In a series of quantitative determinations of drugs by atomic absorption spectrometry, indirect determination of p-aminobenzoic acid (PABA) was attempted. Previously, the authors reported on the formation of 2 : 1 PABA-metal complexes with various metals. The complexes are not extractable with organic solvents, but copper PABA complex is extracted with MIBK in the presence of bathophenanthroline. Therefore, PABA is determined indirectly by measuring copper in the MIBK extract by atomic absorption spectrometry.
Measurement of copper was carried out with a Hitachi model 207 atomic absorption spectrophotometer by using air and acetylene flame at the wavelength of 3247 Å (Cu). To PABA methanol solution was added cupric chloride methanol solution and the mixture was warmed on a water bath until methanol was evaporated to dryness. After being cooled, the residue was washed with ethyl acetate twice in order to remove an excess of copper. Then the residue was extracted with bathophenanthroline MIBK solution, and the copper in MIBK phase was measured by an atomic absorption spectrophotometer. The calibration curve obtained was linear in the range of (13.737.0) μg/ml and the recovery was 100.6%. The species extracted with MIBK was confirmed by means of paper partition chromatography to be composed of three components, Cu (II), PABA and bathophenanthroline as a ternary complex.

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The coprecipitation has generally been studied to eliminate impurities from the precipitates and also investigated by PFHS (precipitation from homogeneous solution) method. In the present investigation the coprecipitation of zinc with copper 8-hydroxyquinolate having dimorphism has been studied from a stand point of crystal transformation.
To a mixed solution of copper and zinc was added 8-acetoxyquinoline solution at pH 9 and the solution was stirred at 25°C. After various time intervals the precipitates formed were analyzed chemically and examined by the electron microscopy and the X-ray diffraction methods.
The logarithmic distribution law held through the precipitation process and the distribution coefficient obtained was 0.025. The precipitates initially formed were composed of needle crystals of copper 8-hydroxy-quinolate belonged to the tetragonal system and were associated with a small amount of zinc. When zinc 8-hydroxyquinolate whose crystal system was monoclinic began to be formed, the needle crystals started to dissolve and transformed to plate crystals belonged to the monoclinic system. The transformed copper 8-hydroxyquinolate deposited at the same time with zinc 8-hydroxyquinolate and they formed a solid solution.
When zinc 8-hydroxyquinolate was precipitated by the PFHS method in the presence of needle crystals of copper 8-hydroxyquinolate, the concentration of copper in the solution increased temporarily and then a solid solution of copper and zinc 8-hydroxyquinolates belonged to the monoclinic system was produced.
The transformation of the needle crystals of copper 8-hydroxyquinolate (unstable form) to the plate crystals (stable form) was promoted by the deposition of zinc 8-hydroxyquinolate.

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A Yanagimoto Polarovision PE-20 (Randles type, single sweeping type) equipped with a 20-inch cathode ray tube was employed. A usual polarographic cell was used as an electrolytic cell. Mercury pool was used as the anode and the peak potentials (E_p) were corrected against a saturated calomel electrode. Characteristics of the dropping mercury electrode were: m=3.92 mg/drop, natural dropping interval: 5.3 s. Measurements were made at room temperature {in the range of (2030)°C, average temperature coefficient for the peak current of aluminum-rubeanic acid complex was less than 1 %}.
A sample solution in a 50-ml measuring flask contained the following reagents : 10 ml of 1 M KCl solution as the supporting electrolyte, 10 ml of ethanol, 0.5 ml of 0.05% PAA (Acrylamide-polymer) as the maximum suppressor, and (10^-410^-3) mol/l of rubeanic acid and aluminum. The peak current (i_p) was measured by the dial indicator reading when the measurement dial on the apparatus was turned to adjust the moving horizontal bright line.
At pH 3.04.0, the peak height with a peak potential of about -0.70 V vs. S.C.E. was linearly proportional to the concentration of aluminum, and also depended upon the concentration ratio of aluminum to rubeanic acid. Results obtained under various experimental conditions showed that the determination of aluminum by oscillographic polarography with linear-sweep is very promising.

