Jurnal Kimia Terapan Indonesia (Indonesian Journal of Applied Chemistry)
Not a member yet
300 research outputs found
Sort by
CARBON MONOXIDE CHEMISORPTION- CHARACTERIZATION AND TESTING OF PREPARED NICKEL CATALYSTS FOR AMINATION OF ETHANOL
Get PDFThree types of nickel metal catalyst supported on silica gel have been prepared using impregnation, ion exchanged sodium hydroxide and ion exchanged ammonia methods, in order to investigate the influence of preparation methods on metal dispersion and their activities for amination of ethanol. All the catalyst samples had a nominal nickel loading of 5 % (w/w). After preparation, the catalysts were activated by a drying stage followed by calcination and reduction. The result of transferring the nickel salt to the support phase has shown that the impregnation method was the most efficient, and the least efficient being the ion exchanged sodium hydroxide method. The results from the carbon monoxide chemisorption studies showed that the nickel is poorly dispersed(2%) in the impregnated sample, and highly dispersed(20%) in the ion exchanged sample prepared by the ammonia method. The dispersion was lower(6%) for the catalyst prepared by the sodium hydroxide method due to the formation of sodium nickel silicates which were difficult to reduce. The amination of ethanol over these catalysts was found to take place at 503 OK with methane being formed as a byproduct. The ion exchanged sample prepared by the ammonia method gave the highest yield(57%) of ethylamine although its specific activity/m2 nickel metal(4 x 10-7) was similar to the sample prepared by the impregnation method. The retained sodium in the ion exchanged sodium hydroxide catalyst poisoned metal sites for ethanol amination
PERKEMBANGAN ANALISA GULA SECARA KLT DAN KCKT*)
Get PDFAnalysis 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
EFFECTS OF MEDIUM COMPOSITION ON OXYTETRACYCLINE PRODUCTION BY STREPTOMYCES RIMOSUS ATCC 33022
No full textThe economical production of antibiotics to some extent depends on the availabilily of cheap substrates. The work reported in the present paper deals with the fermentative production of oxytetracycline by Streptomyces rimosus ATCC 33022 using commerciol high fructose syrup (HFS), vitamin B complex and citric acid of technical grode. The effects of concentration of high fructose syrup (0.5 - 2.5 %, v/v), commercial vitamin B complex (0.03 - 0.07 %, w/v) and the citric acid (0.34 - 1.28 %. w/v) were examined in this study. It was found that fermentation medium (medium-MHFS) containing high fructose syrup 1.0 % produced maximum activily of oxytetracycline after 4 days incubation period. Fermentation tnedium (mediwn-MBpleJ containing 0.05 % commerciol vitamin B complex showed maximum acrivily after 3 days incubation. While the addition of citric acid (0.64 %) to the fermentation medium (medium-MCA) was found optimumfor production oxytetracycline
LOW-TEMPERATURE SYNTHESIS OF LEAD ZIRCONATE TITANATE (PZT) POWDER FROM METAL ALKOXIDES
No full textPZT powder precipitate has been prepared by hydrolyzing a mixture of lead di-i-propoxide, zirconium tetra-n-butoxide and titanium tetrai-propoxide. The crystallization process of the amorphous PZT was studied by means of X-ray diffraction analysis. It was found that the powder precipitate was still amorphous on heating until 400C for 2k As an intermediate product, metastable cubic Pb2Ti2O6 (pyrochlore phase) was found after heating at 450C for 2h. In addition to Pb2Ti206 peaks, the diffraction peaks of perovskite PZT phase were observed after heating at 430C for 24 h. After heating at 600 C for 2h, only diffraction peaks of tetragonal perovskite PZT phase were found. The lattice parameters of the tetragonal PZT have been obtained to be a=4.066 A c=4.196 A This tetragonal perovskite phase was stable on heating until 1000 "C. The density of the compacted powder precipitate after heating at 1000C (a relatively low temperature for the sintering of PZT) for 30 min. was 6.1 g/cm3, about 76% of the theoretical value
PENAPISAN AKTIVITAS ANTIPROTOZOA DALAM BIJI SAGA (Adenanthera pavonina LINN)
No full textThe protozoa Tetrahymena pyriformis GL is an eucaryote. Its metabolism is similar to that of mammalia, so that it is widely used as a biological tool in protein quality as well as toxicity assays. In the framework of searching toxic or antinutritive properties in saga seed (Adenanthera pavonina LINN), extracts of saga bean were tested for their antiprotozoa activity. The saga bean extracts were obtained after successive extraction with nhexane and ethanol. Observation of total and motile cell population indicated that 0,1% saga oil in the medium did not show significant effect on the growth of T.pyriformis GL during 96 hours incubation at 30C. While ethanol extract of saga showed significant inhibition on the growth of T.pyriformis GL. Smaller cell population was already observed at 7 hours incubation at 30C. At 24 hours incubation, 0,1% and 1% ethanol extract of saga in the medium showed 55,1% and 87,6% inhibition respectively. Ethanol extract showed the largest anttprotozoal activity compared to the other extract. Qualitative analysis indicated the presence of saponin and alkaloid in the ethanol extract of saga bean. Chromatographic analysis with high performance liquid chromatography showed the presence of at least eight components in the ethanol extract of saga
