The solubility of 2, 4-dinitrophenylhydrazine (abbrev. as 2, 4-DNPH) in water-ethanol mixed solvent increases by the addition of mineral acids. At the condition of the concentration of 0.81 M phosphoric acid (supporting electrolyte), 30 vol% ethanol and 0.03 wt% gelatin (maximum suppressor), the two step-reduction potential wave, which is incompletely separated, appears in the direct current polarography of 2, 4-DNPH, and these two waves are supposed to be due to the two NO₂ groups. At the dropping mercury electrode E_1/2 of the first wave is-0.330 V and E_1/2 of the second wave is-0.580 V (vs. Hg pool). By the treatment of two-step wave as one (i. e. total wave), E_1/2 is-0.465 V vs. Hg pool at the dropping mercury electrode. In this case applies the linear relation between the square root of mercury reservoire hight and the limiting current value. Accordingly, the diffusion is the rate determining step of this electrode reaction at least at E_1/2=-0.465 V, the Ilkovic equation holds, and consequently the total wave hight is proportional to the concentration of 2, 4-DNPH. The calibration curve of 2, 4-DNPH concentration and total wave hight, at the condition mentioned above, is a straight line passing through the origin. The limiting current is very stable and unaltered during a measurement. In the condition of the concentration of 15.14×10^-4M 2, 4-DNPH, 0.81 M phosphoric acid, 30% ethanol, less than 9.90×10^-4M aldehyde, reaction temperature 0°C and reaction time larger than 120 min, a reducing value of the reduction wave-hight reaches the maximum value and is proportional to an amount of aldehyde in a sample. Accordingly, the quantitative analysis of aldehyde is possible based on this reducing value of reduction wave hight in the condition to maintain the constant concentrations of phosphoric acid and of ethanol during all experiments.
In ordinary direct method, a sample escape causes frequently an error in the analysis of volatile materials such as acrolein, acetaldehyde and formaldehyde. But in the present method, a sample is poured into the reagent solution containing a definite amount of 2, 4-DNPH, which is previousry prepared, and the reaction is completed by shaking the mixture occasionally during 120 min in a water-ice bath. By this procedure, the concern about a sample-escape is unnecessary and from the reducing value in polarogram of the 2, 4-DNPH, drawn under the condition mentioned above, the aldehyde at such a low concentration as 0.709.90×10^-4M can be determined in good precision.
In the condition mentioned above, the gradients of calibration curve of acrolein, acetaldehyde and formaldehyde are quite the same and 1.33×10⁴μA/M. So that when a sample containing more than two sorts of those aldehydes is analysed, it is unable to determine them separately, but able to obtain the total molar concentration of aldehydes.
In the concentration range of total aldehyde, each of which is different in mixing ratio, from 0.95×10^-4M to 7.66 × 10^-4M a quantitative analysis can be done precisely. At the concentration 6.48 × 10^-4M of aldehyde, the relative standard deviation calculated by five our analyses is 0.005%.

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In the studies of the mixed packing gas chromatography, the author had already pointed out that there was a possibility of the identification of an unknown peak appeared in chromatogram by means of the linear relation which held between the retention indices of solute and the composition of the mixed stationary phase. Then, in order to prove this, in this paper, an identification method using a usual column or a multi-channel column which was especially designed in this study was examined.
Silicone rubber SE 52 (SE) was used as a low polar stationary liquid, polyethylene glycol 20 M (PEG) as a high polar liquid, and acid-washed Chromosorb W as a support, and the column packings were prepared by mixing SE-coated support and PEG-coated support in an arbitrary weight proportion. The multi-channel column, the name of which is originated from the existence of several and separated channels in a column, was deviced by combining three tubes (2 mm × 1 m) packed with mixed packings of different composition in parallel, so that it was possible to inject the sample into these channels simultaneously, as shown in Fig. 1. All of the columns were operated at 120°C and the retention times (t_R) or the retention indices (I_R) of various solutes were determined.
If the multi-channel column in which the carrier gas flow rate of each channel was previously adjusted so that the retention time of n-paraffins coincides with each other was used, it enables us to obtain three peaks from a polar solute. The plot of the logarithm of corrected t_R of these peaks vs. the composition (x) of the stationary phase of the channel corresponded to a peak gave a similar relation between I_R and x obtained on usual columns, and it was easy to obtain the gradient (G) and the intercept (I) of a straight line from these results.
Although G was approximately classified according to the type of compound, it had a tendency to decrease with the molecular size in homologous series. However, it became clear that the product of G and I was fixed to a certain value according to the molecular type regardless of molecular size and that then this value was useful for the peak identification. According to its function, this product was termed a “compound index” for qualitative analysis.
From the fact that the boiling point of peak component was estimated with error of about 10 degrees from I on the mixed phase of SE and polar liquid or I_R on SE column and that still I was related to the molecular size, it was recognized that I is one of the useful information concerning the peak identification.
These methods were applied to identify the impurities contained in a standard reagent, and even the retention behavior of a very small peak (0.03% or less) could be followed and this component could be identified easily.

