The changes of the intensity, the pattern and peak position of X-ray emission band spectrum have widely been used to investigate the chemical bonding, because the X-ray emission band spectra depend on the change of the energy levels of electron orbits. Especially, the X-ray microanalyzer is useful for the state analysis of a micro area of several microns and for the analysis of the ultra soft X-ray which is sensitive to the state change. However, the studies of the state analysis by the X-ray microanalyzer are few so far.
In the present study, an accuracy of measurement in the state analysis by the X-ray microanalyzer was determind and its possibility and its reliability were discussed. Therefore, the wavelength shifts of OK_α FeL_α and FeL_β A, the intensity ratio of FeL_β line to FeL_α line, and the spectra patterns of OK_α lines in three iron oxides (FeO, Fe₃O₄ and Fe₂O₃) and the precipitations in FeO layer were measured and the form of these precipitations were analyzed.
Specimen is the scale which is formed on a pure iron rod by heating at 1000°C for 5 hr in air and which consists of three iron oxides layers (FeO, Fe₃O₄ and Fe₂O₃). Precipitations of several microns are included in the FeO layer. The other specimens used to determine an accuracy of measurement are a pure aluminum and an alumina.
An accuracy of measurement was discussed on an error due to the relationship between an electron beam and the Rowland's circle. Investigating the wavelength shift between AlK line of alumina and AlK line of aluminum, the reliability of measurement was discussed in comparison with the result of a fluorescence X-ray analysis.
The main results obtained are as follows;
(1) Wavelength shifts of OK_α line, FeL_α line, and FeL_β line of iron oxides were measured with an arror of 0.0030.01 Å, and these wavelength shifted to short wavelength with increasing concentration of oxygen.
(2) Intensity ratios of FeL_β line to FeL_α line of iron oxides were measured with an error of 5%, and these ratios decreased with increasing concentration of oxygen.
(3) OK_α spectra of iron oxides were analyzed, and using the results of these, (1) and (2), the precipitations in FeO layer were determined to be Fe₃O₄.

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For the determination of impurities in high purity tantalum powders, atomic absorption spectrometry using a heated graphite tube as an atomizer was studied. In comparison with another method, this method has no contamination risk from the pretreatment of the sample, and the operation is performed rapidly and easily. Some factors for the determination, (1) the effect of the carrier gas flow rate on the sensitivity, (2) the effect of a state of sample on the absorption peak, (3) the relation between the spectral intensity and the duration of absorption, and (4) the relation between the spectral intensity and the furnace temperature are examined.
The more the carrier gas rate increases, the more the sensitivity decreases. The flow rate variation of 0.1 l/min. corresponds to the absorption spectral intensity variation of 5% or so. For this reason, the flow rate variation was fixed within 0.05 l/min in the determination. The relation between the spectral intensity and the duration of absorption shows that the element is vapourized more rapidly in an aqueous solution than the tantalum powder. Therefore, when the impurities at different states contained in a substance are measured, it is better to determine the elements by the use of the peak area method than the peak height method. The peak height increases with the atomizing temperature, but the peak area is a constant above a certain temperature. The resulting value does not depend on the amounts of sample, and the value from the peak area method has better accuracy than that from the peak height method. In case of copper in tantalum powders, standard relative deviation was 3.5%, and the detection limit was 5×10^-11 g. The time for a determination was 5 minutes. Cr, Fe, Mn, Ni, and Si, were determined similarly.

