The simultaneous determination of copper, lead and zinc in high purity aluminum was carried out by a square-wave polarographic method.
A square-wave polarographic method which can be carried out simply and rapidly and can avoid the contamination from the reagents has been developed for the determination of impurities such as copper, lead and zinc in high purity aluminum. A squarewave polarograph of Yanagimoto Mfg. Co. type PA 201 was used and the mercury pool at the bottom of the electrolysis cell was used as the anode. The mercury flow-rate and drop time of the capillary were 2.70 mg sec^-1 and 4.05 sec, respectively. The span voltage was 2.0 V, the gate range was -3 to 8 and the time constant was 5-5.
The procedures and the results of each method were as follows;
Method A : 1.0 g of high purity aluminum (99.99% or 99.999%) was heated and dissolved in a mixed solution containing 40 ml of 6N hydrochloric acid, 2 ml of 3% hydrogen peroxide and 8 ml of 0.1% mercury (II) chloride.
It was found that a 1.0 g amount of sample could be dissolved within 913 min. After the metal was dissolved, the solution was transferred to a 100 ml volumteric flask diluted with distilled water to the mark, and a portion of this solution was used as the sample. Well-defined waves which corresponded to these metals were observed. Copper, lead and zinc could be determined from the wave which appeared at - 0.26 V, 0.48 V and -1.05 V, vs. Hg-pool respectively.
Method B: 1.0 g of the sample metal was heated and dissolved in 15 ml of 15% sodium hydroxide solution, and then 35 ml of nitric acid (1:1) was added. The solution was transferred to a 100 ml volumeteric flask and made up to the volume with distilled water. A portion of this solution was used for the polarographic experiments. In this method, the waves of copper, and zinc were observed at the same potentials as in method A, but the wave of lead appeared at -0.65 V. It was concluded that these metals in high purity aluminum can be also determined by this method. The analysis by method B was prepared to compare with method A. The analysis by method A could be carried out within 40 min. The impurities determined by method A and method B are given in the accompanying table.

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Methods for determining traces of various elements in aluminum metal have been published, but no method has been available for determining traces of chlorine. The objective of the work undertaken was to apply our preliminary works of anion exchange in sodium hydroxide solution to the photometric determination of traces of chlorine in aluminum.
The recommended procedure is outlined as follows : 1 g of sample is dissolved in ca. 30 ml of 3M sodium hydroxide solution and diluted to ca. 50 ml with water. After filtration, the resulting solution is introduced onto a column of strongly basic anion exchange resin (Amberlite CG-400, OH-form, 100200 mesh, 12mmφ ×50 mm) at a flow rate of ca. 1.5 m/lmin. The column was washed with 20 ml each of 3 M sodium hydroxide solution and water, and then the absorbed chloride is eluted with 0.5 M ammonium nitrate solution. The first 15 ml fraction of the effluent is discarded, and the following 15 ml fraction is collected for the subsequent photometric determination.
The collected solution is neutralized with 1M nitric acid using a bromo-thymol blue pH test paper. A 4 ml aliquot of the solution is taken into a light-resistant separation funnel. 1 ml of 0.05M nitric acid, 1 ml of the mixed reagent {0.05 mM Hg (NO₃) ₂ 0.55 mM KBr(1 : 1)}, 1 ml of diphenylcarbazoneethanol solution (0.02 g/ml), and 10 ml of benzene are added successively.
After shaking for 1 min, the absorbance of the organic phase at 562 nm is measured. A blank is run through the entire procedure.
The calibration curve for the photometric determination is prepared with the standard solutions containing 07.5μg of chlorine and the same quantity of ammonium nitrate as in the sample solution.
A faster flow rate (for example, 2.5 ml/min) in the ion exchange separation has influence on the efficiency of washing of the column with water, but not on the position of the elution band of the chlorine. Less than 35 mm of the column length produces the leakage and lower recovery of chlorine. The radio isotope, Cl-36 was used in all the experiments of the separation of chlorine in the sample as a tracer. The effects of foreign ions on the photometry are also described.
An analysis requires about 2 hrs. The present method can be applied to the determination of chlorine down to ca. 1 ppm in aluminum.

