A method for the separation and identification of mixtures of substituted phenyl N-methylcarbamates by gas-liquid chromatography with thermal conductivity detector was described. By the combination of two operating conditions, mixtures of seven phenyl N-methylcarbamates could be mutually separated. It was confirmed that 3, 4-dimethylphenyl N-methylcarbamate was converted to 3, 4-dimethylphenol during the operation with gas chromatography. This technique should be useful for analysis of pesticide formulation and residue analysis.

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A rapid method for the determination of phosphorus in ferroniobium, ferrotitanium and niobium ore, which involves the masking of niobium or titanium with fluoride ion and the extraction of phosphovanadomolybdic acid with methylisobutyl ketone, has been presented.
Ferroniobium or ferrotitanium (0.1 g) is dissolved in a few ml of nitric and hydrofluoric acids and 1 ml of (1 : 1) sulfuric acid, and is evaporated nearly to dryness. A definite amount of the acid for giving the optimum acid concentration {5 ml of 10N sulfuric acid, 5 ml of 60% perchloric acid or 6 ml of (1 : 1) nitric acid} and an amount of 2% ammonium fluoride solution, 20 ml for ferroniobium or 15 ml for ferrotitanium, are added, and the salts are dissolved by gentle heating. After cooling, 5 ml of 1.2% ammonium vanadate and 10 ml of 10% ammonium molybdate are added, and the solution is diluted to about 50 ml with water. After standing for 10 minutes, 10 ml of methylisobutyl ketone is added, and it is shaken for 10 seconds. The organic layer is dry-filtered, and the absorbance is measured at 420 mμ.
Niobium ore (0.5 g) is fused with 34 g of sodium peroxide, and decomposed with water. After additions of 1 g of ammonium fluoride and 1 drop of hydrogen peroxide (30%), the solution is neutralized with nitric acid and then 20 ml in excess. After cooling, the solution is diluted to 200 ml with water. To a 40 ml aliquot are added 5 ml of 1.2% ammonium vanadate and 5 ml of 10% ammonium molybdate, and then the procedure is carried through as above.
The methods are very rapid, and the accuracies are 1.54.0% for ferroniobium or ferrotitanium and 3.56.4% for niobium ore.

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X-ray fluorescence method for the determination of alloying elements in zirconium alloys is described in this paper.
The experiment was conducted to develop a method generally applicable to zirconium alloys in a wide variety of analytical elements and sample shapes.
The analyses were made on both the solid disk samples and the glass beads, the latter being prepared by melting 1 g of oxide of alloy with 15 g of sodium tetraborate. The glass beads method would be applied when a solid disk sample and/or its standards were not available. Tin, nickel, iron and chromium in zircaloy and niobium in zirconium-niobium alloy were determined by the metallic disk method, and niobium and copper in binary alloys by the glass beads method.
The accuracy and precision of the methods were superior to those by the emission spectrography.

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The titration apparatus which had been described in the previous report was improved, by use of which was investigated a rapid method for alkalimetric titration of nitric acid solution containing uranium. (1) In order to facilitate the detection of an equivalence point of titration, a microammeter was replaced by an autobalancing recorder, on which a differential titration curve as well as the volume of titrant delivered were recorded. (2) In a direct titration of a nitric acid solution containing uranium alone, one of the equivalence points on the differential titration curve corresponded to free nitric acid. In a titration of the same solution after precipitation of uranium by addition of hydrogen peroxide, the equivalence point corresponded to the sum of the free and the uranium-bound nitric acid. Uranium could then be determined from the difference of the two titres. (3) In a titration of a nitric acid solution containing uranium together with aluminum, both the free acid and uranium could be determined as above by an addition of ammonium oxalate. (4) The titration was carried out with a relative error of less than 3% within a couple of minutes.

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The steam carrier adsorption gas chromatography was applied effectively to the separation of carboxylic acids, especially in dilute aqueous solution.
The separation column was prepared by baking at 500°C for 5 minutes a glass tube (1.83.7 mmφ × 2.64.0 m) packed with Chromosorb P AW 30/60 with 3% phosphoric acid, so that it might be very stable against organic acids and steam carrier at a considerably high temperature.
Fatty acids from C₂ to C₁₈, benzoic acid, salicylic acid and lactic acid were tested in 0.1%0.1 ppm aqueous solution, whereby insoluble materials were supplied as their alkaline metal salts which showed chromatograms identical to those of the free acids in organic solvents such as carbon tetrachloride.
Elution peaks were almost symmetrical, especially at lower temperature. A satisfactory separation with 0.120.17 cm of H. E. T. P. was obtained for lower fatty acids.
Retention times in this adsorption gas chromatography were very short ; enanthic and n-caproic acids were eluted in 35 sec. at 170°C, and stearic and palmitic acids were eluted in 90 sec. at 225°C, both with only slight decrease of separability.
Identification of fatty acids in their extremely dilute aqueous solution was achieved by this method : for example, 0.1 ppm of fatty acids from lower to enanthic and also 1 ppm of palmitic acid were detected by using a hydrogen flame ionization detector.

