Ml Of Concentrated Hydrochloric Acid Research Articles

Studies on the structural, morphological and optical properties of HCl assisted vanadium oxide/tin oxide nanocomposites prepared by sol-gel method

Nanocomposites have gained much importance in different fields, commercially and technologically, due to the possibilities in tuning the properties of nanocomposites. In the present work, vanadium oxide (V2O5)/tin oxide (SnO2) nanocomposites were synthesized using simple sol-gel method. Two independent experiments were carried out to synthesis the V2O5/SnO2 nanocomposites. The V2O5/SnO2 nanocomposites were prepared from the precursors of tin chloride, ammonium metavanadate and ethanol (Experiment 1). A few ml of concentrated hydrochloric acid (HCl) was added in the precursors with and V2O5/SnO2 nanocomposites were prepared (Experiment 2) using ethanol as a solvent. Effect of HCl on the modifications of structural, morphological and optical properties of the V2O5/SnO2 nanocomposites was studied. Coexistence of V2O5 and SnO2 phases was confirmed by the X-ray diffraction studies. Thermogravimetric analysis (TGA) shows the stability of the as-synthesized V2O5/SnO2 nanocomposites from 350 °C. The crystallinity and the surface morphology of the synthesized V2O5/SnO2 nanocomposites were improved effectively due to addition of HCl in the preparation of the precursor solution. UV-DRS absorption spectra showed that the absorbance is modified and the band gap is decreased with increase in crystallite size due to the addition of HCl. The predominant Raman peaks at 140 cm−1 and 991 cm−1 confirm the presence of orthorhombic V2O5 phase. Further, the addition of HCl in the preparation of precursor solution revealed marked difference in the surface morphology of the nanocomposites.

Structural, morphological and optical properties of tin oxide nanoparticles synthesized by sol–gel method adding hydrochloric acid

Tin oxide (SnO2) nanoparticles were synthesized by sol–gel method from cost-effective tin chloride (SnCl2·2H2O) and ethanol by adding ammonia solution. In a separate experiment, 4 ml of concentrated hydrochloric acid was added to this solution and SnO2 nanoparticles were prepared. Further SnO2 nanoparticles prepared without and with adding the hydrochloric acid were annealed at 200 °C for 1 h. The structural, morphological and optical properties of the synthesized SnO2 nanoparticles were studied by X-ray diffraction, scanning electron microscope, UV–Vis spectroscopy, Fourier transform infrared spectroscopy and fluorescence spectroscopy techniques. As prepared SnO2 nanoparticles by adding hydrochloric acid in the synthesis process reduced the crystallite size to ~4 from ~10 nm size of the annealed SnO2 nanoparticles prepared without adding hydrochloric acid. Annealing the SnO2 nanoparticles prepared adding hydrochloric acid improved the crystallite size from ~4 to ~4.5 nm. Addition of hydrochloric acid effectively modified the morphology of the SnO2 nanoparticles from agglomerated spherical structure to cauliflower-like structure. The band gap is increased due to decrease in the crystallite size in the sample prepared adding hydrochloric acid. Fluorescence spectrum exhibits a strong emission peak at 350 nm. Addition of HCl plays a major role to suppress the hydrolysis rate and leads to the formation of SnO2 nanoparticles.

Fatty acids in female’s gonads of the Red Sea fish Rhabdosargus sarba during the spawning season

