The Weisz Ring Oven¹⁾ and apparatus by Ballczo²⁾ have been known to be effective for qualitative and quantitative analysis of microsubstance, but they have many faults. The authers have presented an apparatus made of hard glass which can be handled more easily, noncorrosive, keeps, warm better and is more stable than the previous apparatus. Some experiments were carried out by using the present a glass ring oven and the results were compared with those obtained by using the Weisz Ring Oven.
Bathocuproine and bathophenanthroline were used as detection reagents of copper and iron. The effect of the coexisting ions is smaller by the use of these reagents than by the reagents used in the conventional methods⁴⁾⁶⁾ and thus a more specific and selective detection and determination is possible by the present method (Limit of detection, Cu : 0.005 μg, Fe : 0.009 μg, Range of determination, Cu : 0.013.0 μg, Fe : 0.024.0 μg). The sample solution is spotted on a filter paper (55 mmφ). After copper, lead and cadmium ions are fixed by exposing the disk to H₂S gas stream and silver is fixed by exposing it to HCl vapor. Then it is placed on a oven and heated at 90°C, and iron is allowed to diffuse out of the disk into a ring zone by dropping 0.010.05N HCl solution. For copper, no H₂S gas exposure was made, it was diffused out of disk into a ring zone by dropping 0.010.05 N HCl. The latent rings of iron and copper are sprayed by a 1 : 1 solution of bathocuproine and hydroquinon, and 1 : 1 solution of bathophenanthroline and hydroquinon, respectively. And exposed to ammonium vapor to develop color. Standard rings prepared from samples containing various amount of each metal. The contents of copper and iron in copper base and tin base alloys were measured. The limit of the error was ±1% when the results obtained by the present method were compared with those by polarography. The whole procedures took about 10 minutes. The present method may be applied for the analysis of samples in other field.

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A graphical method for estimating retention indices in gas chromatography of higher dimethyl paraffins than C₁₀ was investigated.
In this method, the retention indices of these compounds are indirectly obtained in the form of "retention index component of methyl radical", (ΔI^Me_R), of methyl paraffins, which are calculated by subtracting linear carbon number, (x), multiplied by a factor of 100 from retention indices of mono- or dimethyl paraffins.
Three rules are derived from the relationship between ΔI^Me_R and x, those are as follows;
(1) ΔI^Me_R values of monomethyl paraffin homologues in regard to substituted position of a methyl group tend to decrease exponentially with increase of the x, and to approach to respective converged values. These values of 2-, 3-, 4-, 5-, and 6-methyl paraffin homologues, for example, are 63.5, 68.8, 57.9, 50.9, and 46.4, respectively, for a squalane column at 80°C. The same tendency was observed in the case of dimethyl paraffins.
(2) when a dimethyl paraffin has one or more methylene groups between the two methyl groups, its ΔI^Me_R value is approximately equal to a sum of the converged ΔI^Me_R of the two corresponding monomethyl paraffins, and the difference between them approaches to zero with increase of x.
(3) the ΔI^Me_R value of k, k-dimethyl paraffin (k≥3) is approximately equal to the double of ΔI^Me_R of k-monomethyl paraffin having the same carbon number, and the difference between them approaches to zero with increase of x.
For this work, the retention indices of lower monoor di-methyl paraffins than C₁₀ were cited from literatures, and calculated their ΔI^Me_R for a squalane column at 80°C. These values are plotted against x, and extrapolated on the basis of the rules mentioned above. The ΔI^Me_R-x curves can be drawn accurately by drawing the straight lines which denote the rate of variation of ΔI^Me_R-x curves.
In the case of monomethyl paraffin homologues such as 6- or 7-methyl, of which retention data is not at hand, their ΔI^Me_R-x curves can be estimated by using ΔI^Me_R values of another lower monomethyl paraffin homologues such as 5- or 4-methyl. The similar estimation technique can be applied to dimethyl paraffins.
By comparing the retention indices of C₁₃ dimethyl isomers calculated by means of this method with experimental values in a literature, the standard deviation of the differences between them is within 2 i. u.

