By using a Tokoshi type oxygen-acetylene premixing burner, the flame photometric determination of vanadium in iron and steel was investigated on the measuring conditions, the influences of coexistent elements and the method of separation of molybdenum from matrix elements. The 379.82 mμ line was used for the determination, and the line intensity had good linearity with Mo concentration. Molybdenum was separated from matrix iron by MIBK extraction of the precipitate of Mo-α-benzoin oxime complex from 2.5 N sulfuric acid acidity. By this means, almost all elements did not interfere except for Cr, Bi, Co, Ce and Nb giving lower results. The influences of the latters were avoided by the standard addition method. The variation coefficient of the analytical results was 4.4%.

View full abstract

The determination of molecular weight distribution (MWD) of commercial high density polyethylene was studied by gel permeation chromatography (GPC), in which the apparatus and column packing materials (polystyrene gels) were designed and prepared by authors.
The calibration curve obtained by three methods, namely using narrow MWD polymer fractions, with broad MWD whole polymers and derived from universal calibration curve, were essentially consistent with each other.
The integrated MWD curves and values of average molecular weights obtained by GPC agreed well with those by traditional column fractionation, and it was deduced that molecular weight distributions of those commercial polyethylene samples show logarithmic normal distribution functions.

View full abstract

A test instrument was specially designed based on the investigations on the selections of X-ray tube, analyzing crystal, window material and counter gas used for the detector, and fluorine in ceramics and their raw materials was determined with special reference to the conditions for excitation of FK_α, the energy resolution and the influence of particle size of samples.
An end window rhodium target 3 kW X-ray tube was superior to the others in the wave distribution of incident X-rays, the intensity of excited FK_α, geometrical relationship between filament, target and sample, the thickness of window material and the peak to background ratio of the fluorescent X-rays. Although mica was excellent in the resolution and LMD was also excellent in the intensity of reflected FK_α, KAP was conclusively most suitable for the analyzing crystal. Polypropylene film of 1 μ thickness with vacuum evaporated aluminum was selected as the window material and a mixture of 30% CO₂+70% He was used for the gas flow proportional counter so as to effectuate the gas discrimination.
Large current under low potential operating condition of X-ray tube was preferable to decrease the matrix effect of coexisting elements and to increase the peak to background ratio. The peak shift of FK_α, caused by the difference of chemical bonding of the fluorine compounds, was clearly recognized, and hence the setting of the detector system must be precise. The effect of particle size could be eliminated by its reduction to 2 μ.
The reproducibility and the estimated analytical error were σ_R = 0.50% and σ_e = 0.112% as absolute weight percentage in fluorspar (about 33 wt%F) andσ_R= 0.059% and σ_e=0.016% in cement clinker (<1 wt%F), respectively. The determination was done within 20 minutes.

View full abstract

An indirect method for the determination of chloride was presented in which the membrance-filtered silver chloride was dissolved in aqueous ammonia and silver was determined by atomic absorptiometry. A sample solution containing chloride ion was made acidic with nitric acid, and silver nitrate solution was added with stirring. It was then cooling-centrifuged for 15 min. and, by keeping the temperature below 3°C the precipitate was suction-filtered through a membrane filter of pore size 0.1 μ. After washing with dilute nitric acid, silver chloride on the filter was dissolved in ammonia. The absorption of silver was. measured by an atomic absorption spectrometer, and the amount of chlorine was calculated by referring to the calibration line. When 30 ml of a solution containing 10 μg or more of chloride ion, the recovery of chlorine was more than 95%. The method was applied to the chlorine in titanium metal with nearly satisfactory results.

View full abstract

The determination of cadmium by combination of MIBK extraction of the iodide with atomic absorption spectrometry was investigated. More than 99% recovery with 10 folds concentration of cadmium was obtained by MIBK extraction from 6 N sulfuric acid solution containing >0.1 M potassium iodide. The calibration line for the MIBK extracts showed good. linearity over the range of Cd 00.8 ppm. The absorbancy was 2.5 times that for aqueous solutions, the sensitivity being 0.04 ppm for 5% absorption. The method was applied to the determination of trace cadmium in zinc die cast with satisfactory results.

