In the conductimetric titration of PCl₃, PCl₅, SiCl₄, BCl₃ and S₂Cl₂ with carboxylic acids (including aminopolycarboxylic acids) in N, N-dirnethylformamide (DMF), ratios of the reaction of the acids with the chlorides were found to be as follows; EDTA : sample=1:4 and 1:2, monocarboxylic acid : sample=1:1, and dicarboxylic acid : sample=1:2 and 1:1.
Inorganic acids and organic solvents gave no influence, but the presence of 10% or more of water gave indistinct end point breaks.

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Determination of inorganic sulfur compounds (H₂S, SO₂) with carboxylic acids by conductimetric titration in DMF (N, N-dimethylformamide) has been reported previously {C. Yoshimura, H. Hara, K. Tamura : This Journal, 18, 689 (1969)}.
This paper deals with the conductimetric titration of organic sulfur compounds (ethylmercaptane, thiophene, thiooxine, etc.) with carboxylic acids in nonaqueous media and its application to the determination of thiophene in benzene.
DMF solutions of sample and titrant were prepared, and from the results of titration in DMF, their reactive ratios were given as follows; thiophene:C₆H₅COOH=2 : 1 and 1: 1, and thiophenol : C₆H₅COOH=2 : 1 and 1: 1.
In the case of aminopolycarboxylic acids, various reactive ratios were obtained. Organic sulfur compounds (soluble in DMF) could be thus titrated with carboxylic acids, and thiophene in benzene was determined after an addition of a large amount, of DMF (about 10 times as much as benzene).

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Some derivatives of dithiocarbamate including Zn-di-n-butyldithiocarbamate, Zn-ethylphenyldithiocarbamate and Zn-dimethyldithiocarbamate were used as coloring reagents in spectrophotometric method for copper and satisfactory results were obtained.
After dissolution of a sample with acids, copper could be extracted into carbon tetrachloride from fairly strong acidic solution with either Zn-DNB or Zn-EPC.
Zn-DNB and Zn-EPC methods were more sensitive than diethyldithiocarbamate method and were recommended for a rapid microgram determination of copper. Zn-DMC was useful in an alkaline solution as well as diethyldithiocarbamate.

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A method for the determination of boron in the. air is described. About 1000 l of air is passed at a rate of 23 l/min through a series of four collecting glass tubes chilled in a dry ice-methanol bath (Fig. 1). Borosilicate glass should be avoided and quartz is preferable. The boron collected in each tube is dissolved with 10 ml of water, and to it are added 1.5 ml of curcumin reagent solution (0.05 g curcumin in 70 g of phenol and 20 ml of glacial acetic acid) and 2 or 3 drops of saturated oxalic acid solution. The solution is then evaporated in a platinum dish on a water bath until the odor of phenol disappears. The residue is dissolved in 10 ml of ethanol and the absorbance is measured at 548 mμ.
The amount of boron in the atmosphere determined by this method is (n±0.2)×10^-4 μg/l.

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Studies on the application of M ssbauer spectrometry to the non-destructive analysis of chemical state of tin in Cu-Sn alloy are described. The effect of variables such as width of γ-ray energy, source-sample-detector geometry and concentration of tin on the spectral parameters was studied. M ssbauer spectrum was taken on several Cu-Sn alloys at room temperature. Their chemical states were analyzed also by spectrophotometry using 8-quinolinol after decomposition of the sample with HCl+H₂O₂ or Br₂+ CH₃OH. From the isomer shift and quadrupole splitting, tin in the Cu-Sn alloy examined was found to be present as a mixture of metallic tin and tin oxide (IV).

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A method is given for overcoming some of the difficulties in determination of micro amounts (below 100 ppm) of water in organic liquids by Karl Fischer procedure.
By enhancing the reaction of water with pyridinesulfur dioxide and by using dead-stop method as indication, the end point of titration can be decided with precision as follow.
From 10 to 30 ml of sample liquid is added to 25 ml of methanol containing 8% of pyridine-sulfur dioxide solution (SO₂ 320g/l C₅H₅N), and it is titrated with Karl Fischer reagent of titer 0.10.5 mg H₂O/ml in an ordinary titration cell.
The method permits the determination of 2×10^-5% (0.2μg/ml) of water in N, N-dimethylformamide, ethyl acetate and other organic liquids by a rapid and simple procedure.

