Determination of phosphorus and sulfur in river- and sea-sediments by X-ray fluorescent analysis was examined. Since the intensities of X-ray fluorescence of light elements are very much affected by the nature of matrix, correction had to be made. The correction was made by assuming that the ratio of the intensities of the light element in two kinds of matrix should be proportional to the ratio of the intensities of the internal standard element (scandium, in the present work) in the same two kinds of matrix, i.e., I_F(i)/I_F(m)=K·I_Sc(i)/I_Sc(m), where IF(i) and I_Sc(i) are the intensities of phosphorus or sulfur and of scandium in the i th matrix, I_F(m) and I_Sc(m) are those in a standard matrix, and K is a constant dependent on the kind of the light element and the instrumental geometry. The value of K was determined by measuring the intensities of the light elements and the internal standard element in various synthetic matrices (the synthetic samples contained 500 μg of the element and 20 μg of scandium per gram).
The standard matrix was made of silica and boric acid (6 : 4 in mass fraction), and the calibration curves of phosphorus and sulfur were constructed with the standard matrix. Three grams of dried sediment powdered in a mixer-mill were mixed with 2 g of scandium oxide-boric acid powder contained 50 μg scandium per gram.
The intensity of the K line of scandium was measured in the sample, and I_F(i) in the sample was also determined. The latter was converted to I_F(m) by using these values and the above mentioned equation, and the contents of phosphorus or sulfur were determined from the calibration curve.
The recoveries in this method were 109.099.6% for phosphorus and 108.291.2% for sulfur, respectively. The lower limit of determination for both elements was 10 μg per gram. The present method is more rapid and more accurate than any other conventional ones, such as colorimetric and volumetric method. The time required for determination of phosphorus and sulfur was about 20 minutes per sample in contrast with 24 hours usually required by other methods.

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In most of papers relating to the making of the glass wall coated open tubular (WCOT) columns, the pretreatment process, which means the inner surface modification of the glass capillary by various corrosive reagents, was regarded as indispensable to achieve the uniform stationary phase coating. We aimed in this paper to dispense with this complicated pretreatment process and produced glass WCOT columns which have no modification on their inner surfaces to investigate the column characteristics.
For the preparation of glass WCOT columns, glass capillaries (0.7 mm outside diameter, 0.25 mm inside diameter, 20 m long) were produced by using a commercially available glass drawing machine, and they were coated with different stationary phases by the dynamic coating method by the use of a newly constructed coating apparatus. The coating apparatus was so constructed that the flow in the glass capillary could be switched without any pressure change by the one-touch action from the gas to the stationary phase solution and vice versa, and that the fluctuation of the flow rate of the stationary phase solution in the capillary was minimized by the two auxiliary capillary attached before and after of the main. For searching the optimum coating conditions, the relationship between the coating flow rate and the column efficiency, and the relationship between the coating flow rate and the partition ratio k were studied by using 0.3 ml of a 10% (w/v) OV-17/n-hexane solution. The suitable coating flow rate was found to be in the range 5 to 8 cm/sec, and the average film thickness coated on the capillary inner wall was confirmed to be proportional to the coating flow rate. From these results, glass WCOT columns having no modification on inner surface were produced, and attached to the newly constructed all-glass capillary column holder, then examined by gas chromatography. The maximum number of theoretical plates determined at 250°C for cholestane was 2300/m. To examine the temperature stability and lifetime, these columns were used continuously for 840 hrs under the condition of the 250°C column temperature, and the minimum HETP values before and after that were compared. Only 30% change could be found out between them. These results show that the glass WCOT columns having no modification on inner surface is promising for the practical use.
For the application, various samples mainly related to biochemical substances such as sterols in soybean, a mixture of cholesterol and cholestanol, amino acids, a mixture of steroids, etc. were analysed with the glass WCOT columns coated with OV-17 (phenyl methyl silicone), OV-101 (dimethyl silicone), Poly I-110 (polyimide). Campesterol and stigmasterol, cholesterol and cholestanol, which were very difficult to resolve completely with a conventional packed column, were separated with these glass WCOT columns by 3.6 and 2.0 of peak resolution R respectively. Good results were obtained for other substances with these glass WCOT columns.

