Thiocyanate, bromide and chloride ions (X^-) reacted with mercury(II)-methylthymol blue complex (HgMTB or HgMe^4-) to form their mixed ligand complexes [HgMe(X)]^5-. The apparent stability constants (K) of these mixed ligand complexes could be calculated with the degrees of dissociation (α) which were determined with the molar ratio method by the following equation.
K=[[HgMe(X)]^5-]/[HgMe^4-][X^-]=1-α/α²C
Since the degrees of dissociation of thiocyanato and chloro mixed ligand complexes at pH 7.0 and ionic strength μ=0.10 were 0.206 and 0.792, respectively, the apparent stability constants as log K of these ions were 5.7 and 3.9₃, The degree of dissociation and the apparent stability constant of bromo mixed ligand complex at pH 7.4 and μ=0.10 were 0.169 and 5.8, respectively.

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Polarographic determination of vanadium in strong phosphoric acid (SPA) and SPA-EDTA solutions was studied. In SPA solutions, no waves were obtained for vanadium (III) and vanadium (IV). Vanadium (V) gave a single wave with E_1/2=-1.03-1.09 V (vs. SCE) at pH 10.011.5, the wave height being proportional to vanadium (V) concentration.
In SPA-EDTA solutions, vanadium (III, IV and V) all gave reduction waves.
The half-wave potential of vanadium (III) was-1.28-1.29 V (vs. SCE) at pH 5.09.0, corresponding to the diffusion-controlled and reversible reduction of vanadium (III) to vanadium (II). Both vanadium (V) and vanadium (IV) gave double wave at the same pH range, the second wave corresponding to the reversible reduction of vanadium (III) to vanadium (II). The double wave heights for vanadium (IV) decreased drastically at above pH 5.5. The second wave for vanadium (V) decreased with the increase of pH or the SPA concentration. Since the value I_d√η was constant in this pH range, it was caused by the change of viscosity of the solution and the second wave was diffusion-controlled.
The optimum condition for the determination is: vanadium in oxidation state vanadium (V) and in concentration below 10^-2 M is determined using 200°C-SPA 5 ml/50 ml+0.06 M EDTA at pH 7.0 as supporting electroyte, and 0.004% polyacrylamide as a maximum suppressor.

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Extraction behaviors of palladium and rhodium using oxine and 2-methyl oxine have been studied. As the result, methods for determining these metals have been established. The methods involve addition of reagent solution, adjusting pH, aging the complex formed, extraction with 10.0 ml of chloroform by shaking for 1 minute, and measurement of absorbance of the extract.
Palladium oxinate is quantitatively extracted in a pH range of 3 to 11 (λ_max=435mμ, ε=7.15×10³), and palladium 2-methyl oxinate 1.8 to 11.2 (λ_max= 428 mμ, ε =7.50×10³). Rhodium oxinate is quantitatively formed by standing it at 80°C for 40 minutes in the presence of acetate. The optimum pH range is 4.7 to 8.3 (λ_max =426 mμ, ε =1.08 × 10⁴). No quantitative extracting condition for rhodium 2-methyl oxinate was found. In all cases, the extract should be washed with sulfuric acid (3 to 4 N) to remove other metals.
Furthermore, a method for consecutive determination of palladium and rhodium was established by applying the fact that the extracted palladium was removed easily by shaking with hydrochloric acid (3.5 to 5 N) for 7 minutes, while rhodium remained in the organic phase. The interferences were examined in each case.

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Determination of nickel was done on the 1/10 diluant of nickel plating solution using stainless steel plate as an external standard. Chloride and sulfate were precipitated as silver chloride and lead sulfate, respectively, by the addition of a definite amount of standard silver-lead solution, and determined indirectly by measuring silver and lead in the filtrate by using scattered X-rays as an internal standard to remove materix effect. The deviation of the results from those by chemical analysis was within 3%.