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Behavior of Fe-Eriochrome Cyanine R (ECR) and Al-ECR complexes in an aqueous solution of cetyltrimethylammonium chloride (CTMAC) of a concentration less than cmc (critical micelle concentration) was examined in detail. The ECR complexes of iron and aluminum reacted sensitively with 1.5×10^-5 M of CTMAC, whereby a shift of absorption maximum to longer wavelengths, an increase of absorbance and an increase of molar ratio of the ligand were observed. The assumed compositions of the complexes were [Fe(ECR)₃(CTMAC)₃] and [Al(ECR)₃-(CTMAC)₃].
On the other hand, Fe-CAS complexes and Al-CAS complex precipitated with CTMAC of a concentration less than cmc. The precipitate was solubilized by a micelle solution of a non-ionic surfactant, polyoxyethylenesorbitane lauryl ester, and showed an absorption similar to that in the micelle solution of CTMAC.

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A combination of square wave polarography with anodic stripping polarography was applied to the simultaneous determination of Zn²⁺, Cd²⁺, Pb²⁺ and Cu²⁺. When those ions were electrolyzed in 0.4M KCl-0.3M HCl solution for 4 min. at -1.2V vs. Hg pool, the metals were electrodeposited on a stationary mercury drop electrode.
An anodic dissolution curve was recorded by a square wave polarograph from -1.2 to - 0.1 V. Instrument parameters were : square wave voltage 10 mV, amp. sens. 1/10 and record. sens. 0.04 μA/mm, or square wave voltage 5 mV, amp. sens. 1/50 and recod. sens. 0.04 μA/mm. The peak height was linear with concentration over the range 0.010.1 ppm for Zn, Pb and Cu, and 0.0010.01 ppm for Cd.
Furthermore, 0.11 ppb of Cd was determined under the square wave voltage of 20 mV with amp. sens. 1/5 and record. sens. 0.04 μA/mm after 10 min. electrodeposition at -1.0V vs. Hg pool.
The proposed method was applied to the determination of Zn, Cd, Pb and Cu in mine water. The effects of diverse anions also studied.

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A sensitive method for the extraction of ammonia in sea water has been developed by using Chloramine T and thymol which are superior in stability and easiness of handling. The procedure established is as follows.
Adjust the pH of 100 ml of a sample solution to 4.1 with 0.45M H₃PO₄ (Fig. 1). Add 3 ml of 2.5% Chloramine T solution (Fig. 2) and shake vigorously. After allowing to stand for 4080 sec. (Fig. 3), add 420 mg of thymol in 15 ml of acetone. Adjust the pH of the solution in 2 min. to 11.4 with 2M NaOH (Fig. 4) and mix well. Stand for 2 hr. at room temperature (1525°C), and then add 10 ml of 5M NaOH and 10 ml of n-hexylalcohol. Extract the produced indophenol by shaking for 20 sec. Centrifuge the extract after an addition of 5 g of K₂CO₃ and measure the absorbance at 675 mμ by using a 1-cm cell. In the case of a much higher concentration of ammonia, it is also possible to determine it by measuring the absorbance of the solution at 670 mμ without extraction. Nitrogen-containing compounds which are supposed to be in sea water do not interfere. The sensitivity of the method is the highest among those ever reported.

