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JURNAL SAINS
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Articles 39 Documents
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Sonai isolate as potential bacteria for fiber sago hydrolysis to monosaccharide Prima Endang Susilowati; Sarni Marwanti
SAINS : Jurnal Kimia & Pendidikan Kimia Vol 1, No 1 (2012)
Publisher : PKimia FKIP Universitas Halu Oleo

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Abstract

Cellulolytic and xylanolytic enzymes play an important role in natural biodegradation processes in which plant lignocellulosic materials are efficiently degraded by microorganisms. Large amount of fiber sago wastes from renewable sago residues are rich sources of cellulose, hemicellulose and lignin. Hemicelluloses wastes bioavailability conversion presupposes the changing of the macromolecular structure by using enzymes and to result free simple compounds (mono-disaccharide). The purposes of this study are isolation bacteria from water collected in the Sonai hot-springs and use bacteria for bioconversion of fiber sago. Bacteria were isolated on cellulose dan xylan agar medium and screened by the cellulolysis dan xylan method. Determining the reducing sugars liberated from cellulose and xylan using dinitrosalicylic acid (DNS) reagent.  The results are identification of bacteria from Sonai hot springs showed 13 isolates potential xylanolitic and cellulose.  Isolate IIIB-3 showed maximum xylanase and cellulose production. The isolate can hydrolysis fiber sago at condition optimum fermentation 500C, pH 6, shaker rate 175 rpm, 5% substrate, and 18 hours incubation.
learning subject and supporting through direct instruction model to increase students’ achievement in Physical Chemistry I classL Aceng Haetami
SAINS : Jurnal Kimia & Pendidikan Kimia Vol 1, No 1 (2012)
Publisher : PKimia FKIP Universitas Halu Oleo

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Abstract

The aim of this research is to know how materials coherent learning subject and supporting throughDirect Intruction Model (DIM) can increase students achievement in learning Physical Chemistry I.The metode used in this research is classroom action research using Direct Intruction Model (DIM).The results show that materials coherent learning subject and supporting through DIM can increase: (a)achievement in learning Physical Chemistry I increasing for every cycle: cycle I (average = 56,36) ,cycle II (average = 56,72), and cycle III (average = 61,36) ; (b) number of students complete learned(getted score ≥ 66) : cycle I (44,44 %) , cycle II (52,78 %), and cycle III (63,89 %) even complete classis not reached.
Analysis of essential mathematics concepts for fluently to study of chemistry Fahyuddin Fahyuddin
SAINS : Jurnal Kimia & Pendidikan Kimia Vol 1, No 1 (2012)
Publisher : PKimia FKIP Universitas Halu Oleo

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Abstract

This study aimed to identification and analysis of basic mathematical concepts that are widely used in studing chemistry, and so as a main required for the good understanding of quantitative chemistry. Chemistry concepts that can be represented in mathematical models, graphs, and tables of numerics were explored from several chemistry textbooks, that it is as the reference classes in college in the first and second years. The structures and properties of mathematical concepts that its have the same with to mathematical models that became the representation of chemistry concepts defined as the mathematical concepts needed to study chemistry. The results of the analysis of structural similarity between mathematics and chemistry concepts suggested that a number of essential mathematics concepts that support the understanding of chemistry, including: numbers, arithmetic operations (arithmetic), approximation, ratios, proportions, scientific notation, computation notation, logarithmic, exponential, laws of algebra, functions, graphs, system of equations, differential, and integral. The concept of algebra is the most widely used in learning or problem solving in quantitative chemistry. Chemistry students who have lack of undesrstanding of such theses mathematics concept will have difficulty to solving quantitative chemistry problems or studing chemistry. So that, those of essential mathematics concepts should became literacy of mathematics for students of chemistry. Each of concept of essential mathematics can be used in studying several quantitative chemical concepts. Conversely, some quantitative chemical concepts, such as a buffer solution, kinetics, and thermodynamics requires an understanding of a number of essential mathematical concepts.
Pengaruh Penyemprotan Ekstrak Daun Teh Hijau (Camellia sinensis) Terhadap Stabilitas Dimensi Hasil Cetakan Alginat Septa S. Arini; Indah Saraswati; Astika W. Utomo; Oedijani Santoso
SAINS : Jurnal Kimia & Pendidikan Kimia Vol 10, No 1 (2021): EDISI JUNI 2021
Publisher : PKimia FKIP Universitas Halu Oleo