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A spectrophotometric method is described for the determination of less than 15 μg of boron. To a 50 ml sample solution are added 3 ml of 3 N sulfuric acid and 1.5 ml of 15% hydrofluoric acid. After allowing the solution to stand for 1.5 hours at a temperature above 15°C, 0.2 ml of 1.33 × 10^-2 M 1, 10-phenanthroline-iron(II) chelate solution is added, and 1, 10-phenanthroline-iron(II)-BF₄^-complex is extracted into 10 ml of nitrobenzene. The absorbance is measured at 515 mμ.
More than 400 mg of SO₄^2-, 25 mg of Cl^-, 0.5 mg of NO₃^- or NO₂^-, 0.01 mg of SCN^- and 0.001 mg of ABS^- interfere. Common cations do not interfere.

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Nitrate is reduced to nitrite in the persence of NH₄Cl with zinc powder at pH 3 with a recovery of 80%, and the nitrite produced is determined spectrophotometrically with GR reagent. To 25 ml of sample is added 0.3 g of NH₄Cl, and pH is adjusted to 3.3 with a KCl-HCl buffer. With the addition of 0.2 g of zinc powder, the solution is kept at 020°C for 10 min. with occasional swirling. The solution is filtered and about 60 mg of GR reagent is added to an aliquot of the filtrate. The total-N(NO₂+NO₃) is determined by its absorbance, and nitrate-N is given by the difference between the total-N(NO₂+NO₃) and nitrite-N which is determined separately. The conditions in the procedure and the presence of salts are not critical.

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Colorimetric determination of cadmium using 2, 2'-bisbenzothiazoline has been studied.
Cadmium formed a red-violet complex with the reagent in a highly basic aqueous solution, and the complex was extracted into chloroform-pyridine (4+1) mixture.
The complex in the organic solvent showed two characteristic absorption maxima, one at 370 mμ and the other at 570 mμ. The color in the organic solvent was stable for 25 minutes. The calibration curve followed Beer's law over the range of 4120 μg of cadmium in 10 ml of the solvent (both at 370 mμ and at 570 mμ). The molar extinction coefficients were 3800 at 570 mμ and 10000 at 370 mμ.
Nickel, cobalt, copper, zinc, manganese, lead, iron, silver, mercury and magnesium interfered, but their permissible amounts were increased by addition of masking agents.
The proposed method was applied to the determination of cadmium in zinc metal with good results.

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A spectrophotometric method is described for the determination of 0.21 ppm of boron in U₃O₈. The sample (1 g) is dissolved by heating with sulfuric acid and hydrogen peroxide. Hydrofluoric acid is added to form tetrafluoroborate ion. Methylene Blue solution is then added, and Methylene Blue tetrafluoroborate is extracted with 1, 2-dichloroethane. The organic phase is washed with water to remove the excess dye. The absorbance of the washed organic phase is measured in a 1-cm cell at 660 mμ. Correction is applied for small amounts of interfering elements (tantalum, etc.) by evaporating the sample solution with hydrofluoric acid (boron is volatilized), adding hydrofluoric acid and Methylene Blue, and extracting with 1, 2-dichloroethane.
Six analyses of U₃O₈ containing 0.5 ppm of boron gave a relative standard deviation of 3.2%. The proposed method has been successfully applied to several standard U₃O₈ samples and a standard uranium metal. The metal was converted into U₃O₈ by igniting at a low temperature and heating at about 800°C for 1 hour.

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An improved method was proposed for the gasliquid chromatographic determination of n-butyl-, n-octyl- and phenyl-tin halogenides, which were treated with Grignard reagents before injection into a gas-liquid chromatograph equipped with a thermal conductivity detector. Grignard reagents and gasliquid chromatographic conditions used in this procedure were as follows.
Butyl-tin compounds: Grignard reagent-n-propyl magnesium bromide; column-3 mm × 0.75 m, stainless steel packed with 25 wt.% silicone DC 550 on 80-to 100-mesh Celite 545; temperature -190°C; carrier gas-helium 50 ml per min. flow rate; internal standard-n-octadecane.
Octyl-tin compounds : Grignard reagent-n-amyl magnesium bromide; column-3 mm × 0.75 m, stainless steel packed with 25 wt.% silicone DC HV grease on 80- to 100-mesh Celite 545; temperature -280°C; carrier gas-helium 90 ml per min. flow rate; internal standard-trioctylpropyl-tin.
Phenyl-tin compounds: Grignard reagent-n-amyl magnesium bromide; column-3 mm × 0.75m, stainless steel packed with 25 wt.% silicone DC HV grease on 80- to 100-mesh Celite 545; temperature -260°C; carrier gas-helium 50 ml per min. flow rate; internal standard-triphenylbutyl-tin.

