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31	Biology Education	ABS-137
The Development of Ethnobotany Based Local Wisdom Learning Materials in Temedak Traditional Forest in Jambi Province to Improve Environmental Literacy and Creative Thinking Skills Defita Permata Sari (a*), Siti Sriyati (b), Rini Solihat (b) Indonesia University of Education Jl. DR. Setiabudi No.229, Isola, Sukasari, Kota Bandung, Jawa Barat 40154 Abstract Local wisdom of Keluru Village community for managing plant diversity in Temedak traditional forest could be internalized well through learning activity by using meaningful teaching materials in learning biology, especially those which related to biodiversity utilization and strategies in biodiversity conservation. This study aimed to develop teaching materials based on ethnobotany local wisdom in Temedak forest. The method in this study was descriptive qualitative. The design of teaching materials development used for ADDIE approach. The subjects in this study were the community and traditional leaders of Keluru Village. The instruments that used by the researcher for collecting the data were interview guides, field notes of observations, and the feasibility of teaching materials consist of content, graphics, presentation, and language based on the National Education Standards Agency (BSNP). The results indicated that the development of teaching materials which included local wisdom showed good and feasible in terms of material with a value of 85.13% (valid) and also feasible in terms of graphics with a value of 88.98% (valid). The conclusion was ethnobotany based local wisdom teaching materials in Temedak forest could be applied in biology learning. Keywords: Ethnobotany, Learning material, Local wisdom, Temedak’s customary forest. PermaLink | Plain Format | Corresponding Author (Defita Permata Sari)

32	Biology Education	ABS-195
The Course of Biology Learning Methodology: Are concept-based learning and drill method effective in enhancing higher-order thinking skills of students? Lufri Lufri (a), Relsas Yogica (a), Arief Muttaqiin (b*), Rahmadhani Fitri (a) a) Department of Biology, Universitas Negeri Padang, Jl. Prof. Dr. Hamka, Air Tawar Padang 25131, Indonesia b) Department of Science Education, Universitas Negeri Padang, Jl. Prof. Dr. Hamka, Air Tawar Padang 25131, Indonesia *muttaqiin.a[at]fmipa.unp.ac.id Abstract Research in education is based primarily on the problems that have found in the field. The habit of memorizing the concept make the students’ thinking skill is not developed. This research aimed to enhance the students‘ higher-order thinking skills through the Concept-Based Learning and Drill Method in The Course of Biology Learning. The concept-based learning leads students to know the basic concept and avoiding misconceptions, while the drill method is unique due to its characteristics, which make students think higher than before. Therefore, the combination of concept-based learning and drill method were applied in the course of Biology Learning Methodology as an attempt to obtain the positive effect of the strategy. A set of higher-order thinking skills questions were given at the end of the course. The implementation of concept-based learning and drill method in this course made students obtained a high score which the average classroom score was 77.87, classified as B+. Implementing the concept-based learning and drill method can be used as an alternative to help students in improving their higher-order thinking skills in Biology Learning Methodology course. Keywords: concept, drill, higher-order thinking PermaLink | Plain Format | Corresponding Author (Arief MUTTAQIIN)

33	Biology Education	ABS-201
The Relation of Cognitive Activities and Students Comprehension to Spatial Isomorphism Diagram of Plant Anatomy in Senior High School Syefia A Malik1*, Adi Rahmat2, and Eni Nuraeni2 1Program Studi Pendidikan Biologi, Sekolah Pascasarjana, Universitas Pendidikan Indonesia, Jl. Dr. Setiabudi No. 229, Bandung 40154, Indonesia 2Departemen Pendidikan Biologi, Fakultas Pendidikan Matematika dan Ilmu Pengetahuan Alam, Universitas Pendidikan Indonesia, Jl. Dr. Setiabudi No. 229, Bandung 40154, Indonesia Abstract Abstrak. Studying complex and abstract plant anatomy, the use of isomorphism diagram is one way to help students to understand the concepts. When studying diagram, students surely involve complex cognitive activities. One of The students’ successes in understanding the various concepts contained in the diagram, can be determined by cognitive activities that occur in working memory. This research is a descriptive study which includes 10 senior high school students in Bandung. The research aims to analyze the relation between cognitive activities and students’ comprehension towards spatial isomorphism diagrams of plant anatomy. The students are asked to analyze the spatial isomorphism diagrams of plant anatomical structures. Then, the students will be given questions to measure the level of comprehension after learning spatial isomorphism diagrams. The result shows that there are five kinds of cognitive activities when students study spatial isomorphism diagram. Those are activating prior knowledge, identifying images, comparing images, interpreting symbols, and drawing conclusion. Hence, there are several students who have low abilities, they only have two kinds of cognitive activities. This is in accordance with the level of students’ understanding of plant anatomy in the medium to low categories. The result shows that the type of cognitive activities that students have contributes the students’ conprehension of plant anatomy. Keywords: Cognitive Activities, Spatial Isomorphism Diagram, Plant Anatomy PermaLink | Plain Format | Corresponding Author (Syefia Azizia Malik)

34	Biology Education	ABS-226
The Implementation of Learning Materials Based on Local Wisdom of Agricultural in Binjai to Improve the Students Problem Solving Abilities Findi Septiani, Siti Sriyati, Amprasto UPI Abstract Teaching materials by integrating local culture makes easier for students to understand the subject matter in the learning process. The aims of the study is to measure the effectiveness of teaching materials based on local wisdom of agriculture in Binjai in improving the students problem solving abilities. The research method was a quasi experimental which use non equivalent control group in the pretest posttest design. The sample of study were students of Senior High School grade X in Binjai that consisted of experiment group which used teaching materials based on local wisdom of agriculture in Binjai and control group that used student handbooks. Teaching materials are tested by material experts and technology experts to ensure the quality of teaching materials. Data collection was conducted through test. The results showed that the teaching materials based on local wisdom of agriculture in Binjai effective in improving students problem solving abilities in the experimental group students based on the results of N gain value was 0.67 which has medium criteria. It means teaching materials based on agricultural local wisdom of agriculture in Binjai can be used as one of the teaching materials in learning activities. Keywords: Local wisdom, teaching materials, effectiveness, problem solving abilities. PermaLink | Plain Format | Corresponding Author (Findi Septiani)