Objective: To determine the fatty acids profiles in female fish, Rhabdosargus sarba (R. sarba) from the Red Sea during the spawning season. Methods: Monthly individual R. sarba were obtained from Bangalah market in Jeddah, Red Sea and transported to the laboratory in ice aquarium. The total length, standard length and weight were measured, fishes were dissected. Ovaries were removed, weighed and 10 mL of concentrated hydrochloric acid were added to 10 g of the ovary in a conical flask and immersed in boiling water until the sample was dissolved and the fat was seen to collect on the surface. The conical was cooled and the fat was extracted by shaking with 30 mL of diethyl ether. The extract was bowled after allowing the layers to separate into a weighed flask. The extraction was repeated three times more and distilled off the solvent then the fat dried at 100 °C, cooled and weighed. Then 50 mg of lipid was put in a tube, 5 mL of methanolic sulphuric acid was added and 2 mL of benzene, the tube well closed and placed in water bath at 90 °C for an hour and a half. After cooling, 8 mL water and 5 mL petroleum were added and shaked strongly and the ethereal layer was separated in a dry tube, evaporated to dryness. The fatty acid methyl esters were analyzed by using a Hewlett Packard (HP 6890) chromatography, a split/splitless injector and flame ionization detector. Results: In female R. sarba, a total of 29 fatty acids were detected in ovaries throughout the spawning season. The main fatty acid group in total lipid was saturated fatty acid (SFA, 28.9%), followed by 23.5% of polyunsaturated fatty acids (PUFA) and 12.9% of monounsaturated fatty acids (MUFA). The dominant SFA were palmitic and stearic, the major MUFA were palmitoleic and oleic, and the major PUFA were C18:2 and C22:2. During spawning stages, there were no significant differences in total SFA, MUFA and PUFA. The highest value of SFA was in late spawning (36.78%). However, the highest value of MUFA and PUFA was in spawning (16.70% and 24.96% respectively). During spawning season there were significant differences in total SFA between March (late spawning stage) and December (nearly ripe stage), P<0.05. Conclusions: From the present study it has been shown that 29 fatty acids were detected in ovaries of R. sarba throughout the spawning season. The main fatty acid group in total lipid was SFA followed by PUFA and MUFA. The dominant SFA were palmitic and stearic, the major MUFA were palmitoleic and oleic, and the major PUFA were C18:2 and C22:2. The highest value of SFA was in late spawning. However, the highest value of MUFA and PUFA was in spawning.

Synthesis and investigation of the physicochemical properties of 2-(5-((theophylline-7'-yl)methyl)-4-phenyl-4H-1,2,4-triazole-3-ylthio)-acetic acid salts

Synthesis and investigation of the physicochemical properties of 2-(5-((theophylline-7'-yl)methyl)-4-phenyl-4H-1,2,4-triazole-3-ylthio)-acetic acid salts

Preparation and biodistribution of 188Re-labeled folate conjugated human serum albumin magnetic cisplatin nanoparticles (188Re-folate-CDDP/HSA MNPs) in vivo

BackgroundThe purpose of this study was to develop intraperitoneal hyperthermic therapy based on magnetic fluid hyperthermia, nanoparticle-wrapped cisplatin chemotherapy, and magnetic particles of albumin. In addition, to combine the multiple-killing effects of hyperthermal targeting therapy, chemotherapy, and radiotherapy, the albumin-nanoparticle surfaces were linked with radionuclide 188Re-labeled folic acid ligand (188Re-folate-CDDP/HSA).MethodsHuman serum albumin was labeled with 188Re using the pre-tin method. Reaction time and optimal conditions of labeling were investigated. The particles were intravenously injected into mice, which were sacrificed at different time points. Radioactivity per gram of tissue of percent injected dose (% ID/g) was measured in vital organs. The biodistribution of 188Re-folate-CDDP/HAS magnetic nanoparticles was assessed.ResultsOptimal conditions for 188Re-labeled folate-conjugated albumin combined with cisplatin magnetic nanoparticles were: 0.1 mL of sodium gluconate solution (0.3 mol/L), 0.1 mL of concentrated hydrochloric acid with dissolved stannous chloride (10 mg/mL), 0.04 mL of acetic acid buffer solution (pH 5, 0.2 mol/L), 30 mg of folate-conjugated albumin combined with cisplatin magnetic nanoparticles, and 188ReO4 eluent (0.1 mL). The rate of 188Re-folate-CDDP-HSA magnetic nanoparticle formation exceeded 90%, and radiochemical purity exceeded 95%. The overall labeling rate was 83% in calf serum at 37°C. The major uptake tissues were the liver, kidney, intestine, and tumor after the 188Re-folate-CDDP/HSA magnetic nanoparticles were injected into nude mice. Uptake of 188Re-folate-CDDP/HSA magnetic nanoparticles increased gradually after injection, peaked at 8 hours with a value of 8.83 ± 1.71, and slowly decreased over 24 hours in vivo.ConclusionThese results indicate that 188Re-folate-CDDP/HSA magnetic nanoparticles can be used in radionuclide-targeted cancer therapy. Surface-modified albumin nanoparticles with folic acid ligand-labeled radionuclide (188Re) were successfully prepared, laying the foundation for a triple-killing effect of thermotherapy, chemotherapy, and radiation therapy.

