Stannum : Jurnal Sains dan Terapan Kimia <p>Jurnal Sains dan Terapan Kimia published research article, minireview/review, and short communication that included studies in Inorganic Chemistry, Organic Chemistry, Analitycal Chemistry, Biochemistry, Physical Chemistry, Computational Chemistry, Chemical Engineering, and Applied Chemistry</p> Department of Chemistry - Universitas Bangka Belitung en-US Stannum : Jurnal Sains dan Terapan Kimia 2714-674X Synthesis of Rare Earth Metal Oxides Based on Monasite Sand with pH Variations <p>In the island of Bangka Belitung, the presence of monazite is quite abundant, monazite minerals contain rare earth metals. Rare Earth Metals are groups of elements that have similar properties, for example neodymium, cerium, lanthanum, and others. Rare earth metal applications are very potential in various fields. In this research, the synthesis of rare earth metals by sol gel method at pH variations of 5.5, 6.5 and 7.5 was carried out. In this case, only changes in the levels of P<sub>2</sub>O<sub>5</sub>, La<sub>2</sub>O<sub>3</sub>, CeO<sub>2</sub>, and Nd<sub>2</sub>O<sub>3</sub> compounds were observed. The results showed an increase in levels of rare earth metals. This is indicated by the increase in La<sub>2</sub>O<sub>3</sub> levels by 4,421% from the initial level at pH 7.5 CeO<sub>2 </sub>which has increased levels by 7,166% at pH 7.5, and Nd<sub>2</sub>O<sub>3</sub> which has increased levels of 5.116% at pH 6.5. On the other hand, of &nbsp;P<sub>2</sub>O<sub>5 </sub>&nbsp;has decreased significantly (22.037%)</p> <h4>&nbsp;</h4> <p><strong>Keyword</strong>: Monasite, Rare Earth, Sol Gel, pH</p> Anisa Indriawati Herman Aldila Verry Andre Fabiani ##submission.copyrightStatement## 2020-10-31 2020-10-31 2 2 1 4 10.33019/jstk.v2i2.1953 Analysis of Total Terpenoids from Maniltoa Grandiflora (A. Gray) Scheff Leaves Using TLC and HPLC Methods <p>Terpenoids screening were carried out using Liebermann Burchard and Salkowski reagent on the extract of Saputangan leaves. It showed that the leaves contained terpenoid compounds with appeared of a reddish brown ring in the extract and a reddish brown stain appeared on the TLC plate tested with 1% CeSO<sub>4</sub> reagent in 10% H<sub>2</sub>SO<sub>4</sub>. The macerate of saputangan leaves processed separation using the partition method (Liquid-liquid Extraction). Extracts dissolved with methanol were partitioned with n-Hexane and then partitioned between aquadest and ethyl acetate in a ratio of 1: 1 to obtain 50 g of total terpenoids. Furthermore, TLC analysis was performed on total terpenoids using n-hexane: ethyl acetate (80:20 v/v) solvent to obtain 11 separate stains on the TLC plate with different Rf each. Analysis was enhanced in HPLC using 100% acetonitrile and 0.1% phosphoric acid at a wavelength of 210 nm, a flow rate of 0.500 mL/min and eluted for 30 minutes. Based on the HPLC results, there were 25 peaks which indicated the presence of total terpenoid compounds with the highest peak being peak no. 8 (ret.time's 6.234, area's 8503532 and height's 276032), peak no. 9 (ret.time's 6.674, area's 3322572 and height's 141859) and peak no. 10 (ret.time's 7.288, area's 2758231 and height's 103927)</p> Jhon Patar Sinurat Visensius Krisdianilo Reh Malem br Karo Rinaldo Berutu ##submission.copyrightStatement## 2020-10-31 2020-10-31 2 2 5 9 10.33019/jstk.v2i2.1976 the synthesis and characterization composite Fe3O4/chitosan/clay Bangka <p><em>Synthesis and characterization