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A sensitive and rapid method for the determination of microamounts of copper in iron and steel by atomic absorption spectrophotometry was investigated.
A sample less than 0.1 g is dissolved by heating in a mixture of hydrochloric, nitric and sulfuric acids, and the resulting solution is evaporated to dryness on a hot plate. The residue is dissolved in 25 ml of 1.5 N sulfuric acid, and the solution is shaken with 5 ml of methyl isobutyl ketone solution(0.05%) of zinc dibenzyldithiocarbamate. The organic extract is introduced into an air-acetylene flame and the atomic absorption readings are taken at 3248 Å.
The proposed method is applied to the determination of copper 0.00020.1% in iron and steel. The accuracy of the method determined by the use of the B.C.S. or J.S.I.S. standards was satisfactory for practical purposes. No appreciable interference was caused by other impurities likely to be present in iron and steel. The sensitivity of the present method was 0.00323 μg/ml/1%.

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Metal ions whose sulfides develop color were separated from each other by paper chromatography using a solution of ammonium sulfide (commercial reagent, JIS first class grade chemical) as a developing solvent.
Antimony, tin and arsenic ions migrated with the solvent as their thionates, whereas other ions remained at the original point as their sulfides. Therefore ions of antimony, tin and arsenic were separated from other metal ions by a solution of ammonium sulfide (colorless).
It is rather difficult to separate tin from antimony by paper chromatography. However the separation was completed by using a mixed solution of ammonium polysulfide and pyridine, regardless of their oxidation numbers.
The sample solution contains 5 mg of each metal ion in 1 ml of 6 N HCl.
One microliter of the sample solution was spotted with a capillary tube 1 cm apart from the end of filter paper (Toyo Roshi, No. 50).
The paper was developed up to 5 cm by the ascending technique for 30 minutes. The volume ratio of ammonium polysulfide to pyridine was 2 : 3. The paper was dried at room temperature, and then the spots of antimony and tin appeared as their sulfides. The R_f values of antimony(III, V) and tin(II, IV) are 0.28 and 0.94.
Arsenic can be separated from tin by the same procedure as antimony separated from tin. The R_f values of arsenic(V), arsenic(III) and tin(II, IV) are 0.12, 0.36 and 0.94, respectively.
When a small amount of 2, 4, 6-collidine was added in the solvent, antimony can be separated from arsenic. The sample solution contains 2 mg of antimony(III, V) with tin(II, IV) and 5 mg of arsenic(III, V) as each metal ion in 1 ml of 6 N HCl.
The paper was developed up to 7 cm by the ascending technique for 60 minutes. The solvent used was ammonium polysulfide, pyridine and 2, 4, 6-collidine in a 35 : 55 : 10 volume ratios. The spot of antimony was in contact with that of arsenic(III) but can be distinguished by their color of sulfides.
Consequently, a mixed solution of ammonium polysulfide and pyridine was effective for the paper chromatographic separation of antimony, tin and arsenic ions.

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Since a mist of sulfuric acid reacts with heated sodium chloride producing hydrogen chloride whereas sulfur dioxide does not virtually, the process was used for the differential determination of a mixture of them. The sample mixture was allowed to react with sodium chloride at about 500°C, and the resulting product was introduced into a 1% solution of hyrdogen peroxide. Both hydrochloric and sulfuric acids thus produced were determined alkalimetrically and argentometrically.
In order to produce the definite amount of a mist of sulfuric acid, the following method was recommendable. An aliquot of a standard solution of potassium hydrogen sulfate was taken in a platinum boat, and was evaporated to dryness. Then the boat was placed in a silica tube heated at about 300°C, and the temperature of the tube was raised gradually up to 800°C. Pure nitrogen was used as the carrier gas of the mist. As a source of sulfur dioxide, a standardized gas mixture of the dioxide and nitrogen were preferable, and were also utilized as the carrier gas of the mist.
The absorbent of sulfuric acid mist was preliminarily investigated in conjunction with the usefulness of potassium hydrogen sulfate as the standard for the production of the mist (Table I). An aqueous solution of 80% isopropanol which was sometimes preferred as the absorbent of the mist was not recommendable. As Fig. 1 shows, a combination of the aqueous solution of 1% hydrogen peroxide with the electrostatic precipitator was most satisfactory for the complete absorption of the mist. About 3φ60% of the mist was deposited on the inner surface of the "cap" in Fig. 1. No effective absorption of the mist could be expected by any solution used.
The reactions both sulfuric acid mist and sulfur dioxide with heated sodium chloride were next investigated. Ninety per cent of the mist and 3.3% of the dioxide were converted to hydrogen chloride by the reaction at 500°C (Table II). These values were used to correct the results of the titrations. It was considerable to be the reason for the lower results from the mist that sodium hydrogen sulfate was produced and was not decomposed completely at the reaction temperature. The conversion ratio of the dioxide was negligible if the dioxide content was small. The mixtures of the mist and the dioxide were analyzed by this method with satisfactory results (Table III).
This method was applied to analyze the mist and the dioxide in the flue gases produced at an ore-sintering furnace and a water boiler furnace by using the apparatus illustrated in Fig. 2, and the results obtained were shown in Table IV.