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In order to separate 68 components of the saturated hydrocarbons from C₅ to C₈ contained in petroleum naphtha by means of capillary gas chromatography with mixed stationary liquid, the retention behavior of these components on several single stationary liquids was investigated.
Squalane (SQ), di-n-butyl maleate (DBM), dipropylene glycol (DPG), or mixtures of SQ and DBM was used as the stationary liquid. Each of the stationary liquids was coated on the inner wall of the capillary tubing (0.25 mm ×90 m) by the following procedure: a weighed amount of the stationary liquid was dissolved in ethyl ether or methyl alcohol to prepare 1015% solution, and this solution was injected into the capillary tubing by an aid of high pressure nitrogen gas. After the tubing was completely filled with the solution, the solvent and the excessive stationary liquid were purged out by a stream of nitrogen gas. Retention data of various components on these columns were measured at 30°C.
In each single stationary liquid, it was observed that there were some components which overlapped with each other. As the linear relationship held between the retention indices (I_R) of a component and the composition (weight fraction of liquid, X) of the mixed. phase SQ/DBM in the same manner as reported previously, separation of many components could be presumed by the use of this relation. From the diagram presuming the separation on SQ/DBM mixed phase, it was found that there is a possibility of separation of nearly all the components on the mixed phase of DBM concentration near 0.95 weight fraction. As a result of measurements of the retention time with this mixed phase, 53 components of the hydrocarbons were successfully separated as shown in Fig. 1.
The measured retention index (I_R) of a component was compared with its ideal retention index (I_P) which was calculated from the vapour pressures of n-paraffins and that of component. It was recognized from this comparison that, in the case of iso-paraffins, the difference (ΔI) between I_R and I_P is positive or negative while in the case of cycloparaffins, ΔI is usually positive, and that the magnitudes of ΔI are classified by the carbon skelton of hydrocarbons. If the polarity of both of the stationary liquid and the solute is low, the effect of enthalpy on the deviation from Roult's law can be ignored and consequently, the effect of entropy which is dependent on the molecular size of the solute and of the stationary liquid mainly dominates the deviation. As a result of the consideration of the relationship between ΔI and the molecular size, it was clarified that ΔI varies inversely as the ratio of the molecular volume of the component to that of n-paraffin whose carbon number is identical with that of the component. Using this relationship, the value of I_R of the component could be estimated. The standard deviation of the difference between the estimated I_R and the measured I_R was smaller than 5 index unit.