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In the previous papers, the characters of the hydroxyl derivatives of chromone, benzo-1, 4-pyrone, as an analytical reagent have been reported. Similar studies were carried out on the hydroxyl derivatives of xanthone, dibenzo-1, 4-pyrone or 2, 3-benzochromone. The present paper deals with the reaction of 1-hydroxy- xanthone, 2, 3-benzo derivative of 5-hydroxychromone which is an useful reagent for the spectrophotometric or fluorometric determination of some cations, with about forty metallic ions.
The reagent was prepared by fusing resorcinol with salicylic acid in the presence of zinc chloride. The investigations were carried out on the solutions ranging in pH from 1 to 12, which contained 1 × 10^-6 mol of metallic ion, 1.5 × 10^-5 mol of reagent and 50 vol% of metanol in 25 ml. When precipitation or coloration was observed, extraction with the organic solvents was attempted. Thirteen ions react with this reagent. The following ions give the precipitates which are insoluble in the organic solvents: magnesium, yellow, pH>10; titanium, pale yellow-green, pH>5 ; zirconium, yellow, pH>4 ; cerium(IV), yellow, pH>8; thorium, yellow, pH>7. Aluminum reacts to form a soluble yellow-brown complex in the range of pH 210 with a maximum absorbance at pH about 5 and uranium to form a yellow-brown complex in the range of pH711 with a maximum absorbance at pH about 9. These can not be extracted. Nickel and cobalt react to form yellow precipitates at pH>7. These can be extracted, but they are very unstable. Palladium forms a yellow precipitate at pH>2. It can be extracted, but the organic phase become slightly turbid. Iron(III) gives dull green in the range of pH 14 with a maximum absorbance at pH about 2.5 and a red-brown precipitate at pH>8.The latter complex can be extracted with the organic solvents, but it is unstable. Beryllium and copper react to form yellow precipitates at pH>5 which can be extracted and they are stable. The beryllium complex shows a strong fluorescence in ultraviolet radiation similarly to its 5-hydroxychromone complex. The number of reacting cations is less than that reacts with 5-hydroxychromone and the complexes extracted are very unstable except those of beryllium and copper. These effects may be attributed to the steric hindrance deu to two benzene rings on both sides of pyrong ring.
Beryllium and copper can be determined spectrophotometrically. An analytical procedure is as follows: To a sample solution containing up to 7 μg of beryllium or 40 μg of copper, are added 10 ml of 3 × 10^-3 M methanol solution of the reagent, 2.5 ml of methanol, 5ml of buffer solution (boric acid-sodium hydroxide, 0.25 M in boric acid, pH 8 for beryllium, pH 11 for copper), and it is made up to 25 ml with water. After about one hour, the solution is shaken for thirty seconds with 10 ml of benzene. The organic phase is separated and dried over sodium sulfate. Its absorbance is measured at 430 mμ for beryllium or 440 mμ for copper. Both analytical curves are linear.