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The usefulness of glassy carbon as a refractory material for atomization device in flameless atomic absorption spectrometry was described.
The glassy carbon strip(0.7 mm in thickness, 45 mm in length and 2.5 mm in width) clamped to the upper ends of the two stainless-steel electrodes was electrically heated by connecting to the leads from a step-down transformer (Fig. 1). It was covered with a demountable Pyrex glass chamber (inner volume, ca. 350 ml). The chamber was purged by a stream of argon or argon-hydrogen gas before atomization.
In order to get high sensitivity and the information about the atom population in narrow space above the glassy carbon strip, the incident light beam from the radiation source was narrowed by passing through a stainless-steel slit(1.0 mm × 1.0 mm). The effects of the chemical composition of samples and additives were studied.
The observed atomic absorption of lead(nitrate) and copper(chloride, nitrate and sulfate) between 5.0 and 6.5 mm above the strip was only about 30% of that observed just above the strip.
The effect of anions on the atomic absorption of copper was investigated at various temperatures using copper chloride, nitrate and sulfate. Copper chloride showed a lower copper absorption when compared with the nitrate and sulfate. This fact, which was not observed in atomic absorption with flame, suggests that the volatility of the compounds might be associated with the efficiency of atomization by the glassy carbon atomizer.
The effect of coexisting salts on the copper absorption was studied using aluminum chloride and sodium chloride. The depression effect on the copper absorption was observed at low temperatures for sodium chloride, but no noticeable effect was observed at higher temperatures. Aluminum chloride had little effect on copper absorption of the chloride, nitrate and sulfate.The difference between sodium chloride and aluminum chloride might result from the different thermal stability of these two salts. As for aluminum chloride, the copper salts could be converted to chloride easily before vaporization by reacting with aluminum chloride.
Strontium was also tested to obtain further information on glassy carbon strip. The absorption became less and lasted for a longer time, and the recorded curve became broader, the fact suggesting that glassy carbon had very little reducing power against strontium. In fact, the addition of hydrogen sharpened the curve. The use of hydrogen would be promising for flameless atomic absorption with glassy carbon mainly because of its reducing ability.