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After drying, the river-and sea-sediment was ground to a powder, and mold into a briquet form specimen. The specimen was followed by X-ray analysis of elements in it. As the fluorescent intensity of analyte was affected by the variation of matrix, so, we adopted the technique of Andermann, which is due to the utilization of compensation method using the value of a ratio of K_α or L_α ray intensity of analyte to scattered background intensity at empirically selected wavelength.
On the selection of the scattered wavelength to be used as internal standard, the calibration curve of a good straight line on the concentration of copper in a range of 0500 ppm was obtained by compensating the 1.530Å of the scattered wavelength for CuK_α line (1.543Å). In the case of ZnK_α line (1.438 Å), the calibration curve of zinc in a range of 0700 ppm was obtained by compensating the 1.410Å of the scattered wavelength. But, PbL_β line (1.177 Å) interfered with the detection of AsK_α line (1.176 Å). So, we determined the intensity AsK_α line by subtracting the intensity of PbL_β line (we can know it by converting the intensity of PbL_β line) from that of overlapped PbL_β-AsK_α line. Using the calibration curve of copper, zinc, lead, arsenic and chromium prepared with the model samples, these elements in the sediment have been measured.
On the repeated analysis of copper, zinc and lead in the sediment, the average(x) and the standard deviation(s) by this method and atomic absorption method were compared. This method obtained x=345 ppm, s=5.25 ppm on copper, x= 1952 ppm, s=83.2 ppm on zinc and x=417 ppm, s= 7.05 ppm on lead, while by atomic absorption method x=346 ppm, s= 10.95 ppm on copper, x=1997 ppm, s=50.7 ppm on zinc and x=416 ppm, s= 8.05 ppm on lead were obtained.
As the treatment of the sediment was very simple, so the analysed specimen maintained almost original properties, and the error induced by the treatment was diminished significantly.
On the whole, more rapid analyses and more accurate results were obtained by this method than any other conventional ones such as chemical or spectroscopic analysis.
This method can be applied also to the analysis of many solid or powder form samples other than the sediment.

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When the following potentiometric titrations using a glass electrode of pH-meter as an end point indicator were carried out in the presence of polar organic solvent in the aqueous solution, steep changes of apparent pH on the scale reading of ordinary pH-meter ( : glass electrode potential) of the solution were found near the equivalence points of the titration.
(1) Argentometry of thiocyanate, ferricyanide and cyanide.
(2) Precipitimetry of ferrocyanide, phosphate, secondary phosphate, sulfate, chromate and iodate using a titrant of lead nitrate solution.
(3) Precipitimetry of various heavy metal ions, for example, silver ion, cadmium ion, nickel ion and zinc ion using a titrant of sodium sulfide solution.
(4) Direct titration of a few weak Bronsted acids (pK_a) more than 9 such as ammonium ion, methylammonium ion using a titrant of sodium hydroxide. Therefore, the end point can be detected graphically and a pH indicator electrode is available to indicate the end point in such titrimetry.
The pH of the titration medium is of importance. End points precisely reproduce at the equivalence point over the limited range of pH. For example, the argentometry of ferricyanide could be achieved by the addition of about 10^-3M sodium hydroxide solution into the solution to be tested to elevate its pH to about 8.59.0.
Many titration curves were drawn under various conditions to find suitable procedure for this purpose.
The recommended conditions, for example, in the precipitimetry using a titrant of lead nitrate were as follows : the optimum amount of acetonitrile in 30 ml total volume should be 3070% for K₄Fe (CN)₆, 3070 for Na₃PO₄, 4080 for Na₂SO₄, 4060 K₂CrO₄, 3040 for Na₂HPO₄, 5080 for KIO₃, the minimum detectable concentration by this method was about 2 × 10^-3M for all cases.
The most suitable organic solvent for obtaining a sharp end point is acetone in (1) (3) (4) titrations and acetonitrile in (2). Other polar organic solvents belong to protophilic or water-like amphiprotic solvents such as dioxane or ethanol could be used for this purpose.
In this potentiometric precipitation titrations, the more insoluble a precipitate, the more complete is the reaction at the equivalence point and the larger in the change in concentration of the reacting ions. It is to be desired that the K_sp of the precipitate M⁺A^-is 10^-10 or less.
In spite of the large number of ammonium determinations being performed at the present time, there is still no simple direct titration procedure available to analytical chemist. But the above stated end point determination is applied to not only various precipitimetry but also direct titration of ammonium compounds.
The quantitative graphimetric end point determination by using a commercial pH-meter in mixed solvents is simple, accurate and practical. Therefore, the method will be especially appreciated in routine analytical laboratories where many daily samples must be quickly analyzed.