N1-Aminopropylagmatine, a New Polyamine Produced as a Key Intermediate in Polyamine Biosynthesis of an Extreme Thermophile, Thermus thermophilus

In the extreme thermophile Thermus thermophilus, a disruption mutant of a gene homologous to speB (coding for agmatinase = agmatine ureohydrolase) accumulated N1-aminopropylagmatine (N8-amidino-1,8-diamino-4-azaoctane, N8-amidinospermidine), a new compound, whereas all other polyamines produced by the wild-type strain were absent from the cells. Double disruption of speB and speE (polyamine aminopropyltransferase) resulted in the disappearance of N1-aminopropylagmatine and the accumulation of agmatine. These results suggested the following. 1) N1-Aminopropylagmatine is produced from agmatine by the action of an enzyme coded by speE. 2) N1-Aminopropylagmatine is a metabolic intermediate in the biosynthesis of unique polyamines found in the thermophile. 3) N1-Aminopropylagmatine is a substrate of the SpeB homolog. They further suggest a new biosynthetic pathway in T. thermophilus, by which polyamines are formed from agmatine via N1-aminopropylagmatine. To confirm our speculation, we purified the expression product of the speB homolog and confirmed that the enzyme hydrolyzes N1-aminopropylagmatine to spermidine but does not act on agmatine.

Evaluation of 5-(4-Nitrophenyl)-2,4-pentadien-1-al (NPPD)as a Tracer for Shadowing Pursuits

The chemical compound 5-(4-nitrophenyl)-2,4-pentadien-1-al (NPPD), called "spy dust," was used in the Soviet Union as a shadowing pursuit, the act of following someone secretly, for investigating the activities of diplomatic personnel. It is also useful for counter-terrorism, and some criminal cases in the forensic science field. In this paper, it was synthesized and evaluated as a tracer for shadowing pursuits. The method for utilizing this reagent was very simple: it was dissolved in methanol (1 mg/mL) and sprayed on the restricted area. If the suspect was to enter this area or touched the sprayed material, NPPD was attached to the suspect's shoe surface or hands. The color examination was a two-steps process: first was the addition of 1 mL of a 0.1% naphthoresorcinol methanol solution to the methanol extracts of a methanol-contained cotton swab used to smear some surfaces of the suspect, and second, the addition of 1 mL of concentrated hydrochloric acid, which turned the solution dark red. The gamma max of the colored solution was 510 nm, measured by ultraviolet-vis spectroscopy. Detection limits for three methods were determined: a visual method (detection limit 100 ng/3 mL), an ultraviolet-visible spectrometric method (detection limit 10 ng/3 mL), and a selected-ion-monitoring gas chromatographic/mass spectrometric method (detection limit 300 pg/injection). The forensic utility of NPPD was demonstrated for two simulated cases: a theft case and a case where NPPD was used as a tracer to prove that an automobile had entered a restricted area. These examinations prove NPPD is a useful shadowing pursuit (spy dust) for the forensic science field.