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The relationship between absorption intensity of resonant γ-ray of europium-151 (21.6 keV) in europium-151 and amount of europium oxide were investigated aiming at establishing the quantitative analysis by Mossbauer spectrometry.
In order to improve the precision of the resonant absorption intensity data, it was tried to reduce the back ground activity consisting of resonant γ-ray and induced fluorescent X-ray through the use of a thin acrylate resin filter in front of a NaI(Tl) detector, and a very favorable result was obtained.
The resonant absorption intensity was found to be saturated even at 95.5 mg/cm² in thickness of europium, or at 0.35 mm in optical γ-ray path of europium oxide.
In order to avoid this inconvenience, an attempt was made to dilute europium oxide with chemically stable compounds. However, elements having high mass absorption coefficients to the 21.6 keV γ-ray, such as rare earth elements, suppressed a resonant absorption intensity seriously. Energy analysis of transmitted γ-ray from an absorber using a high-resolution Si(Li) detector and a 200 channel pulse height analyser elucidated that the resonant γ-ray was attenuated by the K-shell electron of diluents.
Fluorescent X-rays of coexisting elements in the absorber prevailed over resonant γ-ray when yttrium oxide was used as a diluent.
It was proved that the resonant absorption intensity decreased markedly with increasing mass absorption coefficients of the diluents.
Under the condition that europium was diluted with compounds having low mass coefficient absorption, such as LiF, a proportinal relationship was obtained between amounts of europium and the peak intensity in the range from several to 30 (mg-Eu/cm²).
Further, the authors proposed a correction technique for the saturated region by adopting the reduced intensity (A_corr) which was obtained by extrapolating the experimental intensity(A) to the intensity of an ideal absorber with a zero mass absorption coefficient.
In our case A_corr is expressed as A/k, where k= 10^{(-0.24±0.04)μ} and μ is a mass absorption coefficient.

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A distillation-coulometric titration method for the determination of traces of chlorine in sodium, uranium and their compounds has been developed. Sodium sample (0.5-1 g) is decomposed with steam under reduced pressure or with moist carbon dioxide. After the decomposition of the sample, the solution is neutralized with nitric acid and acidified by adding 0.1 0.2 ml of concentrated nitric acid. The vessel containing the sample solution is connected with a distillation apparatus, as shown in Fig. 1, and heated at 230°C for 30 minutes. During the distillation, the chloride separated from the solution is carried with a stream of nitrogen to the trapping vessel containing 10 ml of ethanol. When the separation of chloride by the distillation is complete, 0.05 ml of 1.5 N sodium hydroxide is added to the ethanol, and the chloride is titrated coulometrically with electrogenerated silver ions. A blank is run throughout the entire procedure except the sample decomposition step.
As shown in Fig. 5 (b), 40 μg of chlorine added to the sample is recovered satisfactorily by the distillation at 230°C for 30 minutes. The distillation behavior of chloride in the presence of uranium is shown in Fig. 5 (c). The distillation rate of chloride is affected by the amount of uranium and the chloride added cannot be recovered completely. However, the chloride in uranium is collected if the distillation at 350°C for 10 minutes is repeated three times as shown in Table II. The proposed analytical method has been applied to the determination of chlorine in reagent- and reactor-grade sodium, uranium and their compounds, and typical results are given in Tables III, V and VI. Detection limits of the proposed method are 0.5 and 1 ppm chlorine in 2 g of sodium and 1 g of uranium, respectively.

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Several carboxylic acids produced in the biodegradation process of n-butyl alcohol by activated sludge were determined by liquid chromatography using a flow coulometric detector.
The eluate from a strong acid type-cation exchanger with an aqueous solution of 5% methylcellosolve was mixed with a solution consisting of 10^-2 M p-quinone, 10^-3 M hydroquinone and 10^-1 M potassium chloride, and the resulting solution was introduced to a carbon-cross anode. A mixed solution of 0.5 M potassium iodide, 0.2 g/l sodium sulfite and 10^-3% v/v Triton X-100 was introduced to an Ag-AgI cathode. The hydrogen ion yielded by the ionization of a carboxylic acid was reacted with p-quinone at the constant voltage of +0.45 V vs. Ag-AgI and the coulomb in the reduction to hydroquinone was measured for the determination of the carboxylic acid.
The sample solution was filtered with millipore filter No. GSWP-4700(pore size, 0.22 micron) and the filtrate was bubbled with nitrogen gas after removal of bicarbonate ion by addition of hydrochloric acid, because the chromatogram of the bicarbonate ion shows the same elution time with n-butyric acid.
When oxygen was dissolved sufficiently in the activated sludge, the carboxylic acid was not found in the biodegradation process. When an inhibitor had been added under the conditions described above, acetic and n-butyric acids were found by addition of 2 μg/ml cupric ion as shown in Fig. 5B. When 250 μg/ml formaldehyde had been added, n-butyric acid was found after one hour as shown in Fig. 5C and formic acid after three hours as shown in Fig. 5C. Under the conditions of great lack of the dissolved oxygen, acetic and n-butyric acids were found as shown in Fig. 5D. In the absence of air, acetic, n-propionic and n-butyric acids were found after three days from the addition of 1000 μg/ml n-butyl alcohol as shown in Fig. 5E. They seemed to be derived from autolysis of the activated sludge.

