For the determination of iron in tin-base Babbitt metal, the separation of tin as the main constituent is often to be a troublesome procedure. In the proposed method, the sample is dissolved in approximately 6N HCl, iron is reduced to Fe²⁺, and tin is extracted with methyl isobutyl ketone (MIBK) to be separated from iron. Thereafter, red color developed by adding ammonium thiocyanate is extracted with MIBK and iron is determined colorimetrically, by using the maximum absorbancy at 490 mμ.
The sample (1g) is dissolved in a HCl-HNO₃ mixture and made up to 100 ml with water. A 5ml portion is made to 6N in HCl, Na₂S₂O₃ soln. added and Fe²⁺ and tin are separated by MIBK extraction. The aqueous layer is treated with H₂O₂ and boiled to decompose the excess of Na₂S₂O₃, cooled, and Fe³⁺ of this solution is extracted with 25ml MIBK. The solvent layer is shaken with NH₄NCS soln. and the coloration of iron is developed.
By use of the above method, iron in tin-base Babbitt metal was determined with the result shown in Table III.

View full abstract

Di- (p-bromophenyl) thiocarbazone and di- (o-bromophenyl) thiocarbazone are synthesized and their fundamental properties have been investigated. The maximum absorption wave length of p-bromo derivative and its metal complex solution shifted to a longer wave length side than in the case of dithizone, while o-bromo derivative and its metal complex solution shifted to a shorter side. The reactivity of o-bromo derivative to metal ions is lower than that of dithizone. The molecular extinction coefficients of both derivatives and their metal complex solution at their maximum absorption wave length have been estimated. The molecular extinction coefficient of the solution of p-bromo derivative is larger than that of dithizone, while that of o-bromo derivative is smaller. The change of the molecular extinction coefficient of each metal complex solution did not show a uniform tendency. Also, the extraction coefficients of Hg²⁺ and Cu²⁺complexes have been estimated and the discussions were made on their changes.

View full abstract

By use of a carbon tetrachloride solution of the reagent given in title, its fundamental properties have been investigated. The extraction of the reagent in carbon tetrachloride into an aqueous layer was not sufficient by use of aqueous ammonia and it required to use an aqueous solution of sodium hydroxide. The maximum absorption wave lengths of the reagent and the metal complex solution were shifted towards longer wave length from those of dithizone but they were in a shorter wave length side than those of di-(p-diphenyl) thiocarbazone. The reactivity of the reagent with the metal ion was lower than that of dithizone; only Ag⁺, Hg²⁺, Cu²⁺, and Cd²⁺ are extracted quantitatively in pH ranges up to 8, while Zn²⁺, Pb²⁺, and Bi²⁺ were not extracted quantitatively. The molecular absorption coefficient at the maximum absorption wave length in the visible range has been estimated and the following results were obtained : Reagent solution : 33.9× 10³; Ag⁺ -complex solution : 25.1× 10³; Hg²⁺-complex solution : 57.2× 10³; Cu²⁺-complex solution : 48.6× 10³; Cd²⁺-complex solution : 75.0 × 10³. Also, extraction coefficients (log K) of Hg²⁺-complex and Cu²⁺-complex have been estimated and the values 25.13 for Hg²⁺ and 9.91 for Cu²⁺ were obtained.

View full abstract

Organic phosphorus compound was decomposed in a microbomb with sodium peroxide, the product was taken up in distilled water, boiled gently for 30 min. with platinum foil for decomposition of hydrogen peroxide and the solution was neutralized with conc. nitric acid. The sample solution was titrated at 95°C with uranyl acetate solution previously standardized against an potassium dihydrogen phosphate. The titration was carried out in weak acetic acidity, and the end point was noted by the brown coloration with a drop of mother liquor on powdered potassium ferrocyanide. The sample required was 1020 mg, the time for a run of the analysis ca. 1 hour, and the error within ±0.3%. Since this is done in semi-micro scale, phosphorus in alkaline earth salts of organic phosphoric acid can be determined without any further treatment.

View full abstract

Determination of inorganic chlorine in neutral detergents shown in Table I by the usual method was encountered with various difficulties. The authors established a practical method by applying the flame spectrophotometric determination of silver after converting inorganic chlorine in sample into silver ammine chloride.
The sample is dissolved in hot water, acidified with nitric acid, and silver nitrate is added. After being stirred for 1 min. the precipitate is easily and quantitatively filtered at 6070°C as silver chloride (Table II). The optimal pressures of oxygen and hydrogen gases for the flame spectrophotometry are 0.8 and 0.36 atm./cm², respectively (Figs. 1 and 2). The amount of ammonia required for the conversion of silver chloride into silver ammine chloride is over 230 times of that from the theory. It is recommended to add 10 mlNH₄OH (1 : 10) for the samples containing chlorine less than 0.6mg (Table III). Silver ammine chloride gives the same calibration curve as that for silver nitrate (Fig. 3). The recovery of inorganic chlorine in the neutral detergents was above 95% (Table IV and V) with variation coefficient of ca. 8% (Table VI). The lower limit for the determination of chlorine was 0.005% and the time required for a run was 40 min.. The results on commercial neutral detergents and dairy products are shown in Table VII.