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Resorcinol-formaldehyde resins of various moleratios (F/R=0.30.7) were prepared in the absence of catalyst.
Each sample was evacuated in order to remove water and methanol, and the infrared spectrum was measured by KBr disk method. From the spectra, it was found that the ratio of the intensities, 1170 cm^-1to 1150 cm^-1, and 980 cm^-1 to 960 cm^-1 band, varied as the mole-ratio changes.
Assignments of the 1170 cm^-1 and 1150 cm^-1 bands were not clear. But the 980 cm^-1band was assigned to be an absorption related to the free hydrogen atom at 2-position of 4-substituted derivatives of resorcinol, and 960 cm^-1 band was assigned to be due to unreacted resorcinol.
2-Substituted derivatives of resorcinol had no absorption band in the region 950 cm^-11000 cm^-1.
There were linear relations between mole-ratio and intensities ratio D₁₁₇₀/D₁₁₅₀ and D₉₈₀/(D₉₈₀+D₉₆₀).
The standard deviations of the calibration curves were nearly the same, and were 0.02 by mole-ratio (F/R).
These calibration curves were used to analyze the other samples which were obtained in the presence of various catalysts.
The result obtained by using acid catalyst (HCl) was the same as that obtained under no catalyst. But a large deviation was observed when alkaline catalyst (NaOH) was used.
From the above results, a possibility to determine the structures of resorcinol-formaldehyde resins prepared by various catalysts has been pointed out. The structures found in this resin were unreacted resorcinol (a) (960 cm^-1), 4-, and 4·6-substituted derivatives (b) (980 cm^-1) and 2-, 2·4-, and 2·4·6-substituted derivatives (c).
The determination of the structures was carried out by their acetone solutions.
The structural difference in the resin caused by the use of different catalysts were concluded as follows: about (a) NaOH>no>HCl, about (b) no>HCl>NaOH, about (c) HCl_??_NaOH>no.
These data were useful in order to interpret the difference of physical properties of various samples.

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A rapid method for determination of micro amounts of oxalate ion has been developed by using two-step flow-coulometry. Carbon fiber is used for working electrodes. Supporting electrolyte solution (0.5 M sulfuric acid) is flowed through the flow-coulometric cloumn electrode and 5 to 10μl of sample solution containing 10^-5to 10^-1 M oxalate ion is injected. Since reduction or oxidation of diverse ions occurs at the first-step column electrode, of which working electrode potential is adjusted to +1.20 V vs. Ag-AgCl, the interference in the determination of oxalate ion is eliminated. Then the sample solution is flowed into the second-step column electrode, where oxalate ion is oxidized. At +1.60 V vs. Ag-AgCl, oxalate ion decomposes to carbon dioxide and hydrogen ion with two-electron oxidation reaction. In the range of 0.25.0 M sulfuric acid electrolyte, the reaction occurs quantitatively. The flow rate of electrolyte is sufficient between 1 and 15 ml/min. The quantity of electricity at the second-step column electrode gives the amount of oxalate ion. Time required for the determination is within 20 sec. One tenth to 10 n moles of oxalate ion has been determined within an error of 4%, and 1μ mole within 2%. Cerium, chromium, iron and uranium do not interfere with the determination of oxalate ion. Although aluminum and thorium form stable complex ion and precipitate, respectively, their interference can be eliminated by increasing the sulfuric acid concentration from 0.5 to 2.5 M. Other carboxylic acids such as citric, formic, glycolic and tartaric acid are not oxidized at +1.60 V vs. Ag-AgCl. The interference from hydrogen peroxide can be eliminated by the addition of vanadyl ion.
Decomposition of oxalate ion by light has been studied by using the proposed method. When the concentration of oxalate ion is lowered, the effect of light becomes more pronounced. In the presence of metal ions which have more than two stable oxidation states in aqueous solution. e.g., iron and uranium, oxalate ion decomposes more quickly. Electrode reactions of other organic acids (glyoxalic acid, formic acid, tartaric acid, etc.) have been also studied.
The two-step flow-coulometric method for the determination of oxalate ion has the following advantages over the spectrophotometric and titrimetric methods: small sample size, speediness, high precision, and possibility of remote controlled analysis.