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This paper describes a new analytical method for polynuclear hydrocarbons in coal tar. This method consists of the following procedures; i) extraction of polynuclear hydrocarbons in coal tar by liquid-liquid partitions, ii) separation of polynuclear hydrocarbons into each component by two-dimensional dual band thin-layer chromatography, and iii) spectrofluorometrical analysis of each component.
Polynuclear hydrocarbons in coal tar were extracted by a series of liquid-liquid partitions of cyclohexane containing coaltar-dimethyl sulfoxide(DMSO), (DMSO +20 vol% HCl; 1 : 1, v/v)-cyclohexane, cyclohexane-water, cyclohexane-5% NaOH, and cyclohexane-water. The residual water in the final cyclohexane solution was removed by adding small amounts of sodium sulfate. anhydride. The cyclohexane solution was then evaporated to dryness in a reduced pressure and at low temperature (ca. 40°C) with the help of a rotary evaporator. The residue was dissolved in a small volume of benzene. A part of the benzene solution was applied onto the aluminum oxide G layer of the thin-layer chromatoplate which had been composed of two adsorbent layers of aluminum oxide G and 26% acetylated cellulose. The first development was carried out on aluminum oxide G layer with n-hexane-ethyl ether (19 : 1, v/v) in a chamber kept at about 20% in relative humidity. The second development was carried out on the acetylated cellulose layer with methyl alcohol-ethyl ether-water (4 :4 : 1, v/v). The polynuclear hydrocarbons thus separated were detected on the acetylated cellulose layer as small fluorescent spots under ultraviolet rays (365 and 253 mμ). Each spot on the thin-layer was scraped off into a small centrifuge-tube, and polynuclear hydrocarbon in it was extracted with benzene by centrifugation. Polynuclear hydrocarbon in the benzene extract was analysed by spectrofluorometry.
We applied this method to the analysis of the coal tar which had been used as a raw material for the production of fire-brick. The extract by the liquid-liquid partition was separated into 93 fluorescent spots by the thin-layer chromatography. Of these spots, 24 polynuclear hydrocarbons including benzo(e)pyrene and perylene were identified spectrofluorometrically. The identified hydrocarbons included 10 active or suspected carcinogens such as benzo(a)pyrene, dibenzo(a, h)pyrene and dibenzo(a, i)pyrene. The contents of 13 polynuclear hydrocarbons in the coal tar were also determined. The content of benzo(a) pyrene was 7400 ppm, that of dibenzo(a, h)pyrene 120 ppm, and that of dibenzo(a, i)pyrene 270 ppm.

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An automatic instrument for organic oxygen determination has been constructed by combining a portable nondispersive infrared analyzer with an automatic operation mechanism of CHN analyzer. A sample was instantaneously pyrolyzed in a quartz decomposition tube, and the decomposition gas was passed with carrier gas (helium) through a hot zone of platinized carbon granules. The resultant carbon monoxide was slowly withdrawn during 5.5 min into a stainless steel pump having a reproducible capacity of 150 ml, and the gas was then homogenized in the pump for 1 min. The pump pushed out the gas into the infrared analyzer, which measured the CO concentration as the output signal on an attached recorder. All the flow paths were then scavenged by pure helium for 1 min before starting the next analysis. One cycle of the automatic operation required 13 min.
The concentration in the pump is independent of the pressure and temperature; this fact renders the interpretation of the output signal quite simple. On the other hand, the change of the temperature difference between the pump and the infrared detector caused fluctuation of the sensitivity of the apparatus because the gas expanded or contracted on entering into the detector; for example, with a sample containing 800 μg of oxygen, 1°C change of the temperature difference caused an error of 4 μg in oxygen content. This error could be reduced by isolating the detector unit from the infrared analyzer and installing it together with the pump in a single oven; but still it was found that the temperature variation of the detector produced an error of 20 μg/°C, probably due to the change of radiation efficiency of the light source and to the vibration of the membrane in the detector. Calculation demonstrates that the temperature of the oven containing the pump and the detector unit should be controlled within a limit of ± 0.1°C or less.
A series of analysis of a numbers of standard samples with different chemical constitutions was carried out, and the estimate of standard deviation of oxygen content was 0.18%, which was thought to be acceptable for microanalysis.

