Found 2 Documents

Jurnal MIPA Vol 3, No 1 (2014)
Publisher : Sam Ratulangi University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35799/jm.3.1.2014.3899


Telah dilakukan penelitian tentang skrining fitokimia dan uji aktivitas antioksidan dari daun nasi (Phrynium capitatum) dengan metode DPPH (1,1-difenil-2-pikrilhidrazil). Skrining fitokimia meliputi pengujian alkaloid, flavonoid, saponin, steroid, triterpenoid dan fenolik. Uji aktivitas antioksidan dilakukan dengan penambahan 2 mL larutan DPPH dengan 0,5 mL larutan ekstrak dengan konsentrasi masing-masing 1000, 750, 500 dan 250 µg/mL. Data yang diproleh kemudian digunakan untuk menghitung nilai IC50 dari ekstrak etanol daun nasi. Hasil pengujian menunjukan bahwa ekstrak etanol daun nasi mengandung senyawa alkaloid, flavonoid, saponin, steroid dan fenolik. Ekstrak etanol daun nasi memiliki aktivitas antioksidan trrtinggi pada konsentrasi 1000 µg/mL sebesar 65,77 % dan semakin menurun aktivitasnya dengan berkurangnya konsentrasi ekstrak, konsentrasi 750, 500 dan 250 µg/mL masing-masing sebesar 53,96 %, 43,8 % dan 19,58 % dengan nilai IC50 pada konsentrasi 701,78 µg/mL.A research on phytochemicals screening and antioxidant activity test of daun nasi (Phrynium capitatum) using DPPH (1,1-diphenyl-2-picrylhydrazyl) method had been conducted. Test for alkaloids, flavonoids, saponins, steroids, triterpenoids and phenolic were included in phytochemical screening. Antioxidant activity was tested through the addition of 2 mL DPPH solution into 0.5 mL of the extract having a concentration of 1000, 750, 500 and 250 µg/mL respectively. The data obtained was used to calculate the IC50 value for the ethanol extract of daun nasi. The results showed that the ethanol extract of daun nasi contains alkaloids, flavonoids, saponins, steroids and phenolic. Ethanol extract of daun nasi has the highest antioxidant activity of 65.77% at concentration of 1000 µg/mL. Its activity decreased with decreasing concentration of the extract, which were 53.96 %, 43.8 % and 19.58 % at concentration of 750, 500 and 250 µg/mL respectively. IC50 values was found at a concentration of 701.78 µg/mL.
Transesterification of Used Cooking Oil Using CaO/MCM-41 Catalyst Synthesized from Lapindo Mud by Sonochemical Method Mahardika, Ida Bagus Putra; Trisunaryanti, Wega; Triyono, Triyono; Wijaya, Dwi Putra; Dewi, Kumala
Indonesian Journal of Chemistry Vol 17, No 3 (2017)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (14.303 KB) | DOI: 10.22146/ijc.26561


Transesterification of waste cooking oil using CaO/MCM-41 synthesized from Lapindo mud by the sonochemical method has been carried out. The silica was separated from the mud by reflux method used 6 M HCl and 6 M NaOH. The silica was then analyzed by XRF and used as silica source in MCM-41 synthesis. The synthesis of MCM-41 was carried out by the sonochemical method, then analyzed by XRD, Infrared spectrophotometer, SAA, and TEM. The Ca2+ was loaded onto the MCM-41 by wet impregnation method under variation of the Ca2+ content of 1.15, 1.29, 2.39, and 3.25 wt.% analyzed by ICP produced CaO(1), CaO(2), CaO(3), and CaO(4)/MCM-41 catalyst respectively. Transesterification of used cooking oil was carried out under methanol/oil mole ratio of 15/1, the temperature of 55, 65 and 75 °C, and catalyst/oil weight ratio of 5/100, 10/100 and 15/100 for 2 h by reflux method. The XRD analysis of the MCM-41 showed a characteristic peak at 2θ = 2-5°. The MCM-41 has a specific surface area of 1290 m2/g and pore diameter of 3.4 nm. The TEM images of MCM-41 showed ordered pore distribution with a hexagonal shape. The highest conversion of methyl ester was 78.17 wt.% obtained under the reaction conditions at 65 °C and catalyst/oil weight ratio of 15/100 using the CaO(4)/MCM-41. The lifetime CaO(4)/MCM-41 catalyst was 9.8 h.