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The determination of zinc contained in the sample such as air-borne by non-destructive, neutron activation analysis by measuring a γ-ray spectrum is disturbed by scandium accompanied with zinc. It is difficult to distinguish the photo-peak with 1115 keV of ⁶⁵Zn (half life; 245 days) from that with 1120 keV of ⁴⁶Sc (half life; 83.9 days), even though a Ge(Li) detector is used. These radioactive nuclides are produced by the thermal neutron irradiation of target elements, ⁶⁴Zn and ⁴⁵Sc whose thermal neutron cross section and natural abundance are 0.64 barn and 48.9%, and 23 barn and 100%, respectively.
In this report, after separation of neutron irradiated zinc and scandium by thin-layer chromatography (TLC), zinc was identified by a NaI (Tl) scintilation detector which was not superior to Ge(Li) detector in the resolution of measuring of γ-ray spectrum, but excellent in the counting efficiency and the maintainance. The sample solutions were prepared as follow; after irradiation of scandium oxide or zinc metal by thermal neutron (flux: 1 × 10¹² n/cm².sec) in a reactor for 6 hours, samples were dissolved with an acid. The solutions were developed on cellulose as an adsorbent, with a mixture of n-propanol and 3N HCl in a volume ratio (10 : 1) as a developer which is the most excellent one in several kinds of mixed solutions. The developed spot of zinc was overlapped on the acid front with sharp shape and the Rf values were 0.74 for zinc and 0.02 for scandium. The sample solutions including of different ratios of scandium to zinc such as 50 μg : 0 μg, 50 μg : 1 μg, 50 μg : 5 μg, 50 μg : 50 μg, 50 μg : 500 μg were developed by using the TLC system. No trace of scandium could be detected in each of these zinc fractions on the thin-layer plates. Next, the determination limit of zinc was examined by measuring γ-ray photo-peak of ⁶⁵Zn and total γ-ray of ⁶⁵Zn. Zinc was separated by the TLC system above mentioned from the sample solution containing cobalt, scandium, iron and zinc of which R_f values were 0.02, 0.02, 0.45 and 0.74, respectively, in order to exclude the radio-activities of ⁶⁰Co, ⁴⁶Sc and ⁵⁹Fe which were produced by the irradiation of thermal neutron to target elements. These radioactive nuclides disturb the identification of the photo-peak of ⁶⁵Zn by a NaI(Tl) detector for their long half-lives and γ-ray energy more than 1 MeV. More than 5 μg of zinc can be determined by measuring the γ-ray spectrum and moreover the determination limit of zinc was found to be about 1 μg with an error of 20% by counting total γ-ray of ⁶⁵Zn in the zinc spot developed on the thin-layer plate.

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A highly sensitive and brief fluorophotometric determination for minute amounts of thiourea and cetylpyridinium chloride(CPC) was carried out using 2', 4', 5', 7'-tetrakis (acetoxymercuri) fluorescein(F1.Hg₄), 5', 7'-bis (acetoxymercuri)-2', -4'-dichlorofluorescein (2', - 4'-D.Cl.Fl.Hg₂, ), 4', 5'-bis(acetoxymercuri) -2', 7'-dichlorofluorescein(2', 7'-D.Cl.Fl.Hg₂) and 2', 4', 5', 7'-tetrakis (acetoxymercuri) -3, 4, 5, 6-tetrachlorofluorescein (3, 4, 5, 6-T.Cl.Fl.Hg₄) as the reagents. Among these mercurichlorofluorescein compounds, 3, 4, 5, 6-T.Cl.Fl. Hg₄ produced a very stable and red colored formation with thiourea or CPC solution and showed a marked decrease in its fluorescence intensity, which was applied to the fluorophotometric determination of thiourea and CPC. The fluorescence intensity of 3, 4, 5, 6-T.Cl.Fl.Hg₄-thiourea solution was constant over the pH range of 8.5 to 9.4 adjusting with Na₂B₄O₇-NaOH solution, and the fluorescence intensity of 3, 4, 5, 6-T.Cl.Fl. Hg₄-CPC solution was constant over the pH range of 6.7 to 7.2 adjusting with Na₂B₄O₇-HCl buffer solution. The maximum emission wavelength of difference in fluorescence intensity between 3, 4, 5, 6 T.Cl.Fl.Hg₄, solution and 3, 4, 5, 6-T.CI.Fl.Hg₄thiourea or 3, 4, 5, 6-T.Cl.Fl.Hg₄-CPC solution were about 555 nm. The calibration curves were linear in the range of 0 to 19.5 μg/10 ml thiourea and 0.15 to 1.0 μg/10 ml CPC. The recommended fluorophotometric analytical procedures for thiourea and CPC are as follows:
Thiourea-A sample solution containing less than 19.5 μg of thiourea is taken in a 10.0 ml measuring flask to which 2.0 ml of Sorensen buffer solution(pH 8.9)and 2.0 ml of 5.0 × 10^-4M 3, 4, 5, 6-T.Cl.Fl.Hg₄ solution are added. The whole is made up to mark with distilled water, and the solution is kept at 2035°C for 30 minutes, then the fluorescence intensities of 3, 4, 5, 6-T.Cl.Fl.Hg₄ solution and 3, 4, 5, 6-T.Cl.Fl.Hg₄ thiourea solution are measured at 555 nm.
CPC-A sample solution containing less than 1.0 μg of CPC is taken in a 10.0 ml measuring flask. 2.0 ml of Sorensen buffer solution (pH 6.95), 1.0 ml of 1.0% polyvinylpyrolidone(PVP) solution and 0.25 ml of 5.0 × 10^-4 M 3, 4, 5, 6-T.Cl.Fl.Hg₄ solution are added. The whole is made up to the mark with distilled water, and the solution is kept at 2035°C for 10 minutes, then the fluorescence intensities of 3, 4, 5, 6-T.Cl.Fl.Hg₄ solution and 3, 4, 5, 6-T.Cl.Fl.Hg₄-CPC solution are measured at 555 nm.
The effects of foreign ions on the fluorescence intensity of the colored formation were examined and shown in Table V. The reaction is quite sensitive, and the procedure does not require a long time.