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In the fast neutron activation analysis, the fluctuation of analytical conditions, especially that of neutron flux, is inevitable and this fluctuation of neutron flux results in lower analytical precision. In order to eliminate this disadvantage, the activation analysis using an internal standard was investigated for the determination of silicon.
The determination of silicon by fast neutron activation analysis depends on the ²⁸Si (n, p) ²⁸Al(T_1/2 = 2.3 min; 1.78 MeV) reaction. In this work the use of barium as the internal standard has been investigated. Because the half life of the ^137mBa originated by the reaction ¹³⁷Ba (n, n')^137mBa (T_1/2 = 2.6 min; 0.662 MeV) is nearly equal to that of ²⁸Al and the γ-ray energy of ^137mBa differs sufficiently from that of ²⁸Al, the activity of ²⁸Al is easily normallized by refering to that of the internal standard.
A polyethylene capsule containing the sample and the internal standard (barium as acetate) was irradiated for one minute. After cooling for one minute, activities of ²⁸Al and ^137mBa were measured for 50 seconds with a well type NaI (Tl) scintillation detector connected to an 800 channel pulse height analyzer. Then the activity (area of photopeak) of each peak was calculated by the Covell's method from the γ-ray spectrum and the ratio of the activity of ²⁸Al to that of ^137mBa was determined.
For the preparation of calibration curve, various amounts of standard silicon dioxide, ranging from 9 to 350 mg of silicon were weighed and mixed with graphite powder. In order to keep the geometrical condition in the neutron bombardment and in the measurement of γ-ray constant from sample to sample, each sample was pressed into a pellet (13.0 mm in diameter and 7.5 mm in thickness). This pellet was introduced in the polyethylene capsule and was sealed with a polyethylene cover containing barium as the internal standard. Each capsule was irradiated and measured under the fixed experimental conditions and then the ratio of the activity of ²⁸Al to that of ^137mBa was plotted against the weight of silicon. A straight line was obtained with a coefficient of variation less than 3% for 9 to 350 mg silicon.
Barium as the internal standard served satisfactorily under varying experimental conditions e.g., the neutron flux and the counting time. This method is found to be very effective to improve precision of the activation analysis.
The internal standard method proposed here was applied to the determination of silicon in several organic silicon compounds. Effects of some interfering elements on the results were examined.

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The working property of Orion model 94-11A sodium-selective glass electrode has been investigated for the purpose of the microdetermination of sodium by direct potentiometric measurement. The electrode time response could be evaluated from the slope of the straight line drawn along the plots of antilog (electrode potential/Nernstian slope) vs. reciprocal time. It was shown that Orion 94-11A electrode was relatively quick-responsive compared with other conventional sodium-selective glass electrodes. Further studies on the reproducibility of the electrode potential and the traceability of the calibration curve to the Nernstian slope revealed that it was possible to determine with sufficient accuracy the sodium ion concentration ranging 10^-310^-4 M which was most convenient for the volume of the test solution handled in microanalysis. A co-existence of potassium ion at the same concentration of sodium ion within the range of 10^-310^-4 M in the sample solution gave serious interference with the analytical results, which was not expected from the selectivity ratio measured at the higher concentration of potassium ion as listed in Table I.
The potentiometric measurement was further employed to the flask combustion method for the microdetermination of sodium in the organic substances. A sample was ignited in a closed flask with a sample holder attached to the glass stopper, 10 ml of water being added in the flask as the absorption liquid. The flask was shaken in order to contact well the absorption liquid with sample holder. The solution was then transferred into 100 ml volumetric flask using 50 ml of water. The pH and the ionic strength of the solution were adjusted at 8.8 and 0.02 M respectively by an addition of Tris buffer and by making up the final volume to 100 ml. The 94-11A electrode was rinsed with 10^-4 M sodium chloride solution containing the Tris buffer and was wiped gently with a tissue paper, before it was immersed into the test solution with a double junction silver chloride reference electrode. The electrode potential was read after 5 minutes.
A lower analytical results was observed when a flask with the conventional platinum gauze basket sample holder was used, approximately 2% of relative error. This negative error was interpreted by an inward diffusion of sodium vapor to the hot platinum. The interference could be therefore avoided by using quartz sample holder for ignition of the sample.