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The reagent in the negative cell in the focusing chromatography, which is usually a soluble complex former, has been replaced by a dilute aqueous solution of oxine as a precipitation reagent for copper, nickel, cobalt or iron. The experiments have been made by putting hydrochloric acid or acetic acid in the positive cell, and fundamental factors as pH values, concentration of oxine solution, time of electromigration, potential gradient etc. are examined.
The postulated method gave good result for separating the ions in dual systems i. e., (Cu²⁺, Ni²⁺), (Cu²⁺, Co²⁺) and (Fe³⁺, Cu²⁺).

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A method of the determination of carboxylic acid in the effluent from the ion exchange chromatographic column was established. The effluent was successively led into a " pH control " column of weak acid type cation exchange resin of free acid form, and the carboxylate ions in the solution were converted into free acid. The titration was carried out with an alkali standard solution, and the content of each carboxylic acid in the sample was given by summation of the titration values on each peak of the elution curve.
A correction for the ionization of acids was also described. Even after the treatment of the effluent by pH control column, the carboxylic acids in the solution were partially ionized to carboxylate ion, which could not be titrated with the alkali solution. Correct results were given only by taking account of this effect, whereby the correction factors were calculated from the pH value of the solution before titration and the dissociation constants of respective acids.

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Photometric titration of iron (II) or iron (III) with Co (III) -nitrilotriacetate complex {Co (III) -NTA} has been described. Co (III) -NTA was prepared by the electrolytic oxidation of Co (II) -NTA in an alkaline solution. Since the Co (III) -NTA solution has an absorption maximum at 550 mμ, photometric titration was carried out with a spectrophotometer set at 550 mμ. An aliquot (02ml) of 0.1N Fe (II) solution was placed in a photometric titration cell filled with nitrogen gas, and 55 ml of phosphate buffer solution of pH 2.5 and 5 ml of 0.4M NTA solution were added. This solution was titrated with Co (III) -NTA under a stream of carbon dioxide gas. The end point for iron was obtained as a break of titration curve. The result was not affected by 30 ml of 0.1M ascorbic acid in 2 ml of 0.1N Fe (II), so that the method is fortunately suitable for the determination of iron in the presence of ascorbic acid.
Consequently, the method was applied to the determination of Fe (III), after its reduction to Fe (II) with ascorbic acid. Co (III) -NTA solution was comparatively stable, and was more stable when it was kept in cold and dark place.

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An infrared spectrophotometric method for the determination of hydrogen in chlorine gas was proposed. Sample gas was exposed to the photochemically active light in a quartz reactor tube, to form hydrogen chloride by the reaction Cl₂+H₂^hv→2HCl. Then the reaction gas was led into a 100 mm I. R. gas cell, and the absorption from 3400cm^-1 to 2400cm^-1 was measured by an infrared spectrophotometer.
The absorbance at 2980cm^-1 on 2840cm^-1, each a maximum of saw toothed absorption curve of hydrogen chloride, was calculated by the use of base line method. Since water and carbon dioxide did not interfere at those wavenumbers, the method was suitable for the determination of hydrogen in electrogenerated chlorine gas. The values of hydrogen contents in electrogenerated chlorine determined by this method were well congruent with those obtained by the more complicated explosion method.

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In connection with the previous report, the present paper deals with the application of the red fluorescence, which appears in the reaction of copper ions with thiolized thiamine, to a new qualitative analysis of copper. Cuprous ion was more sensitive to this fluorescence analysis than cupric ion.
The thiolized thiamine reagent was prepared by dissolving thiamine hydrochloride in sodium hydroxide at pH 11. The sample solution was prepared by reducing cupric ion to cuprous with hydroxylamine hydrochloride, and adjusting pH to 7. The fluorescence study was carried out on both spot test and solvent extraction methods.
In spot test analysis, a portion of sample solution was spotted on a filter paper, the thiolized thiamine reagent was then added, and the red fluorescence was measured under ultraviolet rays of 3650Å. The limit of identification was 0.3μg Cu per drop.
In the extraction method, the reaction product of cuprous-thiolized thiamine system was extracted with iso-amyl alcohol and then the intensity of the red fluorescence was also examined in the same way described above. The limit of identification of copper was 6μg per ml.
Further study showed that this red fluorescence was quite specific for copperion, and no other cations and anions except sulfide quenched the fluorescence and interfered with the detection of copper.