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Determination of three isomers for cresol, toluic acid, and toluidine by nuclear magnetic resonance technique was investigated. The NMR spectra of cresols and toluic acids in sodium hydroxide solution, and toluidines in hydrochloric acid solution gave three sharp singlets for the methyl peaks of each isomers. The chemical shifts of methyl protons for cresol isomers showed interesting behaviour of the concentration dependence on sodium hydroxide solution, that is, ortho, meta, and para methyl protons were shifted to low field with increasing the concentration of sodium hydroxide up to 5 N, and high field with increasing the concentration beyond 5 N. On the other hand, the methyl peaks of toluic acid and toluidine were shifted to high field with increasing the concentration of sodium hydroxide and hydrochloric acid solution.
The resolutions of methyl peaks for three isomers depended on the concentration of either cresols and toluidines, but not of toluic acids. The best resolution of methyl peaks was obtained in the concentration of 0.5 g/ml cresols in 2 N sodium hydroxide, of 0.5 g/ml toluic acids in 4 N sodium hydroxide, and of 0.5 g/ml toluidines in 4 N hydrochloric acid. At this concentration, the differences of chemical shifts between methyl peaks of ortho and meta were 0.06 ppm for cresol, 0.18 ppm for toluic acid, and 0.12 ppm for toluidine and between those of meta and para were 0.05 ppm for cresol, 0.06 ppm for toluic acid, and 0.04 ppm for toluidine, respectively. The heights of three methyl peaks of each isomers were proportional to the amounts of respective isomers. The calibration curves obtained by peak height method were linear.
This method was applied to the determination of ortho, meta, and para isomer in cresol, toluic acid, and toluidine samples prepared in our laboratory. The results were in good agreement with prepared concentrations. The standard deviations were smaller than 2%. The errors were within ±1.3%.