35	Biology Education	ABS-227
Enhancing Students’ Problem Solving Ability through Teaching Material based on Tumpek Wariga as Local Wisdom in Bali Kadek Sera Harlistya Udayani, Siti Sriyati, Amprasto UPI Abstract Teaching materials based on wisdom and local potential are needed in environmental education in order to produce learning resources that are appropriate to students cultural, geographical and social environment. The purpose of this study was to obtain a picture of the impact or effect of the use of teaching materials based on local wisdom of Tumpek Wariga on achieving students problem solving abilities. The method used in this study is a quasi experiment with a research design that is non equivalent pretest-posttest design. The study was conducted at one of the high schools in Denpasar. The research sample consisted of 36 experimental class students who used teaching materials based on local wisdom Tumpek Wariga and 36 control class students who used national teaching materials. Teaching material based on local wisdom Tumpek Wariga has previously been validated by reviewers with results worth to using. Data about students problem solving abilities are measured by essay questions arranged according to indicators of problem solving. The research data did not meet the prerequisite test then analyzed through the nonparametric ¬Mann-whitney test. The analysis showed that there were significant differences in posttest results between the control and experimental classes with a significance level of 0.00. This shows that teaching materials based on local wisdom Tumpek Wariga can improve students problem solving abilities. Keywords: Teaching material, local wisdom, problem solving ability PermaLink | Plain Format | Corresponding Author (Kadek Sera Harlistya Udayani)

36	Chemistry	ABS-8
THE DESIGN OF SENSITIVE, SELECTIVE AND REPRODUCIBLE BIOSENSOR WITH ENZYME IMMOBILISATION FOR ANALYTICAL APPLICATIONS Manihar Situmorang Universitas Negeri Medan Abstract The design of sensitive, selective and reproducible biosensors with enzyme immobilisation for analytical application is reported. The study is aimed to develop a versatile and accurate analytical tool to be applicable for the determination of target analytes in real samples. The biosensor device is developed with employ immobilised enzyme as catalyic agent to convert target analytes to product that can be monitored electrochemically. Electrochemical biosensors, both in amperometric and potentiometric detection system have been prepared for different types of analytes. The strategy to immobilise ezyme in a matrix polymer is explained. Analytical performances of the the biosensors have been evaluated based on their detection sensitivity, linearity detection range, limit detection, selectivity, and stability. The enzyme electrode is prepared by immobilization of enzyme throughout polytyramine membrane film and attached tightly onto the surface of electrode. The working electrode was made via electropolymerization of monomer tyramine on an electrode surface from a mixed phosphate buffer/methanol solution containing enzyme at pH 6.0 followed by covalent attachment using EDC/NHS crosslinking agents. The precise control over the charge passed during deposition of the polytyramine polymer allows concomitant control over the thickness of the deposited enzyme layers onto the surface of the electrode. The reproducibility of the biosensors achieved is certainly due to the control of the thickness of the enzyme layer being limited by the resistance of the polytyramine film, and to the enzyme immobilization procedure on to the surface of the electrode. The biosensor showed good stability and to be applicable to determine analytes in real samples. Amperometric biosensor has been developed for the determination of various types of analytes such as glucose, sulfite, and uric acid. Potentiometric biosensor has also been developed with the same procedures for determination of analytes such as malic acid, cholesterol, and urea. The biosensor showed good stability and applicable to determine analyte in real samples. Keywords: Electrochemical biosensor; Reproducible; Enzyme immobilisation; Potentiometric; Amperometric; Polytyramine matrix PermaLink | Plain Format | Corresponding Author (Manihar Situmorang)

37	Chemistry	ABS-19
Effect of Ipomoea batatas L. leaf extract as flocculant on Decreasing Ca2 and Mg2 Levels (Hardness) in Water Treatment for Chemical Practicum Environmental Analysis at the Department of Chemistry, Universitas Pendidikan Indonesia Hana Rohana, Cahyo Puji Asmoro Universitas Pendidikan Indonesia Abstract This study was conducted to determine the effect of Ipomoea batatas L. leaf extract as flocculants on the reduction of Ca2 + and Mg2 + (hardness) levels in water treatment for chemical practicum on environmental analysis at the FPMIPA UPI Chemical Department. This study continued from previous research on the optimization of Ipomoea batatas L. leaf extract as a flocculant in water treatment, the results of the study showed that Ipomoea batatas L. leaf extract can make water clearer and provide greater reduction in turbidity value. In this follow-up study it will be carried out through two stages, the first step is optimizing the optimum processing parameters. The second stage is water treatment using optimum processing parameters, followed by hardness testing in water samples before and after processing. In hardness testing the EDTA titration method is used with the EBT indicator. The results showed the optimum parameters of water treatment with Ipomoea batatas L leaf extract as flocculant was pH 6.5, coagulant dose 50 mg / L, flocculant dose 2 mg / L, stirring coagulant speed 200 rpm for 5 minutes, and flocculant stirring speed 40 rpm for 5 minutes. In testing the total hardness as CaCO3, the initial sample (without treatment) obtained hardness of 285 mg / L, whereas in the sample treated with Ipomoea batatas L. leaf extract as flocculant hardness was obtained at 190 mg / L. From the results of the study it can be concluded that Ipomoea batatas L. leaf extract as flocculant in water treatment can reduce the hardness level in water. Keywords: Biofloculan, Ipomoea batatas L., EDTA titration, Hardness. PermaLink | Plain Format | Corresponding Author (Cahyo Puji Asmoro)

38	Chemistry	ABS-54
The Effect of Steaming on The Color and Amount of Anthocyanin of Purple Sweet Potato Flour Ai Mahmudatussaadah1*, Rita Patriasih1, Rijanti Rahaju Maulani2, Karpin1 1 Universitas Pendidikan Indonesia, Jl Dr. Setiabudhi 229 Bandung Indonesia; 2 STIH Institut Teknologi Bandung, Jl. Jatinangor Sumedang Indonesia Abstract Purple sweet potato is one of the potential sources of antioxidants. Anthocyanin in purple sweet potato is natural to experience enzymatic oxidation after contact with oxygen. The oxidation process causes the brown color to show a decrease in the amount of anthocyanin. The oxidation process was caused due to enzymatic activity. The purpose of this study was to describe the effect of steaming on color and the amount of anthocyanin of sweet potato flour. The method used is a one-factor experiment, namely cooking with water vapor. Stages carried out by material preparation, wet cooking, drying, grinding, and sieving. Color analysis using chromameter, and total anthocyanin amount using the pH difference method. The results showed that the steaming process gave bluish purple, and the amount of anthocyanin was higher than without steaming. This study implies that the steam blanching process of sweet potatoes can maintain the purple color of fresh sweet potatoes. Keywords: Anthocyanin; Flour; Purple sweet potato; Steaming PermaLink | Plain Format | Corresponding Author (Ai Mahmudatussaadah)