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A square wave polarographic determination method of cyanide ions in the industrial water and waste was studied after having distilled according JIS method. As an absorbent, potassium carbonate solution or potassium hydroxide solution was used.
(1) The cyanide ion was distilled and absorbed into a mixture of 20 ml of 1M potassium carbonate and 3.0 g potassium nitrate, until the volume of distillate reached 100 ml. A square wave polarogram of this distillate was recorded without bubbling nitrogen gas. The wave height of cyanide ion did not vary with pH value in the range of 9.911.4. The peak potential of 1 × 10^-4M cyanide ion was - 0.29 V vs. SCE in the pH range of 9.911.4 and at pH 9.2 it was - 0.26 V vs. SCE. Almost same calibration curves were obtained at pH 9.9 and 11.4 in the concentration range of 4 × 10^-61 × 10^-5M and 1 × 10^-51 × 10^-4M for cyanide ion.
(2) The cyanide ion was distilled and absorbed into a mixture of 20 ml of 0.75M potassium hydroxide solution and 3.5 g potassium nitrate, until the volume of distillate reached 100 ml. A square wave polarogram of this distillate was recorded after bubbling nitrogen gas for 1015 minutes. The peak potential of 1 × 10^-4M cyanide ion was - 0.29 V vs. SCE and the wave height of cyanide ion did not vary in the potassium hydroxide concentration range of 0.050.15M.
Almost same calibration curves were obtained at potassium hydroxide concentration of 0.05M and 0.15 M. The concentration of cyanide ion was determined with the wave of which peak potential was about -0.29 V vs. SCE in both cases. The lower the concentration of cyanide ion was, the more positive the peak potential.
When the cyanide ion in the water would be determined without distillation, the interference of coexisting anions in the determination of cyanide ion was also studied. Chloride ion, sulfate ion and sulfite ion which were contained as much as 100 times of cyanide ion did not interfer with the determination of cyanide ion. Bromide ion or thiocyanate ion which were contained more than 10 times of cyanide ion interferred with the determination of cyanide ion. The wave height of 1 × 10^-4M of cyanide ion was increased 10% by adding 5 × 10^-5M iodide ion and thiosulfate ion, because these ions have almost the same peak potential with that of cyanide ion.
These methods have been applied to the analysis of waste water and results were in good agreement with those obtained by pyridine-pyrazolone method.

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A newly precoated plate for thin-layer chromatography (TLC) has been prepared, which is made from silica gel-fused glass powder mixtures. A broken soda-lime glass plate was ground in a ball mill, screened with a 200 mesh sieve, and fractionated by sedimentation in water. The glass powder thus obtained had a particle size slightly smaller than that of silica gel for TLC use. A mixture of one part of silica gel and two to five parts of the glass powder was suspended in solvents such as benzene, chloroform, acetone, ethyl acetate, methanol, ethanol or water. The slurry was spread on soda-lime glass plates in a usual manner, and air-dried for some time. Then the layer was heated in an electric furnace at 450 to 750°C for several minutes to yield a silica gel-fused glass layer. It is essential to fuse the glass powder without melting of silica gel to protect the chromatographic activity of the later. The sintered plate prepared in this way contains no organic binders, and is not charred under any drastic conditions, i. e. by heating after spraying corrosive reagents such as sulfuric acid, chromic acid mixtures, trichloroacetic acid, antimony trichloride etc.
Using this new plate, was studied thin-layer chromatographic separation of various organic compounds such as azo dyes, steroids (estrogens, androgens, corticosteroids, cardiac glycosides and its genin derivatives), alkaloids (indole, opium, tropane and other classes), food preservatives and amino acids (glutamic acid, methionine, lysine, alanine, arginine etc.). In order to test the chromatographic ability of this plate, Stahl's dye mixtures (indophenol, sudan red G and butter yellow) and estrogens (estriol, estradiol and estrone) were used, and good reproducibility of separation as reliable as that of the commercial precoated plates such as Merck's product was obtained. The separation characteristic of our plate was similar to that of a mixed layer of silica gel and Kieselguhr. This plate is mechanically stable, heat-stable and acidresistant, and moreover it can be repeatedly used by soaking the chromatogram into cleaning solutions. The standard deviation in R_f values of steroids developed fifty times on a same sintered plate was less than 0.04.
These properties of our plate enable, besides general use, its special use for separation of radioactive compounds, thin-layer densitometry (TLD), clinical analysis (lipids, sugars, aminoacids, steroids etc.), reversed phase TLC, bioautography, thin-layer electrophoresis (TLE) and, probably, for other various purposes in the vast field of chromatographic analysis.