View full abstract

A methanolic bromine method for determination of chromium oxide inclusion in Cu-Cr alloy has been presented. In order to decide the optimum condition for extracting the inclusion, the effects of decomposition temperature, decomposition time, etc. on the solubility (recovery) of chromium oxide have been studied by the use of synthesized pure chromium oxides and internally oxidized Cu-Cr alloys. The chromium oxide inclusion has been isolated completely as residue from matrix by the methanolic bromine method.
An acid decomposition method has also been studied, but it is not suitable for the determination of the oxide inclusion. On the other hand, it has been found that precipitated metallic chromium and the chromium present as α-solid solution in Cu-Cr alloy can be fractionally determined by the acid decomposition method.
The recommended procedures are as follows.
(1) Methanolic bromine method (determination of chromium oxide inclusion) : 15g of Cu-Cr alloy is decomposed with methanolic bromine (methanol 200ml+bromine 20ml) in a decomposition flask at 6065°C for 3hr. The solution is filtered through a filter paper. The residue is washed with methanol, ignited in a porcelain crucible and fused with 3g of potassium pyrosulfate. The melt is leached with 6ml of 18N sulfuric acid and water, then made up to 50ml with water. The amount of chromium in this solution (chromium present as oxide inclusion) is determined spectrophotometrically with diphenylcarbazide.
(2) Acid decomposition method (determination of precipitated metallic chromium and the chromium present as α-solid solution): 1g of Cu-Cr alloy is decomposed with 16ml of nitric acid (1+2) in a 200ml beaker on a water bath. The solution is filtered through a filter paper and the residue is washed with nitric acid (1+100). The washing solution is combined with the filtrate and the amount of chromium in the combined solution (the chromium present as α-solid solution) is determined spectrophotometrically with diphenylcarbazide. On the other hand, the residue is treated in accordance with the above mentioned procedure (1), and the chromium isolated as residue (precipitated metallic chromium+chromium oxide inclusion) are determined spectrophotometrically. Then, a correction is made by deducting the chromium present as oxide inclusion determined by methanolic bromine method from the chromium isolated as residue in this procedure, and finally the precipitated metallic chromium in Cu-Cr alloy is determined.

View full abstract

A methanolic bromine method for determination of beryllium oxide inclusion in Cu-Be alloy has been presented. In order to decide the optimum condition for extracting the inclusion, the effects of decomposition temperature, water in methanol, etc. on the solubility (recovery) of beryllium oxide have been studied by the use of synthesized pure beryllium oxides and internally oxidized Cu-Be alloys.
The solubilities of metallic copper, metallic beryllium, and beryllium oxide with ester-bromine or with acid have also been studied and the applicability of ester-bromine method or of acid decomposition method to the determination of beryllium oxide inclusion in Cu-Be alloy has been discussed.
The recommended procedure is as follows:25g of Cu-Be alloy is decomposed with methanolic bromine (methanol 100ml+bromine 10ml) in a decomposition flask at 4550°C for 5 hr or at 3035°C for 20hr. The solution is filtered by suction through Cella filter (CF, dense). The residue (beryllium oxide inclusion isolated) is washed with methanol, ignited in a platinum crucible, and fused with 58g of potassium pyrosulfate. The melt is leached with 40ml of 0.3N HCl and made up to 100ml with water. An aliquot of this solution containing 550 μg of beryllium is taken into a 100ml beaker, and 5ml of 4% KCN solution and 10ml of 0.1% Aresenazo-I solution are added. The pH of solution is adjusted to 12.5±0.1 by adding dropwise 20% NaOH solution. It is transferred into a 100ml volumetric flask and made up the volume with diluted NaOH solution (pH=12.5) The absorbance at 580 mμ is measured against the reagent blank and the amount of beryllium is determined from its calibration curve.

View full abstract

Methods for extraction of methylmercury compounds from samples containing sulfide were studied. In solutions containing sulfide, methylmercury compounds gave bis-dimethylmercury sulfide, and the latter could not be changed easily to methylmercury chloride in 1 N hydrochloric acid solution and could not be transferred to the glutathion or cysteine solution from organic solvents. But bis-dimethylmercury sulfide in solution was changed completely to methylmercury chloride by the addition of cuprous chloride, mercuric chloride or silver chloride into the solutions, and methylmercury chloride could be extracted by the glutathion or cysteine solution. By the addition of cuprous chloride into the solution containing sodium sulfide and methylmercury chloride, methylmercury chloride was quantitatively determined by gaschromatography with an electron capture detector. But mercuric chloride had the same retention time to that of methylmercury chloride on the gaschromatogram, and the peak height of the mixture of methylmercury chloride and mercuric chloride was higher than the sum of each peak height of methylmercury chloride and mercuric chloride on the gaschromatogram. Silver chloride inhibited the acitivity of the gaschromatography for methylmercury chloride. It is proposed therefore that samples containing sulfide should be treated with cuprous chloride and then with organic solvents and glutathion solution in the order.