39	Chemistry	ABS-315
STUDY DEGRADATION OF ACID ORANGE 7 USING ZnO-KA Hasri (1) , Diana Eka Pratiwi (1) , Nur Anita Sari (3) , Rachmawaty (2) 1) Chemistry, Faculty of mathematic and natural sciense , Universitas Negeri Makassar 2) Biology, Faculty of mathematic and natural sciense , Universitas Negeri Makassar 3).Alumny chemistry, Faculty of mathematic and natural sciense , Universitas Negeri Makassar Abstract Abstract Synthesize ZnO-Activated Carbon (ZnO-AC) use the time, concentration, pH degradation Acid Orange 7 dyes. The stages preparation of synthesize included sample preparation, making shell activated carbon candlenut, ZnO-KA characterization and degradation study.. SEM-EDX analysis results showed an uneven morphology with a percentage of ZnO mass of 58.46%. ZnO-KA degrade Acid Orange 7 for 8 hours with a concentration of 50 ppm and at pH alkali obtained percentage degrade of 96.23%. Key words: Degradation, Acid Orange 7, ZnO-KA Keywords: fotodegradasi, Acid Orange 7, ZnO-Karbon Aktif (ZnO-KA) PermaLink | Plain Format | Corresponding Author (Hasri Hasri)

40	Chemistry	ABS-66
Chemical Water Type of Unconfined Groundwater in Southern Bandung Wilda Naily (a, b*), Hendarmawan (a) a) Doctor of Environmental Science, Postgraduate School, Padjadjaran University Jl Dipatiukur, Bandung 40132, Indonesia *wilda.naily[at]gmail.com b) Research Center for Geotechnologi LIPI Jl Cisitu Sangkuriang, Bandung 40135, Indonesia Abstract Groundwater provides an overview of environmental conditions in an area. Chemical analysis of groundwater will provide information about the origin and quality of groundwater as a basis for groundwater utilization. In this paper, analysis is carried out by determining the water types of unconfined groundwater. Unconfined groundwater sample were taken from Southern Bandung. Measurement of major ion (sodium, potassium, magnesium, calsium, chloride, sulfate and bicarbonate), also pH and electrical conductivity were carried out in 16 groundwater samples. Paper discusses a) the classification of groundwater types determined by Kurlov method, b) the correlation of chemical properties in groundwater determined by Stiff method. Result showed that unconfined groundwater in Southern Bandung was dominated by calcium cations and bicarbonate anions, and water type were dominated by calcium – alkali – bicarbonate – chloride. Correlation of chemical properties in groundwater is seen in several location which show groundwater in the same flow and is fresh. Keywords: Groundwater, Water type, Major ion, Calcium, Bicarbonate PermaLink | Plain Format | Corresponding Author (Wilda Naily)

41	Chemistry	ABS-333
Speciation of Lead (Pb) and Cadmium (Cd) in Agricultural Farmland Soils of Pancasari Village as A Vegetables Central Area of Bali, Indonesia I Dewa Ketut Sastrawidana Undiksha Abstract The use of agrochemical such as fertilizers and pesticides intensively on agriculture sector contributes to the increase of heavy metals residual in soil and vegetables. Lead (Pb) and Cadmium (Cd) are two types of heavy metal considered toxic, carcinogenic for living organism and persistence in environment. Pb and Cd metals are frequently found as impurities in fertilizer products. Our researches focused on the speciation of Pb and Cd heavy metals on soil which cultivated vegetables. In addition, soil characteristic (organic matter content, pH and cation exchange capacity) as a factor influencing heavy metal speciation and bioavailability for plants also analyzed. Beside that, measurement of Pb and Cd content on several types of vegetables such as tomatoes, cabbage and carrots are conducted then used to determine the level of safety for consumed. Heavy metals speciation carried out using sequential extraction method then the Pb and Cd content on each fraction was analyzed by atomic absorption spectrophotometer. Heavy metal of Pb in various fraction are in the following order F3> F1> F5 > F4>F2 whereas heavy metal of Cd order F4> F1>F3>F5>F2. The organic matter, pH and cation exchange capacity on sample soil was 3.05% ; 5.56 and 20.30 mek/100 g, respectively. The health risk values of daily intake of metal (DIM) and health risk index (HRI)<1 indicates that the vegetables was relatively safety for consumed. Keywords: Cadmium, lead, farmland, fertilizer, health risk index, heavy metals speciation. PermaLink | Plain Format | Corresponding Author (I Dewa Ketut Sastrawidana)

42	Chemistry	ABS-78
Modification of Carbon Paste Electrode with Molecularly Imprinted Poly(Glutamic Acid) for Determination of Rhodamine-B: A Preliminary Study Henry Setiyanto1*, Ferizal1, Muhammad Yudhistira Azis1, Muhammad Ali Zulfikar1, Vienna Saraswaty2, Nandang Mufti3 1Analytical Chemistry Research Group, Institut Teknologi Bandung, Bandung, Indonesia 2Research Unit for Clean Technology, Indonesian Institute of Sciences, Bandung, Indonesia 3Department of Physics, Universitas Negeri Malang, Malang, Indonesia Abstract The modification of carbon paste electrode (CPE) with molecularly imprinted polymer (MIP) for determination of rhodamine-B by potentiometry method has been studied. The experiments were performed using glutamic acid as a monomer. The composition of monomers, the number of electropolymerization cycles and pH of the solution were used to describe modification electrodes made (CPE-MIP’s) and the electrode characteristics were evaluated. It was observed the amount of oxidation current signal increase with increasing glutamic acid concentration. The optimal polymerization molar ratio of the functional monomer to the template molecule rhodamine-B was 3:1; the maximum number of electropolymerization was 15 and the optimum pH of supporting electrolyte solution was 4. Keywords: CPE, MIP, polyglutamic acid, rhodamine-B PermaLink | Plain Format | Corresponding Author (Henry Setiyanto)

43	Chemistry	ABS-334
TOTAL PHENOL AND FLAVONOID LEVELS AND IC50 IN LOCAL GRAPE (Vitis vinifera L) SKIN WASTE WINE Siti Maryam Universitas Pendidikan Ganesha Abstract Grape skin is a waste produced from the process of making wine derived from grapes. Currently the use of grape skins is still limited as a natural fertilizer, so that the presence of abundant waste. This study aims to determine the total levels of phenols and flavonoids in the skin of grapes from the waste of wine making. This research is an experimental study to determine the total content of phenols and flavonoids where this compound is an antioxidant. The power of antioxidants can be known by knowing IC50 from grape skins. The study was conducted by repeating three times from samples in the form of grape skin powder. Antioxidant activity can be determined by using the DPPH test. The results stated that the total phenol, flavonoid and IC50 levels of grape skins were 168.55 (mg / 100 gr); 61.10 (mg / 100 gr) and 1,065.19 ppm. The presence of total phenols, flavonoids and IC50 in grape skins is relatively high, so the use of grape skins from the process of making wine makes attention. Keywords: grape skin, total phenol, flavonoid, antioxidant, IC50 PermaLink | Plain Format | Corresponding Author (Siti Maryam)