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In order to determine molybdenum in steels by high-frequency plasma torch spectrometry, experimental conditions were examined. The most suitable conditions were as follows; magnetron anode current 140 mA, argon gas as the carrier 5.4 l/min, and analytical line Mo I 3864.11 Å. Iron, nickel, chromium, vanadium, copper, bismuth and tungsten did not influence on the intensity of analytical line. The calibration curve had good linearity. Molybdenum in steels could be determined rapidly with high precision, the coefficient of variation being about 3.3%.

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The minute amount of beryllium was determined spectrophotometrically with Chromazurol S(CAS) and zephiramine (tetradecyl-trimethyl-benzyl-ammonium chloride).
The sample solution containing 0.13 μg of beryllium and hydrochloric acid was diluted to 1015 ml with water, 1 ml of 0.5% EDTA solution and 0.6 ml of 0.25% CAS solution were added, and pH was adjusted to 5.1 with 7% hexamine solution. After the dilution to 25 ml with water and allowing to stand for 15 min., the absorbance at 610 mμ was measured against the reagent blank. The apparent molar absortivity was 9.9×10⁴.
Five micrograms of fluoride interfered with the determination of beryllium. The interferences from 1 mg of copper and 100 μg of aluminum were removed by 1 ml of 0.1% sodium phosphate solution, and that from 100mg of vanadium(V)by a filtration of the precipitate of zephiramine vanadate.

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4-(2-Pyridylazo)-resorcin (PAR) reacts with iron(II) to form a water-soluble red complex. It has an absorption maximum at 500 mμ and the absorbance is constant in the pH region from 8.8 to 10.3. The mole ratio of iron(II) and PAR in the complex is found to be 1 : 3 at pH 10. The molar absorptivity of the complex is 5.0×10⁴, being about 5 times as large as that of the 1, 10-phenanthroline complex.
Majority of interfering metal ions in amounts 25 to 100 times that of iron are completely masked by adding L-ascorbate and thiourea preliminarily to the sample solution and by adding EDTA and potassium cyanide after the PAR-iron(II) complex formation is completed. The masking effect was scarcely observed for nickel and cobalt in concentrations comparable to that of iron. This method may be successfully applied to the determination of traces of iron not only in water but also in alloys of copper, tin etc.

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Hopcalite (CuO-MnO_x) is commonly used as an oxidizing agent of carbon monoxide at room temperature. This paper presents a study of selective oxidation of carbon monoxide in the CO-H₂ mixture by CuO-MnO_x with various compositions.
The optimum composition of the selective oxidizing agent was 60% CuO and 40% MnO_x which made it possible to oxidize carbon monoxide below 50°C without oxidation of hydrogen and hydrocarbons.
This agent was also applied to the oxidation of hydrocarbons at temperatures above 100°C, in which no intermediate oxides of hydrocarbons, i. e. aldehyde, alcohol etc., were produced.

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The variations of concentration with time of several metal ions dissolved in fused potassium thiocyanate at 190°C were investigated.
It was found that the concentration of cadmium, lead, or neodymium ion except uranyl ion did not vary with time in this fused solvent for more than ten hours.
In the case of molten salt solution, uranyl ion separated after a few hours as a black precipitate resulting from the chemical reaction with the fused salt solvent. The concentration of uranyl ion therefore decreased with time, while that of the other metal ions mentioned above remained constant.
The chemical analyses of the black precipitate showed that it contained 76.8% of uranium and 10.6% of sulfur, the values being in good agreement with the composition of uranyl sulfide.
The contents of the several metal ions in the black precipitate obtained by heating for a long time at 190°C the molten salt solution containing both the above metal ions and uranvl ion were: Cd 1.86%, Pb 4.36%, Ce 6.97%, and Nd 8.47%.
It is supposed that these were caused by their coprecipitation with uranyl ion.