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Radio-tracer and photometrical studies were made for the determination of the micro amount of cadmium(II) with 1-(2-pyridilazo)-2-naphthol (PAN) in a digested solution obtained by oxidizing biological materials with potassium permanganate and a mixture of H₂SO₄ and HNO₃.
A scheme of photometric analysis of cadmium(II) was designed and the behaviour of cadmium(II) and interfering ions in every step of the scheme was examined radiochemically by using Ge(Li) detector and a 4000-channel pulse height analyser, and the following results were obtained. (1) Cadmium(II) was coprecipitated quantitatively with antimony(III) sulfide from solutions of pH 2.5 (optimum)4.0. The quantitative coprecipitation of cadmium(II) was also observed at pH 2.5 when copper(II) was used as the carrier instead of antimony(III). (2) The extraction with 4, 4, 4-trifluoro-1-(2-thienyl)-1, 3-butanediene (TTA) chloroform solution showed that copper(II) was extracted quantitatively in the pH range of 3 to 10, mercury(II) was extracted partialy in the same pH range, and other ions such as cadmium (II), arsenic (III) and antimony (III) were not extracted at the pH range of 2 to 12. (3) The optimum pH for extraction of cadmium(II) with pyridine-chloroform solution from 0.1 M thiocyanate solution was 4 to 7. Below pH 10, copper(II) was extracted quantitatively. Mercury(II), arsenic(III) and antimony(III) were not extracted at pH range of 2 to 12. (4) The optimum pH for the extraction of cadmium(II) and copper(II) with PAN-chloroform solution was 10 to 11 and 4 to 11, respectively. Mercury(II) was extracted partialy, and neither arsenic(III) nor antimony(III) were extracted at the pH range of 2 to 12.
From these results, the following procedure was established. After 2 mg of antimony(III) or copper(II) was added to 100 ml of the sample solution, the sulfide was precipitated with H₂S at pH 2.5. The sulfide precipitate was collected and dissolved in aqua regia, and the solution was evaporated to dryness. The residue was dissolved in dil. HCl, and copper(II) was eliminated at pH 3.0 by extracting with TTA-chloroform solution. The aqueous phase was made to 0.1 M thiocyanate solution and adjusted to pH 5.0, then cadmium(II) was separated from mercury(II) by extracting with pyridine-chloroform solution. The chloroform solution was evaporated to dryness, and the organic matters were decomposed with HNO₃. The residue was dissolved in dil. H₂SO₄, and potassium sodium tartrate was added to the solution for masking tin(II) and lead(II). The pH of the solution was adjusted to 10.5, and PAN-methanol solution was added. After the solution was let stand for more than 5 minutes, the cadmium-PAN complex was extracted with chloroform, and the absorbance of the chloroform solution was measured at 555 nm.
The overall recovery of the procedure was examined by adding ¹¹⁵Cd tracer to the acid-digested solution of biological materials containing about 10 μg of cadmium(II), and the recovery was 91±2%.