44	Chemistry	ABS-79
MODIFICATION OF CARBON PASTE ELECTRODE WITH Ag NANOPARTICLE FOR VOLTAMMETRIC DETERMINATION OF PHENOL Tri Sulistyorini1, Henry Setiyanto1*, Muhammad Ali Zulfikar1, Vienna Saraswaty2, Nandang Mufti3 1Analytical Chemistry Research Group, Institut Teknologi Bandung, Bandung, Indonesia 2Research Unit for Clean Technology, Indonesian Institute of Sciences, Bandung, Indonesia 3Department of Physics, Universitas Negeri Malang, Malang, Indonesia Abstract Phenol is an aromatic derivative of hydrocarbons from coal which used as a base for making plastic bottles, cans of packaged food, cosmetics, and pesticides. A large amount of phenol in industrial fields cause phenol easily found in water. However, this compound is emerging as a pollutant in the environment and cause harm to animals. Phenol is also known to be highly reactive to human body tissue if absorbed through skin, breathing, and digestion. In this work, carbon paste electrode based on Ag nanoparticle was developed for the detection of phenol. Carbon paste electrode was modified with Ag nanoparticles which were previously synthesized first and then mixed with graphite and paraffin. The best composition of CPE-nAg is 5:70:25 for Ag nanoparticles, graphite, and paraffin. After measurement using CPE-nAg, it is necessary to remove phenol on the electrode surface with 6 cyclic. Measurement was carried out using square wave voltammetry techniques in the potential range of 0 V to 1,2 V, frequency of 10 Hz, and a scan rate of 75 mV/s. The result showed the presence of an oxidation peak of phenol is 0,475 V in sodium hydroxide 1 M solution. Keywords: CPE, Ag nanoparticles, voltammetric, phenol PermaLink | Plain Format | Corresponding Author (Henry Setiyanto)

45	Chemistry	ABS-80
Study of Methylene Blue Degradation Using Mediated Electrochemical Oxidation With Ce (IV) Ions: Effects of Supporting Electrolyte, Ce(III) Concentration and Oxidation Potential Ummu Rokhima1, Henry Setiyanto1*, Muhammad Ali Zulfikar1, Vienna Saraswaty2, Nandang Mufti3 1Analytical Chemistry Research Group, Institut Teknologi Bandung, Bandung, Indonesia 2Research Unit for Clean Technology, Indonesian Institute of Sciences, Bandung, Indonesia 3Department of Physics, Universitas Negeri Malang, Malang, Indonesia Abstract Methylene Blue (MB) is a dye commonly used in the textile industry. Dyes waste from the textile industry harms the ecosystem of the environment. One method of textile dye waste degradation is mediated electrochemical oxidation. This method uses an oxidation-reduction process using metal ion as a mediator. The mediator metal ion acts as an oxidizer which oxidizes textile dyes waste into simpler compounds, namely CO2 and H2O. The mediator ion used in this study was Ce (IV) in an acidic. The results of the degradation were analyzed using the voltammetry method. In voltammetry there are three electrodes are used, namely working electrode, reference electrode, and auxiliary electrode. This study used a carbon paste electrode as a working electrode, a platinum wire as an auxiliary electrode and a homemade Ag/AgCl as a reference electrode. The results of the characterization of the Ag/AgCl reference electrode showed that the Ag/AgCl had the same characteristics as the BAS commercial reference electrodes (bioanalytical systems). The results of cyclic voltammogram showed that the oxidation potential value of MB is 0.2880 V. The oxidation and reduction potential of Ce (III)/Ce (IV) in 0.2 M H2SO4 were 1.2400 V and 0.4520 V. This potential value indicates that the MB oxidation potential was not disturbed by the mediator ion potential. The optimum condition of electrodegradation was obtained at 250 ppm MB in 0.2 M H2SO4 with the addition of 0.015 M Ce (III) for 30 minutes using the potential of 6 V. Keywords: Methylene Blue, MEO, degradation, cerium PermaLink | Plain Format | Corresponding Author (Henry Setiyanto)

46	Chemistry	ABS-81
ADSORPTION-DESORPTION PROPERTIES OF AMMONIUM ION ON ZEOLITE BOTTOM ASH IN AQUEOUS SOLUTION Galuh Yuliani1,a*, Widya Liswanti1,b , Rahmaditha Murida1,c, and Agus Setiabudi1,d Chemistry Department, Universitas Pendidikan Indonesia, Jalan Dr. Setiabudi 229 Bandung 40154, West Java, Indonesia Abstract Coal bottom ash (CBA) waste generated from coal-based industries has been increasing at an alarming rate causing huge problems in its recycling and disposal process. On the other hand, CBA is potentially used as raw material in zeolite manufactures due to its high SiO2 and Al2O3 contents. We report the conversion of CBA into zeolites-like material via a low temperature method of 90°C for 24 h using NaOH solution. The synthetic zeolite was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), and BET surface area measurement. The study of its adsorption-desorption properties was also conducted using ammonium solution. FTIR spectra confirmed characteristic zeolite peaks at 980-1170 cm-1, 740.6 cm-1, 439.7 cm-1, 559.3 cm-1 for Si-O, Al-O and Si-O-Al absorptions, respectively. XRD results indicated the formation of sodium aluminosilicate hidrate belong to the zeolite structure group at NaOH 5M ratio of 1:8. XRF results also indicated the domination of Al2O3 and SiO2 in the zeolite composition. BET analysis resulted the surface area of zeolite was 60.38 m2/g, markedly increased from the initial surface area of CBA of 0.598 m2/g. The maximum adsorption capacity for ammonium ions were 85.22 mg/g and the adsorption data fitted the Freundlich isotherm model. Meanwhile, the desorption study indicated that the ammonium leached rapidly in the first 3 h followed by a plateu in the next 71 h. Keywords: bottom ash; zeolite; adsorption; desorption; ammonium PermaLink | Plain Format | Corresponding Author (Galuh Yuliani)

