Chlorate ion was determined by atomic absorption spectrophotometry. The following three kind of samples containing ClO₃^- were prepared : (1) ClO₃^- alone prepared by using KClO₃ or NaClO₃, (2) a mixture of ClO₃^- and either Cl^-, Br ^-, I^-, BrO₃^-, IO₃^-, ClO₄^-, or IO₄^- prepared by using KClO₃ and either NaCl, KBr, KI, NaBrO₃, KIO₃, NaClO₄, or NaIO₄, (3) ClO₃^- in explosives using KClO₃. The concentrations of sample solutions were 0.75 mg/ml of ClO₃^- in solution 1, and 0.75 mg/ml of ClO₃^- and 0.07?1.3 mg/m/lof Cl^-, Br^-, I^-, BrO3₃^-, IO₃^-, ClO₄^-, or IO₄^- in solution 2.
The recommended procedures are as follows : To a sample solution was added 0.5 ml of 20% FeSO₄ solution, and the solution was heated on a water bath for 10 minutes at 80°C. After the solution had been cooled, degradation product to Cl^- containing Fe-complex salt was dissolved in 5 ml of 6N HNO₃, and 2 ml of 20 mg/ml AgNO₃ solution was added to the solution. After the solution had been filtered, the AgCl precipitate was dissolved in 20 ml of 1.42 N ammonia water. The solution was diluted to 1000 ml with water and was analyzed by atomic absorption spectrophotometry.
The mixed sample of ClO₃^- and either Cl^-, Br^-, I ^-, IO₃^-, or IO₄^-, was dissolved in water and then 1?10 ml of 20 mg/ml AgNO₃ solution was added. The Cl^-, Br^-, I ^-, IO₃^-, or IO₄^- ion in the mixture was removed as the silver precipitate, and ClO₃^- was determined in the same manner as described above. KClO₃ in explosives was dissolved in water, and was analyzed by the method described above.
Other ions did not interfere with ClO₃^- determination, even in the coexistence of about 10 times Cr⁶⁺, Pb²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Ca²⁺, Cl^-, Br^-, I^-, IO₃^-, ClO₄^-, and IO₄^-, but coexistence of 0.05 times BrO₃^-, and about 0.23 times Hg⁺ and Hg²⁺ interfered with ClO₃^- determination. Limit of determination for ClO₃^- was 14.9 μg. Since the measurement of silver was influenced by a concentration of ammonia, the concentration was kept constant at 0.028N at both measurements of the sample and the calibration. The calibration curve was linear ranging from 1.4 × 10^-2to 2.24 mg of ClO₃^-. Per cent recovery of ClO₃^- ranged from 97.0 to 100%.
It was found that the procedure was easy and simple, and this method could be used for a small amount of sample.

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Separation of anthracene and phenanthrene and separation of isomers of dinitrobenzene have been examined by gas-solid chromatography using alcohol vapors as carrier. The apparatus used was the same as described in the previous paper.
The activated alumina (200300 mesh) of Kishida Kagaku and E. Merck Co. were used.
When a commercial sample of phenanthrene was submitted to the gas-solid chromatography by using ethanol vapor as carrier gas and activated alumina as solid adsorbent, the chromatogram obtained at 210°C showed five peaks, which were identified to be fluorene, phenanthrene, anthracene and two unknown components in the order of increasing retention volume; separation of anthracene from phenanthrene is not possible by the conventional gas-liquid chromatography.
Mixtures of o-, m-and p-dinitrobenzene were also separated by this method under the following conditions; column temperature, 160°C; column, 1 m in length and 3 mm in internal diameter; adsorbent, activated alumina, 200300 mesh.
The effect of the composition of the mixed carrier vapors of ethanol and methanol on the retention of dinitrobenzenes was tested. When the mole fraction of ethanol in the mixed carrier vapor was increased from 0.1 to 0.8, the retention volumes of dinitrobenzenes changed slightly; but when the mole fraction was decreased from 0.1 to zero, the retention volumes increased steeply. It is concluded that a small addition of etanol in methanol changes the nature of the surface adsorption layer to a large extent.
By using the carrier vapor of methanol, ethanol, iso-propyl alcohol or 1% acetic acid-methanol, the retention volumes of benzene, p-xylene, dipropyl ketone and naphthalene at 140°C were measured. The retention volumes of these compounds were nearly equal except when pure methanol was used, but the retention volumes in the latter case were doubled.
These results supports the view presented in the previous paper {T. Tsuda, K. Ito and D. Ishii : this journal, 22, 1554 (1973) }.