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Back-extraction of 20 metal carbamates in chloroform with nitric acid, hydrochloric acid and sodium hydroxide solutions has been presented. The metal carbamates, Ag, As, Au, Bi, Cd, Co, Cu, Fe, Hg, In, Mn, Ni, Pb, Sb, Se, Sn, Te, Tl, V and Zn, were investigated. Solutions of 0.54 N nitric acid, 16N hydrochloric acid and 0.55 N sodium hydroxide were used for the back-extraction.
In the case of the back-extraction with nitric acid solutions, As, Bi and Zn at 0.5 N, Ag, Au, Cd, Cu, Mn, Ni, Pb, Sb, Se, Tl and Te at 1 N, In at 2 N, and Hg at 4 N are extracted into the solution from the solvent containing these diethyldithiocarbamates, while Co at 4 N, and Hg and In at 0.5 N are not extracted. In the hydrochloric acid solutions, Bi, Mn and Zn at 4 N, As, Cd, Pb, Sb and Se at 5 N, and Ag, Au, Hg, In and Tl at 6 N are extracted, while Co, Cu and Ni at 6 N, Fe at 3 N, and Hg, In and Pb at 2 N are not extracted. In the sodium hydroxide solutions, As, Bi, In, Se, Sn and Zn at 0.5 N, Mn and Sb at 1 N, and Pb and V at 3 N are extracted, while Ag, Co, Cu, Hg and Ni at 5 N, and Te at 1 N are not extracted. In all the cases, other metal chelates are partialy extracted into each back-extraction solution.
Absorption spectrum of the original solvent containing iron diethyldithiocarbamate is changed after the back-extraction with nitric acid and with hydrochloric acid, especially with hydrochloric acid, the absorbance at 620 nm is increased and the color is changed from dark brown to green.
The back-extraction ratio were measured by the following procedure. (1) Bismuth(370 nm), Co (325 nm), Cu(435 nm), Ni(375 nm) and Te(425 nm) were directly determined from the each absorbance of the chloroform layer.
(2) Arsenic, Au, Cd, In, Mn, Pb, Sb, Se, Sn, Tl, V and Zn were determined by the substitution extraction with copper solution. The organic layer containing each carbamate was transferred into a separatory funnel, and was shaken vigorously with 10 ml of copper solution for 1 min. The amount of each element was obtained from the absorbance of the chloroform layer at 435 nm.
(3) Silver and Hg were determined by the substitution extraction with bismuth potassium cyanide solution instead of the copper solution in (2), and the absorbance was measured at 370 nm.
(4) Iron was determined by the photometric method with 1, 10-phenanthroline after evaporating the solvent.

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“Colloid Titration” is first invented by Prof. Hiroshi Terayama (The University of Tokyo), and developed largely by Prof. Ryoichi Senju (Kyushu University) and his co-workers.
The colloid titration is based on the reaction between positively charged colloidal particles and negatively charged ones. For titrating positive colloid solutions, N/400 potassium polyvinylsulfate, PVSK (negatively charged colloid), is used as titrant, and toluidine blue as indicator. The end point is indicated. by the color change from blue to red-violet. For titrating a negative colloid solution, an excess of N/200 glycolchitosan or methylglycolchitosan (positively. charged colloid) is added to the solution to form precipitate, and the excess is titrated by N/400 potassium polyvinylsulfate.
Glycolchitosan and methylglycolchitosan is synthesized from chitin extracted from carapaces of crabs, for which a synthetic polycation may be the substitute. Cat-Floc (polydiallyldimethylammonium chloride) is chosen among many synthetic polycations such as the polymer of diallyldimethylammonium chloride and sulfur dioxide, Chemiquat-α (poly-N, N-dimethylethyleneammonium sulfate), polyvinylethylpyridinium bromide, polyvinylbenzyl trimethylammonium chloride, polyacrylamide derivatives, and so on. The titration volumes by Cat-Floc are almost constant in the pH range of 2 to 11.
Potassium polyvinylsulfate is the best titrant, because it can be used with Cat-Floc at pH between 2 and 11 and the color change at the end point is sharpest, while the other synthetic polyanions do not give sharp color change. N/400 potassium polyvinylsulfate solution can be easily standardized by N/400 zephiramine (tetradecyldimethylbenzylammonium chloride) or N/400 cetylpyridinium bromide.
Toluidine blue is the best indicator among cationic dyes such as methylene blue, Bismarck Brown, Rhodamine 6GO (fluorescent indicator) and so on.
By this method, cationic and anionic polymers, for example, sodium cellulose sulfate, sodium polyacrylate and agar can be determined successfully.