Cold ultrasonic acid extraction of copper, lead and zinc from soil samples

A cold ultrasonic acid method for extracting Pb, Cu and Zn from soil samples has been studied. This work focused on studying the experimental condition for extrating trace metals from soil samples at ambient temperature (≈25 °C) using Syrian soil samples; the same conditions were applied to reference soil samples(SL-1, Soil-7, SDM, and BCR-32). A short exposure time (4 h), and 2 ml of concentrated hydrochloric acid were found to be best. Under the applied conditions Pb, Cu and Zn were quantitavely extracted, while Sr, Mn, Fe, Al, Cr, Co, and Ni were partialy extracted. The advantages of the cold ultrasonic extraction method are as follows: it is selective, it is matrix free, the extraction time is short, the amounts of consumed chemicals are small, the by-products of the process are negligible and it is environmentally clean, since no fume emissions are emitted. The only disadvantage is that it is not a real total digestion method. Comparable results for the proposed ultrasound method and the hot-plate acid digestion method for Cu, Pb and Zn in certified refrence soil samples(SL-1, SDM, Soil-7, BCR-32, Soil-6) and some Syrian soil samples are obtained.

Synthesis, characterization and thermal properties of boron and silicon containing preceramic oligomers

In recent years, considerable interest has been shown towards developing boron and silicon containing polymers as they possess certain technological advantages when compared to polymers containing only boron or silicon [1, 2]. These polymers on pyrolysis in inert atmosphere give mixed non-oxide ceramics such as B4CSiC, B4C-Si3N4 and BN-SiC. These mixed non-oxide ceramics are reported to possess superior high temperature properties, oxidation resistance and thermal shock resistance when compared to boron and silicon based simple non-oxide ceramics [1, 3, 4]. Boron and silicon containing polymers have also gained importance as protective coatings for materials which are constantly exposed to oxidizing environment [5–8]. When these coatings are exposed to oxidizing environment at elevated temperatures, a protective passive borosilicate glassy layer is formed on the surface which prevents further oxidation of the protective coating and the substrate. Boric acid is considered to be the cheapest source of boron for making boron and silicon containing polymers. Yajima and coworkers [9] synthesized poly (borodiphenylsiloxane) through the reaction of boric acid with diphenyldichlorosilane in n-butylether at 300 ◦C. Hoshii et al. [10–12] prepared borodiphenylsiloxane oligomer by reacting boric acid and diphenylsilanediol. However, these polymers give relatively low ceramic residue on pyrolysis (<50%) and also require high temperature (∼300◦) for their synthesis. In this communication, we report the synthesis of boron and silicon containing oligomers, capable of giving a high ceramic yield, through the condensation of boric acid with phenyltrimethoxysilane and vinyltriethoxysilane at a relatively low temperature (150–160 ◦C). A mixture containing 57 g (0.3 mol) of vinyltriethoxy-silane, 9.27 g (0.15 mol) of boric acid, 50 ml of diglyme and 1 ml of concentrated hydrochloric acid was taken in a three necked round bottom flask equipped with a mechanical stirrer, an inlet and outlet for nitrogen. The contents of the flask were heated under the flow of nitrogen in an oil bath maintained at 150–160 ◦C. The reaction mixture was stirred for 3 h at this temperature, after which it was allowed to cool to room temperature. Ethanol which was formed as a by product was distilled off. Diglyme was distilled off