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Determination of alcohols in aqueous solution with bromine chloride were studied.
It is known that halogens react as an oxidant. We found that bromine chloride also oxidizes primary and secondary alcohols to acid and ketone, respectively. After oxidation of alcohols with bromine chloride, excess bromine chloride is titrated iodometrically with sodium thiosulfate. Butanol-1, propanol-1, and ethanol are able to be determined in the range of 0.001349 to 0.03373 mole solution. Butanol-2 and propanol-2 also can be determined in the range of 0.002698 to 0.08094 for the former, 0.003328 to 0.04992 for the latter. The consumption of bromine chloride is two equivalents for primary alcohols and one for secondary. The coefficient of variation of recovery of the whole concentration range determined is ±1.01% for the primary alcohols and ±0.80% for the secondary.
The concentration of alcohol in some liquid detergents and cosmetics was determined.

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Chromazurol S reacts with Co in the presence of hydroxydodecyl trimethylammonium bromide to form a blue association complex. Its absorption maximum is at 654 mμ, and the absorbance shows a constant value at pH 10.611.5. The sensitivity is very high, the molar absorptivity being 1.09×10⁵. KF is used for masking reagent, but Zn, Mn, Zr, Mg, Cu, Fe, Ni, Cr, U, Ti, Pt, and Be interfere remarkably. The molar ratio of Co to Chromazurol S in the complex is estimated to be 1 to 5. Beer's law is obeyed over 0.020.32 μg Co/ml.

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A study was made on the method for sensitive and rapid photometric determination of uranium with Arsenazo III.
Uranium(VI) forms Arsenazo III complex in 5 M perchloric acid. It has an absorption maximum at 655 mμ; the molar absorptivity is ca. 7.1×10⁴, and Beer's law holds over the range of 02.0μg U/ml. Zirconium, thorium and rare earth elements also form the complexes with Arsenazo III in the acidic solution, which interfere with the determination of uranium. Uranium, however, can be separated from the elements by 8-quinolinol extraction method.
Uranium is extracted with chloroform as 8-quinolinolate from the solution whose pH has been adjusted to 6.06.5, after masking the interfering elements by an addition of EDTA. Uranium is back-extracted with a definite volume of 0.02% Arsenazo III-5 M perchloric acid solution. The absorbance of the aqueous phase is measured at 660 mμ. In this case, the absorption maximum shifts to 660 mμ, and the molar absorptivity is ca. 6.7×10⁴.
In the determination of uranium, uranium(IV)-Arsenazo III complex is usually used. The complex of uranium(VI) is less sensitive but more stable, than that of uranium(IV). Further, the procedure presented is fairly simple, whereby uranium need not be reduced to the quadrivalent state.

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The analytical conditions in fluorescent X-ray determination of small amounts of hafnium in zirconium alloys were examined.
The best result was obtained by using HfL_β as the analytical line and an X-ray tube with gold target. The interference from ZrK line was removed by a yttrium filter, giving the best result with the combined use of a pulse-height analyser. The limit of detection of Hf was ca. 7 ppm.
The standard deviation of the results of determination of 50500 ppm Hf in zirconium alloys was 5 ppm.
The relation of the sort of target metals in the X-ray tube and the limit of detection of hafnium, together with the limit of detection and the error in the calibration line, was also examined.