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A new highly sensitive method for the quantitative determination of mercury is described. The method consists of the following procedures. Sample is first digested with a mixture of sulfuric and nitric acids as usual, and the mercury ions produced are reduced with hydroxylamine sulfate and stannous sulfate under continuous bubbling of N₂ gas so as to vaporize mercury. The gas which carries elemental mercury is then dried and passed through a quartz tube filled with activated charcoal. After the complete adsorption of mercury on charcoal, the tube is put into a furnace adjusted to 500°C and the mercury vapor desorbed is introduced into a quartz-windowed absorption cell and the absorption of 253.7 nm is measured with an atomic absorption spectrometer. The schematic diagram of the apparatus used in the present work is given in Fig. 1.
Because mercury is enriched by the adsorption on charcoal, a very narrow absorption peak is obtained (Fig. 3). Consequently, the sensitivity becomes five to ten times higher than that of the conventional reduction-aeration method or the recycling technique (Fig. 4). Even when the mercury content in sample is too small to be detected in a single reduction procedure, a detectable absorption peak can be obtained by accumulating mercury on charcoal through the repeated reductions and adsorptions. As demonstrated by an example given in Table I, this technique is promising for the analysis of a trace amount of mercury.
Absorption peak height increases with increasing temperature of the furnace and finally becomes constant above about 300°C (Fig. 5). In the present work, 500°C is adopted in order to avoid possible irreversible inactivation of charcoal at an excessively high temperature. Effect of the flow rate of carrier gas is shown in Fig. 6. The temperature and volume of sample solution has little influence on the analytical data. This is one of the advantages of the present technique over the conventional methods, in which profiles of absorption peak depend largely on the condition of sample solution. Sulfur dioxide evolved in the course of the digestion with sulfuric and nitric acids interferes with the absorption peak. This interference, however, has been found to be avoided by the treatment of the solution with KMnO₄ before the reduction procedure.
As an application of the present method, various forms of mercury added to sugar have been analyzed. The results are shown in Table II. Recoveries of more than 95% were obtained in every case. The technique described in this paper will be applicable to trace analyses of other volatile metals or metalloids, e. g., arsenic and antimony.

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The determination of free phenols and isomers of mononuclear methylol phenols in phenol resole resins was studied by gel permeation chromatography (GPC) with the high molecular weight polystyrene as an in ternal standard. The phenol, alkyl phenols and methylol phenols and cresols used as standards were reagent grade. The monodispersed polystyrene purchased from Pressure Chemical Co. Ltd. of which M_vis was 160000 (M_w/M_n≤1.06) was used as an internal standard.
The chromatographic parameters were as follows: porosity rating of five polystyrene gel columns, 1500050000Å, 100150Å, 5080Åand 5080Å; solvent, tetrahydrofuran (THF) ; temperature, 25°± 2°C; equipment, Waters Associates GPC Model-200; sensitivity, 2X; experimental theoretical plate number of polystyrene gel columns obtained with o-dichloro benzene, 505 plates per foot; sample concentration, about 100mg of resole resins and 25mg of the polystyrene per 25ml of THF in a. volumetric flask.
The peak of the free phenol was enough separated to perform the quantitative analysis.
However, peaks of isomers of mononuclear methylol phenols were not separated completely, so net peak areas of each isomer were obtained by deviding a peak area of chromatogram in proportion to the adjacent peak heights. The reproducibility of the determination of the free phenol was about 4 per cent by the coefficient of variance. The observed values of the free phenol were in close agreement with added values and values obtained by gas chromatography with mcresol as an internal standard. Correction coefficients of 2- and 4-methylol phenol were obtained with standards, but those of 2, 4- and 2, 6-dimethylol phenols and 2, 4, 6-trimethylol phenol were obtained by using standards in which dimethyl phenols, 2, 4, 6 trimethyl phenol, dimethylol cresols and monomethylol xylenols were substituted to these isomers, respectively. However, the peaks of 4-methylol phenol and 2, 6-dimethylol phenol were not separated in this analytical condition.
This procedure is also applicable to the determination of free monomers in only pure phenol novolac resins, p-terbutylphenol resins, p-phenyl phenol resins, other alkyl phenol resins and other thermosetting uncured resin, i. e, epoxy resin and furan resins, but is not applicable to the determination of free monomers in these resins modified with other kinds of phenolic monomers.