Acid hydrolysis of 3-aryl-5-trinitromethyl-1,2,4-oxadiazoles

of compound I or II, 50 ml of acetic acid, and 10 ml of water was refluxed for 1 h. The solution was evaporated, and the residue was subjected to column chromatography (10 250-mm column) on activated silica gel (Silicagel 100/400 m) using diethyl ether as eluent. We isolated 0.5 g (63%) of 5-hydroxy-3phenyl-1,2,4-oxadiazole (III), mp 203 C [3], or 0.6 g (68%) of 5-hydroxy-3-(4-tolyl)-1,2,4-oxadiazole (IV), mp 220 C [4]. Hydrolysis of 3-aryl-5-trinitromethyl-1,2,4-oxadiazoles I and II in hydrochloric acid. A mixture of 3 mmol of compound I or II, 30 ml of concentrated hydrochloric acid, and 10 ml of water was refluxed for 3 h. The solution was evaporated, and the residue was purified by column chromatography (see above) with benzene as eluent. We isolated 0.2 g (53%) of benzamide oxime (V), mp 78 80 C [5], or 0.3 g (61%) of 4-methylbenzamide oxime (VI), mp 147 C [6]. Hydrolysis of 3-aryl-5-hydroxy-1,2,4-oxadiazoles III and IV in hydrochloric acid. A mixture of 3 mmol of compound III or IV, 15 ml of concentrated hydrochloric acid, and 5 ml of water was refluxed for 2.5 h. The solution was evaporated, and the residue was purified by column chromatography (see above) with benzene as eluent. We isolated 0.15 g (35%) of Scheme 1.

Spectrophotometric Method for Heme Iron Determination in Foods.

A simple and rapid method for the determination of heme iron in foods was investigated. A sample was weighed in a centrifuge tube and the fat in the sample was removed with diethyl ether. The residue was mixed well with 1-2 ml water, and added 10 ml of methyl isobutyl ketone (MIBK) and 5 ml of concentrated hydrochloric acid. The tube was placed in an ultrasonic water bath for 10 min. Five ml of water was added to separate the MIBK layer from the aqueous layer. After shaking for 5 min, the mixture was centrifuged for 5 min at 3000 rpm. Heme iron in the MIBK layer was determined by spectrophotometer at a wavelength of 640 nm. The calibration curve was linear from 2.5 to 15μg Fe/ml. The recoveries of heme iron added to foods were within the range from 80.5% to 90.0%. An interlaboratory study of this method for the determination of heme iron in cookie, liver and meat was conducted in 3 laboratories. The coefficient of variation for each sample was within the range of 6.29-7.15%. This method is simple and useful for the determination of heme iron in foods.

Improved molecular fluorescence method for the determination of selenium in biological samples

A procedure for the determination of selenium in whole blood and urine has been improved by optimization of the digestion and derivatization procedures. An overnight pre-digestion step with 4 + 1 concentrated nitric-perchloric acids reduced the time of mineralization at 170 degrees C from 4 h to 30-45 min. Conversion of all the selenium to selenite (SeIV) was optimized by addition of 1 ml of concentrated hydrochloric acid, with heating to 100 degrees C for 30 min. The rate of formation of the 2,3-diaminonaphthalene (DAN) complex of selenium was improved by heating to 70-100 degrees C for a minimum of 30 min. Co-addition of hexane during derivatization simplified the extraction procedure. The modified method was applied successfully to the analysis of Seronorm quality control whole blood and urine (83 and 24 micrograms l-1 Se, respectively). Samples from 12 healthy adults, gave results in expected ranges (mean concentrations of 75 +/- 8 micrograms l-1 in blood and 25 +/- 8 micrograms l-1 in urine). The structure of the Se-DAN complex was investigated using elemental analysis, FTIR spectrometry, 1H and 13C NMR spectroscopy, and FAB MS. The information obtained indicates that the selenodiazo group does not contain an Se-O bond or protonated nitrogens, as proposed in other studies.

Factorial design approach to microwave dissolution

A fractional factorial design has been used to explore the variables that affect microwave dissolution using perfluoroalkoxy (PFA)-Teflon digestion vessels. Optimum operating conditions for National Research Council of Canada, certified reference material TORT-1 Lobster Hepatopancreas and National Institute of Standards and Technology, Standard Reference Material (SRM) 1575 Pine Needles, were obtained using this procedure. The optimum conditions found for each variable are: 0.25 g sample mass, 6 ml of concentrated hydrochloric acid, 6 ml of concentrated nitric acid, 3 ml of concentrated hydrofluoric acid and 90% microwave power for a total dissolution time of 15 min. Results for Ca, Fe, Cu and Zn in TORT-1 and Ca and Fe in SRM 1575 were in agreement with the certified values.