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An oxide-direct current excitation method using a sifter type electrode and ammonium bifluoride buffer has been applied successfully to the spectrographic determination of B, Fe, Mg, Mn, P, Pb, and Sn in yttrium metals and oxides.
Series of standards covering 0.1 to 100 and 1 to 1, 000 ppm of the above impurity elements each in four steps (e. g. 0.1, 0.3, 0.7, and 1.0 ppm) are prepared by diluting measured quantities of base materials with weighed quantities (1 to 5 g) of spectroscopically pure yttrium oxides. Every base material was prepared by adding dropwise each standard solution (1 mg/ml) containing the impurity element on spectroscopically pure yttrium oxide in a platinum crucible. It was dried on a hot plate, ignited in a muffle furnace at 800°C for 3 hours and ground in an agate mortar. The samples are treated in exactly the same manner as the base materials.
The spectrographic conditions are as follows: amounts of the oxide 50 mg, Shimadzu Littrow type spectrograph, excitation voltage D. C. 200 V, arc current 10 amp., slit width 15 μ and duration of exposure 40 sec.
Variation coefficients for 0.1 to 1, 000 ppm of impurities in yttrium are within 20%.

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The presence of terephthalaldehydic acid (TAA) is known in the terephthalic acid (TPA) produced from p-xylene. In case of preparing bis(β-hydroxyethyl)-terephthalate (BHET) from this TPA, the TAA in it comes into the product as its hydroxyethyl ester which again returns to TAA by hydrolysis.
With an aim of determining aldehyde in TPA, BHET and their mixture by a single procedure, a simple method using Tollens' reagent was applied for the aldehyde in BHET. As a result, a method was established for aldehyde in BHET, in which 200 mg of sample was dissolved by heating with 4 ml of 3% aqueous solution of NaOH, its 1 ml aliquot and 2 ml of Tollens' reagent were mixed in a small glass vessel, and the reflectance at 440 mμ was measured after 1213 min., the valués of which were compared on a calibration curve. The time required for an analysis was 30 min., and the lower limit of determination of aldehyde was ca. 0.01%.

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A study was carried out on the spectrophotometric determination of 040 μg of copper by extracting its salicylidene-ο-aminophenol(SAP)complex in to methyliso-butylketone (MIBK).
Copper (II) was extracted as its SAP complex from weakly acidic to alkaline aqueous media into MIBK phase and a constant absorbance was obtained in the pH range between 4.3 and 8.3. The complex extracted was very stable and had an absorption maximum at 423 mμ. Its composition was confirmed to be 1 to 1. A linear relationship was maintained between the concentration of copper and the absorbance. The molar extinction coefficient and the sensitivity for log(I₀/I)=0.001 at 423 mμ were 16200 and 3.9×10^-3μg Cu/cm², respectively. Several ions including iron-(III), vanadium (IV and V), molybdenum (VI), perchlorate and citrate interfered with the determination. Interference due to iron (III) could be removed by reducing it to ferrous state with ascorbic acid.

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Paper-, thin layer-, and column-chromatography of p-hydroxyphenacyl esters of saturated fatty acids were investigated. In the paper chromatography, each p-hydroxyphenacyl esters of C₂C₂₀ fatty acids gave different R_f values depending on the number of carbon atoms of the acid. The solvent systems were 30 and 80 per cent aqueous acetone (0.1 N NaOH).
The separation of the esters of C₂C₁₂ fatty acids was achieved by the silica-gel thin layer chromatography with acetic acid-cyclohexane as the solvent system.
Using the same solvent, cellulose powder column chromatography was successful for separating the esters of C₂C₁₄ fatty acids. The esters could be detected with phenolic color reactions.

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An instrument with a hydrogen flame ionization detector and a continuous sample inlet system has been developed for the measurement of the total hydrocarbon content in automobile exhaust gases. The sampling line can be heated to above 100°C and has a minimized space, so that there is reduced hang up, and the response to the change of concentration of sample gases was only 2.5 sec. It can follow any rapid changes in engine operating condition. The possible concentration range of determination is 15050, 000 ppm C₃/full span, in which the range can be selected at will. The values of hydrocarbon emission obtained by this apparatus were considerably higher but more accurate than those by a non-dispersive infrared analyzer.

