Julia Kantasubrata
Pusat Penelitian Kimia – Lembaga Ilmu Pengetahuan Indonesia

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ANALISIS ANDAL HASIL UJI PROFISIENSI UNTUK PRODUK AGROINDUSTRI Budiantari, Fajarina; Arkeman, Yandra; Kantasubrata, Julia
JURNAL STANDARDISASI Vol 14, No 3 (2012): Vol. 14(3) 2012
Publisher : Badan Standardisasi Nasional

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Abstract

Sampel yang sama dapat mempunyai data hasil analisis yang berbeda apabila dianalisis pada beberapa laboratorium yang berbeda. Perbedaan hasil pengujian yang cukup besar dapat menimbulkan keraguan dalam mengambil suatu keputusan atau kesimpulan. Untuk mengetahui unjuk kerja laboratorium dan meningkatkan kinerja laboratorium dapat dilakukan uji profisiensi. Evaluasi hasil uji profisiensi yang berbeda dapat menyebabkan interpretasi hasil uji profisiensi yang berbeda pula. Hal ini berarti berpengaruh pula bagi penilaian kinerja laboratorium peserta. Penelitian ini bertujuan menganalisis beberapa metode evaluasi hasil uji banding (Metode 1: seleksi data Grubbs 1 kali kemudian terhadap data yang tersisa dilakukan perhitungan Robust Z-Score; Metode 2: seleksi data Grubbs berulang kali sampai tidak ada lagi data yg keluar, kemudian terhadap data yang tersisa dilakukan perhitungan Robust Z-Score; Metode 3: langsung Robust Z-Score). Selain itu dalam makalah ini akan dinalisis juga jenis metode pengujian yang digunakan oleh peserta uji profisiensi. Data yang digunakan adalah data hasil uji profisiensi yang dikoordinasikan oleh Komite Akreditasi Nasional (KAN) tahun 2011 untuk komoditi kakao bubuk dan saus cabai. Hasil penelitian menunjukkan metode evaluasi hasil uji 2 adalah yang paling sensitif (memberikan jumlah laboratorium outlier paling banyak) apabila dibandingkan dengan metode evaluasi hasil uji 1 dan 3. Hasil kinerja laboratorium peserta yang menggunakan metode pengujian Standar Nasional Indonesia (SNI) cukup memuaskan.
PEMISAHAN KROMATOGRAFI PADA FASA TERIKAT DIOl Kantasubrata, Julia
Jurnal Kimia Terapan Indonesia Vol 1, No 2 (1991)
Publisher : Research Center for Chemistry - LIPI

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2973.912 KB) | DOI: 10.14203/jkti.v1i2.302

Abstract

Chromatographic separation could not all be done on silica and alumina, therefore bonded phases have been developed by reacting organochiorosilane with the silanol group of silica. One of the new development of polar bonded phase is diol phase, which is prepared by reacting the silanol group of silica with GOX (glycidoxypropyttrimethoxysilane), Diol phase is widely applicated in TLC and normal phase HPLC. In -reversed phase HPLC, its application is limited, since with eluent containing water, it lasily swelled. Depending on the solute being separated, hidrogen bond, electron density and basicity play an important role in the retentiop mechanism. Its application on TLC plate make it possible to be used in bidimensional analysis. The application of dial phase is also discussed, eitherfor the exclusion separation of solutes with large molecular weight or for the separation of simple organic compounds such as steroids with normal phase chromatography mechanism.
KROMATOGRAFI LAPISAN TIPIS (KLT) DAN KROMATOGRAFI CAIRAN KINERJA TINGGI (KCKT) DARI SOLASODIN, AD DAN ADD Kantasubrata, Julia; Loyniwati, Loyniwati; Jamilah, Jamilah; T. Karossi, A.
Jurnal Kimia Terapan Indonesia Vol 3, No 2 (1993)
Publisher : Research Center for Chemistry - LIPI

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (5533.056 KB) | DOI: 10.14203/jkti.v3i2.273