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Small amounts of titanium in silicate materials were determined by spectrophotometric method after an extraction of titanium (IV) into benzene with N-benzoylphenylhydroxylamine (BPA).
A sample was disintegrated with hydrofluoric acid in the presence of sulfuric acid, treated with potassium pyrosulfate, and then finally made up to about 8N hydrochloric acid solution. (A sample which could be easily taken up with hydrochloric acid was directly dissolved in hydrochloric acid). Titanium (IV) in an aliquot of the resulting solution was extracted into benzene phase with BPA, and the absorbance was measured at 380 mμ against a reagent blank.
The extraction of titanium (IV) into benzene phase from 7 to 10N hydrochloric acid solution was quantitative. The extracted complex had a composition of 1 to 2 (metal to ligand) and showed characteristic absorption in visible and near ultraviolet regions. There was a linear relationship between the amounts of titanium (IV) and absorbance, the molar extinction coefficient at 380 mμ being 7, 100. Diverse ions usually found in silicate materials did not interfere with the determination except vanadium (IV and V) and chromium(VI). Vanadium must be removed before the extraction, and chromium (VI) must be reduced to non-interfering chromium (III).
The method was applied satisfactorily to several silicate materials. The results were comparable to those by other analytical methods.
The paper also presents some extraction characteristics of titanium (IV) -BPA complex in benzenehydrochloric acid solution system.

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A solution technique in fluorescent X-ray spectrography was recommended for the rapid determination of zinc, selenium and tellurium in photoconductive single crystals of zinc selenide-telluride.
The sample was dissolved in concentrated nitric acid and diluted with water. The fluorescent X-ray intensity ratios of elements in the solution were measured, with the correction for interelement effects by equations composed of linear functions, and the three elements in the sample were determined referring to calibration curves. The relative error for synthetic solutions was about 1 %, and the time required for an analysis of practical samples was about 100 min.

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A photometric method for the determination of vanadium with N-benzoyl-N-phenylhydroxylamine (BPHA) in magnetite, ilmenite, chromite and igneous rocks was investigated.
Magnetite, ilmenite and ordinary igneous rocks are treated with hydrofluoric-sulfuric acid in a platinum crucible. The contents are evaporated until sulfuric acid fume evolves, and then dissolved in hot water. Since chromite is not decomposed with above treatment, chromite and chromite-rich igneous rocks are fused with sodium peroxide in an alumina crucible, and dissolved in sulfuric acid. The chromate formed is reduced by the addition of ferrous sulfate solution, and the excess of ferrous sulfate is oxidized by concentrated nitric acid. Silica is then eliminated with hydrofluoric acid.
Sample solution thus obtained is transfered into a separatory funnel. To it are added 2% sodium fluoride solution for masking titanium ion and 0.1N potassium permanganate for oxidizing vanadium. Immediately after the adjustment of the acidity of the sample solution to 6N by hydrochloric acid, 15 ml of BPHA-chloroform solution (0.067%) is added, and the funnel is shaken for 30 seconds. Chloroform layer separated is filtered through a filter paper, and the absorbancy of the filtrate is measured with a 532 mμ filter.
The proposed method is rapid and accurate as compared with the Sandell's method.

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Spectrophotometric determination of zinc in cadmium metal was carried out by using Xylenol Orange as the reagent. The absorption maximum was at 570 mμ, and the optimum pH was 6.0. Beer's law held for the concentration lower than 60μg Zn in 50 ml.
The sample was at first dissolved in an acid, and the solution was heated to dryness. This treatment was effective for avoiding interferences from Bi, Sb and Sn. The salts thus obtained was dissolved in water. The solution was adjusted to pH 6.0 by sodium acetate buffer.
Interferences from Cd, Cu, Pb, Al, Fe etc. were avoided by adding potassium iodide, ammonium bifluoride and sodium thiosulfate to the solution. Attempts to remove interferences from Ni and Co failed. As an example, 17 ppm of zinc was determined with the coefficient of variation of 2%.

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Sensitivity of the determination of microamounts of lead in iron oxide by atomic absorption spectrometry has been improved by an employment of organic solvent extraction.
Two tenth gram of sample is dissolved in hydrochloric acid and nitric acid. The solution is evaporated to near dryness (ca. 2 ml) with 1000 μg of manganese, and, after cooling, 5 ml of ammonium citrate solution (30%) and 5 ml of DHEG solution (10%) are added. The pH is adjusted to about 10 with ammonia water (28%).
It is transferred into a separatory funnel, and shaken with 5 ml of dithizone(0.1%)-MIBK solution for one minute. The extract is subjected to atomic absorption spectrometry. Five hundreds μg each of Mn, Cr, Co, Ni and Zn and 200 μg of Cu do not interfere with the determination.
The method is recommended for the rapid determination of extremely low concentration (0.00010.0100%) of lead in iron oxide, with the coefficient of variation_ about 3%.