Automated determination of lead in urine by means of computerized flow potentiometric stripping analysis with a carbon-fibre electrode

Five different digestion procedures have been investigated. In the recommended procedure 5 ml of concentrated hydrochloric acid—nitric acid mixture (1:1) were added to a 5-ml urine sample. After 1 min the sample was diluted to 100 ml with distilled water. The sample was divided into two 50-ml samples and to one of them a standard addition of 10 μg/l. lead(II) was made. The two samples were analysed fully automatically by means of computerized flow potentiometric stripping analysis, the main features of the procedure being mercury-film precoating, electrolysis of the sample for 90 sec and subsequent stripping in 1 M calcium chloride/0.1 M hydrochloric acid. Tin and copper were found not to interfere if present at concentrations below 50 mg/l. but high concentrations of tin had to be masked by the addition of copper in order to form a copper—tin intermetallic compound. Complexing agents used in lead poisoning therapy did not interfere with the determination. The lead concentration in a Seronorm® reference urine sample was found to be 93 μg/l. with a standard deviation of 8 μg/l. ( n = 5), the certified value being 88 μg/l.

Gas chromatographic determination of ultramicro amounts of nitrite ion in inorganic salts.

A new reagent, 1-methylamino-2-amino-4, 6-dibromobenzene (MADB) for the gas chromatographic determination of ultramicro amounts of nitrite ion was synthesized. It reacts with nitrite ion to form 1-methyl5, 7-dibromobenzotriazole(MDBT) which can be extracted into toluene. The extract is very sensitive to electron capture detection in gas chromatography. Therefore, the conditions for the gas chromatographic determination of ultramicro amounts of nitrite ion were investigated by using MADB. A typical procedure is as follows; Take the sample solution containing less than 60ng of nitrite ion into a 25ml of stoppered test tube and dilute to 15ml with distilled water. Add 2ml of concentrated hydrochloric acid and 0.5ml of MADB solution(2×10-4mol dm-3), and allow the mixture to stand for 30min. Extract the MDBT formed into 2ml of toluene by shaking for 5min, and wash the toluene extract with 4ml of 3mol dm-3hydrochloric acid. Inject 2μl of the toluene extract into gas chromatograph(ECD) and measure the peak height. The calibration curve(peak height) is linear in the range of 2.5 to 10ng of nitrite ion in 15ml of solution. The reproducibility at 3.5ng ml-1 was 3%. Trace nitrite ion in commercially available inorganic salts was determined by the proposed procedure.

Fluorometric determination of scandium in minerals with 2, 4-dihydroxybenzaldehyde-semicarbazone

Scandium in several minerals { (0.0020.3) % Sc} was determined by the fluorometric method. The procedure is as follows : (0.050.1)g of mineral sample is treated with 30 ml of concentrated sulfuric acid for 3 hrs on a sand bath, and the solution is evaporated to dryness. The residue is dissolved in (35)ml of concentrated hydrochloric acid, and the solution is diluted to (7080)ml with water and filtered. Seventy milligrams of Ca2+ as a carrier and oxalic acid solution are added and the pH of the solution is adjusted to 2.0. After the solution has stood for ten minutes, the precipitate is centrifuged and decomposed by evaporating with perchloric acid to dryness. The residue is dissolved in 5 ml of 6M HCl. Scandium is separated by extracting at pH 1.6 with 10 ml of 0.2M TTA-benzene followed by backextracting with 10 ml of 1M HCl. The solution is made up to 25 ml, and an aliquot of the solution is taken. Two ml of 0.1% 2, 4-dihydroxybenzaldehyde-semicarbazone solution, 2 ml of 20% ammonium acetate solution are added, and the pH of the solution is adjusted to 6 with hydrochloric acid or ammonia, and the solution was diluted to 25 ml with water. The fluorescence intensity of the solution is measured (λexcitation360nm, λemission 425 nm).In this procedure, the recovery of scandium was found to be about 95%. Several mineral samples (naegite, allanite, yamaguchilite, lepidomelane, hokutolite) were analyzed.