of Fe<sub>3</sub>O<sub>4</sub>/chitosan/clay Bangka has been carried out. </em><em>Synthesis of composite was done with variations the composition of clay</em><em> (0; 25; 50; 100 %) at the composition of Fe<sub>3</sub>O<sub>4</sub> 95 mg of Fe<sub>3</sub>O<sub>4</sub> and 1 gr of chitosan. Characterization of composite Fe<sub>3</sub>O<sub>4</sub>/chitosan/clay have been analysed with XRD, FTIR, porosity test, the degree of development, and adsorption efficiency test for Cu<sup>2+ </sup>ion. The results of the analysed with XRD show the difractogram of clay and Fe<sub>3</sub>O<sub>4</sub></em><em> at </em><em>2θ= 8,92<sup>o</sup>, 29,57<sup>o</sup>, and 45,61<sup>o </sup>(clay)</em><em>; </em><em>26,90<sup>o</sup>, and 35,64<sup>o </sup>(Fe<sub>3</sub>O<sub>4</sub>). </em><em>Results of the analysed with ftir show the spectrum of the chitosan, clay, and Fe<sub>3</sub>O<sub>4</sub> at</em> <em>3825, 3689, 2103, 1425 cm<sup>-1 </sup>(chitosan), 1028, 884,41 cm<sup>-1</sup> (clay), 791,11 cm<sup>-1</sup> (chitosan) and 696,95 cm<sup>-1</sup> (Fe<sub>3</sub>O<sub>4</sub>)</em><em>. The results of porosity test and the degree of development showed the high point are 1,547 and 754,63% without composition of clay. The adsorption test for Cu<sup>2+ </sup>ion show percentage of adsorption efficiency is </em><em>72,41% </em><em>at composite of Fe<sub>3</sub>O<sub>4</sub>/chitosan with the clay added 1 gr. </em></p> <p><em>&nbsp;</em></p> <p>&nbsp;</p> <p><strong>&nbsp;</strong></p> Eva Julianti Verry Andre Fabiani Ristika Oktavia Asriza ##submission.copyrightStatement## 2020-10-31 2020-10-31 2 2 10 15 10.33019/jstk.v2i2.1897 Antibacterial Activity of Flavonoid-Rich Fractions Of Citrus Maxima Peel Extract <p>Natural products can be used as an alternative in the treatment of various diseases such as infectious diseases due to the bioactive compounds contained therein. Moreover nowdays, there are many antibiotic resistance in the treatment of infectious diseases. <em>Citrus </em>maxima is one of the natural products. Citrus maxima have been used for many diseases in traditional medicine.The aim of this study was to investigate the antibacterial activity of flavonoid-rich fractions of <em>citrus maxima </em>peel extract. The bioactive compounds contained in<em>&nbsp; Citrus maxima </em>peel were extracted by maceration method using 96% ethanol solvent. Fractionation was conducted using liquid-liquid extraction using a solvent of water and ethyl acetate obtained ethyl acetate fraction. In this fraction, the TLC test was carried out to confirm the presence of phenolic and flavonoid compounds. The antibacterial activity testing for ethyl acetate fraction&nbsp; against <em>S.aureus </em>and <em>E.coli </em>was determined&nbsp; by disk diffusion method with concentration of 25 ppm, 50 ppm, 75 ppm and 100 ppm. The ciprofloxacin and distilled water were used as positive and negative control, respectively. The result of this study showed that ethyl acetate fraction ( flavonoid-rich fractions) Of <em>Citrus Maxima</em> has potential as antibacterial for bacterial <em>S.aureus </em>and <em>E.coli</em> with medium inhibitory ability in all of concentration ranges. The highest inhibition zone for <em>S.aureus </em>&nbsp;was found&nbsp; at a concentration of 100 ppm while for <em>E.coli </em>was at a concentration of 75 ppm.</p> Reh Malem br Karo Putranto Manalu Jhon Patar Sinurat ##submission.copyrightStatement## 2020-10-31 2020-10-31 2 2 16 21 10.33019/jstk.v2i2.1977