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In the case of research of ultrapure materials, manufacturing, analysis and containers are most important. It is impossible to produce pure materials without any one of these items. Polyethylene has been widely used for containers of ultrapure materials on a commercial basis. However, it is not so stable with strong acids. Teflon is the best one of many plastics protected from reagent as strong acids or alkalies and also against temperature. It is natural that Teflon, having these good properties, is considered to be good containers. However, the particles in Teflon being contained as metalic and oxide compounds of inorganic materials become a problem. Therefore, this investigation was carried out to confirm numbers, size, distribution and constituents of particles in plastics, especially in Teflon, with microscope and laser micro probe.
Particles in the Teflon bottles were from less than several microns to about 200 microns and many were less than 50 microns in diameter. Over about 5 microns particles which were detected with microscope were found in bottles about four or five times more than in pellets. Quantity of particles in plastics were 720 × 10³/cm³ in Teflon, 9 × 10²/cm³ in polyethylene and 7 × 10²/cm³ in polypropylene bottles. As a result of this fact, it is known that the contamination was occurred remarkably during the process of molding from pellets to bottles. All particles distributed throughout and embdded in the Teflon bottles, in some cases the covering layer was very thin and the particles produced a rough inner surface in the bottles, and their state contaminates easily the storage materials. Particles in the Teflon bottles were analyzed and found that iron, titanium, magnesium, calcium and silicon as the major constituents, and nickel, chromium, copper and manganese as the minor constituents using the laser micro probe. Their colors were black, dark brown, white and others. The contents of iron, one of the typical element contained in the particles, were determined by 1-10 phenanthroline method and were 18 ppm in Teflon bottle and <0.5 ppm in original Teflon pellet.

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Cleaning method for the containers which contained inorganic particles was investigated by rigorous chemical leaching. The important condition for removing the particles from plastics is that the leaching solution diffuses into the plastics and it reacts with the particles.
About 0.1 percent of nitric acid and about 0.02 0.03 percent of hydrochloric acid were absorbed in Teflon but water was scarcely absorbed in it. However, after dealing by nitric acid leaching, the absorption of hydrochloric acid and water in Teflon increased up to 0.05 percent. In the case of polyethylene, about 0.1 percent of hydrochloric acid and about 0.05 percent of water were absorbed but nitric acid reacted with it and decomposed it.
Pieces of Teflon sample were placed in each leaching solution (1: nitric acid, 2 : hydrochloric acid, 3: three-to-one mixture of concentrated nitric acid and hydrochloric acid) under boiling, and after every an adequate period, the samples were taken out and the change of the particles was observed under a microscope. This experiment showed that nitric acid was more active to the particles than hydrochloric acid. The degree of the dissolution of the particles by the leaching solutions decreased in an order, nitric acid, mixture of nitric acid, hydrochloric acid and hydrochloric acid. Some of the particles were not dissolved by any acids. However, the quantity of such particles was rather small, especially by the dissolution with the mixture of nitric acid and hydrochloric acid.
The dissolution of particles can be divided into three steps, the first is the diffusion (introduction) step, where the solution reaches the particles, the second is the reaction step, where the crack between particles and plastic is occupied by the dissolved solution, and the final is the growth of branch pattern step where the dissolved solution diffuses into plastic and a branch pattern grows slowly and steady. A leaching period up to five days was necessary in order to remove large particles (200 microns). The recommended procedure is as follows.
Teflon bottles, washed by water are immersed in a three-to-one mixture of concentrated nitric acid and hydrochloric acid for two days and then immersed in concentrated nitric acid for three days. (The presence of hydrochloric acid may be favorable in order to dissolve some metal oxide particles.) The leached Teflon bottles are then immersed in boiling water for three days (the water is changed every day) and are finally dried under vacuum.