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Rapid and non-destructive 14 MeV neutron activation method for the determination of silicon in high alloyed steels was studied using barium as an internal standard.
The radioactive nuclides produced were measured by a Ge(Li) detector. For the determination of silicon, the γ-ray of 1.78 MeV of ²⁸Al which is the product of the ²⁸Si(n, p) reaction was measured, and for the internal standard, that of 0.662 MeV of ^137mBa produced by the ¹³⁸Ba(n, 2n) reaction was measured. An interference by the γ-ray of 1.81 MeV of ⁵⁶Mn which is the product of iron and/or cobalt as matrices in high alloyed steels by the ⁵⁶Fe(n, p) and ⁵⁹Co(n, α) reactions was removed by high resolution γ-ray spectrometry and an advanced total peak area method for data processing of experimental results.
The adaptability of ^137mBa as an internal standard for ²⁸Al was ensured with experiments of purposely fluctuated 14 MeV neutron flux.
The calculated results of the above experiments were satisfied within the errors of less than 1%.
The deviation of the present results from the usual analytical results were less than ±5%, and the reproducibility was of the same order as the statistical errors of radioactivity measurements.

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Mercury, arsenic, antimony and tin thionates were separated on a filter paper by the electrophoretic separation when glycine zone and 8-hydroxy quinoline (oxine) zone were used as precipitate reagents. A Toyo filter paper No. 50 (3 × 15 cm) was marked at 3 cm(SL), 3.5 cm(A), 5 cm(B), 6 cm(C), 7 cm(D), 9 cm(E) and 13 cm(F), respectively, from anode side. Three moles of glycine in 0.05M sodium hydroxide solution (pH 8.0) was applied between (A) and (B). One per cent ethanol solution of oxine was applied between (C) and (D). Three moles of glycine in water (pH 6.2) was applied between (E) and (F) and then dried at room temperature. One milli liter of 1M sodium sulfide solution contains 5 mg of each metal ions.
Electrolyte vessels (100 ml) were filled with 0.1 M ammonium acetate solution. The sample solution (1 micro liter) was spotted on a point(SL). Then, d.c. potential of 300 V/15 cm, current (715) mA/3 cm (width) was applied to the filter paper for 20 minutes. The paper was dried in an oven at 80°C for few minutes. The metal ions were separated on the filter paper as a black spot of mercury in glycine zone (pH 8.0), yellow green spot of tin in oxine zone, orange spot of antimony and yellow spot of arsenic in glycine zone (pH 6.2).

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Since the authors' publications on the tables and figures for elucidation of ¹³C NMR spectra, a number of papers concerning ¹³C NMR have been reported, and more elaborate graphic representation of chemical shifts covering both the data already processed by us and subsequently accumulated informations is needed. Here we present more detailed charts for methyl carbon chemical shifts.
As ¹³C NMR chemical shifts are greatly influenced by neighboring atoms, it is found better that the methyls are firstly classified in terms of substituents at α pasition and then each of the α substituents is subdivided into β and γ substituent.
The relationship between methyl carbon chemical shifts and the sorts of α substituents is schematically shown. The shifts range from -5 to 65 ppm (from TMS) except halogen containing compounds. In case where α substituents are sp³ carbons, methyls which are attached to methylene resonate at higher field than those attached to the methine or quaternary carbon. There is a tendency that electronegativeα substituent lowers the resonance field of methyl carbons.
When α substituents are -CH₂-, -CH- and -C-, there are tendencies that the effects of β substituent of sp³ carbons are reversed to that of α.
The γ substituent effects are shown in a figure.
In case of olefins as α substituents the methyls resonate at 8 to 28 ppm. The resonance field of cis and trans isomers are never overlapped, and this figure must be valuable for assignment of these kinds of spectra.
Methylamines range from 26 to 48 ppm and the relationship between chemical shifts and substituent species is nearly similar to the case where α substituents are -CH₂-, -CH- and -C-
Data of methoxyl compounds are listed.