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Fluorescence of isonicotinic acid hydrazones of a number of carbonyl compounds {2-hydroxy-1-naphthaldehyde (2HNA) salicylaldehyde, 2-hydroxy-m-tolualdehyde, 3-hydroxy-p-tolualdehyde, 4-hydroxy-m-tolualdehyde, 3-chloro-2-hydroxybenzaldehyde, 5-chloro-2-hydroxybenzaldehyde and 2-hydroxyacetophenone} was examined. They exhibited yellowish green fluorescence in an alkaline medium similar to that of their parent carbonyls but 2HNA gave violet fluorescence. Isonicotinic acid hydrazones in an acetate buffer solution gave yellowish green fluorescence in the presence of aluminum but Al complexes of parent carbonyl exhibited only feeble fluorescence. The fluorescence of the hydrazone of 2HNA in the presence of Al was particularly strong, and 2HNA was found to be a good reagent for the fluorometric analysis of isonicotinic acid hydrazide (INAH).
A new method for the fluorometric determination of INAH is as follows : To a 5 ml of INAH sample solution are added 1 ml of 0.08% 2HNA in ethanol and 0.5 ml of 0.05N HCl. After 1 hour, to the solution are added 4 ml of DMF, 0.5 ml of 1% kalium alum and 1 ml of an acetate buffer solution (pH 4.3), and the mixture are warmed for 30 minutes at 4042°C. Its fluorescence intensity is measured using a primary filter with excitation near by 413420 mμ and secondary filter passing near by 495 mμ.
It was not interfered from hydrazine and p-aminosalicylic acid, and applicable to fluorometric determination of 0.11.0 μg per ml of INAH.

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Silica gel and alumina have a strong adsorption effect and are utilized widely in analytical chemistry and industrial chemistry.
The authors synthesized silica-alumina as an alternative of silica gel, and studied of its adsorption effect dependence upon its surface characteristics and heat treatment by comparing adsorption of Na⁺, specific surface area and its acidity. The adsorption quantity of sodium ions was proportional to its specific surface area and the acidity of its surface.
The greatest value of the specific surface area changed from the lower temperature to the higher temperature as the amount of aluminum increased. Silica-alumina (1.44%Al) showed the strongest acidity.
The silica-alumina produced was divided into three groups : (1) 01.09%Al, (2) 1.091.91%Al, and (3) 1.914.27%Al, from the standpoint of quantity of adsorption of sodium ions, acidity of its surface and specific surface area. According to temperature, the silica-alumina was then further divided into four additional groups; (1) 150350°C, (2) 400450°C, (3) 500°C, and (4) 550600°C.
It has been made clear that the silica-alumina with 2.70%Al, ignited to 500°C has larger surface area than silica gel and the other silica alumina and was superior adsorbent.

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Bi (III) formed a complex with 3, 4, 5, 6-tetrachloro 3', 4', 5', 6'-tetrahydroxyfluoran methyl ester (Cl·gall·CH₃) in the presence of polyvinyl alcohol (PVA) at pH 1.2. The colour of the complex disappeared by the addition of potassium persulfate. To the solution containing 017 μg of Bi (III) were added 1.0 ml of 1.0% PVA and saturated potassium persulfate and 1.5 ml of 1.0×10^-3M Cl·gall·CH₃ and the solution was made up to 10.0 ml and to pH 1.2 with 1.5% nitric acid and water. It was allowed to stand at 35°C for 60 min. The absorbance at 380 mμ, and 495 mμ were measured against water, and were compared with that of the solution prepared by carrying through the same procedure with an exception of Bi(III).

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Atomic absorption method for n-butyl scopolamine bromide (I) and n-butyl scopolamine tannate (III) in urine, blood and faeces was examined, and a method for their micro analysis was established. It was based on the formation of water-insoluble and solventsoluble cobalt (II) thiocyanate complex from aqueous solution of I and III, and atomic absorption spectroscopic determination of cobalt in the organic extract.
The assay method was as follows. To a biological sample were added 57 ml of cobalt (II) thiocyanate solution, prepared by dissolving 20 g of potassium thiocyanate and 5 g of cobalt nitrate in 100 ml of water, and 510 ml of 20% tartaric acid solution. After extracting the resulting complex with four 20 ml portions of chloroform, the combined extract was evaporated to dryness under reduced pressure. The residue was taken up and made to volume with methyl-iso-butyl ketone, and filtered through the Toyo filterpaper No. 2, if necessary. The atomic absorption was measured by using 2407 Å of cobalt. Standard solution in each case was prepared in the same way.
The minimum detecting limits of I and III were, respectively, 6 μg/ml and 10 μg/ml in urine, 75 μg/ ml and 150 μg/ml in blood and 4 μg/mg and 14 μg/ mg in faeces.
The complex of I was found to have the formula [Co(SCN)₄] (I)₂.