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Direct determination of trace amounts of arsenic and antimony in water was investigated by flameless atomic absorption spectroscopy using a carbon tube atomizer. A sample solution (20 μl) was placed in the cavity of the atomizer. The solution was dried, ashed, and atomized by passing a high electric current through the atomizer. Argon gas was employed as an inert sheath at a flow rate of 2.0 l/min. The concentrations of arsenic and antimony were calculated directly from the calibration curves by measuring the absorbance of arsenic at 193.7 nm and that of antimony at 217.5 nm.
Depressing effects on the arsenic and antimony absorbances were found in the presence of high concentrated acids. In particular, the effect of phosphoric acid on the arsenic absorbance was so remarkable. The absorbance of arsenic was decreased by the addition of 100 ppm bismuth, cobalt, lithium, antimony, selenium, and titanium, and that of antimony was also decreased by the addition of 100 ppm aluminum, arsenic, gold, bismuth, lithium, platinum, and selenium. Spectral interference from lead with the antimony absorbance at 217.5 nm was masked by decreasing the spectral slit width.
Anions do not interfere with the determination of antimony seriously. The arsenic absorbance was depressed on addition of ammonium halides. These interferences were considered that arsenic was vaporized with ammonium halides or arsenic halides during the drying or ashing. Furthermore, in the presence of phosphate ion, the arsenic absorbance was also lowered strongly. This effect was probably due to the formation of the stable undissociated arsenic phosphate during the drying or ashing. The background absorptions of matrix salts were corrected by measuring the absorbances of the salts at a non-resonance line.
This technique was applied to the direct determination of trace amounts of arsenic and antimony in river water and industrial waste water. Analytical results were in good agreement with those obtained by a colorimetric method. The limits of detection were 5 ppb for arsenic and 1 ppb for antimony when the signal to noise ratio was 2. The coefficients of variation were less than 4% in both arsenic and antimony determinations.

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The 5000 infrared spectra included in the IRDC cards were coded numerically into the numbers of twelve figures, and were retrieved by the use of an electronic computer. The wavenumber region from 1800 to 650 cm^-1 was divided into twelve parts, and the coded number of twelve figures was constructed by the position of the strongest peak in each part. The error, which is the sum of absolute differences in twelve figures between unknown and reference spectra, was computed and stored in the electronic computer. For twenty compounds whose errors were the smallest, their serial numbers and errors were printed out on a line printer. The histogram of errors for 5000 compounds shows a maximum around an error of 40, which is about twice as large as in the case of Rann {Anal. Chem., 44, 1669 (1972)}. When 76 unknown samples were searched, 61 showed the smallest errors between the unknown and correct spectra, and it can be concluded that the probability of finding the correct spectra in this method is about 95% or higher.

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As a series of studies on automatic chemical analysis of steel, an automatic spectrophotometric method for determination of manganese has been developed using the automatic analyzer that the present authors have previously reported for determination of acid-soluble aluminum in steel.
The analyzer (Fig..1) was automated and mainly composed of a sample changer, solution adding devices, a coloring reaction vessel, a spectrophotometer, a controller and a recorder.
The spectrophotometric method based on the principle of oxidizing manganese by sodium periodate under the co-existance of silver nitrate, was found to be suitable for automatic determination of manganese in steel by the analyzer.
The optimum conditions obtained from the fundamental studies (Fig. 28) were as follows. The concentration of sulphuric acid was 2.3 N. The amount of urea (5%)-silver nitrate (2%) solution was 5.9 ml, sodium periodate solution (10%) was 25.5 ml. The coloring reaction time was 30 seconds. Effects of less than 100 mg of Cr(III) and less than 1 g of Fe were negligible in the present automatic analytical procedure in which the absorbancy of permanganate ion was always corrected by the blank absorbancy.
The automatic analysis of manganese is performed according to the predetermined program (Fig. 9). The sample solution with beaker washings (28 ml) are transferred quantitatively to the reaction vessel from the automatic sample changer. The sample solution is preliminarily prepared manually by dissolving 0.100 g of steel sample by heating with 50 ml of mixed acid (H₂SO₄: 7 ml, H₃PO₄: 7 ml, HNO₃: 6 ml, H₂O: 30 ml). The solutions in the reaction vessel are heated and circulated through the circulating pipe which is composed of a bubble remover, an absorbancy measuring flow-cell, a gas blowing tube and a magnetic drain cock. After measuring of the blank absorbancy, 25.5 ml of sodium periodate solution and 5.9 ml of urea-silver nitrate solution are added at the same period by opening a magnetic cock of the reagent solution adding devices. The absorbancy of colored solution was measured by the spectrophotometer. The solution in the reaction vessel is drained off and the vessel is washed by water.
This automatic analysis had a merit of simplicity and rapidity. The time required for analysis of one sample was only 5 minutes as compared with the manual analysis which occupies about 25 minutes. The analytical results of carbon steel, low alloy steel, chromium steel and stainless steel were well agreed with the standard values.

