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All Journal Prosiding Seminar Nasional MIPA Jurnal Pengelolaan Laboratorium Pendidikan
Putu Lilik Pratami Kristiyanti
Universitas Pendidikan Ganesha
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SKRINING FITOKIMIA DAN UJI AKTIVITAS ANTIOKSIDAN EKSTRAK ETANOL DAUN MATOA (Pometia pinnata) DENGAN METODE DPPH Ni Wayan Martiningsih; Gede Agus Beni Widana; Putu Lilik Pratami Kristiyanti
Prosiding Seminar Nasional MIPA 2016: PROSIDING SEMINAR NASIONAL MIPA UNDIKSHA 2016
Publisher : Prosiding Seminar Nasional MIPA

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Abstract

Penelitian ini bertujuan untuk mengetahui kandungan metabolit sekunder dan menguji aktivitas antioksidan ekstrak etanol daun matoa (Pometia pinnata). Sampel daun matoa yang digunakan berasal dari daerah Banyuasri, Singaraja. Ekstraksi dilakukan dengan metode maserasi menggunakan pelarut etanol. Hasil maserasi tersebut kemudian diuapkan menggunakan rotary evaporator sehingga diperoleh ekstrak kental etanol sebanyak 10,44 gram. Ekstrak kental etanol dianalisis kandungan metabolit sekundernya dengan cara skrining fitokimia. Pengujian aktivitas antioksidan dilakukan dengan metode 1,1-difenil-2-pikrilhidrazil (DPPH). Analisis kekuatan antioksidan dilakukan dengan menghitung nilai IC50 yang didasarkan pada persen peredaman radikal bebas oleh sampel uji. Kekuatan antioksidan ditentukan berdasarkan perbandingan antara IC50 dari sampel ekstrak etanol daun matoa dengan vitamin C. Hasil skrining fitokimia terhadap ekstrak kental etanol daun matoa mengindikasikan adanya senyawa flavonoid dan tanin. Berdasarkan perhitungan nilai IC50 diperoleh hasil bahwa nilai IC50 dari ekstrak etanol daun matoa sebesar 45,78 ppm dan vitamin C sebesar 7,53 ppm. Hal ini menunjukkan bahwa aktivitas antioksidan ekstrak etanol daun matoa lebih lemah dibandingkan dengan vitamin C. Kata-kata Kunci: daun matoa, skrining fitokimia, antioksidan, DPPH AbstractThis research aimed at evaluating the  secondary metabolites as well as antioxidant properties of the ethanol extract of matoa leaves (Pometia pinnata). The research samples were collected at Banyuasri, Singaraja. The extract of matoa leaves was prepared by maceration in ethanol and followed by evaporation using rotary evaporator to give 10,44 gram of crude extract. Crude extract was analyzed the secondary metabolites by phytochemical screening.The antioxidant properties was calculated by measuring the reduction precentage of free radical DPPH (1,1-Diphenyl-2-Picrylhydrazyl). The antioxidant strength was determined based on comparison between IC50 from ethanol extract of matoa leaves with vitamin C. Phytochemical screening of the extract strongly indicated the presence of flavonoid and tanin. The IC50 value of ethanol extract is 45,78 ppm and vitamin C is 7,53 ppm. These values suggested that the ethanol extract of matoa leaves exhibited weak antioxidant properties compound to that of vitamin C. Keywords : matoa leaves, phytochemical screening, antioxidant, DPPH
Optimasi Kinerja Alat Fourier Transform Infrared (FTIR) Melaui Studi Perbandingan Komposisi dan Ketebalan Sampel-KBr I Dewa Putu Subamia; Ni Nyoman Widiasih; I Gusti Ayu Nyoman Sri Wahyuni; Putu Lilik Pratami Kristiyanti
Jurnal Pengelolaan Laboratorium Pendidikan Vol.5, No.2, Juli 2023
Publisher : UPT Laboratorium Terpadu, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/jplp.5.2.58-69

Abstract

Problems often occur in sample testing using the FTIR instrument, one of which is that the spectrum quality of the measurement results is not optimal. This has implications for the accuracy of the test results. This condition indicates that the performance of the tool is not optimal. The non-optimal quality of this spectrum is thought to be influenced by the composition factor and the thickness of the sample-KBr which is measured not in accordance with the legibility limits of the instrument. To overcome this problem, it is important to conduct a study to find out the optimum composition and thickness of the KBr-sample which can be measured properly by the instrument. The purpose of this study was to optimize the performance of the FTIR device through a study of the optimum composition and thickness of the KBr-sample so that a good spectrum was produced in the sample measurement using FT-IR type IRAffinity-1 Shimadzu. This research is an experimental research with infrared spectrophotometry method, using the One Shot Case Study design. The treatment is a measurement of the variation in the composition of the sample-KBr and the thickness of the sample. The spectrum resulting from the reading of the FT-IR spectrophotometer is interpreted to include wave number and transmittance percent. The results of the readings of each variation are compared with the standard spectrum to see the optimization of the measurement results so that the best spectrum is obtained. The results showed that the optimum ratio of the sample-KBr composition was 4% and the optimum thickness was 1/2 pan.
Co-Authors DWI SURYANTO Gede Agus Beni Widana I Dewa Putu Subamia I Gusti Ayu Nyoman Sri Wahyuni Ni Nyoman Widiasih