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Abstract

Alginate has imbibition and sineresion properties. Green tea leaves (Camellia Sinensis) contain phenols which are antibacterial and can minimize changes in dimensional stability. This study aims to analyze the effect of 50% green tea leaf extract as a disinfectant on the dimensional stability of the alginate impression sprayed at different times. Post-test only experimental laboratory research. Dimensional stability is measured by the difference between the anteroposterior (A'-B ') and mediolateral (B'-C') die stone and the master die using digital calipers with an accuracy of 0.01 mm. Data on anteroposterior and mediolateral dimensions were analyzed using the One Way Anova test, followed by the Post Hoc LSD test. The results of the One Way Anova test for anteroposterior and mediolateral dimensions were significant (p = 0.00). The results of the Post Hoc LSD test for the anteroposterior dimension were significant, while for the mediolateral dimension, the results were not significant between the K1 and K2 and P1 groups. The smallest dimensional stability changes in the anteroposterior and mediolateral dimensions occurs in the alginateimpression group sprayed with green tea leaf extract stored for 5 and 10 minutes.
Karakterisasi Geopolimer Semen Berbasis Terak Feronikel dari Antam Pomala dengan FTIR Saddam Husin
SAINS : Jurnal Kimia & Pendidikan Kimia Vol 10, No 1 (2021): EDISI JUNI 2021
Publisher : PKimia FKIP Universitas Halu Oleo

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Abstract

Portland cement production produces 1 tonne of CO for every tonne of cement produced. The increasing release of CO2 can cause an increase in the greenhouse effect and environmental damage. Slag, which is a residual material from the smelting of ferrous and non-ferrous minerals in a blast furnace, has the main composition of silica (SiO) and lime (CaO) which can be used as a substitute for conventional cement as a cement geopolymer. Geopolymers are obtained through geopolymerization reactions. Geopolymerization involves a chemical reaction between a solid aluminosilicate material and an alkaline solution. In this study, geopolymer cement was obtained by reacting a mixture of ferronickel slag (Fe-Ni) with various particle sizes of 106, 90, 75 and 63 m mixed with an alkaline solution (NaOH 7 molar and Na2SiO3 with a ratio of Na2SiO3/NaOH = 2.5). The mixture was molded into cubes with dimensions of 50x50x50 mm3 and allowed to stand for 2 days and then in the oven (80oC, 24 hours). Furthermore, the characterization and testing of the physicalmechanical properties of the geopolymer was carried out. Based on the results of the study the content of oxide compounds in the form of SiO (43.07%), and Al2O3 (9.13%). The FTIR spectra show SiO4 bending vibrations (500-620 cm) and SiO4 stretching (830-1010 cm) where an increase in absorbance at a wavelength of 868 cm indicates the formation of geopolymers, the formation of a new absorption peak of 1419 cm in the form of CO3 2- asymmetry.
Potensi Imunomodulator Alami Ekstrak Daun Kelor (Moringa oleifera Lam.) dan Daun Salam (Eugenia polyantha Wight) dalam Meningkatkan Sistem Imunitas Tubuh W.O. Mulyana; M. Agustinus W.; Fatahu Fatahu; A.L. Nugrawati M.; Y. Tewa
SAINS : Jurnal Kimia & Pendidikan Kimia Vol 10, No 1 (2021): EDISI JUNI 2021
Publisher : PKimia FKIP Universitas Halu Oleo

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Abstract

Research on the natural immunomodulatory potential of Moringa leaf extract (Moringa oleifera lam.) And Salam leaf (eugenia polyantha wight) in enhancing the immune system has been carried out. This study aims to determine the antioxidant activity that has the potential as a natural immunomodulator that can increase the body's immune system. Stages in this study is the extraction of the sample leaf maceration using ethanol for 3 x 24 hours and then extract the results of maceration concentrated by rotary evaporator. Testing of sample extracts includes phytochemical tests to determine the secondary methobite content contained in the sample extract and antioxidant activity testing using the DPPH free radical inhibition method. Results of phytochemical analysis showed extracts of moringa leaves and salam leaves contain alkaloids, flavonoids, saponins, polyphenols and tannins are strong.Meanwhile, the steroid and triterpenoid tests showed the opposite result. The results of the analysis of the antioxidant activity as measured by IC50 value indicates that the optimal inhibitory concentration of ethanol extract of moringa leaves, salam leaves and extracts a combination of both, respectively, are 95.08 ppm, 41.71 ppm and 43.67 ppm. As for vitamin C as comparison had IC50 value of 52.16 ppm. The relationship between antioxidant activity and the immune system (body immunity) is seen in maintaining the balance and availability of antioxidant compounds present in the body in protecting the body from guilty foreign substances from outside the body
Karakterisasi Geopolimer Semen Berbasis Terak Feronikel dari ANTAM Halmahera Timur dengan FTIR Yulianti Malik
SAINS : Jurnal Kimia & Pendidikan Kimia Vol 10, No 1 (2021): EDISI JUNI 2021
Publisher : PKimia FKIP Universitas Halu Oleo