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A mixture of Rhodamine B, potassium iodate and the arsenic(III) compound formed an ion-association complex in an aqueous solution of hydrochloric acid. The complex was extracted into benzene and the solution fluoresced. The fluorescence was applied to the fluorometric determination of micrograms amounts of arsenic(III).
The ion-association complex has maximum absorption at 565 nm and highest intensity of fluorescence at 590 nm, respectively. A high-pressure Hg-lamp with a 550 nm filter was used for excitation and a 580 nm filter was put in a fluorescence path. The ion-association complex showed the highest fluorescent intensity when it was extracted from about 1.5 N hydrochloric acid.
The recommended procedure was as follows; To 1 ml of the sample solution containing from 0.3 to 1.5 As μg/ml, 1 ml of 1.0×10^-4 M potassium iodate, 1 ml of 1.0×10^-4 M Rhodamine B, 1 ml of 6 N hydrochloric acid and 5 ml of benzene were added in a stoppered test tube. After shaking, the fluorescent intensity of the benzene solution was measured at 590 nm. The calibration curve showed a straight line in the range of 0.3 to 1.5As μg/ml.
Interference from diverse ions was studied in 100 times as much testing ions as 1.5 μg of arsenic(III) by molar ratio. Cations and anions such as Fe²⁺, Cu⁺, Sn²⁺, Hg₂²⁺, Hg²⁺, Ga³⁺, Tl³⁺, ClO₄^-, and NO₃^- interfered more or less in this method.
The authors confirmed by the Ag-diethyldithio-carbamate-pyridine method that arsenic(III) was not extracted into the benzene, being left in the aqueous layer. The optimum condition of extraction solvent, reagent concentration and development time were established.
In order to study the structure of the anion in the ion-association complex, the absorption spectrum of the aqueous solution before the addition of both Rhodamine B and benzene was recorded. The spectrum showed the maximum absorption at 345 nm, and differed entirely from the spectra of I₃^-, I^- and I₂.
By the use of both iodine monochloride and iodine trichloride, it was concluded that the anion was ICl₄^- and supposed that the ion-association complex, (Rhodamine B⁺)(ICl₄^-), was extracted into benzene. The sensitivity of this method was ten times higher than that of the ordinary spectrophotometric method.

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For the purpose of the control of the reaction for synthesis and the management of products, it is necessary to determine phenol(PH), o-hydroxybenzenesulfonic acid (o-PSH) and p-hydroxybenzenesulfonic acid (p-PSH) respectively in the process of preparation of p-PSH.
Spectrophotometric method to which is applicable the complementary tristimulus colorimetry(CTS method), is utilized to the determination of the mixture.
In CTS method, absorption spectra are devided into three portions which are named “Range”. For the simultaneous determination of phenol derivatives, three ranges are settled on 230240 nm, 250270 nm and 275295 nm in spectra to represent each species characteristically.
A series of absorbances are measured at a regular nm interval in each of the three ranges and the sum of absorbances in each range is represented by u, v and w respectively and then total amount of u, v and w is represented by J.
Q_r is the generic name of Q_u Q_v and Q_w corresponding to u/J, v/J and w/J. E equals to J of 1 mol solution. Q_r value of a chemical species is represented as a Q_r-plot in which two kinds of Q_r among Q_u, Q_v and Q_w are coordinates. And Q_r-plot is drawn by connecting the Q_r points of pure chemical species and their mixtures which are plotted in graph.
In a solution cotaining three species, Q_r of the solution can be represented by a point on the straight line connecting two fixed points Q_ra and Q_rb, where Q_ra and Q_rb are Q_r of the pure chemical species a and b respectively. When Q_rm is obtained as Q_r of the mixed solution from its absorption spectrum, the molar fraction of a, q_a, can be derivated as follow.
q_a=E_b(Q_rb-Q_rm)/E_a(Q_rm-Q_ra)+E_b(Q_rb-Q_rm)
In a solution containing three species, Q_r of the solution can be represented by a point in the triangle connecting three fixed points Q_ra, Q_rb and Q_rc, as vertices, where Q_ra, Q_rb and Q_rc are Q_r of the pure chemical species a, b and c respectively. When M is obtained as Q_r of a solution as shown in Fig. 2, following equations can be derivated by CTS method.
C_a : C_b =q_a : 1 - q_a
C_a : C_c= q_a' : 1 - q_a'
C_a:C_b : C_c= q_aq_a' (1- q_a)q_a': (1-q_a')q_a
where C_a, C_b and C_c represent analytical concentration of pure chemical species a, b and c respectively.
So that C_a, C_b and C_c can be determined, if total amount of phenol derivatives is known. The simultaneous determination of a mixture which contains PH, o-PSH and p-PSH can be done with 2% relative error.