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The ¹³C chemical shifts of carbonyl carbons are greatly influenced by neighbouring functional groups and the resonance signals appear at the low-field range in all sorts of organic compounds. Previously, the authors reported the graphic representation of the chemical shifts of carbonyl compounds in the 2nd paper in this series. More detailed charts of carbonyl carbons in esters, carboxylic acids and amides are presented here.
The chemical shifts (from TMS) for carbonyl carbons in esters, carboxylic acids and amides lie in the ranges, 163 to 179 ppm, 161 to 186 ppm and 151 to 180 ppm respectively, but the values for some triazol derivatives are found at higher field, 140 ppm region (Figs. 3 to 5).
In methyl esters of benzoic acids, the chemical shifts of carbonyl carbons for compounds with the electron-withdrawing substituents resonate at the higher field with respect to the shift of benzoic acid, while the electron-donating substituents result in the lower field shift (Fig. 3). The same tendency in chemical shift is observed for the α-substituted compounds in uracils (Fig. 5).
In α, β-unsaturated carboxylic acids, in which halogen atoms are bonded to the α-carbon, the resonances for the carbonyl carbons are gradually shifted to higher field in the order of I, Br and Cl (Fig. 4), while the order is reversed for acid halides in which the halogen atoms are bonded directly to the carbonyl carbon.
The carbonyl carbons of cis-isomers in esters and carboxylic acids resonate at higher field than that of trans-isomer by (1.5, 5) ppm, and it is considered to be due to the effect of steric compression between the oxygen atom of the carbonyl group and the substituents.

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A rapid and simple method for the determination of total-sulfur in igneous rocks has been developed by combining combustion method with ultraviolet photometric method. Sulfur trioxide formed by igniting samples with vanadium pentoxide at 1000°C in a current of nitrogen is reduced to sulfur dioxide by copper wire heated at 950°C. After sulfur dioxide is absorbed in sodium tetrachloromercurate(II) solution, the absorbancy of this solution is directly measured in the ultraviolet region without any procedures for color development.
Only small amount of powdered samples from 0.1 to 0.3 g in weight is used in this method. Each sample is placed in the porcelain combustion boat and then mixed with 1 g of vanadium pentoxide. Ten milliliters of sodium tetrachloromercurate(II) solution of 5×10^-4 M are added into each of two receivers and diluted to 30 ml. Then the boat is carefully introduced into the hot zone of a combustion tube of silica glass heated at 1000°C. The mixture is ignited in a slow current of nitrogen for 40 minutes. Sulfur dioxide is absorbed in this solution as disulfitomercurate(II). After 40 minutes' ignition both receivers are disconnected and each of the contents is diluted to 50 ml with redistilled water respectively. The absorbancy of each solution is measured at the wavelength of 228 nm against the 10^-4 M sodium tetrachloromercurate(II) solution using 10 mm silica glass cells.
The results were in good agreement with those by Tin(II)-strongphosphoric acid method reported before by the same authors. The accuracy of this method is 5% at the total sulfur content of 0.02%. The totalsulfur content of as low as 0.001% can be determined.

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Potassium ethylxanthate(KEtX) reacts with cobalt and nickel ions to form chelate compounds which are easily extracted with methylisobutylketone(MIBK). This paper describes optimum pH regions and interferences of diverse ions in the extraction of Co-EtX and Ni-EtX complexes and optimum conditions in the atomic absorption spectrophotometry.
The procedure was as follow; To sample solution containing cobalt or nickel in a 50-ml separatory funnel, add 5.0 ml of 10% ammonium acetate buffer. If necessary, adjust the pH to 8.0 with potassium hydroxide solution or acetic acid. Add 5.0 ml of 5% KEtX solution, and extract Co-EtX or Ni-EtX with 10.0 ml of MIBK by shaking for 3 minutes. Aspirate the MIBK phase into the flame.
Cr(III), Al(III) and Fe(III) interfered with the determination of cobalt at a 200-fold excess. This interference is probably caused by coprecipitation of cobalt with hydroxides of the coexisting elements at ca. pH 8.0. The optimum pH regions for the extraction were 6.511.5 for Co-EtX and 5.59.8 for Ni-EtX. No significant difference in the coefficient of variation of analytical results was observed between this method and a method using APDC as chelating agent. Nickel in human tissues was successfully determined by this method.