View full abstract

A method of chromatographic separation of β-naphthol-3, 6-disulfonic acid (R acid) and -6, 8-disulfonic acid (G acid), in which cation exchange resin and cation exchange paper were used as a stationary phase and concentrated acidic salt solution as a developer, was investigated.
Studies on the adsorption behaviors of R and G acids on Amberlite CG-120 or Amberlite CG-50 in calcium chloride or sodium chloride solution showed that (1) in calcium chloride solution, the distribution coefficient (K_d) of these two acids became greater with increasing salt concentration, but in sodium chloride solution, the acids were not adsorbed, (2) the K_d of the acids was reduced with increasing pH value from 1.0 reaching minima at pH 4.04.5 and then became greater, (3) the rate of adsorption of the acids on Amberlite CG-120 was slow at room temperature (23°C) but was accelerated at 40°C, and (4) the separation factor of R and G acids on Amberlite CG-120 was larger than that on Amberlite CG-50.
The best separation was achieved with a peak resolution of 0.84 when a mixture was eluted at 41°C through a column of 17 mmgφ×700 mm of Amberlite CG-120 (200400 mesh) with 25 M calcium chloride solution of pH 2.9 at a flow rate of 0.37 ml/min. The acids in effluent were determined by u.v. spectrophotometry at 238.0 nm.
Moreover, the studies on paper salting-out chromatography using cation exchange paper showed that, when Amberlite WA-2 and Amberlite SA-2 were compared for the resolution of the isomers, the former gave a satisfactory result but the latter did not. The development (ascending) with 4M calcium chloride solution of pH 3.0 on Amberlite WA-2 gave the R_ƒ values of 0.34 and 0.18 for R and G acids, respectively.

View full abstract

Using electrodes of aluminum alloy (Al-Fe, Al-Cu, Al-Mn and Al-Zn), iron alloy (stainless steel, tool steel and Fe-Mn) and copper alloy (Cu-Sn), the relation of the composition of the electrode (solid phase) and the composition of that eroded (gaseous phase) by spark discharge was examined by the chemical analysis.
The results indicated that the compositions of the gaseous phases were the same as those of solid phases and were not affected by discharge conditions. It showed that the erosion of the electrode was the explosive eruption of vapor jet from the cathode.

View full abstract

Fluorescent X-ray analysis of Sn and Zr (below 0.3%) in aluminum alloys was investigated. Measurements were made for total X-ray intensities (I_E+B) at the wavelengths of SnK_α (n=2) and ZrK_α (n=1), and background intensities (I_B) in the vicinits of the characteristic lines. I_B's of individual samples were subtracted from corresponding I_E+B's to obtain fluorescent X-ray intensities (I_E) of the elements of interest. Correlations of I_E to C_E, content of the elements, however, were poor due to the presence of heavy metals in some of the alloys.
Correction for the absorbing constituents, Zn, Cu and Ni, was made to establish satisfactorily linear relationship of corrected I_Sn to C_Sn. Further, application of an internal standard method was studied because the correction for absorption is not convenient in industrial analyses. I_B's of some metals and binary alloys of aluminum were investigated, and it was shown that I_B was an adequate internal standard to eliminate the effect of absorption. Linear calibration lines were obtained by plotting I_E/I_B against C_E for both Sn and Zr. Precision data were shown.

View full abstract

Eriochrome Black T and its magnesium complex is extracted into various organic solvents, i.e. benzene, chloroform, 1, 2-dichloroethane etc., in the presence of tetradecyl-dimethyl-benzyl-ammonium chloride. The sensitivity increases several times as much as that of aqueous phase by this extraction and calcium ion does not interfere with the determination of magnesium. The magnesium complex and ligand extracted into 1, 2-dichloroethane have absorption maxima at 560, 658 and 690 mμ with constant absorbance in the pH range from 11.2 to 12.2. The difference of absorbance at 690 mμ between the blank and sample gives the highest sensitivity for determination of magnesium. Under optimum conditions, Beer's law is obeyed at least up to 5×10^-6 M magnesium in 1, 2-dichloroethane.