47	Chemistry	ABS-337
Effect of Sugarcane as an organic source on biomass and lipid production of Chlorella vulgaris and Navicula salinicola Gun Gun Gumilar, Alya Mardhotillah Azizah, Heli Siti Halimatul Munawaroh, Dewi Kurnia, Siti Aisyah, Andriati Ningrum UPI Abstract Chlorella vulgaris and Navicula salinicola have been reported to have high lipid content and are potential to be used as an alternative source of bioenergy precursor compounds. However, to obtain a high biomass and lipid with autotropic cultivation condition is still a challenge therefore other cultivation condition such as photoheterotropic need to be explored. In addition, the influence of cultivation conditions on the production of biomass and lipid for diatomic microalgae, especially Navicula salinicola, is still rare explored. This study aims to analyze the effect of organic carbon sources namely sugarcane addition on the production of biomass and lipid of Chlorella vulgaris and Navicula salinicola. Analysis of biomass concentrations is evaluated by measuring dry cell weight (DCW), while lipid concentrations is evaluated by measuring total lipid levels from the extraction results using the Folch method. Lipid concentrations is calculated based on total lipid levels and biomass concentration obtained. The profile of fatty acid methyl ester (FAME) is analysed by using GC-MS. Based on the results of this study, it was observed that addition of sugarcane as an organic carbon source has increased the biomass production in Chlorella vulgaris and Navicula salinicola by 50.10% and 69.40% respectively than those are cultivated without the addition of sugarcane. Similarly, the addition of sugarcane has been showed to induced lipid accumulation in Chlorella vulgaris and Navicula salinicola by 34,45% and 25,51% respectively compared to those are cultivated with carbon source from the air. On the other hand, the addition of sugarcane as an organic carbon has decreased the variations of fatty acid in Chlorella vulgaris and Navicula salinicola by 3 and 4 types respectively than those are cultivated without the addition of sugarcane. The addition of sugarcane can suppress the variations of fatty acids in Chlorella vulgaris and Navicula salinicola but it stimulates the synthesis of palmitic acid (C16:0) which has potential to be applied to the biodiesel industry. Keywords: Biomass, Chlorella vulgaris, Lipid, Navicula salinicola, Photoheterotropic PermaLink | Plain Format | Corresponding Author (Heli Siti Halimatul Munawaroh)

48	Chemistry	ABS-338
Phycocyanin from Spirulina plantesis: In silico approach, in vitro evaluation, and storage stability as antidiabetic candidate Heli Siti Halimatul Munawaroh, Gun Gun Gumilar, Fina Nurjanah, Dewi Kurnia, Ihsanawati, Galuh Yuliani, Asri Peni Wulandari, Isman Kurniawan, Andriati Ningrum UPI Abstract Phycocyanin is the main pigment in Spirulina platensis which is reported has potential to be used as a natural inhibitor for α-amylase and α-glucosidase. The pigment can effectively treat type-2 diabetes mellitus by lowering blood glucose. However, molecular interactions between phycocyanin and the two enzymes are less studied. In this study, an in silico study through molecular docking simulation was carried out to predict the molecular interactions of phycocyanin and both of α-amylase and α-glucosidase. In vitro evaluation of phycocyanin as an anti-diabetic is determined through the inhibitory activity of phycocyanin against α-amylase derived from human saliva. Storage stability in three conditions was evaluated in its application as a functional supplement. Docking simulations between phycocyanin and acarbose as commercial drugs with α-amylase and α-glucosidase enzymes were performed using the AutoDock Tools program. Determination of inhibitory activity was carried out using the FUWA method, while the measurement of absorption values with a UV-Vis spectrophotometer. Storage stability study was performed on solid and solutions-stated of phycocyanin at three different conditions, namely dark conditions at -4°C, dark conditions at room temperature, and bright conditions at room temperature. The stability was determined by measuring the absorption values at λ620 and λ652 using UV-Vis spectrophotometer. Molecular docking simulations show that phycocyanin, inhibits by binding to the active site of the enzyme, causing disruption of the attachment of the substrate to the enzyme. The simulation indicates that phycocyanin has potency to be used as a candidate for anti-diabetic natural therapy agents. An in vitro inhibition activity test showed that phycocyanin inhibits α-amylase from human saliva at average 50.13%. Storage stability tests showed that the concentration of phycocyanin in the form of solutions and solids, was stable for seven days of testing under conditions of dark storage and low temperatures. Keywords: Diabetes mellitus type-2, Phycocyanin, Molecular Docking, Stability, α-amylase, α-glucosidase PermaLink | Plain Format | Corresponding Author (Heli Siti Halimatul Munawaroh)

49	Chemistry	ABS-90
Effect of Temperature on Sorption of MB from Aqueous Solution using Composite Nanofiber Muhammad Ali Zulfikar1,*), Siti Oryza Sativa1, Megawati Zunita2, Muhammad Yudhistira Azis1,*), Henry Setiyanto 1Analytical Chemistry Research Group, Institut Teknologi Bandung, Jl. Ganesa 10 Bandung 40132 Indonesia 2Chemical Engineering Product Design and Development Research Group Institut Teknologi Bandung, Jl. Ganesha 10 Bandung, 40132 Indonesia Abstract Water contamination caused by dye industries, has caused more and more attention, since most dyes are harmful to human being and environments. Some dyes like methylene blue (MB) and their degradation products have carcinogens and toxic properties so that the removal of dyes from surface water or wastewater is very important. Physical adsorption using solid adsorbents has been a promising method for treating dyes, pigments and other colorant wastewater, owing to its advantages such as operational simplicity, low cost, availability in large amount and ability to treat pollutants in a sufficiently large scale operation. In this study, the sorption of MB from aqueous solution onto composite nanofiber under the influence of temperature has been investigated. It was observed that the amount of MB adsorbed increase with increasing temperature. Thermodynamic parameters data indicated that the MB adsorption process was non-spontaneous and endothermic under the experimental conditions, with the Gibbs free energy (?Go) in the range of 1.721-0.610 kJ mol-1, enthalpy (?Ho) and entropy (?So) of 7.24 kJ mol-1 and 18.52 J mol-1.K-1, respectively and the activation energy was 13.85 kJ mol-1. Keywords: Effect of Temperature on Sorption of MB from Aqueous Solution using Composite Nanofiber PermaLink | Plain Format | Corresponding Author (Muhammad Yudhistira Azis)