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A new method for simple colorimetric determination of alkylbenzenesulfonate (ABS) has been proposed using polyvinyl chloride as adsorption material of Crystal Violet (CV) and ABS complex. A small amount of ABS was selectively adsorbed on a polyvinyl chloride sheet in the presence of excess CV. The color intensity of the sheet adsorbing the CV-ABS complex was proportional to the ABS concentration of the aqueous solution, and thus the concentration of ABS could be determined visually or spectrophotometrically. The absorption maximum wavelength of the sheet was 596 nm, and color was very stable. When the sheet was immersed in 100 ml of ABS aqueous solution containing 0.001% CV at pH 2 for 15 minutes, the detection limit of ABS was found to be 0.2 ppm by the visual method. The applicable concentration range of ABS was 0.2 to 10 ppm. The color intensity increased gradually with immersing time; the absorbance came to above 2 when the sheet was immersed in 100 ml of 5 ppm ABS solution for 1 day. It was observed that the polyvinyl chloride containing plasiticizer, such as dioctyl phthalate or tricresylphosphate, adsorbed the CV-ABS complex, and that the color intensified with the increasing concentration of plasticizer in the polyvinyl chloride. Polyvinyl chloride not containing plasticizer slightly adsorbed the colored complex or not at all.
The recommended analytical procedure is as follows. Add 1 ml of 1 N sulfuric acid and 2.5 ml of 0.04% CV solution to the neutralized sample solution which containes less than 1 mg of ABS, and dilute to 100 ml with water. Immerse a plasticized polyvinyl chloride sheet (for example, 15×35×1 mm) in the solution for 15 minutes. Take up the sheet from the solution, wash it with water, and wipe the sheet to remove the water. Visually compare the color intensity of the sheet with the standard series previously prepared, or spectrophotometrically measure the absorbance at 596 nm. One hundred ppm of the other anions such as chloride, bromide, iodide, nitrate and stealate, colored very slightly the sheet by the proposed method.

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The author reported in the previous paper that mercury vaporized from dilute solutions of mercury salts. Recently, it was found that mercury vapor was permeated through various types of polymers. The permeation of mercury vapor through a film of polymers was investigated by the atomic absorption method as shown in Fig.2.
In this paper, polyvinyl chloride was mainly chosen as a sample film. Various conditions such as temperature, thickness, and addition or none of a plasticizer (dioctyl phthalate) on the permeation of mercury vapor were performed using closed and open systems.
The experimental procedure for the open system is as follows: The sample film forms a barrier between the two chambers of a permeation cell. After the cell was placed in an airbath maintained at constant temperatures, a drop of mercury is added to the chamber of the cell. Mercury vapor is passed through the sample film little by little, and mixed with a carrier gas at a constant rate of flow and temperature. The mixed gas is introduced to an absorption cell and detected by the atomic absorption method.
It was found from the experiment at the closed or open system that mercury vapor was permeated through the film of polymers such as polyvinyl chloride, polyethylene, polyvinylidene chloride (Fig.4), their permeability was clearly increased with increasing temperature (Fig.5) and moreover, the vaporization of mercury could not be inhibited completely by covering the vapor with water as shown in Fig.6; and their permeability was extremely increased with the addition of the plasticizer as shown in Fig.7 and Fig.8. This phenomenon was resulted from the fact that the microstructure of the polymer was loosed by the addition of the plasticizer.
As an example of the physical properties of polymers, the diffusion coefficients, D, were determined from the half-times, t/2 which correspond to the steady-state plates as shown in Fig.7 and Fig.8. In the plot of Log D vs. 1/ T as shown in Fig.9, the maximal change in the slope was found and its inflection point corresponded virtually to the calorimetrically determined glass transition temperature as shown in Table I.