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The method for the determination of total mercury levels in organic materials by means of combustion and use of gold trap has been improved. Mercury in organic materials can be analyzed by both oxygen combustion method and air combustion method. In the oxygen combustion method, samples are burned in the stream of oxygen followed by complete combustion in the high temperature zone heated in the range from 800 to 900°C (Fig. 1). In the air combustion method, combustion is completed at 850°C in the combustion tube which is packed with copper oxide wire through which air flows as shown in Fig. 2. In both methods, oxides of nitrogen and oxides of sulfur formed during the combustion are removed by absorbing them into the layer of alkali metal carbonate. Mercury vapor generated by the combustion is led to the gold trap where mercury is trapped forming amalgam. On heating the gold trap, mercury vapor is released and determined by a mercury vapor analyzer.
The gold trap is prepared by impregnating HAuCl₄ into porous support, followed by thermal decomposition of HAuCl₄ forming thin layer of gold on the surface of the support. Results of repeated test for trap and release of mercury by this gold trap show good reproducibility. Within the scope of this study, no oxidation of mercury during the combustion is observed. Capability of present methods are demonstrated by analyzing for mercury in fish or other biological materials, and good agreement of results with wet digestion method is obtained. The optimal sample amount in oxygen combustion method and air combustion method are 100300 mg and 100200mg of fresh fish, 1040 mg and 1030 mg of hairs, about 500 mg and 300 mg of white of egg, and about 200 mg and 150 mg of cereals respectively. However, upper limit of sample amount in the oxygen combustion method can be increased by increasing the flow rate of oxygen. In case of samples containing mineral acids or relatively large amounts of sulfur compounds, acidic gases which flow past the alkali carbonate layer condense at the inside wall of the condenser causing interference in the measurement of mercury. This interference is removed by heating the sample covered with thin film of lime. The time required for combustion and measurement is within about 5 minutes.

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The simultaneous determination of fluoride and chloride in calcium halophosphate phosphors was studied by a direct potentiometry by using fluoride and chloride ion-selective electrodes.
In order to isolate the halide components from a phosphor, it was dissolved and steam distilled in the presence of phosphoric acid. The phosphor sample could be easily dissolved during the distillation. Test solutions for potential measurements were prepared from the distillates by adjusting the pH and ionic strength to appropriate values.
Two different buffer solutions were tested to minimize the errors in the measurements of the electrode potential. One was a modified constant ionic strength buffer solution prescribed by Elving {Anal. Chem., 28, 1179 (1958)}, the other was a modified TISAB based on Frant's prescription {Anal. Chem., 40, 1169 (1968)}. The results showed that the latter was better than the former in the electrode response and reproducibility of the electrode potentials. The linearity of the calibration curve for the fluoride ion was affected by the conditioning of the ion-selective electrode. The procedure established is as follows: A 300 mg sample of calcium halophosphate is put into a distillation flask and a small amount of water is added to disperse the sample. Then 30 ml of phosphoric acid is added. After assemblage of the apparatus, the halides are steam distilled at 145150°C. The distillate is stored in a graduated cylinder, in which about 10 ml of water is placed beforehand. The 150 ml of the distillate obtained is transferred into a 200 ml volumetric flask, and 40 ml of modified TISAB (97 g of sodium nitrate, 17 g of glacial acetic acid, 116 g of sodium acetate and 0.3 g of sodium citrate/1 liter) is added and diluted to 200 ml, the pH and ionic strength are adjusted to 5 and 0.4, respectively.
The test solution is stirred magnetically with a rotating teflon encapsulated bar. The fluoride and chloride electrode potentials, vs. a silver-silver chloride reference electrode with a saturated potassium nitrate salt bridge, are measured simultaneously after 15 minutes by using an electrode switch. Both fluoride and chloride can be determined by the ordinary calibration curve method. Approximately 100 minutes were required to determine the halides by the above mentioned procedure. Average recoveries for the synthetic fluoride and chloride samples were 100.0% and 100.3%, respectively. The relative standard deviations were 2% at the 3% fluoride level and 1.2% at the 0.3% chloride level in the phosphor samples.