View full abstract

A graphite capsule method was applied to the determination of oxygen in ferro-boron powder by the vacurn fusion method in order to eliminate incomplete fusion and/or extraction of oxygen from samples.
Neither tin foil nor iron capsule gave good results from flashing-out of sample when the sample was dropped into the crucible. Good results were obtained when a high purity grade graphite capsule (20 mm × 10 mmφ) loaded 18 mg of sample powder and 1 g of platinum as bath metal was dropped at 1850°C. An isotope dilution method using aluminum oxide containing 70.9 atom% ¹⁸O was applied to the same procedure and gave good agreement with the results obtained by the vacuum fusion analysis.

View full abstract

Uranium contents in some rocks were determined by means of a conventional fission track method. For making the standard samples, an aliquot of standard uranium solution was mixed with the known amounts of fine silicagel powder. Both the standard and pulverized rock samples were pressed on muscovite into thin tablets using a hand press. These tablet samples were irradiated in a reactor, KUR, and then subjected to the chemical etching procedure of mica surface in HF solution. The number of fission tracks on mica was counted upon the microscopic photograph. The relationship between uranium contents and track number was linear as expected from the calculation. Thus the uranium contents of rocks could be easily determined by the use of a standard calibration curve. The effects of powder grain and of thorium, which is only one fissile element in naturc except uranium, were also investigated. Uranium contents of four U.S. Geological standard rocks together with JG-1 and JB-1 have been conveniently determined by this fission track technique and the results were compared with those by other works.

View full abstract

Short-lasting, high-current argon arc excitation (30 A, 0.7 sec) was applied to the analysis of nanogram amounts of elements deposited on the end of a graphite electrode. A simple tube-chamber was used to control the atmosphere. Strong enhancement of the line intensities and reduction of matrix effects were found when small amounts (20 μg) of alkali elements were added, but their effects on the arc temperature and electron density were not significant. The investigation using radioactive tracer ⁶⁴Cu indicated that the alkali elements raised the evaporation rate of the elements deposited on the electrode which accounted for the enhancement of line intensities. The sensitivity of the method was much higher than that of the copper spark method and comparable to that of the impulse argon arc method.

View full abstract

A method of chemical separation of GTP from ATP, CTP and UTP, and interactions between them were studied. The determination of GTP especially in micro amounts after the separation from other nucleotides was established by thin layer chromatography with DEAE-cellulose ion exchanger. GTP sample was spotted on the DEAE-cellulose by a micropipette and developed with 0.04 N HCl as usual. After drying, the blue emission spots of GTP under 2537 Å were extracted from the plate with 0.1 N HCl, and this extract was measured at 253 mp against blank, which was treated in non-emission portion in the same manner as the emission parts described above. A standard calibration curve of pure GTP and working curve using a known amounts of GTP added to homogenate solution were prepared. Measurements made at the absorbance maximum (253 mμ) followed Beer's law in the range between 0.9 and 15 μg of GTP per milliliter of 0.1 N HCl extract. The standard deviation (20 variates) was 1% at μg/ml of GTP. This method was applied to biological materials, especially to rat liver and blood, and simultaneous determination of GTP and ATP was achieved. Results showed that equal amounts of ATP and GTP were present in rat liver and GTP could not be detected in rat blood, although ATP content of rat liver was generally 3.5 times more than that of rat blood. The interference due to various nucleotides was studied and it was found that ATP and GTP could be differentiated by R_ƒ, absorption and emission on the thin layer, or absorbancy ratio illustrated in the Table IV.

View full abstract

To determine the residual percentage of material scopolamine in the preparation of n-butyl scopolamine bromide, a method by infrared absorption was examined.
An aliquot of the reaction product was made acidic with 1 N hydrochloric acid and shaken with carbon tetrachloride. The aqueous layer was then made alkaline with ammonia. It was then extracted with an equi-volume mixture of chloroform and carbon tetrachloride, and the extract was evaporated to dryness under reduced pressure. The residue was taken up and made up to volume with carbon tetrachloride and filtered through absorbent cotton. The infrared absorption was measured by using a 0.5 mm KRS-5 cell against carbon tetrachloride employing 1720 cm^-1as the key band. The minimum detecting sensitivity (S/N=2) was 0.1 mg/ml.

