of Cu and Zn extracted by EDTA was the highest in the land of cabbage, followed by tomatoes land, and lastly carrots land, while Cu and Zn extracted by HCl in order of tomatoes land > cabbage land > carrot land.

KANDUNGAN LOGAM Pb DAN Cu DALAM BUAH STROBERI SERTA SPESIASI DAN BIOAVAILABILITASNYA DALAM TANAH TEMPAT TUMBUH STROBERI DI DAERAH BEDUGUL Putu Desitha Pratiti Kameswari Wisnawa; I Made Siaka; Anak Agung Bawa Putra
Jurnal Kimia (Journal of Chemistry) Vol. 10, No. 1 Januari 2016
Publisher : Program Studi Kimia, FMIPA, Universitas Udayana (Program of Study in Chemistry, Faculty of Mathematics and Natural Sciences, Udayana University), Bali, Indonesia

A study about speciation and bioavailability of heavy metals Pb and Cu in strawberry fruits and in the strawberry soils in Bedugul areas has been carried out. This study was aimed to determine the concentrations of Pb and Cu in the fruits and the soils, as well as speciation and bioavailabilities of both metals in the soils. Wet digestion method with reverse aqua regia was applied for determining the total metals, while sequential extraction method was performed to fractionate the metals bound to the various phases of the soils. The measurement of both metals was carried out by the use of AAS (Shimadzu, AA-7000). The total Pb and Cu contents in the fruits were 2.5903-9.2019 and 0.8744-1.1567 mg/kg, respectively while in the soils were 20,7912 -39.0144 and 39.3154-42,6620 mg/kg, respectively. In the speciation of both metals in soils, it was found that Pb and Cu associated with EFLE phases were 3.4944 and 1.2454 mg/kg, respectively, while those bound to Fe/Mn Oxides phases were 5.6652 and 3.1860 mg/kg, respectively. The Pb and Cu bound to organic/sulfide phases were 7.9553 and 5.5913 mg/kg, respectively and those bound to resistant phases were 13.4471 and 31.0796 mg/kg, respectively. Bioavailabilities of Pb and Cu in the soils were dominated by non bioavailable fractions, i.e. 43.69 and 76.11%, respectively, followed by the fractions of potentially bioavailable, and the lowest fractions were found as readily bioavailable.

BIOAVAILABILITAS LOGAM Fe DAN Ca DALAM TANAH PERTANIAN SERTA KANDUNGAN LOGAMNYA DALAM TANAMAN BAYAM DENGAN PEMBERIAN PUPUK KANDANG SAPI I M. Siaka; P. A. Rupadewi; P. Suarya
Jurnal Kimia (Journal of Chemistry) Vol. 15, No.2, Juli 2021
Publisher : Program Studi Kimia, FMIPA, Universitas Udayana (Program of Study in Chemistry, Faculty of Mathematics and Natural Sciences, Udayana University), Bali, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/JCHEM.2021.v15.i02.p08

Penggunaan pupuk kandang sapi pada tanah pertanian dapat memperbaiki kondisi tanah tersebut, terutama meningkatkan kesuburannya. Disamping sebagai penyubur tanah, pupuk kandang tersebut dapat sebagai pengikat logam berat dan menurunkan bioavailabilitas logam berat. Penelitian ini bertujuan untuk mengetahui pengaruh pupuk kandang terhadap bioavailabilitas Fe dan Ca serta kandungannya dalam tanaman bayam. Metode ekstraksi bertahap dan digesti basah digunakan untuk mengekstraksi logam tersebut dari tanah dan tanaman bayam. Instrumen AAS (Atomic Absorption Spectrophotometer) digunakan untuk mengukur konsentrasi logam yang terekstraksi tersebut. Pada penelitian ini, diperoleh bahwa pola penyebaran spesies logam Fe dan Ca sebelum penanaman dan saat panen sama. Logam Fe didominasi oleh spesies resistant sedangkan logam Ca didominasi oleh spesies bioavailable. Kandungan logam dalam tanaman bayam yang tanpa dan penambahan pupuk kandang sapi berturut turut 2.844,627 ± 28,139 mg/kg dan 2.469,281± 16,779 mg/kg untuk Fe sedangkan, 31.657,305 ± 699,147 mg/kg dan 41.515,559 ± 754,808 mg/kg untuk Ca. Penambahan pupuk kandang sapi pada tanah pertanian mampu meningkatkan kandungan logam Fe dan Ca dalam tanaman bayam, dan juga meningkatkan logam Fe dan Ca yang bioavailable. Kata Kunci: bioavailabilitas, Ca, Fe, logam, pupuk kandang sapi. The use of cow manure on agricultural soil can improve the condition of the soil, especially increasing its fertility. Apart from being a soil fertilizer, manure can act as a heavy metals binder and reduce their bioavailabilities. This study aimed to determine the effect of manure on the bioavailability of Fe and Ca and their contents in spinach plants. The sequential extraction and wet digestion methods were used to extract the metals from the soil and spinach plants. An AAS (Atomic Absorption Spectrophotometer) instrument was applied to measure the concentration of the extracted metals. In this study, it was found that the distribution patterns of Fe and Ca metals species before planting and at harvesting were the same. Fe metal was dominated by resistant species, while Ca metal was dominated by bioavailable species. The content of those metals in spinach plants without and the addition of cow manure were 2,844.627 ± 28.139 mg/kg and 2,469.281 ± 16.779 mg/kg for Fe while, 31,657.305 ± 699.147 mg/kg and 41,515.559 ± 754.808 mg/kg for Ca, respectively. The addition of cow manure to the agricultural soils could increase the contents of Fe and Ca metals in spinach plants, and also increased the bioavailable of those metals Keywords: bioavailability, Ca, cow manure, Fe, metals