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The molecular weight distribution of phenol-formaldehyde resins was determined by a turbidimetric titration. The Kotaki Model NT-3 turbidimetric titrator was used. Phenol random novolac resins were fractionated in methanol-water system as a sample.
Methanol and water were used as a solvent and a precipitant, respectively. The turbidity was measured at 15°C± 1°C. Scattered light perpendicular to incident light was received by photomultipliers.
A molecular weight distribution curve was obtained from Morey-Tamblyn equation;
γ=K log C+f (M),
where γ is the critical volume fraction of precipitant at the precipitation point, K is a constant, C is the concentration of the solute in a solution and f(M) is a function of molecular weight.
The C is related to C₀ by the equation; C=C₀ (1 -γ), where C₀ is the initial concentration of solute in a solution.
It was found that low molecular weight fractions in the molecular weight distribution curve by turbidimetric titration method less than that obtained by a solvent fractionation method and gel permeation chromatography.
Furthermore, the dependence of K-value on the molecular weight was observed. This procedure is only applicable to determine molecular weight distribution of phenol novolac resins which have almost the same structure with each other.

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In gas or liquid chromatography it is essential to process noises of digital integrator in an appropriate manner so that a high reliability can be obtained. Low pass filters, minimum-count filters, etc. have been generally used, but they are not quite satisfactory. For example: if a noise signal which is not eliminated by a minimum-count filter emerges, it is integrated as if it were a peak signal; if a spike noise which is not eliminated by a low pass filter emerges while a peak area is being integrated, the peak may be processed as if it were two separate peaks, or the integration may be stopped at that point where the noise emerges. This paper describes a newly-developed method to eliminate noise of digital integrators.
The new digital integrator can generate three timing pluse signals: the first pulse is generated at the beginning of peak, the second pulse at the end of peak rising, and the third at the beginning of peak falling. The widths of the pulse are selected beforehand according to the width of noise. In Fig. 2, the top of signal (1) is within the width of the first pulse, so that this signal is judged as a noise and the integration is stopped at this point.
The new integrator also has a variable noise discrimination level. The timing of the top of signal(3) is same as signal (1), but because the height of signal (3) is over the discrimination level this peak is judged as a peak and the integration is not stopped. Although the height of peak (2) is under the discrimination level, the integration is not stopped because its top is out of the timing of the first pulse. When the noise is detected during a peak integration, if the timing of the point is within the width of the second and third pulses and if the level of the point is over the discrimination level, the integration is not disturbed and continued (Fig. 3).
Peaks with much noise (Figs. 46), which are almost impossible to be handled in the conventional methods, can be well processed by the present method.

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The subtractive technique has been utilized in gas chromatography in order to have simpler chromatograms and to make identification of peaks easier. In applying this subtractive technique, chemical absorbing agents (scrubbers) are often employed. Attempts have been made by combining such scrubbers with hydrogen flame ionization detector (FID) in evaluating the emission of hydrocarbons in automotive exhaust gases. As the scrubbers that can be applied for such a system, those prepared by coating HgSO₄-H₂SO₄, PdSO₄-H₂SO₄, Ag₂SO₄-H₂SO₄ and Hg (ClO₄)₂ onto firebrick or diatomaceous earth have been known so far.
However, the effect of the operating conditions of a scrubber on the selectivity in absorbing hydrocarbons is not sufficiently understood.
In this paper, it was noted that a scrubber would be affected by its water content and the temperature under which this scrubber was applied. For instance, the Hg(ClO₄)₂ scrubber, that is generally used in its dry state, removes olefins, acetylenes and aromatics at the room temperature. When this scrubber is put to use at a temperature in excess of 80°C, it further removes isoparaffins and cycloparaffins as well. As oppose to this trend, it does not remove specific portion of olefins and aromatics when the scrubber is wet. On the other hand, the HgSO₄-H₂SO₄ scrubber (this is normally used in its wet state) absorbs olefins (2-butenes, however, are not absorbed completely) and acetylenes at the room temperature. When this scrubber is put to use under its dry state and at a temperature higher than the room temperature, it functions in similar fashion as a scrubber using nothing but sulfuric acid. Other scrubbers are also affected by water content and operating temperature.
In addition, a scrubber was prepared on trial basis by coating HgI₂-KOH on diatomaceous earth in order to fractionate acetylene from olefins. It has been found that this scrubber could remove acetylene alone on selective basis out of a mixture consisting of hydrocarbons.
Based upon the characteristics of such scrubbers, systems have been assembled on trial basis by combining the scrubbers and FID in order to apply such systems on the type analysis of hydrocarbons contained in automotive exhaust gases. For such systems, scrubbers by coating HgSO₄-H₂SO₄, Hg (ClO₄)₂ and HgI₂-KOH onto diatomaceous earth have been put to use. It is for this reason, it is possible to measure paraffins, olefins, acetylenes and aromatics through such a system. The analyses of hydrocarbons found in automotive exhaust gases were done by using such systems. The results thus obtained agreed well with those obtained by the gas chromatographic analyses.
The results noted in this paper can very well be applied in carrying out the type analysis of hydrocarbons in atmosphere.