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An analytical method for determining the total 1, 4-content of polybutadiene and the composition of copoly-butadiene-acrylonitrile was investigated by means of curie point pyrolysis-gas chromatography.
The molar ratio of butadiene and 4-vinyl cyclohexene calculated from the corresponding peaks appearing on the pyrogram at 434°C by making relative sensitivity correction for the flame ionization detector showed a linear relation with the total 1, 4-content.
In the case of copoly-butadiene-acrylonirile, the yield of acrylonitrile (molar fraction) calculated from the peaks at 541°C showed a linear relation with the acrylonitrile content (mole %) in the polymer.
The ratios of the corresponding peak heights, i.e., ethylene/butadiene, propyrene/butadiene, C₅-hydrocarbon/butadiene, methacrylonitrile/acrylonitrile, and 4-vinylcyclohexene/butadiene, were compared and the "Boundary effect", or the different probability of splitting off of a monomer unit from the end of the polymer chain depending on whether the neighboring monomer unit is the same or not was estimated for random or alternated copolymers as well as for a mixture of homopolymers.

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This paper describes a new analytical method for polynuclear hydrocarbons in petroleum. The method consists of extraction of polynuclear hydrocarbons in petroleum, separation of the extract into each component, and identification and determination of each spot.
Extraction of polynuclear hydrocarbons in petroleum is carried out by a series of liquid-liquid partitions of petroleum (or cyclohexane containing petroleum) dimethylsulfoxide (DMSO), (DMSO +20 vol% HCl ; 1 : 1, v/v)-cyclohexane, cyclohexane-5% NaOH, and cyclohexane-water. After evaporation under low temperature (ca. 40°C) and reduced pessure, the concentrated extract is applied onto the aluminum oxide G layer of thin-layer plate which are composed of aluminum oxide G layer and 26% acetylated cellulose layer. The first development is carried out on aluminum oxide G layer using n-hexane-ethylether (19 : 1, v/v) as developer in a chamber of 20% in relative humidity. The second development is carried out on acetylated cellulose layer using methanol-ethylether-water (4 : 4: 1, v/v). The separated polynuclear hydrocarbons are detected as small spots by their fluorescences under ultraviolet rays (365 and 253 mμ). Each spot on thin -layer is scraped-off into a small centrifuge-tube, and is extracted with benzene by the help of centrifugation. Polynuclear hydrocarbons in the benzene solutions are analysed by spectrofluorometry.
We applied this method to the analysis of several petroleum such as residuum oil, fuel oil and kerosine, and found the presence of many polynuclear hydrocarbons in these oils by two-dimensional dual band thin-layer chromatography. Of these hydrocarbons, 11 polynuclear hydrocarbons were identified by spectrofluorometrical analysis. They were fluoranthene, pyrene, benz (a) anthracene, chrysene, benzo (a) pyrene, benzo(b) fluoranthene, benzo ( j) fluoranthene, benzo (k) fluoranthene, perylene, indeno (1, 2, 3-cd) pyrene, and benzo (ghi) perylene.
Benzo (a) pyrene contents were 5200 μg/kg for fuel oil C, 310 μg/kg for residuum oil, 71 μg/l for fuel oil A, and 0.0670.19 μg/l for 3 kerosines.