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A method has been developed for the spectrophotometric determination of microgram amounts of zinc, in which the preliminary extraction of zinc (II) from an aqueous solution into chloroform is done with 2- (salicylideneamino) thiophenol (SATP) in the presence of pyridine.
Zinc (II) reacts with SATP to form a complex, which can be extracted quantitatively into chloroform in a pH region between 7.5 and 10.7 in the presence of pyridine. The complex extracted is stable and has an absorption maximum at 415 mμ. Beer's law is obeyed over the range from 0 to 55 μg of zinc. The molar absorptivity at 415 mμ is 10, 700 and the sensitivity for log (I₀/I) = 0.001 is 6.1×10^-3 μg Zn/cm².Several ions including cadmium (II), copper (II), cobalt (II), iron (III), nickel (II) and titanium (IV) interfered with the determination. The molar ratio of zinc to SATP in the extracted complex has been confirmed to be 1:1.

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The variation of diffusion current in the digital polarography decreases with 1/√n where n is the number of mercury drops at dropping mercury electrode. The variation of diffusion current in 10^-3F solution of cadmium is 0.0005 as the coefficient of variation for the sum of the diffusion current of each drop from the first to the thirtieth drop, and also the same for the sum of the diffusion current from the tenth to the fifteenth drop with constant depletion effect.
The plot of log i vs. log t on the current-voltage curve of the first drop is linear, but those of the second and subsequent drops are not linear because of the depletion effect which is greatest at an early stage of the drop life. The degree of the depletion effect is dependent on the outside diameter of capillary tip.

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Thin-layer chromatography on polyamide (Nylon 6) was applied to the separation of estrone, estradiol and estriol, by using twenty-three kinds of single solvent and three kinds of binary solvent mixture.
The R_f values of estrogens with a few exceptions depended on hydrogen-bonding parameter (γ values) and solubility parameter (δ values) of the single solvent used. The R_f values became larger with increasing γ values in solvent systems with their values above 5. Solvent systems with both γ and δ values above 10 caused desorption and the thin-layer of polyamide hardly showed separation ability.
For better resolution of estrogens, the suitable developing solvent systems would be protophilic solvents with γ values above 5 or aprotic polar solvents with γ values below 5. A mixture of these or the aprotic polar solvents with an addition of a small amount of protic solvent with δ value above 10 would be also useful.

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Periodate oxidizes Mn (II) to permanganate and is detected by the color of permanganate. This reaction is not specific, since bromate also shows a similar reaction. Comparison of the oxidizing power of chlorate, perchlorate, bromate, iodate, periodate, peroxodisulfate, dichromate, permanganate, cerium (IV) sulfate and vanadate indicated that the oxidation of manganese (IV) oxide to permanganate was specifc for periodate. A small amount of fine powder of manganese dioxide was taken into a small test tube and a drop of sample solution was added with a drop of 6N nitric acid. By heating the solution, periodate gave pale red coloration. The detection limit was 20 μg with critical concentration 1 : 2500.

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Zinc dibenzyldithiocarbamate was used for a rapid determination of copper with spectrophotometric method.
A simplified analytical procedure is as follows. After dissolution of the sample with an acid, it is diluted with water to an appropriate concentration (0.54N in case of nitric acid, 111N in sulfuric acid and 110N in hydrochloric acid) and 10 ml of 0.03% Zn-dibenzyldithiocarbamate in carbon tetrachloride is added. After shaking for 3 minutes, the absorbance of the organic phase at 438 mμ is measured against the reagent blank.
This method was more sensitive than diethyldithiocarbamate method and was applied to the determination of microgram quantities of copper in high purity metals. The zinc salt as the reagent could be replaced also by sodium or potassium salt.

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The color reaction of uranium (VI) with phenol was applied to the detection of uranium (VI). A drop of the sample solution as added on a drop of phenol solution on a porcelain plate. Uranium gave brown to pale yellow color depending on its amount. Iron (III), cerium (IV) and molybdenum (VI) gave similar coloration, but the color by iron and cerium dissappeared by reducing them to Fe (II) and Ce (III). Phenol is thus useful as a reagent for uranium (VI) which is more specific than thiocyanate, ferrocyanide, oxine and Rhodamine B.