50	Chemistry	ABS-111
ACTIVITY OF PVDF-TiO2/ZnO NANOFIBER PHOTOCATALYST FOR DEGRADATION OF HUMIC ACID SOLUTION Siti Oryza Sativa (1*), Muhammad Ali Zulfikar (2), Ervin Trisuryandari (1,3), and Muhammad Nasir (4) Laboratory of Analytical Chemistry, Department of Chemistry, Bandung Institute of Technology, Bandung 40132, Indonesia1, Analytical Chemistry Research Division, Bandung Institute of Technology, Bandung 40132, Indonesia2, Department of Chemistry, Science and Technology Faculty, UIN Walisongo, Semarang3, Research Unit for Clean Technology Indonesian Institute of Science, Jl. Cisitu Sangkuriang, Bandung 40135, Indonesia4Technology, Bandung 40132, Indonesia zulfikarmuhammadali[at]gmail.com Abstract Peat water source could be found in many lowland and marshy areas in Indonesia such as in Sumatra, Kalimantan, and Papua. This type of water could be a problem for resident living around it as fresh water is one of the basic needs for human being. It formed from decayed of plants, animals, and microbes. The main component of peat water is humic acid which is a complex of organic compound and natural polymer. One of the potential process to treat humic acid is by using photocatalytic degradation method. This research aims to conduct activity of PVDF-TiO2/ZnO/CoO nanofiber photocatalyst for degradation of humic acid solution. Photocatalytic activities was studied inside photoreactor with artificial UV radiation with 254 nm wavelength. The percentage of degradation was determined by measuring humic acid solution before and after degradation using UV-Vis spectrophotometer with maximum lambda in 219 nm. Study of kinetic for photocatalytic reaction was calculated with rate constant 4,29 x 10-5 min-1 ppm-1 and the kinetic of photodegradation on this research was pseudo second order kinetic model. Keywords: nanofiber, photocatalyst, photocatalytic activity, TiO2, humic acid PermaLink | Plain Format | Corresponding Author (Siti Oryza Sativa)

51	Chemistry	ABS-124
Synthesis of Magnetic Molecularly Imprinted Polymer for Recognition of Di-(2-ethylhexyl) Phthalate Asyifa Rizqi Utami (a*), Muhammad Ali Zulfikar (b), Deana Wahyuningrum (c) a) Laboratory of Analytical Chemistry, Bandung Institute of Technology, Jalan Ganesha 10, Bandung 40132, Indonesia asyifarizqi[at]students.itb.ac.id b) Analytical Chemistry Research Division, Bandung Institute of Technology, Jalan Ganesha 10, Bandung 40132, Indonesia zulfikar[at]chem.itb.ac.id c) Organic Chemistry Research Division, Bandung Institute of Technology, Jalan Ganesha 10, Bandung 40132, Indonesia deana[at]chem.itb.ac.id Abstract A novel magnetic molecularly imprinted polymer (MMIP) was prepared for the recognition of di(2-ethylhexyl) phthalate, using methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a crosslinker and benzoil peroxide as an initiator. MMIP was characterized using Scanning Electron Microscope and infrared spectrophotometer. IR spectrum show successfull preparation of MMIP. The peak at 586 cm-1 is a typical vibration of Fe-O. The strong peaks at 1728 cm-1, 1261 cm-1 and 1153 cm-1 correspond to the C=O stretching vibration and C-O vibration of methacrylic acid and DEHP. The peak at 1462 cm-1 corresponds to C-C aromatic vibration of DEHP. A broad absorption band at 3468 cm-1 correspond to the stretching vibration of O-H bonds. Experimental results show the potential of magnetic molecularly imprinted polymer for selective recognition of di-(2-ethylhexyl) phthalate. Keywords: di(2-ethylhexyl) phthalate, imprinted polymers, magnetite PermaLink | Plain Format | Corresponding Author (Asyifa Rizqi Utami)

52	Chemistry	ABS-143
Molecularly Imprinted Polymer as a Sorbent for Alpha Mangostin Neena Zakia (a,b*), Handajaya Rusli (a), M. Ali Zulfikar (a), M. Bachri Amran (a) a) Division of Analytical Chemistry, Institut Teknologi Bandung Jalan Ganesha 10, Bandung 40132, Indonesia *neena.zakia.fmipa[at]um.ac.id b) Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang Jalan Semarang 5, Malang 65145, Indonesia Abstract Alpha mangostin is a major component in the mangosteen rind, which has activity as an antioxidant, antitumor, hypo-allergenic, and anticancer. The aim of this study is to synthesize molecularly imprinted polymer (MIP) for alpha mangostin adsorption. The MIP was prepared by bulk polymerization with alpha mangostin as template, methacrylic acid as the monomer, ethylene glycol dimethacrylate as the crosslinker, and benzoyl peroxide as the initiator and acetonitrile as porogenic solvent. A molar ratio of template:monomer:crosslinker is 5:4:20. A non-imprinted polymer was synthesized in the absence of alpha mangostin. Solvent extraction is carried out to remove the template used methanol:acetic acid (90:10, %v/v) as the solvent. The surface morphology of MIP was visualized by scanning electron microscopy (SEM). The synthesized MIP was characterized by infra red spectroscopy. It showed that wavelength number were 2957, 1603, and 1456 cm-1 assigned to characteristic vibration of a C-H bond, a chelated carbonyl group and a methoxy groups, respectively, which indicated the present of template molecule. The adsorption capacity of MIP for alpha mangostin was 12,17 mg/g with the imprinting factor 1,2. Overall, this MIP has a good chance to be used as functional material for alpha mangostin adsorption. Keywords: alpha mangostin, molecularly imprinted polymer, adsorption PermaLink | Plain Format | Corresponding Author (Neena Zakia)

53	Chemistry	ABS-146
Characterization and Application of N-doped Carbon Nanodots from Molasses Produced by Microwave-Assisted Extraction Method for Photocatalytic degradation of Methylene Blue Mentik Hulupi, Muhamad Ariq Al Badar, Ahya Sularasa, and Haryadi* Department of Chemical Engineering, Politeknik Negeri Bandung Jl. Gegerkalong Hilir, Bandung 40559, Indonesia *haryadi[at]polban.ac.id Abstract The growth of the textile industry in Indonesia brings harm to the environment as disposal of wastewater to the river bodies still contains dangerous dyes. This affects the life of aquatic biota and the health of surrounding communities that use river water for domestic needs. To overcome this problem, N-doped Carbon Nanodots (N-doped CNDs) as photocatalysts can be used as an alternative in degrading Methylene Blue through photocatalytic process. N-doped CNDs from molasses have been successfully synthesized using H2O2 followed by the Microwave-Assisted Extraction (MAE) method. The synthesized N-doped CNDs possess average particle size of 1.5 nm observed by TEM. The properties of N-doped CNDs emit blue fluorescence under UV light 365 nm and show peak absorption at wavelength of 220 nm. Vibration peaks of OH, C-H, C = O, N-H, C-N functional groups are observed by FTIR at wavenumbers 3246.94 cm-1, 2929.06 cm-1, 1656.08 cm-1, 1590.27 cm-1 and 1036.98 cm-1 respectively. The success of nitrogen doping within CNDs is proven by FTIR analysis showing an increase of absorbance of C-N and N-H groups of N-doped CNDs. The potential of N-doped CNDs as photocatalysts for the degradation of methylene blue became the object of this study. The results showed that the degradation efficiency of methylene blue using 3 mL N-doped CNDs at pH 10 exhibited the most optimal degradation efficiency. Under these conditions, the degradation efficiency resulting from the use of 254 nm 11 W UV lamps and 14.5 W Philips LED lamps in 270 minutes is 96.8% and 97.2% consecutively. Keywords: Methylene Blue; N-doped Carbon Nanodots; Molasses; Photocatalysts PermaLink | Plain Format | Corresponding Author (Muhamad Ariq Al Badar)