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Potentiometric titration with lead tetraacetate as an oxidizing agent was investigated to apply for the determination of sodium hydrogen sulfite.
The solution of lead tetraacetate in which 4060 vol% acetic acid was added to avoid the hydrolysis of lead tetraacetate during the titration course, was used as a titrated solution. The titration procedures are as follows:
Into a 200 ml beaker, 3050 ml of glacial acetic acid and 10.00 ml of 10^-110^-2N lead tetraacetate were mixed, diluted to about 100 ml with distilled water, and titrated with a test solution of sodium hydrogen sulfite at an appropriate concentration. A platinized platinum wire electrode as an indicator electrode and a saturated calomel electrode as a reference electrode, connected through a 30% KNO₃ agar bridge to the beaker, were used. The electrode potential after each addition of the titrant, was read within 12 minutes before and after the end point and within 58 minutes in the vicinity of the end point.
A remarkable potential drop, 400500 mV per 0.10 ml of the titrant, was observed in the vicinity of the end point when both concentrations were 0.1 N in lead tetraacetate and sodium hydrogen sulfite. Sodium hydrogen sulfite over the concentration range of 10^-1 10^-2N could be determined within the error of ±1.0% and with the coefficients of variation of ±0.1 %, by titrating 50 vol% acetic acid solution of lead tetraacetate with the test solution of sodium hydrogen sulfite.
The titration results under the proposed conditions were not affected by the change in concentration of acetic acid and temperature of the titrated solution within the range investigated. The deposits of lead sulfate on an indicator electrode were removed by rinsing it in 2N hydrochloric acid after each titration.
The proposed method is a direct titration method and is better than the conventional iodometry for the standardization of sodium hydrogen sulfite because the titration is carried out without any restriction caused by the loss of sulfur dioxide.

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Although fluorescent X-ray analysis of a variety of elements in aluminum alloys have been reported, little is known about magnesium analysis. This is because of anomalous behavior of this element under conventional technique and thus an individual calibration curve is necessary for each alloy type. An investigation of the effect of the coexisting heavy elements was intended since the MgK_α line (9.89 Å) is easily absorbed by such elements. Zinc (16%), copper (15%) and nickel (13%) were chosen as examples of the coexisting elements because they are often contained in commercially available aluminum alloys at higher concentrations.
Measurements were made for the MgK_α intensities from aluminum alloys containing 110% Mg. The relationship between the Mg concentration and the MgK_α intensity in Al-Mg binary alloy was linear within the above Mg concentration range. However, the MgK_α intensity decreased upon the presence of the heavy metals (See Fig. 1 for Al-Mg and Al-Mg-Zn alloys). This is apparently due to an absorption of the fluorescent X-ray by the heavy metals. Therefore, Matsumura's equation and Andermann's equations were used and the reported values of the mass absorption coefficients were introduced in order to correct the absorption. The results, however, were unsatisfactory except those for Zn; the magnitude of correction was too large for the Al-Mg-Cu and Al-Mg-Ni alloys, whereas the corrected MgK_α intensity from Al-Mg-Zn alloys agreed with that from Al-Mg alloys (See Fig. 2 for Al-Mg-Cu alloys). This is presumably due to an inaccuracy of the mass absorption coefficients for Cu and Ni because the equation successfully corrected the absorption by Zn which is the adjacent element to Cu and Ni on the periodic table. Incidentally, the mass absorption coefficients at 9.89 Å calculated from our experimental results were 34703950 and 31603100 for Cu and Ni, respectively, while the values obtained by an interpolation of the reported coefficients were 5800 and 5400.
Correction without using the mass absorption coefficients was then intended. A correction equation (eq. 7), composed of weight fractions of the absorbing components and constants, was deriven from Beattie's equations. This equation is convenient for the practical analytical work (The weight fractions of the absorbing heavy metals can be easily determined by an X-ray fluorescent analysis). An assumption, verified by experiments, was made in order to derive the equation. It is based on the fact that major component of the sample is aluminum and that the difference between the mass absorption coefficients of Al and Mg, (μ_Al-μ_Mg), is much smaller than (μ_Zn-μ_Mg), (μ_Cu-μ_Mg) and/or (μ_Ni-μ_Mg). The constants were calculated from the experimental results. The equation thus determined was successfully applied for the analysis of multi-component commercial alloys. Addition of another correction term was recommended when more than 2% of Fe is present.