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A concentration cell was applied as a novel sensor to the continuous determination of sulfur dioxide by the authors (this journal, 20, 828, 1971).
Further improvements of the sensor were proposed to raise its sensitivity as follows. Fluctuation of the voltage reducing the sensitivity in the potentiometry had been caused by the pulse flow of the iodine solution applied by a pump into the sensor. The modified sensor succeeded in giving a constant flow of the solution as shown in Fig. 1, in which the flow rate could be regulated by the liquid height in the reservoir or the permeability of the glass membrane.
The shape of the sensor was modified to improve the efficiency of the reaction of sulfur dioxide with iodine. The type III sensor was the most preferable. The optimum position of the working electrode was also given.
By using the sensor type III, sulfur dioxide could be determined (the lower limit 0.07 ppm) under the following conditions; concentration of iodine solution, 0.3×10^-8M (the generating current, 0.05 mA, the flow rate of generating medium, 0.6 ml/min); the drop rate of iodine solution from the sensor, 0.4 ml/ min; the flow rate of a sample gas, 500 ml /min.

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A drop (ca. 0.05 ml) of test solution involving ammonia-nitrogen was taken in a small test tube. To it were added with thorough mixing a drop of hypochlorite-carbonate buffer (Dissolve 5 g of NaHCO₃ and 8 g of Na₂CO₃ in 500 ml of water. Then add 100 ml of NaClO with available chlorine 0.3% and dilute to 1 l) and a drop of thymol solution (Dissolve 5 g of thymol in acetone to make 50 ml and add equal volume of 0.7M NaOH solution). It was immersed in a hot water bath (90°C or higher) for 30 sec. to develop blue color of iodothymol. The detection limit was 0.005 μg as N.
Alternatively, The test tube was removed from the water bath, and 2 drops of isobutanol was added with vigorous shaking. After standing, the blue color was transferred into the butanol layer. The detection limit was 0.0025 μg as N.
The reagent blank should be referred to.

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A colorimetric method for the determination of homatropine has been developed by means of solvent extraction, In the recommended procedure for preparing calibration curve, 210 ml of a standard homatropine solution (2.0×10^-5M) is taken in a separatory funnel, and 5 ml of borate (0.1M) -phosphate (0.3M) buffer (pH 8.5) and 2 ml of a tetrabromophenolphthalein ethyl ester (TBPE) ethanol solution (4×10^-3M) are added. It is diluted to 25 ml with water, and shaken with 10 ml of 1, 2-dichloroethane for 2 min. The extract is filtered through a dried filter paper to remove droplets of water. The absorbance is measured at 570 mμ against a reagent blank.
The colored species was assumed to be [homatropine]·[H(TBPE)] (red-violet) and [quaternary ammonium ion]⁺·[TBPE]^- (blue).

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The microdetermination of halogen (except fluorine) in organic compound was carried out by Micro-Carius' method using a silver boat in place of silver nitrate.
Chlorine and bromine in standard samples were determined satisfactorily but lower results were obtained for iodine. The authors found that the result was affected by the amount of silver and the excess of silver caused the negative error. Good results were obtained by using about 40 mg of silver boat.
The weighing is easier than in ordinary method and the errors in weighing magnetized or adhesive sample may be minimized.

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The brownish precipitate in Nessler's reaction was used for the gravimetric determination of ammonium ion in an aqueous solution. The composition of the precipitate is NHg₂I, and the gravimetric factor of nitrogen is very small (0.02584).
The recommended procedure are followings; The two-fold equivalent amount of Nessler's reagent (HgI₄^2- : 2×10^-2F, OH^- : 4×10^-1F ) is added slowly to 25 ml of sample solution. It is allowed to stand for at least ten hours at room temperature and then warmed for three hours on steam bath. The digested precipitate is filtered through a fine-pored glass filter (average pore size : 1 μ), washed by deionized water and dried at 150°C in air.
Ammonium ion ranging from 2 to 4 mg as nitrogen in 25 ml of ammonium chloride solution was determined within error of 2.1% and standard deviation of 6.8%. Negative errors were observed for the lower contents of the ion, and also significant positive errors for the higher contents.
The recognized interfering substances are comlexing agents such as potassium cyanide, potassium thiocyanide, ethylenediamine and pyridine, and reducing agents such as hydroxylamine hydrochloride and hydrazine hydrochloride.

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