View full abstract

An X-ray diffraction analysis was done by using a fluorescent X-ray apparatus without any modification. Pure metal was placed on the sample holder of fluorescent X-ray spectrometer, and the analysing crystal was substituted by the analytical specimen. The pure metal was bombarded by the X-rays from the X-ray tube, and the fluorescent X-rays produced were diffracted by the sample. The diffracted X-rays were detected by a scintillation counter. Copper plate as pure metal and calcium carbonate, calcium oxide and quartz as specimen were used in this experiment, and the detection limit was examined on the mixture of calcium carbonate and calcium fluoride. The limit of detection was about 10% for calcium carbonate.

View full abstract

The separation efficiency of a preparative gas chromatography is often reduced by the counter-current of sample, carbonization of materials etc. Detailed examination on the temperature of the injector, amount of injection and the injecting pressure revealed that an instantaneous pressure just at the time of sample injection was quite effective to maintain good separability.

View full abstract

The spectrophotometric method for the determination of ammonia nitrogen with thymol which had been established by the authors for uranium metal and its compounds was successfully applied to as low as 3 ppm of nitrogen in zirconium and zircaloy.
Satisfactory results were obtained in the analysis of the NBS zircaloy-2 standard and other samples. Twenty milligrams of tin, 3 mg of iron, 4 mg of nickel, . 2 mg of chromium and 0.2 mg each of aluminum, copper, silicon and titanium did not interfere. The molar absorptivity was the same as that previously reported (1.15× 10⁴ at 670 mμ).
In the recommended procedure, up to 0.8 g of a sample was dissolved with 2 ml of sulfuric acid (18 N), 3 ml of hydrochloric acid and 5 ml of fluoboric acid (10%) by heating on a water bath. After dissolution, 1 ml of hydrogen peroxide solution (30%) was added to oxidize iron and the solution was then evaporated to almost dryness to remove the excess peroxide and acids. The residue was dissolved with 50 ml of water, and 20 ml of sodium citrate solution (25 w/v%) was added. After adjusting the pH of the solution to 9.8 10.3, 0.5 ml of sodium hypochlorite solution containing 0.3% of active chlorine was added with stirring. After 20seconds, 2.5 ml of a freshly prepared mixture of equal volumes of thymol solution (10% in acetone) and sodium hydroxide solution (1 N) was added. Sodium hydroxide solution (6 N) was then added to dissolve the deposited thymol, and the pH of the solution was adjusted to 11.6 11.9 with sodium phosphate solution (0.05 N) and sulfuric acid (6 N). Four milliliters of acetone was added and the resultant solution was diluted to 100 ml with water. After standing for 1.5 hours in darkness, the absorbance of the colored solution was measured against the blank at 670 mμ.

View full abstract

Nondispersive infrared method (NDIR) is one of the most reliable and accurate methods for the measurement of cffrbon monoxide (CO) concentration in urban air. Detector tube method is widely used for the same purpose as a field method because of its simplicity. Four types of detector tube (A, B, C and G) are available in the market and, in this paper, the obtained CO values by the four detector tubes were compared with NDIR results as the reference. Type B and C of the tube gave slightly larger values and type G gave values agreeing with NDIR. The type A tube gave remarkably higher results, which were due to, probably, the influence of hydrocarbons in the sample air.

View full abstract

Silver ion reacts with tetracyanonickelate to form dicyanoargentate. The substitution reaction proceeds quantitatively by the following equation.
Ni(CN)₄^2-+2Ag⁺→Ni²⁺+2Ag(CN)₂^-
The stoichiometrically released nickel ion then reacts with 4 (2-pyridylazo) resorcinol (PAR) forming Ni-PAR chelate which shows absorption maximum at 496 mμ. A molar extinction coefficient of Ni-PAR chelate is 7.30×10⁴. The micro amount of silver in concentration of 5.00×10^-6 1.95×10^-5mol/l can be indirectly determined by measurement of the absorbance at 496 mμ.

View full abstract