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The mechanism of higher order complexation in the neighborhood of charge-cluster has been investigated spectrophotometrically by using beryllium complex of Eriochrome Cyanine R. Polyvinylbenzyl trimethylammonium and tetradecyldimethylbenzylammonium chloride were chosen as charge-clusters.
The higher order beryllium complex with Eriochrome Cyanine R in a 1 : 2 molar ratio is incompletely formed in the presence of polyvinylbenzyl trimethylammonium chloride and nonionic surfactant, but is easily formed at the surface of the charged micelle consisted of the tetradecyldimethylbenzylammonium chloride. An increase in the concentration of the micelle ion depresses formation of the higher order beryllium complex because of an decrease in the concentration of Eriochrome Cyanine R per unit micelle, and the competitions between beryllium ion and micelle ion for Eriochrome Cyanine R. These facts indicate that the formation of the higher order beryllium complex is concerned with the charge of charge-cluster, the adsorption of Eriochrome Cyanine R on the micelle surface and the solubilization by the micelle.
The rates of complex formation in the presence of charge-clusters were measured for system A, obtained by adding the beryllium to an Eriochrome Cyanine R solution containing charge-clusters and for system B, in which the charge-clusters were added to the beryllium complex of Eriochrome Cyanine R. Absorption spectra give isosbestic points in the polyvinylbenzyl trimethylammonium and tetradecyldimethylbenzylammonium chloride solutions. The absorbance of the beryllium complex increases with the formation of the higher order complex, whereas the absorption band of Eriochrome Cyanine R decreases. The rate of complex formation of system B, is larger than that of system A, and accordingly this suggests Eriochrome Cyanine R is restrained to charge-clusters. Besides, the rate of complex formation is A<B in polyvinylbenzyl trimethylammonium chloride not having a hydrophobic region such as the micelle interior, so Eriochrome Cyanine R may exist in the neighborhood of micelle surface, where the higher order beryllium complex may be formed.
Both acid dissociation of Eriochrome Cyanine R and formation of the higher order beryllium complex are promoted in a polyvinylbenzyl trimethylammonium chloride solution. Then, polyvinylbenzyl trimethylammonium ion was taken up as a model of the charged micelle ion, and the orientations of both Eriochrome Cyanine R and the higher order beryllium complex of Eriochrome Cyanine R to charge-cluster were investigated by measuring the dichroic spectra. The results indicate that both Eriochrome Cyanine R and the higher order beryllium complex are oriented in the direction perpendicular to the molecular axis of polyvinylbenzyl trimethylammonium ion.

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Oxygen in both inorganic and organic tin compounds was determined. The oxygen cannot be determined by the usual method to determine oxygen in organic compounds. Therefore the determination of oxygen in inorganic and organic tin compounds by the reaction carrier gas method designed by the authors was attempted.
In the present study carrier gas methods were examined: (1) with addition of a reaction agent, (2) of a solid reaction agent and (3) of a reaction gas. The determination procedures are as follows: In the first method naphthalene as a reaction agent is placed on a reaction agent boat after weighing and the boat is put into the apparatus with a sample boat at the same time. In the second method carbon powder is sprinkled over a sample boat, a sample is placed on it, and carbon powder is sprinkled over the sample again. In the third method hydrogen is added to a carrier gas, and the oxygen is determined in a mixture of hydrogen and the carrier gas.
In the first method the oxygen content of stannous oxide and stannic oxide was less than the theoretical value by a factor of 2%.
In the second method the value of stannous oxide and stannic oxide was less than the theoretical value by a factor of 1%.
In the third method the results of the oxygen determination in stannous oxide, stannic oxide, stannous sulfate, stannous oxalate, stannous acetate, di-n-butyloxo stanne and di-n-butylbis (lauroyloxy) stanne were in good agreement with those of their theoretical values. The determination occupied 40 min.