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To obtaine an excessive analytical result against theoretical value has often experienced in our laboratory when applying more than 5 mg of the sample to NA1 rapid nitrogen analyser¹⁾. This phenomenon was independent from the increase of the furnace temperature, the changes in the carrier gas flow-rate, the prolongation of the combustion time, the ages of the combustion tube packings and an addition of tricobalt tetroxide to the sample.
The relations between sample size and the volume of combustion gas formed were shown in Fig. 1 and 2. Now, present authors were collected a considerable amounts of alkaline non-absorbed gas, obtained upon combustion of cholesterol or sucrose instead of nitrogen containing substances to simplify the composition of the gas, in a vial vessel through sample gas collector (Fig. 3). The gases collected were analysed by infrared spectrophotometry (Fig. 4), and fine structurs at 12001400 cm^-1 and 8501100 cm^-1 were quite agreed with that of methane and ethylene (Fig. 5 and 6).
Another experiments were carried out by gas chromatography. As in Fig. 7, carbon monoxide+ air, methane, ethylene, propylene and propane peaks were identified in all of the combustion gases, but allene and allylene were hardly recognized only when 50 mg of choresterol was burned.
Scanning mass specrum of the incomplete combustion gas among M/e 12 to 100 was shown in Fig. 8, and considerable peaks above M/e 44 were not detectable. Three peak groups, M/e 16, 28 and 40, were found in this figure. It was considered that M/e 16 would be a parent peak of methane. M/e 28 was triplet as in Fig. 9 and each peak was overlapped with that of carbon monoxide, nitrogen and ethylene. The sample gas would be contaminated by nitrogen which is dissolved in water, when the gas is collected in a vial vessel.
M/e 40 peak, doublet, was resolved as in Fig. 10. Lower large peak was overlapped with parent peak of ⁴⁰Ar. The mass number of a higher small peak was calculated as 40.027848 and was quite agreed with that of C₃H₄ (M/e 40.031299) with the difference of -3.45 mmu. Therefore, this suggested the presence of allen or allylene in the sample gas.
From the experimental result obtained above, it was considered that the composition of incomplete combustion gas would became more complicated when over 5mg of nitrogen-containing substance is burned in this instrument.
Finally, many experiments were carried out in order to avoid the formation of incomplete combustion gas. Reasonable analytical results were obtained for 2 to 15 mg samples if the volume of oxygen chamber was increased to 15 ml (originally 5 ml) (Fig. 11 and 12).

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In order to make it clear that the effect of the difference in the ratio of the stationary liquid to the solid support, in the kind of the solid support, or in the grain size of the solid support on the retention index of the solute on the mixed packing column, the retention behaviors of typical compounds on column containing a mixture of two types of the packing which is prepared by coating various supports with non-polar or polar liquid at various ratios were investigated.
Squalane (SQ) was used as the non-polar stationary liquid and polyethylene glycol 600 (PEG) was used as the polar liquid. Solid support Chromosorb W (3060 mesh, 80100 mesh) or Chromosorb P (3060 mesh) was impregnated with 20 weight % or 5 weight % of any one of the stationary liquids, and the mixed column packing was prepared by mixing the SQcoated support and PEG-coated support in the weight proportion of the stationary liquids 9 : 1, 4 : 1, 1 : 1, 1 : 4, or 1 : 9. The specific retention volumes of various compounds were measured at 100°C and then the retention indices were calculated graphically from these values.
From these experimental results, it was found that some differences in the retention index of solute on a single liquid column arose from the difference in the ratio of the stationary liquid to the solid support, the kind, or the grain size of solid support. Though the mixed columns which were prepared by mixing two types of packing material with different coating ratio of the liquid or kind of the solid support was used, the retention index of a certain solute on these columns agreed with each other within the experimental error if the liquid composition (weight fraction) of the column was the same with each other.
The retention index of the polar solute on the SQ column increased and that of on the PEG decreased as the coating ratio of the liquid decreases or the surface area of the solid increases. These phenomena seem to occur by the adsorption of the non-polar solute on the interface between gas and liquid (polar) or of the polar solute on the interface between liquid (non-polar) and solid. Since the adsorption effects of the polar and non-polar solutes in the intermediate region of the liquid composition may be compensated. on calculation of the retention index, the same retention indices can be obtained whatever packing meterials were used. It is convenient for the treatment of the mixed packing gas chromatography that the retention index of the solute or the polarity of the stationary phase changes proportionally to the weight fraction of the stationary liquids in the mixed phase.

