FTIR spectroscopy in combination with multivariate calibration of Partial Least Square (PLS) has been developed for quantification of curcumin in the ethanolic extracts of Curcuma longa Linn and Curcuma xanthorriza Roxb. The optimization was done by selecting the best wavenumbers regions capable of providing the high coefficient of determination (R 2) and low values of Root Mean Square Error of Calibration (RMSEC). Finally, wavenumbers region of 2000-950 cmG 1 was selected for prediction of curcumin in the extracts. The correlation between actual values of curcumin determined by HPLC and FTIR predicted values using FTIR spectroscopy combined with PLS in ethanolic extract of C. longa and C. xanthorriza at 2000-950 cmG 1 revealed R 2 values of 0.96 and 0.99, respectively. The RMSEC values obtained are 0.299 and 0.089 for C. longa and C. xanthorriza, respectively. The high value of R 2 and low value of RMSEC indicated the high accuracy and precision of FTIR spectroscopy for quantification of curcumin in the extracts. These results indicated that FTIR spectroscopy combined with PLS is an alternative technique for determination of curcumin in Curcuma species. The developed method (FTIR spectroscopy) is rapid, no sample preparation and not involving excessive solvents and reagents.
Penelitian ini bertujuan untuk untuk mengetahui efektivitas penggunaan laboratorium virtual sebagai media pembelajaran praktikum analisis farmasi di Universitas Islam Indonesia. Metode yang digunakan adalah deskriptif dengan pendekatan kuesioner. Laboratorium Virtual membantu mahasiswa memahami proses praktikum. Hal ini dibuktikan dengan peningkatan rata-rata nilai akhir dan respon kinerja dosen. Hasil belum bisa dibandingkan karena perbedaan kondisi dan metode penilaian dengan praktikum luring.
A simple and isocratic liquid chromatographic using UV detection at wavelength of 425 nm have been validated and used for quantitative analysis of curcumin in ethanolic extract of turmeric (Curcuma longa Linn.) and Curcuma xanthorriza (Zingiberaceae), indigenous to Java region, Indonesia. The method was optimized for separation of three curcuminoids namely curcumin, demethoxycurcumin and bisdemethoxycurcumin using Waters Xterra MS C18 column (4.6×250 mm, 5 μm). The mobile phase used consisted of aquabidestilata and acetonitrile (65:35 v/v) containing 1% acetic acid. The analytical method was validated in terms of linearity, sensitivity, precision and accuracy. The developed method was linear over the curcumin concentration range of 10-60 μg mLG 1 with correlation coefficient value of 0.999. The precision of the developed method expressed as Relative Standard Deviation (RSD) value was in the range of 0.17-1.17% for three different levels of sample. The recoveries obtained for the accuracy assessment were 8.50-101.23%. The sensitivity of analytical method was expressed with Limit of Detection (LoD) and Limit of Quantification (LoQ). The values of LoD and LoQ were 1.13 and 3.34 μg mLG 1 , respectively. The method was successfully used for quantitative analysis of curcumin in the rhizomes of Curcuma longa and Curcuma xanthorriza. The levels of curcumin found in those rhizomes are in the range of 3.03±0.01-7.31±0.02 (C. longa) and in the range of 1.69±0.02-4.92±0.01 (C. xanthorriza).
<span>Metadiscourse is an integral element of writing since it helps writers to organize and shape their arguments, but at the same time reflect their stance towards both the content and readers. There have been numerous studies concerning metadiscourse markers. However, little research has been done where Americans are directly compared with Indonesians. Furthermore, most of them have focused more on opinion, editorial, and sport articles, but not many have examined business ones. Considering this situation, the writer has become interested in investigating whether there are similarities and differences between how American and Indonesian writers incorporate metadiscourse markers in their opinion and business articles. The data for this research is taken from articles from two online newspapers, i.e. Washington Examiner and The Jakarta Post with a corpus size of 7,000 words for each type of article. The AntConc software version 3.5.6 by Anthony (2018) is used to analyze the data. The findings of the study reveal that there are some similarities and differences in the way American and Indonesian writers employ these markers in the writing of opinion and business articles.</span>
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