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When βray of ¹⁴C radiated the scintillator (toluene 1l+PPO 4 g +POPOP 0.1 g), liquid scintillation was observed with the apparatus of short resolving time for measurement of light pulses. Overall high voltage ( -2170 V) was supplied to the cathode of photomultiplier 56AVP/03. Signal pulses were led to the sampling oscilloscope SAS500.
Output of the hold circuit of the oscilloscope was led to X-Y recorder and the signal pulse curves of the scintillation were recorded.
The scintillator was poured in the cell (2 ×25 × 30mm) of sheet glass with toluene-¹⁴C. This cell was made "Optical coupling" with the photocathode ofphotomultiplier by silicone oil TSF451 (500, 000cs).
About 75% of β rays of ¹⁴C were observed, and average energy of these β rays was about 72.1 keV.The recorded pulse curve was the average pulse curve of many scintillations. The peak height maximum of the obtained pulse curve was about 810 mV high (R=25 Ω). From the area below the curve, total anode pulse current was calculated. It was about 2.67 × 10^-10 coulomb. Then the number of ejected photoelectrons from the photocathode was about 53.8.
Corrected fluorescent spectra and absorption spectra of liquid scintillator, and absolute quantum efficiency curve of photomultiplier were obtained. Averageenergy of fluorescent photons was 2.85 eV. The product of these three spectra give the conversion efficiency from fluorescent photons to ejected photoelectrons.
When pathlength of absorbance were 1 cm, 5 mm, 2.5 mm, and 1.25 mm, conversion efficiency were 0.155, 0.160, 0.163, and 0.165 respectively.
Because the effective pathlength was estimated about 23 mm, conversion efficiency was about 0.163.
The refractive indexes of liquid scintillator and silicone oil were measured by Pulfrich refractometer.Geometrical collection efficiency was calculated with these indexes by the Fresnel equations for refraction.Photons of liquid scintillation, which were radiated from the cell to the opposite side, were reflected at the boundary face of sheet glass and air, and went to the photocathode, were large enough not to be disregarded.When this reflected light was involved, geometrical collection efficiency was about 0.50.
Number of total radiated photons was calculated with these data and was about 670 ± 50. Then the fluorescent efficiency of liquid scintillation was about 2.6 ± 0.3%. The fluorescent efficiencies of the fast component and the slow component were 2.1 % and 0.47% respectively.

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Anionic surfactants such as sodium dodecylsulfate (SDS), sodium dodecylbenzenesulfonate (SDBS), sodium di (2-ethyl-hexyl) sulfosuccinate (Aerosol OT), and sodium butylnaphthalenesulfonate (BNS) were determined by a polarographic desorption potential measurement.
Surfactant solutions were prepared as follows; a weighed portion of surfactant was placed in a polarographic cell which had been deaerated by nitrogen gas and a certain volume of deaerated water or aqueous salt solution was added to the cell and a surfactant solution at a desired concentration was prepared. The solution was then stirred by a magnetic stirrer. Polarograms were recorded against a saturated caromel electrode by using Yanagimoto P-8 and Yokogawa POL-21 polarographs.
The surfactants studied showed well-defined adsorption-desorption waves which were the same kind as those observed in the absence of the supporting electrolyte. In the case of the SDS solution, care must be taken for the waves due to the reorientation of the surfactant molecules on the electrode which appeared simultaneously. The values of the desorption potential were measured in the following way. The bottompoint of the oscillations on the residual current curve preceding the wave was extrapolated toward the wave and the bottompoint of the oscillations on the plateau was extrapolated toward the wave. The one-half of the rising portion of the wave between the two lines was read as the desorption potential. The values measured by this method were more reproducible and less affected by the irregularity of dropping than the ordinary half wave potential.
The desorption potential shifts toward negative by an increase in the surfactant concentration and a linear relationship was obtained between the desorption potential and the logarithm of surfactant concentration. For the determination of an anionic surfactant, the linear line above mentioned was used as the calibration curve. The determination was limited by the critical micell concentration (cmc), as the desorption potential remained constant above the cmc of the surfactant.
The presence of the supporting electrolyte affects the nature of the surfactant solution such that the cmc and the solubility of the surfactant decrease. The polarographic adsorption-desorption potential also changed by the change in the concentration and in the nature of the electrolyte. Thus, the same supporting electrolyte at a constant concentration should be used throughout a series of experiments. The decrease of the cmc result in lowering the determination limit, but a high concentration of salt which caused a large cmc decrement made the wave indistinct. The suitable salt concentration was 0.1.2N. Deaeration should be continued until the oxygen wave disappeares.
The proposed method applied to the determination of anionic surfactants (the concentration between a few ppm and a few hundred ppm) was very simple and showed a good reproducibility.