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2, 3-Quinoxalinedithiol has been known as a highly sensitive reagent for Ni and Co ions. In order to find a more superior reagent among quinoxaline drivatives, the reactions of Ni(II) and Co(II) with three quinoxalinethiol derivatives, i.e. 2-amino-3-quinoxalinethiol (AQT), 2-(N-methylamino)-3-quinoxalinethiol (MQT) and 2-(N-phenylamino)-3-quinoxalinethiol (PQT), were examined.
AQT and MQT were superior to PQT in its sensitivity, stabilization of color, and effect of diverse ions. Furthermore, AQT was more sensitive for Ni(II) than 2, 3-quinoxalinedithiol. The acid dissociation constants pK₁ and pK₂ obtained spectrophotometrically in 50% aqueous ethanol solution are 2.86 and 8.56 for AQT and 3.12 and 9.07 for MQT, respectively. These reagents formed colored compounds with Ni(II), Cu(II), Co(II), and Pd(II). The successive formation constants (log K₁, log β₂) of these complexes with AQT in 50% aqueous ethanol solution were found to be 7.07, 12.04 for Ni and 5.77, 11.07 for Co, respectively. Similarly, the formation constants of MQT with Ni and Co were determined.
The quantitative determination of Ni(II) and Co(II) were spectrophotometrically performed with AQT, MQT and PQT in 50% aqueous DMF solution. The recommended analytical procedure is: Two milliliter of neutral sample solution containing less than 25 μg Ni/ml or 15 μg Co/ml and 5 ml of ammonia-ammonium chloride buffer are taken in a 20 ml volumetric flask and diluted to 10 ml with water, to this solution 8 ml of DMF is added with stirring. Standing for 10 minutes, 2 ml of 0.01 M reagent DMF solution is added, and diluted to 20 ml with 50% aqueous DMF solution. Five minutes later the absorbance of the solution is measured at the analytical wavelength against blank. In the case, for example, of AQT the reddish Ni and yellowish brown Co complexes show absorption peaks at 495 nm and 428 nm. These complex formation with Ni and Co ions took place favorably in the solutions of pH 11.0 and 9.60, respectively. The coloration were rapid and stable for several hours. A linear calibration curve was obtained in the concentration ranges 0.1 to 2.5 μg Ni/ml and 0.05 to 1.5 μg Co/ml. The sensitivity expressed in 0.001 of absorbance was 0.0024 μg Ni/cm² and 0.0016 μg Co/cm². The molar absorption coefficient of the complex was found to be 2.4×10⁴ liter mol^-1 cm^-1 for Ni and 3.78×10⁴ liter mol^-1 cm^-1 for Co. Similar examinations were made to the reagents MQT and PQT with the same metal ions. The interference of diverse ions on the electronic absorbance of the complexes was slightly observed in Fe(III), Cu(II) and Pd(II).

