scholarly journals Fourier Transform Infrared Spectral Analysis of Polyisoprene of a Different Microstructure

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Dongmei Chen ◽  
Huafeng Shao ◽  
Wei Yao ◽  
Baochen Huang
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Spectral Analysis ◽  
Fourier Transform ◽  
Magnetic Resonance ◽  
Detailed Analysis ◽  
Fourier Transform Infrared ◽  
Ftir Spectra ◽  
H Nmr ◽  
Infrared Spectral

Some polyisoprene samples of different microstructure contents were studied by Fourier transform infrared (FTIR) and1H Nuclear magnetic resonance (1H NMR). On the basis of detailed analysis of FTIR spectra of polyisoprene, the shift of absorption peaks caused by microstructure content’s variation was discussed. The contents of the polyisoprene samples’ microstructure which was determined by the1H NMR was used as the standard. Through the choice, calculation, and comparison with the corresponding absorption peaks of FTIR, a method based on the results of the analysis has been developed for the determination of the microstructure contents of polyisoprene by FTIR.

scholarly journals Isolasi Senyawa Metabolit Sekunder dari Ekstrak Metanol Kulit Batang Bauhinia semibifida Roxb. dan Uji Aktivitas Antioksidan

2021 ◽  
Vol 17 (1) ◽  
pp. 132
Author(s):  
Haiyul Fadhli ◽  
Nur Fitria Rohmatul Ummah ◽  
Noveri Rahmawati
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Antioxidant Activity ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Magnetic Resonance ◽  
Vitamin C ◽  
Fourier Transform Infrared Spectroscopy ◽  
Fourier Transform Infrared ◽  
Proton Nuclear Magnetic Resonance ◽  
H Nmr

<p>Kulit batang <em>Bauhinia semibifida </em>Roxb. telah lama digunakan sebagai obat tradisional oleh masyarakat Melayu Lingga, Kepulauan Riau. Penelitian ini bertujuan untuk mengisolasi dan menguji aktivitas antioksidan senyawa metabolit sekunder dari ekstrak metanol kulit batang <em>B. semibifida </em>Roxb. Tiga isolat murni berupa satu senyawa alkaloid (BR1) dan dua senyawa flavonoid (BR2 dan BR3) telah berhasil diisolasi dengan cara ekstraksi menggunakan metode maserasi dan dilanjutkan fraksinasi dengan metode kromatografi kolom. Uji aktivitas antioksidan dilakukan terhadap isolat dengan metode 2,2 difenil-1-pikrilhidrazil (DPPH). Senyawa isolat BR1 menunjukan IC<sub>50 </sub>&gt;1000 µg/mL dikategorikan tidak aktif sebagai antioksidan, sedangkan senyawa isolat BR2 dan BR3 menunjukan IC<sub>50</sub> 2,92 µg/mL dan 4,39 µg/mL dikategorikan sangat kuat sebagai antioksidan jika dibandingkan dengan vitamin C sebagai kontrol. Berdasarkan evaluasi aktivitas antioksidan senyawa BR2 adalah senyawa pilihan yang dilanjutkan identifikasi dengan spektroskopi <em>Fourier-Transform Infrared Spectroscopy </em>(<em>FTIR</em>) dan <em>Proton Nuclear Magnetic Resonance</em> (<sup>1</sup>H-NMR) sehingga diduga senyawa isolat memiliki struktur dasar senyawa flavonoid.</p><p><strong>Isolation of Secondary Metabolite Compounds of Methanolic Extract of Steam Bark <em>Bauhinia semibifida</em> Roxb. and Their Antioxidant Activites</strong>. Stem bark of <em>Bauhinia semibifida</em> Roxb. has been long consumed as a medicinal herb by Lingga Malaya Ethnic. Therefore, this research aimed to isolate and examines the antioxidant activity of secondary metabolites from methanol extract of stembark of <em>Bauhinia semibifida</em> Roxb. Three pure compounds which are an alkaloid (BR1) and two flavonoids (BR2 and BR3) have been isolated by extraction using maceration method followed by fractionation using column chromatography method. Antioxidant activity assay was carried out by 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) method. Compound BR1 showed IC<sub>50</sub> &gt;1000 µg/mL categorized as inactive as an antioxidant, while compounds BR2 and BR3 showed IC<sub>50</sub> 2.92 µg/mL and 4.394 µg/mL, respectively, categorized as very strong as an antioxidant when compared to vitamin C as a control. Based on the evaluation of the antioxidant activity, the BR2 was selected compound and continued to identification by <em>Fourier-Transform Infrared Spectroscopy </em>(<em>FTIR</em>) and <em>Proton Nuclear Magnetic Resonance</em> (<sup>1</sup>H-NMR) spectroscopy so that the isolate has the basic structure of flavonoid compound.</p>

Formation Mechanism and its Pozzolanic Activity of Metakaolin

2014 ◽  
Vol 602-603 ◽  
pp. 620-623 ◽  
Author(s):  
Mei Rong Wang ◽  
Ning Guo ◽  
Pei Gang He ◽  
Jing Bo Yu ◽  
De Chang Jia
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Fourier Transform ◽  
Solid State ◽  
Magnetic Resonance ◽  
Formation Mechanism ◽  
Infrared Spectra ◽  
Fourier Transform Infrared ◽  
Pozzolanic Activity ◽  
Different Temperatures ◽  
Increasing Temperature

In this paper, the process of the transformation from kaolin to metakaolin was investigated. The kaolin was calcined at different temperatures and analyzed by Xray diffraction (XRD), Fourier transform infrared spectra (FTIR) and solid state nuclear magnetic resonance (NMR). The formation of metakaolin structure was based on the stacking polyhedrons changes, which originated from dehydroxylation of kaolinite. With increasing temperature, kaolin kept structure of kaolinite unchanged in the course of dehydroxylation and then structure of kaolinite transformed to metakaolin when the dehydroxylation was over. It was demonstrated that the essence of pozzolanic activity of metakaolin. The result revealed that the pozzolanic activity of metakaolin increased with increasing temperature at the range of 600~900 °C.

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