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Fluorine is extensively distributed throughout nature and has been detected in such diverse substances as soil, biological materials, water and air. Also, a recent remarkable development of fluorine industrialization has increased the possibility of air contamination from effluent fluoride.
In general, plants are mostly effected by fluoride contamination of air. This paper describes a micro method for the determination of fluoride content of plants particularly of the leaves.
Before fluorine can be measured quantitatively by colorimetric procedures it must be present in solution as the fluoride ion essentially free from organic and ionic interferences. This is necessary because there is no reagent available for colorimetric determination which react specially with fluoride. The most time consuming and tedious operation in fluoride analysis were the ashing and distillation of the sample in preparation for its determination. However, a simple and rapid method for determining traces of fluoride in plant has been established by using fluoride-selective electrode.
In this method fluorine is determined directly, without the need for any separation steps, like the steam distillation process.
The dried plant sample should be in a divided state as finely as possible. One gram of the sample, containing 2 micro grams of fluorine, is placed in a nickel crucible and mixed with 5 ml of 5% sodium carbonate solution sufficient to maintain the sample alkaline during the evapolation and ashing procedure. The mixture is dried and charred on the sand bath. It is then placed in a electric furnace or muffle and ashed at 650700°C, 5 ml of 20% sodium hydroxide is added, and then the mixture is fused for 10 minutes at about 700°C. The melt is cooled, dissolved in 50 ml of hot water, and then neutralized with 1 ml of 60% perchloric acid. The solution is transferred into a 100 ml volumetric flask, adjusted by pure water by making up the final volume to 100 ml. The sample solution and TISAB is transferred to 50 ml volumetric flask, make up by pure water. The fluoride activity is then measured by the fluoride-selective electrode.

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For improvement of analytical sensitivity using quantrecorder or vacuum quantrecorder, iron, copper and silicon in high purity aluminum were analyzed under argon atmosphere by low voltage spark discharge.
The electrode erosion rate under argon atmosphere is higher than under nitrogen or oxygen atmosphere. The electrode erosion rate has a linear relation with the integrated value of discharge current ∫idt. Spectral line intensity depends mainly on the electrode erosion rate. Therefore, 50 μF, 50 pH, 10 Ω, 900 V and argon atmosphere may be better analytical condition rather than the now routin work conditions.

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Hitherto the detection of free sulfur has been made by changing it into sulfide, thiocyanic acid, thiosulfuric acid or others and utilizing their characteristics. In this study, sulfur was subjected to react with manganese oxide(IV) on heating, in order to change it into manganese sulfate, and then the manganese was oxydized into permanganic acid. By doing this, manganese was sharply detected, and consequently sulfur could be sharply detected indirectly. However, part of sulfide and part of sulfate also react similarly with manganese oxide(IV) and produce manganese sulfate, it is necessary to separate them by carbon disulfide, if they are present. Since manganese dioxide reagents sometimes give a positive result for this test, it is better to use manganese dioxide ore instead. In this case, however, a blank test is indispensable.

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Boron oxide in boron nitride was determined by an acid-base titration and by a colorimetric method. The outline of the recommended procedure is as follows. The sample (1 g) is heated in dilute sulfuric acid (1/10 N, 5 ml) for 2 hours. After filtering the residue, the filtrate is divided into two parts. The total amount of boron oxide (A) is determined by the acid-base titration with mannitol, and the amount of ammonia (B) which is the decomposition product of boron nitride is determined by the colorimetric method with Nessler's reagent. The amount of boron oxide due to the decomposition of boron nitride (C) is estimated from (B). The content of boron oxide in the sample is obtained from the difference between (A) and (C). Determinations at 0.1 and 4% levels were illustrated.

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[in Japanese]

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