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The Van Slyke procedure for the determination of primary aliphatic amino group in a micro scale sample is modified by using the reaction of aliphatic amino groups on the surface of solid sodium nitrite and the amount of nitrogen gas generated by the reaction was determined by gas chromatography by using tetrahydrofuran as the internal standard. The apparatus consisted of gas chromatograph having a reaction tube. The reaction tube was made of cupper, the inner diameter was 8 mm and the length was 120 mm and was packed with firebrick C-22 (4060 mesh) which was coated by about 33% of sodium nitrite. About 2 μl portion of the sample solution which contained acetic acid and tetrahydrofuran as the internal standard, was injected into the reaction tube by using a micro syringe, and after the completion of the Van Slyke reaction, the 4-way cock in the gas chromatograph was operated to make the carrier gas pass through the reaction tube. The reaction products (N₂ and NO) and internal standard were separated by polyethylene glycol column and molecular sieve column.
The amount of the evolved nitrogen gas was dependent on the mole ratio of acetic acid/amino group, the reaction temperature and the reaction time. When the value of the mole ratio of acetic acid/amino group was larger than 5, the amount of the evolved nitrogen gas became constant. When the reaction temperature was varied from 40 to 90°C, the amount of nitrogen gas increased gradually untill 60°C, but above 60°C it became constant. The relations between the reaction time and the amount of evolved nitrogen gas at 60 and 90°C were also examined. The amount of nitrogen gas increased as the time lapse, and became constant after 5 min at 90°C, but after 10 min at 60°C. When the reaction time was 10 min, the temperature was above 60°C and the mole ratio of acetic acid/amino group was larger than 5, the reaction of primary amino group and sodium nitrite were completed. Tetrahydrofuran as internal standard was added in the primary amine-acetic solution. Its concentration in sample solution, which was varied 622%, was independent on the amount of the evolved nitrogen gas.
It is possible to determine 0.3 mg of primary amino group in the sample within 15 min and the standard deviation was 2.5%. Methyl amine, n-butyl amine, n-amyl amine and 6-aminocaproic acid were used as the samples.

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The method used for a rapid determination of active hydrogen in organic compounds, which is based on the chemical reaction of Grignard reagent with active hydrogen, is described. The apparatus consits of a gas chromatograph with a micro reaction cell.
(I) The quantitative determination of active hydrogen; About 250 μl of methyl magnesium iodide-di-n-butyl ether solution was put in the micro reaction cell, which had an injection at upper part. Sample or sample solution, about 0.1 to 5 μl, was injected in the Grignard reagent with a micro syringe, and after the completion of the reaction the 4-way cock in gas chromatograph was exchanged to make carrier gas pass through the cell. The amount of methane gas, which was one of the reaction products and equal to the amount of active hydrogen, was estimated by the peak area of its gas chromatogram. The reaction time was varied from 30 second to 3 min at room temperature. When the reaction time was above 1 min, the methane gas evolved was constant. The active hydrogen of lower alcohols, such as isopropanol and n-butanol, was determined quantitatively within 5 min. The sample sizes were in 0.1 mg order, and the standard deviations were within 2.5%.
(II) The selective detection of active hydrogen ; The carrier gas and the sample components, which was separated in the gas chromatograph, was introduced into the solution of Grignard reagent in a micro reaction cell continuously. They foamed small bubbles and rise to the surface of solution. In the solution, the sample component containing active hydrogen reacted and evolved methane gas, but the sample component containing no active hydrogen did not. After passing through silica gel column, the carrier gas and methane gas was led into the thermo-conductive detector. Comparing the regular chromatogram with that after the micro reaction cell, the sample components containing active hydrogen could be known. The mixture of lower alcohols and other organic compounds were used as samples.