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Fluoride ion activity electrode was applied to the coulometric titration method developed recently by the authors. The relative standard deviation of this method was 0.4% for 10mg of fluorine and the lower limit of detection was 2ppm. The readiness to repeated titration may enable to give automated systems.
The current efficency was 97±1% within the current density 416mA/cm² in the 70% ethanol-0.3M potassium chloride-0.3M acetic acid solution. The effect of chloride to bring dissolution of the aluminum generating electrode was confirmed by the measurement of the polarization characteristics of the rotating aluminum electrode in several electrolytes.
The endpoint of this titration corresponded to AlF₆ in the potassium-containing electrolytes and AlF₇ in the sodium-containing electrolytes. Even traces of sodium salts influenced on the endpoint in the potassium-containing electrolytes.

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Determination of small quantity of thallium in cadmium by square wave polarography was studied. One mol hydrochloric acid solution containing hydroxylamine hydrochloride was found to be suitable as the supporting electrolyte, but preliminary separation of tin, cadmium and lead from thallium was necessary.
The recommended procedure is as follows. Five grams of sample is decomposed with aqua regia added with a small amount of water. The solution is evaporated to dryness and evaporated again with hydrochloric acid and saturated bromine water. The residue is dissolved with perchloric acid, evaporated to dryness and made to IM hydrobromic acid solution. Thallium is extracted with ethyl ether, and washed with IM hydrobromic acid in order to remove cadmium. The ether extract is evaporated nearly to dryness. Hydrobromic acid and perchloric acid are added, and evaporated again.
The residue is dissolved with 4.5ml of 6M hydrochloric acid and diluted to 25ml with 5ml of 10% hydroxylamine hydrochloride and water. The oxygen dissolved in the solution is removed by passing nitrogen, and the square-wave polarogram is obtained between -0.25 to -0.75 volt against mercury pool.
As little as 1ppm of thallium in cadmium was determined with good accuracy and reproducibility.

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In the case of determining silicon in iron and steels spectrophotometrically by molybdenum blue method, white cast iron is excluded from this application as it gives abnormally low analytical values.
The authors established a quantitative procedure for the determination of silicon in white cast iron without annealing of the sample. The results obtained agreed with those of the gravimetric analysis.
The procedure established was as follows. One tenth gram of white cast iron sample was dissolved in the mixed acid consisting of 15ml of (1+11) sulfuric acid and 5ml of 15% hydrogen peroxide, and the solution was made alkaline with 16ml of 10% ammonia water. After the solution was boiled for ten minutes and cooled, 15ml of the mixed acid was added in order to adjust the acid concentration. Subsequent procedure was followed by the usual analytical method.
By this procedure, we obtained the values agreeing with those by the coefficient of variation about 0.7%.

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Conventional methods for determining fluorine in cryolite, including those by Offerman, Willard-Winter, Ion-exchange resine and ALCOA, were examined, and a simple and rapid method was proposed. The outline of this method was as follows.
By using the apparatus of Willard-Winter, 0.2g of cryolite was taken into a Claisen flask, and 12g of anhydrous silica, 50ml of 68% sulfuric acid and 10ml of 85% phosphoric acid were added. It was steamdistilled for 3.5 hours at 135140°C. Then, fluorine in the distillate was determined by the thorium nitrate titration.

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A high-sensitive method for the spectrophotometric determination of trace amounts of cobalt(II) with 2-thenoyltrifluoroacetone(TTA) was established. The pH of a sample solution containing up to 20μg of cobalt(II) was adjusted to about 5.5, and cobalt(II) was extracted into a mixture of TTA(5×10^-4M) and pyridine (5×10^-2M) in benzene. In order to eliminate the excess amount of TTA which reduces the sensitivity of the TTA method to a great extent, the organic phase was washed with an aqueous solution of NaOH(5×10^-3M) and the absorbance was measured at 340mμ. The sensitivity of this method was 0.0020 μg/cm². Although nickel(II) interfered with the determination, most interference caused by the presence of diverse cations could be eliminated by adding fluoride and tartrate ions.

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[in Japanese]

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