Abstract

Thin Layer Chromatography (TLC) and High Performance Liquid Chromatography (HPLC) have been used to separate solasodlne, 4androstene-3,17-dione (AD) dan 1,4-androstadiene-3,17-dione (ADD)resulted from bloconversion process of solasodlne using Mycobacterium phlei DSM 43286. In order to minimize the consumption of materials, the separation condition of HPLC could be looked for through TLC method. Two kinds of chromatographic interaction i.e. normal phase and reversed phase chromatography using respectively silica and CIS as stationary phase have been tried. In normal phase chromatography, there are still difficulties for eluting solasodine from silica column, since solasodine has relatively low Rj value. While in reversed phase chromatography, solasodine could be eluted from CIS column, only if the mobile phase is buffered. The selection of solvent systems for this separation should also consider the relatively low UV-Cut-Off of individual solvent, since detection of solasodine requires operation at 205nm. The minimum limit detection which is measured at 240 11m was found to be 0.92 ng AD and 1.54 ng ADD, while the smallest amount of solasodine which could be detected at 205 nm was 3.39 ng. Diode array detector could be used for confirming the solute peaks produced in bioconverslon process.
THE DETERMINATION OF SUGARS BY CHROMATOGRAPHIC METHOD Sumartini, Sri; Kantasubrata, Julia
Jurnal Kimia Terapan Indonesia Vol 2, No 1-2 (1992)
Publisher : Research Center for Chemistry - LIPI

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2814.138 KB) | DOI: 10.14203/jkti.v2i1-2.289

Abstract

Experiments have been carried out to analyse sugars using TLC and HPLC methods, In the TLC method, separation of sugars was performed on silica plates impregnated with monosodium phosphate and using mixture of ethylacettuel pyridinde/water as an eluent. Whilst in the HPLC method, the use of three column types i.e. diol, RP-18 and modified silica column were tested. The results showed that TLC method was able to measure three sugars i:e. sucrose, glucose and fructose with standard deviations of 11.6%, 7,6% and 1,9%, respectively. On the other hand, the HPLC method with silica column modified by polyamine and compressed with WATERS RCM-l00, showed the best results, in which mixtures of nine sugars were well separated and measured quantitatively with good precisian.
PENGGUNAAN EKSTRAKSI FASA PADAT UNTUK ANALISIS TETRASIKLIN DALAM CONTOH UDANG Boes, Evita; Kantasubrata, Julia; T. Karossi, A.
Jurnal Kimia Terapan Indonesia Vol 3, No 2 (1993)
Publisher : Research Center for Chemistry - LIPI

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (3628.598 KB) | DOI: 10.14203/jkti.v3i2.275

Abstract

A great quantity of Indonesian frozen prawns were exported to Japan and America. Unfortunately these products have often been rejected due to their content of tetracycline derivative residues. Qualitative analysis of frozen prawn samples being exported by means of HPLC, indicated that they are contaminated by oxytetracycline and tetracycline residues. A problem of quantitative analysis of such residues could be due to several peaks of the matrix being eluted closely to the peaks of the tetracycline derivatives. An experiment was carried out to eliminate the peaks of the matrix origin using SPE (Solid Phase Extraction) in order to quantify the derivatives more accurately. Application of SPE in the sample pretreatment is useful not only for separating the solute being analyzed from the matrixs, but also for concentrating the tetracycline derivatives of the extract. The recovery of SPE column elution process was about 90% and the SPE octadecyl (1 ml) column capacity for oxytetracycline, tetracycline, demeclocycline and doxycycline i.e. 2.4-7.9 ug; 3.5-11.8 ug; 3.4-11.2 ug and 17.3-57.5 ug respectively.
PERKEMBANGAN ANALISA GULA SECARA KLT DAN KCKT*) Kantasubrata, Julia; Sumartini, Sri
Jurnal Kimia Terapan Indonesia Vol 2, No 1-2 (1992)
Publisher : Research Center for Chemistry - LIPI

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (4744.974 KB) | DOI: 10.14203/jkti.v2i1-2.290