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Mass fragmentographic methods were described for determination of polynuclear aromatic hydrocarbons in water.
After river water was filtered through 1 μ Whatman GFC filters under added pressure {(12) kg/cm²}, it was separated into both filtered water and suspended solids. The method consisted of the following procedures. i) Polynuclear aromatic hydrocarbons in the filtered water were extracted by liquid-liquid partitions with chloroform. And polynuclear aromatic hydrocarbons in the suspended solids were extracted by cyclohexane-ethyl alcohol (4 : 1) in soxhlet extractor. ii) Elimination of interfering compounds on florisil column with benzene. iii) The concentrated benzene was fractionated on silica gel column. The first fraction contained aliphatic hydrocarbons, was eluted with isooctane. And the second contained polynuclear aromatic hydrocarbons, was done with isooctanebenzene (1 : 1). iv) Mass fragmentographic analysis (20 eV) of polynuclear aromatic hydrocarbons.
Recoveries of them in the filtered water and in the suspended solids were at least more than 80% in the amounts ranging from 50 ng to 500 ng. Samples of the Tama river water were determined with fluoranthene, pyrene, 3, 4-benzpyrene, 1, 12-benzperylene etc. The contents of them were very small ranging from several ppt to 100 ppt.

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Gas chromatographic determination was modified for 1, 1-bis-(p-chlorophenyl) ethanol (chlorfenethol), p, p'-dichlorobenzilic acid ethyl ester (chlorobenzilate) and p, p'-dichlorobenzilic acid isopropyl ester (chloropropylate) and its applicability to forensic chemistry was tested. All of these acaricides have tertiary hydroxy group, which is quickly and quantitatively esterified with trifluoroacetic anhydride (TFAA). In the gas chromatographic system with the column packed with 2% SE-30 on Celite 545 AW-DMCS, the retention time of the esters was shortened, and the peaks were more symmetric than those of the parent substances. Adequate amounts for the complete esterification of 5 mg of the acaricides were 20 to 50μl of TFAA and 10 to 500μl 111 of pyridine, and tetrahydrofuran was suitable as a reaction solvent. Anthracene was used as an internal standard, and its calibration curve showed a good linearlity in the range of weight ratio 0.22. Coefficient of variance were 3% in chlorfenethol, 3.5% in chlorobenzilate and 3.2% in chloropropylate. Miso-soup, milk, fermented milk and triturated liver, containing 50 ppm of acaricide, were prepared and after the addition of anhydrous Na₂SO₄, acaricides were extracted with acetone. Acetone was evaporated and the residual liquid were again extracted with hexane. The extracts were separated from other impurities by hexane-acetonitrile distribution and thin-layer chromatography. Recoveries were (6073)% for chlorfenethol, (7178) % for chlorobenzilate and (7380)% for chloropropylate.

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Boric acid and BF₄^- in ordinary natural waters are determined by the following procedure. Thirteen milliliters of the sample solution, 2 ml of 0.001 M methylene blue and 10 ml of dichloroethane are added to a polyethylene separatory funnel, and the mixture is shaken. The organic phase is separated from the aqueous phase and washed with silver sulfate solution. Its absorbance is measured at 660 nm for the determination of BF₄^-. Three milliliters of 1 N H₂SO₄ and 5% HF are added to the aqueous phase, and the mixture is allowed to stand for 30 min. Then, boric acid is determined by the same procedure as used for the determination of BF₄^-. The determination of boric acid and BF₄^- in a condensed water from a fumarole is as follows. After the decomposition of disturbing materials in the sample by oxidation with hydrogen peroxide, the total boron is determined by the above procedure for boric acid. Part of the sample is taken into a separating funnel, and boric acid is determined by the procedure for total boron from the aqueous phase in which the BF₄^- has been removed by extracting with methylene blue and dichloroethane. The amount of BF₄^- is the difference between the total boron and boric acid. The existence of BF₄^- in condensed water from a fumarole in Satsuma Io-zima was confirmed. However, the presence of BF₄^- in sea and river water was not confirmed within the detection limit (0.02 μg as boron) of this method.