54	Chemistry	ABS-239
DETERMINATION OF ANTIOXIDANT ACTIVITY AND PHYSICO-CHEMICALS CHARACTERISTICS OF FORTIFIED YOGURT POWDER BY SUPER RED DRAGON (Hylocereus polyrhizus) FRUIT PEEL POWDER Florentina Supriyanti, Zackiyah, Fiona Finandia Chemistry Study Program Department of Chemistry Education UPI Abstract The research aims to investigate the antioxidant activity and physico-chemicals characteristics of yogurt powder fortified by peel of super red dragon (Hylocereus costaricensis) fruit. Methods include of making super red dragon fruit peel powder, making yogurt, fortification of yogurt using super red dragon fruit peel powder and freeze drying. The analysis consist of antioxidant activity with the DPPH method and Physico-chemicals characteristics includes water content by gravimetric method, ash content by ashing method and pH by potentiometric method. Produced yogurt without fortification (F0) and three fortified yogurt variants F1, F2 and F3 with 10%; 20%; 30% successive fortification. The super red dragon fruit peels had antioxidant activity 93.08% ± 2.51; powdered yogurt before fortification 15.86% ± 3.39 while F1, F2 and F3 fortified powdered yogurt were 63.69% ± 1.70 ; 76.33% ± 2.79 and 92.67% ± 1.61 respectively. The water content of powdered yogurt before fortification were greater than fortified yogurt. The ash content of yogurt before fortification and fortified powdered yogurt are greater than the value of standard ash content. The pH value of yogurt powder before fortification and fortified yogurt is in the pH range of yogurt. Keywords: Antioxidant activity, super red dragon fruit peel, yogurt powder PermaLink | Plain Format | Corresponding Author (Florentina Maria Titin Supriyanti)

55	Chemistry	ABS-254
Preparation and physicochemical properties of superabsorbent hydrogels based on poly (vinyl alcohol)/ poly (ethylene glycol) Fitri Khoerunnisa (a), Cantika Setya Permatasari (a), Hendrawan (a), Fitri Dara (b), Yaya Sonjaya (a), Widda Rahmah (a,b) a) Department of Chemistry, Indonesia University of Education Bandung, Indonesia 40154 b) Clean Technology Research Division, Indonesian Institute of Science, Bandung, Indonesia, 40135 c) Department of Chemical Engineering, Bandung Institute of Technology, Bandung, Indonesia, 40116 Abstract This study aims to prepare and to investigate the physicochemical properties of superabsorbent hydrogels (SH) based on poly (vinyl alcohol)/ poly (ethylene glycol) with an aid of glutaraldehyde crosslinker. The SH was synthesized using solution mixing method. The physicochemical properties of synthesized SH were determined by means of FTIR spectroscopy, X-ray diffraction, scanning electron microscopy, thermal gravimetric analysis, tensile strength, swelling ratio, and water retention tests. The results revealed that the optimum volume ratio of PVA (2.5% w/v): PEG (2.5% w/v): GA (3.33x10-5 % v/v) composition on SH was 2:3:3. The predominant interaction between polymer precursors involved functional moieties of C–O/C–O–C, C=O, C–H and –OH via hydrogen bonding. Copolymerization with PEG was not only modified crystallinity, tensile strength, thermal stability, and elasticity but also improved porous structure of PVA. The synthesized SH has huge water absorption capacity with water swelling ratio (% SR) and water retention (% WR) of 1230% and 53%, respectively. Keywords: Superabsorbent; hydrogel; PVA; PEG PermaLink | Plain Format | Corresponding Author (Fitri Khoerunnisa)

56	Chemistry Education	ABS-4
THE IMPLEMENTATION OF ASSESSMENT BASED ON HIGHER ORDER THINKING SKILLS (HOTs) IN CHEMISTRY SUBJECT OF HIGH SCHOOL IN MALANG CITY Hayuni Retno Widarti, Herunata, Oktavia Sulistina, Habiddin Universitas Negeri Malang Abstract This research aimed to identify the profile of Higher Order Thinking Skill (HOTs) instrument in the questions of students’ learning outcome assessment in chemistry for Senior High School in Malang City. This study used descriptive qualitative with a content analysis method. The data were collected by documentation. The populations were all Senior High Schools in Malang City. The samples were determined using cluster random sampling technique and were represented by SMAN 3, SMAN 8, and SMAN 9 Malang. The data used in this study were 576 questions of learning outcome assessment in chemistry used in those three schools, including 201 question for class X and 366 question for class XI, respectively. The finding validity was tested based on the analysis results of rater 1 and 2 using interrater and Cohen-Kappa reliability. The research results showed that the HOTs questions had been implemented, and the percentages of HOTs questions used in class X and XI were 9.00% and 13.39%, respectively. The validity test indicated a strong-perfect interpretation with the agreement coefficient value of 0.61-0.86. The research results are expected to be an evaluation in improving the quality of education, especially in the chemistry for Senior High School in Malang City. Keywords: Learning Outcome Assessment, HOTs, Chemistry PermaLink | Plain Format | Corresponding Author (hayuni retno)