Abstract

Analysis of sugars plays an important role, mainly in foods. Up to now, the search of spesific, selective, reproducible and accurate methods for sugar analysis is still being made. Sugars in foods consist of monosacharides, disacharides and trisacharides. Using conventional and spectrophotometric methods, which are based on measuremen of physical properties or chemical reactions, such individual amount of sugars can not be determined. The emergence of chromatographic techniques has initiated the development of individual sugar analysis. Thin layer chromatography (TLC) is widely used in sugar analysis, since is is simple, cheap, fast and ir has a capability to analyse several samples sinwltaneously. Commonly, lie analysis of sugars is conducted using silica gel as stationary phase. Satisfactory separation could only be produced with impregnated silica plates and multiple TLC runs. In order to reduce the separation time, new stationary phase was developed. The rapid separation of sugars has been achieved by using HPTLC plates Si 50000. In line with the development of bonded phase column, analysis of sugar using HPLC method has received considerable attention, using among others ion exchange columns, amino bonded silica phase, diol and C-18 columns. A relatively new type of sugar separation with a silica based column and eluen containing polyamine reagent has been developed by WATERS. This technique is called a SilicaAmine Modifier (SAM), in which the formation of Schiff base can be eliminated, the life time of the column becomes longer and better monosacharide separation can beproduced compared to other HPLC techniques.
THE USE OF TITRIMETRIC, NELSON SOMOGYI AND HPLC METHODS FOR THE ANALYSIS OF CASHEW APPLE JUICE FERMENTATION BROTHS Kantasubrata, Julia; T. Karossi, A.; S. Pramudi, A.
Jurnal Kimia Terapan Indonesia Vol 3, No 1 (1993)
Publisher : Research Center for Chemistry - LIPI

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/jkti.v3i1.295

Abstract

In cashew apple juice fermentation to produce wine and vinegar, analysis of organic acids and sugars in fermentation broths is very important, due to the fact that optimum conditions of fermentation could only be established from results obtained on monitoring the concentrations of those components during the fermentation process. Analysis of organic acids by tiirimetric method and analysis of sugars by Nelson-Somogyi method only give a total amount of acids and sugars. HPLC is one of the promising method for determining the acids/sugars individually, although this method needs costly facilities such as columns and so/vents. In this work, organic acids were separated by HPLC on a u-Bondapak C1B column using aqueous solution of 2% NH4H2O4 as the mobile phase, while sugars were separated on silica-based column using an eluent containing a polyamine reagent. In this investigation the results of determination of organic acids by titrimetric method and those of sugars by Nelson-Somogyi method were compared respectively with the results of individual organic acids and sugars obtained from the HPLC methods. It was found that for organic acids, results of the determination using the titrlmetric method is correlated linearly with the results of acetic acid obtained by the HPLC methods. The same results were obtained for total and reducing sugars determination by the Nelson-Somogyi and individual sugar by the HPLC methods. The regression equation obtained for each of the organic acids and sugars can be used for the estimation of each of the respective components present in the cashew apple juice fermentation broths based on the results obtained from both titrimetric and Nelson-Somogyi methods. For routine monitoring of large number of fermentation broth samples, the proposed method was found to be a better alternative to the more castly HPLC method.
PENGEMBANGAN METODA ANALISA KIMIA UNTUK PEMANTAUAN PROSES FERMENTASI PEMBUATAN ASAM CUKA, ANTIBIOTIKA DAN HORMON STEROID T. Karossi, A.; Kantasubrata, Julia
Jurnal Kimia Terapan Indonesia (Indonesian Journal of Applied Chemistry) Vol 1, No 2 (1991)
Publisher : Research Center for Chemistry - LIPI

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (3987.639 KB) | DOI: 10.14203/jkti.v1i2.301

Abstract

Chemical analysis plays an important role in monitoring fermentationprocess and determining product quality of the process. Nowadays the development of analytical methods, which commenced from relatively conventional method to instrumental method, has become a reality. The development does not only increase either sensitivity or reproducibility, but also could identify the existence of substances produced during fermentation, which could not be achieved by conventional methods. In this article, several chemical analyses used for monitoring the production of vinegar, antibiotic and steroid harmon are described. In vinegar fermentation, analyses cover the determination of sllgars, ethanol and organic acids, while in antibiotic fermentation, in addition to determination of sugar, analyses of tetracycline derivatives as fermentation products, is also carried out. In steroid fermentation, analysis covers the determination of solasodine as substrate, AD and ADD as fermentation products.