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A simple, sensitive and selective spectrophotometric method for the determination of zinc with 1-(2-pyridylazo)-2-naphthol, PAN, and surfactant was established. The sensitivity was found to be 0.0011 μg zinc/cm² for the absorbance of 0.001 (molar extinction coefficient, 5.6×10⁴) at 555 nm, which was superior to that of the dithizone or the zincon method currently used for the analysis of zinc in water.
Zinc reacts with PAN in an alkaline medium to form a water-insoluble and red-colored complex, which can be solubilized into water by a non-ionic surfactant such as Triton X-100. The absorbance of the solubilized complex is constant at pH 8.09.5. The calibration curve obeys Beer's law over the concentration range from 0 to 100 μg zinc/50 ml. The following ions interfere significantly with the determination of Zn; Mn(II), Fe(II, III), Co(II), Cu(II), Cd(II) and Ni(II). The interferences from Mn(II) and Fe(III) are eliminated in the presence of sodium citrate and sodium metaphosphate as masking agents and the other metals except Ni are effectively masked by the addition of N-(dithiocarboxy)-glycine prior to the color development. Though Ni(II) remains unmasked under the conditions described above, it is possible to correct the absorbance due to Ni-PAN complex by the use of EDTA. Adding EDTA, the Zn-PAN complex was rapidly and quantitatively decomposed, while that of nickel remains unchanged. The difference of the absorbance before and after adding EDTA is due to the Zn-PAN complex.
Thus the recommended procedure is as follows; (I). Transfer test solution containing less than 100 μg of zinc to a 50 ml volumetric flask. Add 1 ml of 5% sodium citrate solution, 1 ml of 5% sodium metaphosphate solution and about 10 mg of ammonium persulfate successively. Adjust the pH to 8.5 with an ammonium buffer solution, then add 2 ml of 20% Triton X-100 solution. Then, add about 50 mg of N-(dithiocarboxy)-glycine and finally 2 ml of 0.1 % alcoholic PAN solution. Dilute to the mark with water and shake the solution vigorously. (II). Add 5 ml of 0.05M EDTA solution to another solution treated as the above procedure (I) through the addition of PAN and dilute to the mark. Measure the absorbance of the solution (I) at 555 nm against the solution (II).

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Vanadium(V) is selectively extracted with 1-butanol according to the reaction: HVO₃+2BuOH, _org_??_ HVO₃(BuOH)₂, _org and the maximum extractability was obtained in the pH range of 3 to 4. The analytical procedure is as follows :
Take a sample solution containing 020μg of vanadium(V) in a separatory funnel. Adjust the pH of the solution to 3 with 1 ml of 0.01 N nitric acid and dilute to 10 ml with water. Add 10.0 ml of 5 M 1-butanol in benzene and shake the mixture for 5 minutes. Discard the aqueous phase, add 10.0 ml of the back extracting solution containing the phosphate buffer(pH 6.4) and 4-(2-pyridylazo)resorcinol (PAR) to the organic phase. Shake the mixture for 5 minutes and measure the absorbance of the aqueous phase at 545 nm against water.
The calibration curve was linear over the concentration range of 020μg vanadium(V)/10 ml and the Sandell sensitivity was 0.0020 μg · cm^-2.
The effect of diverse ions was also investigated (Table I). Although cobalt(II) slightly interfered with the determination, no interference by other ions except tungsten(VI) was observed within a 5% error. From the above investigation, the present method was found to be effective in separating vanadium(V) from chromium (VI ).
Since the color development and the back extraction are performed simultaneously, the present method has some advantages over the previous ones. The analytical procedure was simplified and the absorbance of the reagent blank due to an excess PAR was reduced. In addition, the selectivity was much improved by introducing an extraction technique.
The method was applied to the determination of trace vanadium in rocks. The analytical results for JG-1 (granodiorite) and JB-1 (basalt) agreed well with those reported previously (Table II).