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As one of the studies on automation of the chemical analysis of steel samples, an automatic method and apparatus for dissolving steel samples have been developed. The dissolving operation is the most common among the four main unit-operations of iron and steel chemical analysis, weighing, dissolving, determining and calculating operations. The dissolving operation, now manually carried out, is laborious and time-consuming.
The schematic diagram of the apparatus is shown in Fig. 1. The samples in the test tubes on the turntable sample changer are transferred in turn into the reaction vessel by vacuum suction. The samples are dissolved by adding concd. hydrochloric acid (35%) and hydrogen peroxide (30%) by means of the solution adding device (Fig. 2). The experimental details are shown in Table I. The whole solution is heated to complete the dissolution and to remove the remaining hydrogen peroxide. The prepared sample solutions are finally transferred to the beakers through the drain cock. The above-mentioned whole operations are automatically and successively carried out in accordance with the program on the sequence programmer. One cycle of the program is 5 minutes per sample, and its detail is shown in Fig. 3.
The results of the dissolving test on steel samples are presented in Table II, which shows that less than 0.3 g of steel samples of various kinds are easily dissolved except tungsten bearing samples.
The analytical results of nitrogen, silicon and aluminum in steel samples are shown in Table III. Nitrogen and silicon were determined spectrophotometrically by the bispyrazolone method and molybdenum-blue method, respectively, after the samples are dissolved by the present apparatus. Aluminum was determined by atomic absorption spectrophotometry. The analytical results agree well with those obtained by the manual techniques.
The present apparatus can be easily connected with an automated atomic absorption spectrophotometer and automated spectrophotometer.

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As a series of studies on automatic chemical analysis of iron and steel, a new automatic spectrophotometric analyzer was developed and applied to determine acid soluble aluminum.
The developed analyzer is shown in Photo. 1 and the schematic diagram is shown in Fig. 1. The analyzer is mainly composed of the devices for supplying the sample solution, for adding the reagent solutions, for coloring and measuring the absorbancy, in addition, a controller and a recorder. The device for supplying the sample solution is used for transferring quantitatively the sample solution to the reaction vessel under vacuum. The device for adding the reagent solution is used for adding aliquots of the reagent solutions by opening a magnetic cock for a definite period. The coloring and absorbancy measuring device is composed of the reaction vessel and the solution circulating pipe with a gas blowing tube, a bubble remover, a absorbancy measuring cell and a magnetic drain cock. The device is used for mixing and stirring the added solutions in order to develop color and for measuring continuously the absorbancy. The controlling device is a program-timer which controls the above-mentioned devices according to the predetermined program. The recording device is a conventional recorder or a digital printer.
The analyzer performs automatically and continuously all the analytical procedures, if beakers containing sample solutions are placed on the sample changer.
Acid soluble aluminum in steel was determined by the analyzer using the following Eriochrome Cyanine R spectrophotometry. On heating 2.5 g of steel sample was manually dissolved with 30 ml of sulfuric acid (1+5) and 10 ml of hydrogen peroxide (1+1). After cooling and filtration, the combined filtrate and washings are diluted to 100 ml and 20 ml of the aliquot was put into a 100 ml beaker. The beakers were placed on the automatic sample changer. Automatic analysis was carried out according to the predetermined program as shown in Fig. 2. Acid soluble aluminum was determined from the calibration curve (Fig. 4). The time required for analysis of one sample was 6 minutes in comparison with the manual analysis which occupies about 40 minutes. The analytical results were well agreed with those by the manual work.