Spectrophotometric determination of trace amounts of carbazole in anthracene

A method for the separation of carbazole by the combination of chromatographic technique and the Diels-Alder reaction with maleic anhydride was studied. Carbazole, which was thus separated from large amounts of anthracene and other interfering impurities, was determined spectrophotometrically by the color development with xanthydrol. Five hundred milligrams of the sample and 500 mg of maleic anhydride were added to 10 ml of ο-dichlorobenzene, and then the mixture was heated to a boiling temperature for 10 minutes to complete the adduct formation. After 50 ml of 0.5 M NaOH aqueous solution was added, the mixture was heated at 95°C for 10 minutes untill the adduct was hydrolyzed and dissolved. ο-Dichlorobenzene phase containing carbazole was separated and dried with anhydrous sodium sulfate. Then, the solution was passed through a column (6 mmφ × 50 mm) packed with alumina, followed by 10 ml of ο-dichlorobenzene. Carbazole was eluted with 5 ml of acetic anhydride. After 5 ml of glacial acetic acid was added, acetic anhydride was hydrolyzed by the addition of 1.0 ml of 0.1 M of hydrochloric acid and by letting the mixture stand for 30 minutes. Five milliliters of glacial acetic acid solution of xanthydrol (1 mg/ml) and 0.5 ml of concentrated hydrochloric acid were added. The solution was heated at 80°C for 45 minutes, then cooled and diluted to 25 ml with glacial acetic acid. The absorbance was measured at 570 nm against the reagent blank. By this method, carbazole in anthracene can be determined down to 0.0003%.

Determination of rhenium in rhenium-tungsten alloy

Spectrophotometric determination of rhenium according to thiourea method has been applied to rheniumtungsten alloy.A sample of the alloy was fused with a mixture of sodium carbonate and potassium nitrate, and it was dissolved in water and then diluted. An aliquot of the solution containing 0.12.0 mg of rhenium is taken in a volumetric flask and it is diluted to 100 ml, after 0.2 g of urea, 10 ml of 50% citric acid solution, 25 ml of concentrated hydrochloric acid, 12 ml of 5% thiourea solution and 6 ml of 1 M stannous chloride in 4 M hydrochloric acid solution beeing added, more than 50 minutes later, the absorbance is measured at 380 mμ. The method can be applicable to the rapid determination of rhenium in rhenium-tungsten alloy without separating any rhenium from a large quantity of tungsten.

On the Determination of Urinary 17-Ketosteroids in the Rat

On the abject of knowing the function of adrenal cortex, we have examined a few Points in the method for the determination of 17-Ketostosteroids (abbreviated 17-KS).In summation: 1. The condition for hpdrolysis of rat urine, 10ml of concentrated hydrochloric acid is added to 5ml of urine and let it stand for thirty mimites.2. In order to absorb chromogens, it is better not to use absorbent carbon powder, because it will a considerable amount of 17-KS too.3. The best conditions for developing color, the following condition is used, namely: aqueous 5N potassium hydroxide, at 25°C, and leaving 110 minutes for reaetion.4. The value of non-ketone fraction is remarkable high in Rat urine. Therefore in case of Rat urine, non-ketone fraction is to remove by Girard treatment in each sample.5. The amount of excretion of 17-KS in adult rats is between 52.5-39.7μg in males, and 19.9-32.6μg in females.