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The sensitivity of the atomic absorption analysis of antimony in flame is so low that the method cannot be of practical use.
To increase the sensitivity, solvent extraction-atomic absorption analysis was investigated. In this method antimony iodide complex anion formed by addition of iodide solution was extracted with a solution of high molecular amine (Amberlite LA-1) in ethyl acetate, and then the organic phase obtained was used for the atomic absorption analysis.
The following procedure is recommended. A sample solution containing up to 100 μg of antimony is placed in a 100 ml separating funnel. The concentrations of potassium iodide and hydrochloric acid in the aqueous phase are adjusted to 0.25 M and 0.8 N, respectively, and the total volume is made up to 50 ml with pure water. The solution is shaken with 10 ml of 1 vol. % solution of Amberlite LA-1 in ethyl acetate for 2 min.
After standing for 10 min., the organic phase is separated from the aqueous phase.
Using the organic phase, the absorbance in the airacetylene flame is measured at 2175.8 Å.
A calibration line obtained was straight up to 100 μg of the antimony content. The standard deviation obtained from 5 runs 1.13% in the determination of 50 μg of antimony.
The presence of 1000μg of Sn (II) gives an error of about -30%, but Fe (III), Cu (II), Pb (II), Cd (II) and Zn (II) etc. do not interfere the determination.
This method has several advantages of easiness in opertion, high sensitivity and precision, but a disadvantage of this method is that high volume ratio of water phase to organic phase can not be attained because the solubility of ethyl acetate in water is large.

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Higher order complexation of beryllium with Chromazurol S at the charged micelle surface has been investigated for the improvement in operating conditions of highly sensitive spectrophotometric method using quaternary ammonium salt. Alkyl dimethyl benzylammonium, trimethyl alkylammonium and alkylpyridinium chloride were used as the quaternary ammonium salts. The insoluble ion associate forms in the lower concentration of quaternary ammonium chloride, the other hand, higher order complexation is difficult with the increase of quaternary ammonium chloride in the higher concentration region. The higher order complexation is often prevented because of the restriction of chelating group in the ligand by the micellar charge. In this case, the restriction of chelating group with micellar charge is suppressed by the existence of organic solvents such as ethanol, acetone, etc., and the formation of higher order complex is easy with the acceleration of complexation rate.The increase of counter ion by addition of potassium chloride gives the same effects as with organic solvent. The concentration region of quaternary ammonium chloride which the higher order complex forms quantitatively is extended by existence of ethanol, and also the effect of organic solvents are very useful for the spectrophotometric method using the charged micelle surface because of the decrease of foaming and the stabilization of the solution.

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In the commercial material of carbazole containing 2, 3-benzocarbazole as impurity, the absorption of anthracene could not immediately be measured for the interference of the impurity. Therefore, a method for the separation of anthracene by chromatographic technique was studied. The separation of anthracene from large amounts of carbazole and 2, 3-benzocarbazole was carried out by using a 6 φ × 100 mm column packed with alumina.
About 50 mg of the sample is dissolved in 10 ml of ο-dichlorobenzene. The sample solution is passed through the column, then the column is washed with 10 ml of ο-dichlorobenzene. About 99% of anthracene in carbazole can be recovered by this process. The effluent is diluted to 25 ml. Anthracene is determined by the difference between the absorbance at 380 nm and that of 390 nm. By this method, anthracene in carbazole can be determined down to 0.005%.

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The analysis of trace amounts (ppb order) of chloride ion is very difficult because contamination of the sample is inevitable during the analytical procedures in the atmosphere. A new instrument which consists of an ion-exchange column and a coulometric detector has been developed. With this instrument, it has become possible to complete the analysis without exposing the sample to the environmental air after sampling.
First the instrument was tested in the analysis of chloride and bromide ion in the range of 5 to several hundreds ppb. It has been found that the instrument is sensitive enough in this concentration range of Cl^- and Br^-. Next the instrument was applied to the study of chloride ion behavior during the analytical procedures. The chloride in a sample is observed to increase by a few ppb by only exposing the sample in a beaker to the atmosphere or pouring into the other beaker. When a ground glass apparatus was used in making a standard sample, heavy contamination was observed to occur. An ultrasonic washing was confirmed to be very useful for the decontamination. With this instrument the chloride ion concentration in a deionized water was measured to be 1.3 ppb, indicating that little contamination was occurred during the analytical procedures. This method, which is based on the ion-exchange concentration and the coulometric detection, is found to be very suitable for the trace analysis.

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