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Two methods, methanolic bromine method and acid decomposition method, for the determination of aluminum oxide in internally oxidized Cu-Al alloy have been presented. The effects of decomposition temperature, decomposition time etc. on the recovery of aluminum oxide have been studied by the use of synthesized aluminum oxides and internally oxidized Cu-Al alloys. The recommended procedures are as follows.
(1) Methanolic bromine method : 25 g of Cu-Al alloy is dissolved with methanolic bromine (100 ml of methanol + 10 ml of bromine) in a decomposition flask at 6065°C for about 3 hr. The solution is filtered by suction through a Cella filter (CF, dense). The residue is washed with methanol, ignited in a platinum crucible and fused with 58 g of potassium pyrosulfate. The melt is leached with 5 ml of HCl(1+1) and 40 ml of water. The solution is made up to a definite volume with water, and to its aliquot containing 560 g of Al are added 5 ml of 20% tartaric acid solution, 5 ml of saturated Na₂SO₃ solution, 10 ml of 20% NH₄NO₃ solution, and 5 ml of 10 % KCN solution. The pH is adjusted to 9.59.6 with ammonia. It is transferred into a separatory funnel, and 3.0 ml of 3% 8-hydroxyquinoline solution is added. The solution is shaken vigorously with 20.0 ml of chloroform for 2 min. The absorbance of the chloroform layer at 390 mμ is measured against pure chloroform. The amount of Al is determined by referring to the calibration curve.
(2) Acid decomposition method : 25 g of Cu-Al alloy is dissolved with nitric acid in the ratio of 15 ml of HNO₃ (1 + 1) to 1 g of alloy at 1020°C. The solution is filtered by suction through a Membrane filter (MF 15). The residue is washed with water and treated in accordance with the above mentioned procedure (1).

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A quantitative method for the determination of S-benzyl-O-n-butyl-S-ethylphosphorodithiolate (Conen®) and several other organophosphorus pesticides has been improved. Pesticides were digested to inorganic phosphoric acid by 50% sulfuric acid and nitric acid in stead of perchloric acid, which was dangerous in handling, and colorimetrically determined.
One ml of pesticide in chloroform solution containing about 1.2 mg of P was spotted with a whole pipette on a silica gel plate with a thickness of 500 μ and dimension of 20 × 20 cm. After the development with the adequate solvent system shown in Table I, the spot was visualized with a UV lamp and quantitatively scraped from the plate, transferred to a glass filter and eluted with chloroform under a reduced pressure. The eluate was diluted to 50 ml with chloroform. Twenty ml aliquot of the above solution was transferred to a 100 ml digesting flask and solvent was removed in vacuo. To the resinous matter, 2 ml of 50% sulfuric acid and 5 ml of nitric acid was added, and the mixture was heated on a sand bath gently until yellowish brown smoke evoluted and then vigorously until white smoke evoluted. After allowed to stand for cooling, 5 ml of nitric acid was added and the mixture was digested again in a similar manner as above. Finally 5 ml of water was added and the mixture was heated. The digested matter was washed with water into a 50 ml volumetric flask, to which 5 ml of 0.25 % ammonium metavanadate solution and 5 ml of 5% ammonium molybdate solution were added, the whole was diluted with water to 50 ml. The absorbance of the solution was measured at 420 mμ against a reagent blank and the content of pesticide was calculated from the absorbance of inorganic phosphorus standard solution.
By this method, such pesticides as Conen®, Sumithion®, Surecide®, Cyanox®, Malathion, Dimethoate, Papthion, EPN, Salithion and Diazinone were accurately determined. Neverthless, DDVP was not determined by this method, because it was decomposed on a TLC plate and partially lost during the procedure, but it could be quantitatively analysed by the use of a TLC plate containing 10% PEG-1000 or PEG-2000 for the separation and perchloric acid for the digestion. This proposed method was superior to that previously reported because it was not dangerous but rapid.