OPTIMASI KONDISI REAKSI HIDROGENASI METIL ESTER DALAM PENINGKATAN AKTIVITAS SURFAKTAN BERBASIS MINYAK JELANTAH I Made Siaka; Yuky Astary Hermanto; Ida Ayu Gede Widihati
Jurnal Kimia (Journal of Chemistry) Vol. 6, No. 2 Juli 2012
Publisher : Program Studi Kimia, FMIPA, Universitas Udayana (Program of Study in Chemistry, Faculty of Mathematics and Natural Sciences, Udayana University), Bali, Indonesia

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This paper discusses the optimization of reaction condition of methyl ester hydrogenation in the process of making surfactant from used cooking oil. The synthesis of surfactant involved the esterification reaction of used cooking oil, base-catalyzed transesterification, and hydrogenation reaction of methyl ester (methyl laurate), followed by the sulfatation using sulfuric acid and neutralization using sodium hydroxide. The hydrogenation reaction was performed in the presence of Zn, as the catalyst, at various temperatures (200oC, 220oC, and 240oC) and reaction times (1, 1½, and 2 hours). The surfactant activities testing was conducted through surface tension measurement using the drop weight method and emulsion stability duration testing to find out the optimum condition of each variable.The result indicated that the temperature of the hydrogenation reaction had no effect to the activities of surfactant produced, but the time reaction had. The surfactant activities testing showed that the reaction time of the hydrogenation reaction needed to give the smallest surface tension of water (32 dyne/cm average) was 1½ to 2 hours. More over, the reaction times ware also able to give the longest emulsion stability of 450.6 seconds for cooking oil-water emulsion and 454.6 seconds for used cooking oil-water emulsion. Therefore, the reaction times of 1½-2 hours could be categorized as the optimum reaction time.

SPESIASI DAN BIOAVAILABILITAS LOGAM BERAT TIMBAL (Pb) DAN TEMBAGA (Cu) DALAM SEDIMEN SUNGAI TUKAD BADUNG Nanik Wijayanti; I Made Siaka; Ida Ayu Gede Widihati
Jurnal Kimia (Journal of Chemistry) Vol. 9, No. 2 Juli 2015
Publisher : Program Studi Kimia, FMIPA, Universitas Udayana (Program of Study in Chemistry, Faculty of Mathematics and Natural Sciences, Udayana University), Bali, Indonesia

A study of speciation and bioavailability of heavy metals, Pb and Cu in sediments of Tukad Badung river with sequential extraction method has been carried out. This study aimed to determine the levels of bioavailability of both Pb and Cu heavy metals. The determination of total heavy metal contents was performed by digestion technique with the use of a mixture of HNO3 and HCl (3:1) in ultrasonic bath for 45 minutes at 60oC followed by heating on a hotplate for 45 minutes at 140oC. The mesurement of total heavy metals and heavy metal species was established with the use of Atomic Absorption Spectrophotometer (AAS) with calibration curve method. Concentration of total Pb and Cu in the sediments of Tukad Badung river ranged from 4.2669 to 27.9171 mg/kg and 20.5240 to 69.3782 mg/kg respectively. The speciation of Pb obtained in carbonate fraction of the EFLE (easly, freely, leachable and exchangable) fractions ranged from 1.5952-11.6315 mg/kg, in Fe/Mn oxide fraction ranged from 0.4001 to 6.7680 mg/kg, in organic/sulfide fraction ranged from 0.8759 to 13.6600 mg/kg, and in the silicate fraction (resistant) ranged between Nd (not detected) to 4.6598 mg/kg. The level of bioavailability Pb in sediments ranged from 9 to70% while the non-bioavailability levels ranged from 0 to 30%. Carbonate fraction (EFLE) of Cu ranged between Nd (not detected) to 6.3527 mg/kg. The fraction of Fe/Mn oxides ranged from 0.7331 to 9.9033 mg/kg, organic sulfide fraction ranged from 8.1790 to 41.5756 mg/kg, and the silicate fraction was foud vary between 7.5138 and 21.0200 mg/kg. The level of Cu bioavailability in sediments ranged from Nd (not detectable) to 18%, while the level of non bioavailability ranged from 15 to 44%.

Co-Authors A. A. Bawa Putra Dwinda Safitri Emmy Sahara Gusti Agung Putu Merta Dharmayoga H. Nurcahyani I B. P. Manuaba I M, Sukadana I Made Bakta I Made Jawi I Made Oka Adi Parwata I Made Sutha Negara I Putu Bagus Mahendra I Putu Meda Parmiko I Putu Ngurah Apri Susilawan I W BUDIARSA SUYASA I Wayan Putu Sutirta Yasa I Wayan Suarsa I. A. Gede Widihati I. G. Eka Saputra Jaya Iryanti Eka Suprihatin K. A. P. D. Putra K. G. D. Putra K. Wardani Karna Wijaya Luh Putri Kriswidatari N. K.D.S. Widari N. W. B. S. Devi Nanik Wijayanti Ni Desak Komang Ayu Hartani Ni G. A. M. Dwi Adhi Suastuti Ni Made Dwita Prasetyawati Ni Putu Diana Febriyanti Ni Putu Diantariani Oka Ratnayani P. A. Rupadewi P. Suarya Putra Manuaba, I. B Putu Desitha Pratiti Kameswari Wisnawa Putu Dona Oka Putri Putu Suarya regi mahendra Tri Rahayu WIWIK SUSANAH RITA Yuky Astary Hermanto

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