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In the activation analysis of oxygen using, ¹⁶O (n, p) ¹⁶N reaction with 14 MeV neutrons the coexistence of fluorine in the sample seriously interferes with the oxygen analysis, owing to production of the same nuclides by ¹⁹F (n, α) ¹⁶N reaction. However, since there is a large difference between the threshold energies for the above-mentioned reactions (fluorine, 1.6 MeV; oxygen, 10.2 MeV), a double, irradiation technique provides a means to discriminate between ¹⁶N activities induced by both the reactions.
As the result of application of the technique to ¹⁹F (n, α)¹⁶N-¹⁶O (n, p) ¹⁶N reaction system, the possibility of simultaneous determination of fluorine and oxygen was demonstrated. Analyses were made by means of 14 MeV neutrons produced by bombarding a tritium target with deuterons. In the double irradiation technique with 14 MeV neutrons, a neutron moderator is used in order to realize another irradiation position with different energy distribution. Fluorine and oxygen contents are evaluated by a mathematical treatment of the ¹⁶N specific activities of the analyzed samples and of the standard ones after the double irradiation with and without the neutron moderator. The use of a compound moderator in Fig. 6 which is composed of polyethylene and copper proved to be more effective to improve the analytical precision than a moderator that made of polyethylene only. The irradiation positions of samples and pneumatic transfer and detection systems in the double irradiation are shown in Fig. 1.
As a preliminary experiment, synthetic samples prepared with sodium oxalate and sodium fluoride were analyzed, and the analytical results for the elements in those samples were in good agreement with the calculated values (Table II). Then, various samples such as other fluorides, slags and fluor spars were analyzed, and successful results were also obtained (Table III, IV).
The analytical precision of the method depends especially on the mass ratio of fluorine to oxygen, m_f /m_o. The problem is discussed, based on the expected coefficient of variation as a function of the m_f /m_o ratio under various conditions (Fig. 8 and Table V). When the tolerable maximum coefficients of variation for the elements are 40, 20, 10 and 7.5% for the analytical levels of 50, 300, 700 and 1000mg, respectively, the application limits of the method are shown by curves 1 and 2 in Fig. 9.
The method is useful in the determination of fluorine and/or oxygen above ca. 1% in materials which do not contain much boron impurities. Compared with the chemical analysis, it is rapid and nondestructive and one sample can be analyzed within 15 minutes in the case of 3 measurements. The double irradiation technique is very promising to avoide the mutual interference between fluorine and oxygen in neutron activation analysis.

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Determination of ε-caprolactam by formol titration was studied. ε-Caprolactam was hydrolysed to ε-aminocaproic acid with sulfuric acid, and the amino groups were converted to Schiff base with formaldehyde. The remaining carboxyl groups were determined by potentiometric titration with 0.02 M standard sodium hydroxide solution. Fifty milligrams of ε-caprolactam was determined within 1% error.

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A technique has been developed for preconcentrating trace elements in high-purity tellurium metal. One gram of metal sample was placed in a 50-ml beaker, and dissolved in 20ml of 7 M nitric acid. To the solution was added 1ml of 0.1 M nitric acid containing 1μg each of cobalt, zinc or cadmium labelled with cobalt-60, zinc-65 or cadmium-115 m, respectively. The solution was evaporated to dryness, and the resulting solid (TeO₂) was roughly triturated with a glass rod. Four milliliters of one of the solvents as described below were added to the beaker, which was put into water in a 35-1 cleaning tank, and ultrasonics (29 kHz, 150W) was applied to effect vigorous stirring. After 10 min, the contents of the beaker were filtered trough a glass fibre filter paper, which was then washed with 1 ml of the solvent, and the gamma activity of the combined filtrate and washings was measured with a well-type NaI (T1) scintillation counter. All the desired trace elements were extracted in more than 95% yields with water, 0.1 M nitric acid, 0.1 M hydrochloric acid, 1 M phosphoric acid and ethanol-12 M hydrochloric acid (99 : 1). Concentration factors of the trace elements with respect to tellurium matrix were (0.081) × 10⁴. The time required for a separation was approximately 1.5 hrs.

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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%.

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The thermodynamic profile of the electron capture reaction for aliphatic nitro compounds has been studied. The temperature dependence of the electron capture coefficients indicated that each nitroalkane dissociated into anion and radical via the anion radical state. On the basis of the values of the electron affinities, EA, for nitrogen dioxide and alkyl radicals and those of the C-N bond dissociation energies, D_C-N, from literature, it is expected that the dissociative reaction for each compound produces a nitrite ion and an alkyl radical endothermically and that the reaction energy, ΔE(=D_C-NEA_NO22), is nearly equal to the activation energy, E*. The average difference between the activation energy (experimental value) and the reaction energy calculated was 0.3 kcal/mol for C₁? C₃ nitroalkanes. This result verifies the validity of the above assumption and indicates that the activation energy could be used to calculate the bond dissociation energy. The bond energies were calculated for C₄, C₅ nitroalkanes.