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Colorimetry : In the well known method of the determination of arsenic by arsine-silver ·diethyldithiocarbamate (DDC) -pyridine system, burcine ·chloroform was found to be more suitable absorbing medium of arsine than pyridine. The procedure involves evolution of arsine by adding 5 ml of potassium iodide (15%), 3 ml of stannous chloride (40%) and 5 g of elemental zinc granular (10001410 μ) in the sulfuric acid medium (ca. 3N), absorption of the arsine into 5 ml of silver · DDC (0.25%) -burcine (0.1%) · chloroform solution, and subsequent measurement of color intensity at 510 mμ. The absorbing of arsine to the burcine· chloroform solution should be continued for about an hour at 25°C. Other organic bases such as piperazine, 1, 10-phenanthroline, 2, 2'-bipyridyl, ethylenediamine, 8-hydroxyquinoline were tested and burcine was found to be best in the point of view of sensitivity and color stability. Antimony interferes with the determination when it is present in a concentration of several times of arsenic, but even then the interference can be masked by adding more amount of stannous chloride solution.
Atomic absorption spectrometry : An indirect atomic absorption method for arsenic was also developed. After oxidizing arsenic (III) to arsenic (V) by potassium iodide and iodine, molybdoarsenic acid is formed in the acidic medium, and the heteropoly complex is quantitatively extracted into MIBK in the range of 0.21.6N hydrochloric acid medium. After washing excess of molybdenum in the extract with hydrochloric acid (1+10), the molybdenum remained in the organic phase, which is equivalent to a specific amount of arsenic, is determined by aspirating the organic phase in an air-acetylene flame and by measuring the atomic absorption at 3133Å using MIBK saturated with water as a reference. It is necessary to repeat the washing with 10 ml of the hydrochloric acid solution at least four times in order to eliminate completely the excess of molybdenum involved in the extract. Moreover, it was confirmed, by use of radiochemical technique with ⁷⁶As, that the arsenic remained quantitatively in the MIBK phase during the washing. The sensitivity of the method could be enhanced tenfold or more when nitrous oxide-acetylene flame is used. By the two methods presented here, ppb level of arsenic in various types of water could be determined in connection with pollution.

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The degradation mechanisms of polybutylacrylate (PBA) under the various pyrolysis temperatures were studied by means of pyrolysis-gas chromatography. When the degradation of PBA is performed at the pyrolysis temperature of 530°C or below it, a little yield of monomer (butylacrylate) was observed in addition to the hydrocarbons and acrylic acid which were formed from the competitive reactions of chain scissions and elimination of butene. Observing the relationship between relative yield of products and pyrolysis temperature from PBA, it was suggested that the mechanisms of the thermal degradation of PBA vary with the pyrolysis temperature used. And also we discussed the analysis of butylacrylate-acrylonitrile copolymers by use of the relative yield of the acrylic acid and acrylonitrile.

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A method for determining 0.0020.1% of tin in light alloys (Al-base and Mg-base alloy) was investigated, and the following procedure was established.
One gram of sample was dissolved with 40 ml of 4N hydrobromic acid and 12 drops of 30% H₂O₂. The solution was filtrated through a filter paper (No. 5A). The filter paper was then washed thoroughly with 4N hydrobromic acid, and the solution was diluted with 4N hydrobromic acid to 100.0 ml. A 0.510 ml portion of the solution was transferred to a 50 ml separating funnel, and tin was extracted into ethylether from the 4N HBr medium. The ether layer was transferred into 100 ml beaker, and evaporated gently. The residue was dissolved with 2 N hydrobromic acid and transferred into a separating funnel. To the solution, 1.5 ml of 0.5% Rhodamine B solution and 5 ml of benzene were added, and the whole was shaken for 1 minute. The fluorescence intensity of the benzene solution was then measured.
These procedures took 45 minutes, and 0.0020.1% of tin in light alloys (Al-base and Mg-base alloy) could be determined.

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Zirconium formed a red-violet complex with Methylxylenol Blue (MXB) in weakly sulfuric acid solution. This complex showed an absorption maximum at 575 nm, and the absorbance was constant over the acidity range from 0.180.28N (sulfuric acid). The calibration curve was linear for 560 μg of zirconium in 25 ml solution. The molar absorptivity was about 14, 000.
The analytical procedure was as follows. A sample solution containing 560 μg zirconium was mixed with suitable amounts of 1N sulfuric acid and 1.0 ml of 0.1% MXB, and made up to 25 ml with water (the final acidity 0.180.28N). It was then heated in a water bath of 55 ± 2°C for 3 minutes. After 5 minutes, the absorbance of the colored solution was measured at 570 nm against the reagent blank. Many ions did not interfere, but bismuth, hafnium, thorium, iron (III) and fluoride interfered even when their amounts were one fold of zirconium. The permissible amounts of iron (III) was increased by addition of thioglycollic acid.

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[in Japanese]

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