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It has been generally known that the sensitivity in atomic absorption spectrometry increases with the decrease of the hollow-cathode lamp current. The author examined the effect of the current upon the sensitivity and the linearity range of various analysis lines, using Westinghouse hollow-cathode lamps for Ca, Co, Pb, Mn, K and Na (Nippon Jarrell Ash AA-IE).
The result indicated that the sensitivity increased exceptionally with an increase of the lamp current by Co 3454 Å, Mn 4031Å and all lines of K and Na. The analysis lines giving maximum sensitivity were: Ca 4227Å, Co 2407Å, Pb 2833Å, Mn 2795Å, K 7665Å and Na 5890Å. Co 2425Å showed a wider range of linearity, but its sensitivity was a little lower for minor concentrations of Co.

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The author examined the effect of the current upon the sensitivity and the linearity range of various analysis lines, using Westinghouse hollow-cathode lamps for Ba, Fe, Mg, Sn and Zn (Nippon Jarrell Ash, AA-1E), succeeding to the first technical report.
The sensitivity increased with an increase of the lamp current by Ba 5536Å, Fe 2967Å; the line Zn 3076Å was not affected. All the others increased their sensitivity with decreasing lamp current. The examination on Sn 2863Å, however, was done only at the maximum current on account of its too weak light intensity.
The analysis lines giving maximum sensitivity were: Ba 5536Å, Fe 2483Å, Mg 2852Å, Sn 2863Å and Zn 2139Å.

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Quinine ethylcarbonate in pharmaceutical preparations could be determined conveniently by the infrared spectrophotometry. The absorption band at 1755 cm^-1 of its carbon disulfide solution was chosen as the key band.
The recommended procedure is as follows:
A sample which contains about 25 mg of quinine ethylcarbonate is placed in a centrifuge tube, add 25 ml of carbon disulfide and shake the tube for 10 minutes. Centrifuge the contents of the tube, and the residue is treated similarly with 15 ml of the same solvent three times. The whole supernatant liquid is put together, condensed to about 5 ml in vacuo, and diluted to 10 ml with carbon disulfide. Measure the absorbances of this solution (E_T) and a standard solution (2.5 mg/ml) (E_S) against a solvent blank, and estimate the amount of quinine ethylcarbonate from the ratio of E_T to E_S.

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Polarographic determination of minute quantity of lead in cadmium metal by JIS method requires chemical separation of lead from majority of cadmium.
The authors determined, using oscillopolarograph by differential method, 0.0005% or less of lead in cadmium without preliminary chemical separation. The method of analysis is as follows.
Five grams of sample is dissolved with nitric acid and hydrochloric acid and evaporated to dryness. Hydrochloric acid is added and dried up again. The residue is dissolved with hydrochloric acid, and the solution is made up to 100 ml with 1 N hydrochloric acid.
This solution is subjected to the oscillopolarographic determination. The proposed method was very rapid and gave comparable result to that of the JIS method.

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Carbon monoxide and dioxide, methane, ethylene and acetylene in auto-exhaust gases were determined by their infra-red absorption spectra. Characteristic bands for the determination were: carbon monoxide 2360 cm^-1, carbon dioxide 660 cm^-1, methane 1300 cm^-1, ethylene 950 cm^-1 and acetylene 730 cm^-1. Minimum detectable limits were: carbon monoxide 0.1%, carbon dioxide 0.3%, methane, ethylene and acetylene 0.02%. Concentration of five components in the exhaust gases of ten vehicles were: carbon monoxide 1.09.7%, carbon dioxide 2.610.0%, methane trace0.42, ethylene trace0.13% and acetylene trace0.42%.

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The determination of microamounts of fluorine in the existence of aluminum has been done by the photometric method with alfusone.
The solution of AlF₆^3- complex ions was made alkaline (Ph>12), and the liberated aluminum was removed by an extraction with oxine-chloroform. As small amounts of chloroform and oxine remained in the aqueous layer, chloroform was removed by heating. The solubility of oxine became minimum by making pH 8 when it was extracted, and its color could be minimized by increasing the amount of alfusone to be added.
Less than 504 μg of fluorine in the presence of 20 μg of aluminum was satisfactorily determined by this procedure.

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[in Japanese]

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