57	Chemistry Education	ABS-10
IMPLEMENTATION OF INNOVATIVE LEARNING MATERIAL WITH PROJECT TO IMPROVE STUDENTS PERFORMANCE IN THE TEACHING OF COMPLEXOMETRY TITRATION Rafidah Almira Samosir(a), Jecky Bukit(b), Manihar Situmorang(b)* and Murniaty Simorangkir(a) a)Department of Chemistry Education, Graduate Study Program, Universitas Negeri Medan (State University of Medan), Medan, North Sumatera, INDONESIA, 20221, E-mail : rafidahalmira7[at]gmail.com b)Department of Chemistry, Universitas Negeri Medan (State University of Medan), , 20221, E-mail: msitumorang[at]unimed.ac.id *Correspondence: Manihar Situmorang, Jl. Willem Iskandar, Medan, North Sumatra, INDONESIA 20221, Phone: 062-61-6613365, Faximile: 062-61-6613319, E-mail: msitumorang[at]unimed.ac.id Abstract An afford to chose the right teaching and learning strategy in the teaching of chemistry topic is very crusial as it is known that chemistry knowledge and skills are involveed. The teaching and learning paradigm have to be ajusted to support the enactment of competence curriculum suited to Indonesian National Qualifications Framework (Kerangka Kualifikasi Nasional Indonesia, KKNI). The policy has been stated in Universitas Negeri Medan to adopt KKNI curiculum, including in Analytrical Chemistry. Therefore, innovation in the teaching and learning have to be made for all subjects in the implementation of a competence-based curriculum suited to KKNI. The aim of the research is to implement an innovative learning material with project to improve students’ performance in the teaching of complexometric titration topic of Analytrical Chemistry. The research steps are consisted of providing sets of mini project on complexometric titration topic, innovation of a learning package with multimedia, and implementation of innovative learning material as learning media in the class. Research results showed that a standard and innovative learning package containing of mini projects for complexometric titration topic have been developed suited to the KKNI curriculum. The project example and the video to do the projects that are provided in the learning package are found effective to guide the students to do the desire project. Integration of multimedia in the learning package has motivated the students to learn the topic and make chemistry easy to learn. An innovative learning material with project has been proved to be able to improve students performance in analytical chemistry procedures. The facility available in a learning package adequate to guide the student to learn chemistry independently and students centre learning style was achieved. Keywords: Innovative, Learning Material, Contextual Learning, Multimedia, General Chemistry PermaLink | Plain Format | Corresponding Author (Rafidah Almira Samosir)

58	Chemistry Education	ABS-11
THE DEVELOPMENT OF INNOVATIVE LEARNING MATERIAL WITH PROJECT AND MULTIMEDIA FOR REDOX TITRATION Rohazmy Rizki (a), Habib Hernando (b), Manihar Situmorang (b*) and Simson Tarigan (a) a) Department of Chemistry Education, Graduate Study Program, Universitas Negeri Medan (State University of Medan), Medan, North Sumatera, INDONESIA, 20221, rohazmyrizkipurba[at]gmail.com b) Department of Chemistry, Universitas Negeri Medan (State University of Medan), Medan, North Sumatera, INDONESIA, 20221, E-mail: msitumorang[at]unimed.ac.id *) Correspondence: Manihar Situmorang, Jl. Willem Iskandar, Medan, North Sumatra, INDONESIA 20221, Phone: 062-61-6613365, Faximile: 062-61-6613319, E-mail: msitumorang[at]unimed.ac.id Abstract The development of innovative learning material with project and multimedia for redox titration is explained in this study. The study is aimed to provide an innovative learning material with project based learning that are integrated with multimedia to be used as learning facility to improve students competence in chemistry. Research procedures are consisted of preparation of complete and standard learning material with mini projects for redox titration topic of Analytical Chemistry, integration of multimedia and hyperlink to the main learning topic, standardization of the developed learning material, and implementation of the innovative learning material in the class. The results has showed that an innovative learning material with project and multimedia for redox titration topic has been developed as required in the competence curriculum of Indonesian National Qualifications Framework (Kerangka Kualifikasi Nasional Indonesia, KKNI). Redox titration topic consisted of 5 sub subjects, they are: Principle of redox titration, Indicator in Redox titration, Preparation of standard solution for redox titration, and Application of redox titration. The learning facilities such as multimedia, video, the hyperlink and help are provided in the the leaning material to make it easy to to use and be able to help the learner. Implementation of the projects with multimedia provide independent and enjoyble learning. Sets of mini projects given in the learning materials are found to be effective to facilitate the learner to learn redox titration topic. The facility available in a learning package adequate to guide the student to learn chemistry independently and students centre learning style was achieved. The developed learning material with project along with the recovery target to be assigned in the sample motivate the students to do project seriously. It has been proved that the developed innovative learning material is able to improve students skills to do titration and students outcomes are improved. Keywords: Innovative learning, Project based learning, Multimedia, Analytical Chemistry PermaLink | Plain Format | Corresponding Author (Rohazmy Rizki)

59	Chemistry Education	ABS-277
The validity of Problem-Solving Based Teaching Materials for The Exploration of Conceptual Change and Metacognitive Skills Dr. Utiya Azizah, M.Pd.*, Dr. Harun Nasrudin, M.S., Mitarlis, S.Pd. M.Si. Chemistry Department Universitas Negeri Surabaya Surabaya, Indonesia Abstract The learning process must be based on the aim to facilitate the formation of college students metacognitive skills so that the learning process for conceptual change can occur. The aim of the study was describing the validation of Problem-Solving based teaching materials for the exploration of conceptual change and metacognitive skills theoretically and empirically. Research and Development (R & D) design was utilized in the research method. This study involved three experts for theoretical validation and 31 college students for empirical validation. The instrument used for this study was the validation sheet and questionnaire of college students’ perception of problem-solving based teaching materials. The research obtained findings: (a) Theoretical validity from the expert has met the valid and very valid include the construct validities categories and the content validities as well as reliable, (b) empirical validity of the college students perception of the teaching materials based problem-solving includes the construct validities and content validities, all of them have valid and very valid categories. From this study, it can be concluded that the Problem-Solving based teaching materials were feasible and suitable for use on the exploration of conceptual change and metacognitive skills. Keywords: validity, teaching materials, problem-solving exploration conceptual change, metacognitive skills PermaLink | Plain Format | Corresponding Author (Utiya Azizah)

60	Chemistry Education	ABS-23
Implementation of Dubido Based on Contextual in Improving Students’ Achievement on The Topic of Rate Reaction Angeline Viska Ayu Rosalia(1), Saronom Silaban(2), Zainuddin Muchtar (2) Magister of Chemistry Education Study Program, Postgraduate School, Universitas Negeri Medan, Medan 20221, Indonesia(1) Departement of Chemistry, Universitas Negeri Medan, Medan 20221, Indonesia (2) Abstract The aim of this research was to know the gain of students achievement that taught by using dubido. The research has been done in Chemistry Educational Study Program in Unimed. The experimental class was given treatment with teaching by using dubido media based on contextual. The experimental class has fulfilled the requirement for normality and homogenity test. The mean of pretest results and posttest results were 42.240 and 84.480. The increase of posttest results indicated that learning by using dubido based on contextual can improve students achievement. The increase of students achievement signed by gain percent with the percent of gain value was 73.3. The result of t test was obtained from tcount is more than t table (2.590 is more than 1.677) at alpha is 0.05, it means that the implementation of dubido based on contextual was given positive effect to increase students achievement. Keywords: Contextual, Dubido, Rate reaction, Students Achievement PermaLink | Plain Format | Corresponding Author (Angeline Viska Ayu Rosalia)

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