Evaluation of Uncertainty in the Determination of Pesticide Residues in Tea using GC-ECD
No full textKey indicator of quality in test results is the uncertainty value, which could be evaluated using several common approach. Uncertainty evaluation in a-endosulfan and bifenthrin in Oolong tea, and cypermethrin in green tea using bottom-up approach showed that uncertainty component arising from GC-ECD instrument calibration, method performance i.e. repeatability and recovery were the main contributors to total uncertainty. Uncertainty component arising from weighing, dilution factor, stock standard solution, calibration solution, and moisture correction had no significant effect to total uncertainty, hence they could be neglected. Relative standard uncertainty obtained for all of pesticides residue were 18.23, 10.44, dan 14.98% for a-endosulfan, bifenthrin, and cypermethrin, respectively. Comparison with 2/3 CV Horwitz of 17.33, 10.62, and 12.44% respectively for all pesticide residues indicated that the evaluation of uncertainties were realisti
AMOBILISASI ENZIM PENISILIN ASILASE SEL TRANSFORMAN ESCHERICHIA COLI SC 50 MENGGUNAKAN GEL POLIAKRILAMIDA
No full textResults of study on the immobilization of dialysed fraction of penicillin acylase using various concentrations of acrylamide at BIS concentration 0,8 % are described. The study is an effort to increase the stability and efficiency of the enzyme use. The highest specific activity of the immobilized enzyme (1.38 U/mg protein) was found on immobilization using acrylamide 12.5 %. The penicillin acylase used in this study was obtained from the extraction of Escherichia coli Sc 50 cells. The optimum conditions of catalytic reaction of the enzyme were found 65C and pH 7.00 both for immobilized and free enzymes. Theoptimum catalytic time was 230 minutes for the immobilized enzyme and 100 minutes for the free one. The immobilized enzyme was found more stable against pH, temperature changes, and storage at the experimental conditions and could be used five times repeatedly with remaining activity of 50 %. The Km value of free enzyme was 7.21 mM and the Vmax was 0.065 unol 6APA/mg protein/minute. Immobilization increased the Km value to 20.26 mM, and decreased Vmax to 0,033 unol 6-APA/mg protein/ minute. Phenylacetic acid was found to be a mixed inhibitor for penicillin acylase E. coli Sc 50 with the inhibition constants of Ki 720.31 mM and Ki' 504.31 mM. Immobilization decreased Ki to 176.58 mM and Ki' to 27.61 mM
STUDI PEMISAHAN Co(II), Cu(II), Fe(III) DAN Ni(II) SECARA EKSTRAKSI PELARUT DENGAN ZAT PENGKOMPLEKS NATRIUM DIETILDITIOKARBAMAT
Get PDFSodium diethyldithiocarbamate (NaDDC) as a chelating agent reacts unselectively with cobalt(II), copper(II), iron(III) and nickel(II). Their maximum wavelengths are very similar in carbon tetrachloride solution and hence these complexes could not be determined by UV/VIS spectrophotometer without prior separation. A scheme of separation has been found for qualitative analysis of cobalt(II), copper(II), iron(III) and nickel(II) at a certain pH using a specific masking agent. It was found that pH 9 turned out to be the best condition for iron(III) masking but neither for cobalt(II), nor for copperill] and nickel(II). The addition of 10 mL HCI 12 N to the complex solutions of Co(II), Cu(II) and Ni(II) would remove Cu(II) and Ni(II) complexes from CC14 to water phase whereas Co(II) complex was still in the CCl4 phase. Cu(II) and Ni(II) ions in the water phase were then treated with 10 mL Titriplex 8,66 x 10-5 mole at pH 9 in which Ni(II) was masked but not Cu(II)
KLON GEN PENISILIN ASILASE PADA COSMID pHC79
Get PDFPenicillin acylase plays an important role in the catalysis of benzylpenicillin hydrolytic reaction, prodeucing 6-aminopenicilanic acid (6- APA), a precursorfor the formation of penicillinderivatives. Cloning of the penicillin acylase gene of Escherichia coli B130 chromosomal DNA on pHC79 cosmid vector to increase the enzyme activity has been investigated. The cloning was cooducted with several steps, including isolation of the chromosomal DNA. digestion by restriction enzyme, ligation by T4-DNA ligase, transformation of the recombinant DNA, and selection of the transformans. Microbial assay utilizing Serratia marcescens was carried out for screening the penicillin acylase colony, whereas the determination of the enzyme activity was examined based on Kornfeld method. From 2070 colonies screened by S. marcescens, only 4 positive colonies were obtained. The enzyme activity of these colonies was 4-6 fold higher than the penicillin acylase activity from E. coli B 130
ISOLATION AND IDENTIFICATION OF SIMIARENOL FROM THE LEAVES OF FICUS AURANTIACEA GRIFF (MORACEAE)
Get PDFoai:ojs.localhost:article/177Ficus aurantiace a Griff (Mor aceae) collected from BukitKaba forest park, Bengkulu, was studied for the isolation andidentification of its bioactive constituents. This plant is a climbingtree, having large colored fruits, orange to red marbled withwhite spots. The methanol-soluble extract of the leaves was eluted10 silica-gel column chromatography several times using mixturesof chloroform-methanol as the elution solvent, leading to theisolation of a known compound, simiarenol. The structure ofsimiarenol was judged by its data comparison to published values,and based all the evaluation results of its physical andspectroscopic data. such as UV, IR, MS, one- and two-dimensional NMR, HMQC and HMBC