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Abstract

Slag is a solid waste that still contains several mineral elements such as Si and Al so that it can be used as an ingredient in the manufacture of cement known as geopolymer cement through the geopolymerization process. In the geopolymerization process, several parameters are used to improve the physical and mechanical properties of the geopolymer, one of which is temperature and curing time. In this research, the synthesis of geopolymer based on ferronickel slag and (NaOH 7 M + Na2SiO3 1.3 M) as a solvent has been carried out. The synthesis of geopolymer based on ferronickel slag has been successfully carried out through a geopolymerization process where the FTIR analysis shows that symmetrical (Si-O-Si) and (Al-O-Si) strain absorptions appear at wave numbers 500-700cm-1 and asymmetrical strain (Si-O-Si) -Si) at wave number 750-1000 cm -1
Penentuan Hydroquinon menggunakan Metode The Reverse Phase-High Performance Liquid Chromatography (RP-HPLC) R. K. Sanjaya; A. Restyana; N. Ismillayli; D. Hermanto
SAINS : Jurnal Kimia & Pendidikan Kimia Vol 10, No 1 (2021): EDISI JUNI 2021
Publisher : PKimia FKIP Universitas Halu Oleo

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Abstract

The reverse phase high performance liquid chromatography (HPLC) method was used to determine the hydroquinone content. Determination was carried out under the optimum conditions of the RP-HPLC method including methanol as the mobile phase, flow rate 1 mL/min, running time 5 minutes, injection volume 20 L, UV detector, wavelength 290 nm with internal standard hydroquinone. The measurement results show that the reversed-phase HPLC method is a sensitive and high-precision method with a detection limit below 0.5% w/w. The results of determining the hydroquinone content in the preparation sample in the form of cream using the reverse phase HPLC method in sample A and sample B were 2.26% and 2.32%, respectively. Statistical analysis based on the RPD value of sample A and sample B has a value of less than 10%. Therefore, the reverse phase HPLC method is expected to be an accurate method for routine analysis of hydroquinone in cosmetic samples and pharmaceutical products.
Identifikasi Resiko pada Proses Pengujian Bahan Kimia di Laboratorium PT. ABC Balikpapan K. Rusba; Maslina Maslina; S. Purwanti; Hardiyono Hardiyono; J.E.A. Liku; I. Siboro; L.M. Zainul; S. Hartono
SAINS : Jurnal Kimia & Pendidikan Kimia Vol 10, No 1 (2021): EDISI JUNI 2021
Publisher : PKimia FKIP Universitas Halu Oleo

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Abstract

Chemical laboratories in the company are included in the work area that has a hazard and high risk. Therefore, effective safety management is required to control the risk of. Research on initial risk assessment and end risk and effectiveness of risk control in the activities of practicum finalizing bottle test in laboratory of PT. ABC Balikpapan. Assess the level of risk on activities in the chemical laboratory of PT. ABC. Hazard identification method finalizing bottle test using task risk analysis, while for risk analysis is done using semi-quantitative risk analysis method with risk assessment criteria (consequence, likelihood) and risk control is also made and then analyzed the result. The results of the average major risk of the end of the initial risk indicating that risk control in the activities of practicum chemical bottle Test finalizing in the laboratory of PT. ABC is good, but there are some high risk value of the end, such as the risks associated with the incidence of fire and explosion. So it is necessary to improve the laboratory safety management through the risk analysis program at every practice activity in the laboratory of PT. ABC.
Sintetis Senyawa Caffeic Acid Phenethyl Ester dan Karakterisasinya Menggunakan 1H NMR La Ode Kadidae
SAINS : Jurnal Kimia & Pendidikan Kimia Vol 10, No 2 (2021): EDISI DESEMBER 2021
Publisher : PKimia FKIP Universitas Halu Oleo

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Abstract

Thesynthesis ofcaffeic acid phenethyl ester (CAPE) and its characterization using 1H NMR has been carried out. This research aims to discloseseveral potential ways of CAPE synthesis.The study was conducted by reacting some precursors in effort to produce CAPE.The progress of the synthesis was monitored using TLC and the characterization of the synthetic products was performed with 1H NMR.Three different approaches in effort to synthesize CAPE were conducted.The first approach was a direct rection between caffeoyl chloride and phenethyl alcohol. The second approach was including a protection using benzyl group and the last one was utilizing acetyl protecting groups where both these protecting groups were used to protect the catechol groups of the caffeic acidmoiety. However, the first and second methods failed to achieve the compound target, CAPE. There was only one procedure hasbeen successful, namely the reaction between phenethyl ester with acetyl-protected caffeic acidresulting inthe production of the synthetic compound target, CAPE, as much as 42%

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