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An end point detection in some titration systems was achieved by measuring the interfacial tension between mercury and a solution. The stalagmometric titration developed by Kambara et al. is based on the measurement of drop-time of a polarographic dropping mercury electrode(DME) immersed in the solution being titrated (mercury drop-time method). The drop-time gives an approximate relative value of interfacial tension between mercury and the solution according to the Tate's law.
The present paper deals with three types of mercury drop-time methods, i.e., (1) An open circuit method: A DME is used at an open circuit, (2) A Hg pool short-circuit method: A DME is short-circuited with a Hg pool counter electrode, (3) A fixed potential method: A DME is used at a fixed potential vs. SCE.
The stalagmometric titration curves of sodium tetraphenylborate (Na·ph₄B) with Zephiramine (Zeph·Cl:tetradecyldimethylbenzylammonium chloride) were examined. The shapes of the titration curves were discussed in relation to the electrocapillary curves (drop-time vs. potential curves) for the components taking part in the titration reaction. In the case of method (1), the drop-time at zero-current potential of the DC polarogram for the solution is followed during the course of the titration, as Fig. 1 shows. In the case of method (2), the drop-time at 0 V vs. Hg pool is followed, as shown in Fig. 2. In the case of method (3), the change in the drop-time at the fixed potential vs. SCE is followed in the course of the titration, as Fig. 3 clearly indicates. In Fig. 4 is shown the concentration dependence of drop-time, and the stalagmometric titration curve predicted theoretically is compared with the experimental one.
Some chelatometric titration {Cu(II) with CyDTA, Fe(III) with CyDTA} and an acid-base titration (NaOH with HCl) were achieved by the aid of “surface-active indicators”. Namely, as the surface-active indicator, KSCN was used in these chelatometric titrations as Fig. 6 shows, and sodium oleate was successfully used in the acid-base titration, whose curve is reproduced in Fig. 5.
In method (2) the stalagmometric titrations of Cu(II) with EDTA and Al(III) with CyDTA were carried out without an indicator, as shown in Fig. 7. The sudden jump in the drop-time at the equivalence point is due to a sudden increase in the negative potential of the mercury pool counter electrode, which occurs on addition of the excess chelating agent (Fig. 8).
Some examples of stalagmometric titrations newly examined are listed in Table I. All the experiments were carried out at room temperature under the atmospheric conditions, i.e., O₂ dissolved.
It may be safe to say that the stalagmometric titration method has an equal weight in accuracy and precision as compared with visual and potentiometric methods.

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Direct determination of trace amounts of copper and lead in water was investigated by flameless atomic absorption spectroscopy using a carbon tube atomizer. A sample solution (20μl) was atomized by passing a high electric current through the atomizer. The concentrations of copper and lead were calculated directly from the calibration curves by measuring the absorption peak heights of copper at 324.7 nm and of lead at 283.3 nm.
The absorbances of copper and lead were decreased by the addition of high concentrated acids. The absorbance of copper was decreased by the addition of 1000-fold silver, barium, lithium, and strontium, and that of lead was also decreased by the addition of 1000-fold silver, barium, cobalt, lithium, mercury, and strontium. The background absorption such as molecular absorption and light scattering of a matrix salt was corrected by measuring the absorbance of the salt at the non-resonance line.
This method was applied to the direct determination of trace amounts of copper and lead in river water and industrial waste water. The analytical results were in good agreement with those obtained by a method of atomic absorption combined with a solvent extraction. The limits of detection were 0.2 ppb of copper and 0.4 ppb of lead when the signal to noise ratio was 2. The coefficients of variations were less than 4% in both determinations.

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A method of Davies and Gray for the determination of uranium has been improved. Air oxidation of uranium(IV) can be avoided by the addition of vanadium(IV) prior to titration (Table I). Plutonium does not precipitate if the sulfuric acid concentration during titration is greater than 1.5 M.
A sample containing 50 mg of uranium is dissolved. in nitric-hydrofluoric acids and the solution is evaporated to 3 ml. After addition of 0.5 ml of 2 M sulfamic acid, 10 ml of 14.5 M phosphoric acid and 1 ml of 0.5 M iron(II) sulfate, the solution is allowed to stand for one minute. Seventeen ml of 9 M sulfuric acid, 3 ml of 4 M nitric acid-0.1 M sulfamic acid mixture and 1 ml of 1% ammonium molybdate solution are added to the solution, which is permitted to stand for at least one minute. Adding 1 ml of 0.4 M vanadyl(IV) sulfate, the solution is diluted to 100 ml with water and potentiometrically titrated with 0.1 N potassium dichromate.
Data in Table II for synthetic uranium-plutonium solutions show a relative standard deviation of 0.1 to 0.3%. Uranium was also determined in actual samples of 590% uranium-plutonium mixed oxides (Table III). The results agree well with those obtained by another method.

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