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Trace amounts of cadmium were determined by direct flameless atomic absorption spectroscopy using a carbon tube atomizer. A sample solution of 20 μl was placed in the cavity of the carbon tube atomizer. The solution was dried for 10 seconds at 1.0 V (about 170°C), ashed for 15 seconds at 1.5V (about 330°C), atomized for 5 seconds at 4.0V (about 1400°C). The absorption signal of cadmium was appeared at 228.8 nm. The cadmium concentration was calculated directly from the calibration curve obtained by a peak height method. Argon gas, at a flow rate of 2.0 l/min, is continuously flushed through the carbon tube during heating in order to prevent the oxidation of the carbon tube and to carry out hot residual gases.
Interferences from matrices such as acids, metals, anions, and salts on the absorbance of cadmium were studied. Depressing effects were found from the concentration more than 0.6 M hydrochloric acid, 0.4 M nitric acid, 0.1 M sulfuric acid and perchloric acid, and 0.05 M phosphoric acid. Interferences were also found in the presence of more than 100-fold metals. The absorbance of cadmium was decreased to 79% and 76% by the addition of a 100-fold lithium and strontium, about 90% by the addition of a 1000-fold molybdenum, palladium, platinum, and zirconium, and 83%, 90%, and 84% by the addition of a 5000-fold iron, manganese, and nickel, respectively. Interference from anions was not so serious. No interference was caused by the addition of 5000-fold fluoride, chloride, bromide, iodide, carbonate, nitrate, and thiocyanate ions added as their ammonium salts.
In some cases, the alkali halides and sulfates gave enhancing effects on the cadmium absorbance. These effects were probably owing to the molecular absorption and light scattering of the salts. The background absorption could be corrected by measuring the absorbance of a cadmium non-resonance line at 226.5 nm and by subtracting the absorbance at 226.5 nm from that at 228.8 nm, because many common salts showed an almost identical absorbance at both wavelengths. However, in the presence of the salts of high concentrations, the background absorption could not be corrected by this technique.
The proposed method was applied to the direct determination of trace amounts of cadmium in industrial waste water and river water. Results obtained by the proposed method gave a good agreement with those obtained by a flame atomic absorption method combined with APDC-MIBK extraction. The coefficients of variation were from 2.0 to 4.0%. The limit of detection was 6.0×10^-13 g when the signal to noise ratio was 2.

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Many methods of detection of gallium, indium and thallium which belong to the IIIA group are interfered by the presence of elements of other groups. Hydroxyhydroquinone reacts with gallium, indium and thallium to produce a sensitive coloration, and color was not developed by other cations. Zirconium, hafnium, thorium and uranium develope a similar color, which is much weaker than that produced by gallium, indium or thallium, and the limit of detection of zirconium etc. is about 20100 times that of gallium etc. Filter paper is impregnated with a 1% alcoholic solution of hydroxyhydroquinone. A drop of the test solution is placed on the dried paper. The color and the limits of detection are as follows: Gallium, blue, 0.2 μg: indium, red, 0.2 μg: thallium, brown, 0.1μg: zirconium, red-violet, 4.5μg: hafnium red-violet, 9 μg; thorium, blue-violet, 11 μg: uranium, yellow-brown, 12 μg. Gallium, indium and thallium can be detected and differentiated from the others by the difference of their coloration.

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A method for the determination of total fluorine in aqueous fluoroborate solution without distillation of fluorine was investigated. In order to decompose fluoborate complex to fluoride ion several methods were tested. Fluoroborate was not fully hydrolyzed on heating on a water bath even in an alkaline solution, and did not decompose completely with only evaporation to dryness. Complete decomposition was accomplished by fusing a residue after evaporation to dryness.
Analytical method for total fluorine was established as follows: A 1 ml of sample solution containing 120 ppm fluorine was taken into a nickel crucible and 1 ml of 5% NaOH solution was added. The liquid was evaporated to dryness and then the residue was fused for a few minutes on a burner. After cooling 10 ml of an ionic strength adjustment buffer solution was added. The fluoride concentration was then measured by a fluoride sensitive electrode.
The method was rapid and simple, and was applicable to the total fluorine analysis of waste water in plating industry.

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[in Japanese]

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