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The end point detection in the chelatometric titration of EDTA with copper sulfate using surface-active indicator was achieved by the stalagmometric measurement of the surface tention between mercury and the solution. All the experiments were carried out at a room temperature under the atmospheric conditions. The capillary characteristics at h=60 cm are : m=0.633 mg s^-1, in pure water and t=6.23 s in 10^-2 M Na₂SO₄, at open circuit.
Chloride and bromide ions were selected as the indicator. The drop time of the polarographic dropping mercury electrode at 0 volt vs. SCE was plotted against the volume of titrant added, and the titration curves as shown in Figs. 3 and 4, were obtained. This method was compared with the ordinary visual method using Murexide indicator. The F- and t-tests showed that there is no significant difference between the variances and the means of these two sets of data. Since the stability constant of copper-EDTA chelate is much greater than those of copper-halide complexes, before the end point copper ion reacts with EDTA, as shown by eqn. (1), where H₄Y is EDTA. Since CuY^2-is surface-inactive, the drop time does not change. After the end point, however, copper ion reacts with halide ion, according to eqn. (2), and the surface-active halocomplex CuX_n^{(2 -n)+} is formed as shown in Fig. 2. Thus, the drop time decreased remarkably as shown in Figs. 3 and 4.

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A dynamic behavior of both extracted gas and metal vapor evolved from fused steel sample (NBS#1041) in the vacuum fusion analysis was studied. Metal vapor was trapped on a moving surface of an alkalineless glass tape which passes by a 10 mm wide window at a speed of 2 mm per sec. Iron and manganese deposited on the surface of the tape were extracted in an ethanolamine-NaOH solution and determined by a polarographic method.
A variation in the pressure change of the extracted gas was recorded with a Pirani gauge at an outlet of the extraction pump. And these results were compared with the analytical values of oxygen obtained by an ordinary method [See Bunseki Kagaku, 14, 540 (1965) ].
The difference in the extent of gas absorption in the successive analyses was closely related to the degree of the overlap with the metal vapor which at first evolved within 4 to 20 sec after the addition of a sample in a crucible.
The gas absorption in a vacuum fusion analysis was proved to be reduced by such a method using a metal bath or graphite capsules, which prevent the overlap of the evolution of gas and metal vapor.

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Lanthanum in a mixture of rare earth oxide, consisting of the elements of cerium and yttrium groups, was determined indirectly by using a combination of gravimetric, volumetric and colorimetric procedures. The two groups were separated from each other by the double sulfate method, and the rare earth elements of the cerium group were determined by weighing the oxide. In addition to lanthanum and cerium, the cerium group contained praseodymium, neodymium and samarium, which were determined colorimetrically by utilizing their sharp absorptions at 444.5 nm, 521.8 nm and 401.5 nm, respectively. Cerium was determined volumetrically by the method of JIS 8404 without group separation. The lanthanum content was calculated by the equation
La₂O₃(%) =Cerium group rare earth oxide (%)
-CeO₂(%)-Pr₆O₁₁(%)
-Nd₂O₃(%)-Sm₂O₃(%).
The results obtained showed good precision, and were in fairly good agreement with those by the X-ray fluorescence method. It suggests that at the stage of the group separation the lanthanum and cerium in the sample were completely precipitated as their double sulfates and all the yttrium group elements were removed from the precipitate.
The method reported here is expected to be generally applicable to the determination of lanthanum in a mixture of rare earth oxide which consists mainly of cerium group elements.

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Countercurrent chromatography is the technique to achieve partition chromatography without solid supports, and therefore, no absorptive effect is included in the separation. This is the first application of countercurrent chromatography to solvent extraction of metal ions.
In this report, rotation locular countercurrent chromatography which is one of the several techniques of countercurrent chromatography was used. The column was made in this laboratory as shown in Figure 1, following the procedure of Ito {Y. Ito, R.L. Bowman: Science, 167, 281 (1970)} with some modifications.
The alkaline earth ions were separated, as an example and the result is shown in Figure 2. Distribution ratios of Ba²⁺, Sr²⁺ and Ca²⁺ from 3M acetate buffer pH 6.60 into an MIBK solution of 0.2M TTA are 1.14, 2.00 and 5.50, respectively.

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