View full abstract

A method of separation has been developed for the photometric determination of microgram quantities of gold in copper metal by the use of anion exchange resin. After dissolution of the sample with HNO₃ and HCl, the solution is introduced into an anion exchange resin column (Amberlite IRA 400, Cl-form, 50100 mesh, 4 mmφ × 20 mm). Gold is retained strongly in the column, whereas copper passes through thoroughly. The resin is then converted to ash in an alumina crucible, and gold in the ash is determined by the photometric p-dimethylamino-benzylidenerhodanine method. Experiments using ¹⁹⁸Au and synthetic sample solutions indicate that gold in copper can be determined by this method within an accuracy of 5 to 10% in the range of 0.5 to 100 ppm. Three copper samples were analyzed by this method with the results in good agreement with those obtained by the standard fire assay and other methods of analysis. The time required for a determination is approximately 2 to 3 hrs.

View full abstract

An absorptiometric determination of small amounts of carbon in iron and steel with Alizarin yellow R as an indicator utilizing induction heating combustion has been studied. The procedure obtained is as follows:
Add 10 ml ofN/100 sodium hydroxide, 40 ml of water and 6.5 ml of Alizarin yellow R (0.006%) into carbon dioxide absorption apparatus, fit with carbon dioxide detection trap, and connect with sulfur oxides removal apparatus. Weigh a sample into an induction heating combustion crucible, add 1g of metallic tin, insert to the combustion tube, flow purified oxygen at about 600800 ml/min. for a minute, displace the air in the tube by oxygen and unite with sulfur oxides removal apparatus. Switch on the induction heating apparatus, open the kock of carbon dioxide absorption apparatus after a minute or so, flow oxygen at 60 ml/min. for 8min., with the induction heating switched off at 12min. after opening the kock. Transfer the carbondioxide absorption solution to a cell of photometer, measure the absorbance with filter S 50. Aliquot 10 ml of N/100 sodium hydroxide, 40 ml of water and 6.5ml of Alizarin yellow R(0.006%) to another cell, agitate, measure the absorbance. Calculate the difference of the absorbances and determine the amount of carbon with the calibration curve. The time required for an analysis was about 12 min..
By using a newly designed combustion gas sampling apparatus, the time required for the analysis could be shortened to be about 7 min..

View full abstract

The presence of lead in Japanese metallic toy paints, which was once claimed to be very harmful, has been successfully controlled by X-ray fluorescence method since 1958, and then, no Japanese toys carry dangerous amount of lead in their paint films, whatsoever.
An accurate and rapid method of determination of lead in paints was developed by using a new type of dilution technique for liquid samples on the application of X-ray fluorescence method. Intensity measurements of Pb Lα₁, lines from plain lead plate, (I_pb)₀, paint sample, I_pb, and diluted paint sample, (I_pb)_D, by lead-free paint with dilution ratio D, which is weight ratio of sample to sample plus diluent, are only necessary to make a basic equation (8) of this new method, in which undesirable absorption effects would never appear for different matrix composition, whereas absorption parameter β of diluent, ratio of mass absorption coefficient of diluent to lead for the case, takes an important role, like as in the method of Beattie and Brissey. Absorption parameter of diluent can be easily determined by mixing an known amount of lead into the diluent and using the method based on equation (6).
The method was rapid enough to need only ten minutes for the analysis of a sample and was found to be accurate to 2.5% of the amount present for the range of 0.47% Pb in various kinds of metallic toy paints.

View full abstract

Metallic chromium was dissolved in hydrochloric acid, passing the air to convert chromium into chromium(III), then potassium chlorate was added to complete the dissolution in hydrochloric acid. The solution was passed through an anion exchange resin for absorption and separation of chromium from iron, copper, zinc, and cobalt. Since an insufficient separation of copper and cobalt, or copper and iron was obtained, two columns were used for the determination of those, elements; copper and zinc were eluted from one column with 35 ml 2.5N hydrochloric acid and 60 ml 1N nitric acid, respectively, and determined by use of neocuproine and dithizone; the cobalt and iron were eluted from another column with 35 ml 4N hydrochloric acid and 40 ml 0.5N hydrochloric acid, respectively, and determined by use of nitroso-R salt and o-phenanthroline. Similarly the impurities in thorium nitrate were determined.

View full abstract

[in Japanese]

View full abstract