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A handy-type anodic stripping polarograph which has only basic circuit of polarograph was presented for an ultra trace analysis of metal ion. The schematic diagram was given in Fig. 1. Its sweep rate driven by a synchronous motor and gear-head was 15 sec/full span. Limit switches were attached to both sides of a potentiometer and load resistors were 2 kΩ, 5 kΩ and 10 kΩ. A recoder chart speed was 60 cm/min and a full-scale was 10 mV for 25 cm.
The wave height of cadmium was linearly proportional to 0.0010.01 ppm for 10 min pre-electrolysis and 0.010.1 ppm for 2 min pre-electrolysis. The standard deviation was 5% for 0.08 ppm Cd in 0.2 M KCl at 10 measurements. This handy-type anodic stripping polarograph was applied to the determination of Cd in mine water. These results obtained with this anodic stripping polarograph were in good agreements with that obtained with atomic absorption spectroscopy.

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Thin-layer chromatographic behavior of 45 metal ions on microcrystalline cellulose(Avicel SF) has been surveyed in ether-14 M nitric acid media. R_f values were measured as a function of the solvent volume ratio. The more than a half of the tested metal ions, which was not extracted from nitric acid solution into ether, remained at the starting points regardless of the solvent volume ratio, while several ions, gold(III), rhenium(VII), tin(IV), and uranium(VI), which were well extracted, showed high R_f values. The others, possessing some extent of the possibilities of the extraction, exhibited increased R_f values with decreasing the solvent volume ratio. It can be expected that this rise of the R_f values suggests an increase of the abundance of the species available for the extraction. Inspection of R_f values of metal ions allowed many useful separations like mercury (II)-cadmium, thorium-zirconium-lanthanum, gold (III)-palladium (II)-platinum(IV), which had been difficult in both paper chromatography and cellulose thin-layer chromatography using ether-nitric acid media. These were easily achieved by using ether-14 M nitric acid (1: 1, v/v) as a developing solvent.

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Separation and determination of ring substituted furfural diethyl acetal derivatives have been carried out by gas chromatography (GC). Diethyl acetal derivatives of furfurals seemed to decompose on the usual columns of GC and their peaks were not detected. But, when sodium tetraborate or phosphate buffer component between pH 7.5 and 10.5 was coated on the supporter and DEGS was used as a liquid phase, fine chromatograms of acetals were obtained and they were separated from parent furfurals and other acetals. Acetals used for experiments were furfural diethyl acetal, 5-chloromethylfurfural diethyl acetal, 5-ethoxymethylfurfural diethyl acetal and 5-propagylfurfural diethyl acetal. GC operating conditions were as follows. Apparatus: Yanagimoto GCG-550 with FID; column: glass, 1.5 m in length and 3 mm in diameter; column packing: 6080 mesh, acid-washed and silanized Chromosorb W coated with 3 % sodium tetraborate and 10% DEGS; column temperature: 130°C; carrier: nitrogen, 15 ml/min.

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A fluorophotometric method with tetrabromofluorescein ethylester (TBFE) has been proposed for the determination of quaternary ammonium salt. Fluorescent TBFE was synthesized by esterification of tetrabromofluorescein. Various conditions were examined to determine the optimal condition. The proposed method are as follows. Determination of tetraethyl-ammonium bromide; To a 20 ml test tube are added 1 ml of tetraethylammonium bromide solution of a concentration ranging between 0.5 and 5.0 μg/ml, 2.5 ml of borate buffer (pH 10), 0.2 ml of TBFE ethanolic solution (250 μg/ml) and 5.0 ml of 1, 2-dichloroethane.
In order to ensure complete extraction of TBFE tetraethylammonium complex, the mixture is throughly stirred for 1 min. After being allowed to stand for a few minutes, the aqueous phase is removed. About 4 ml of the 1, 2-dichloroethane phase is transferred to the cell. The fluorescence intensity is measured at its excitation (542 nm) and emission (562 nm) maxima. The reagent blank is run through the whole procedure.
Interference of ascorbinic acid, several amino acids, antipyrine, creatin, thiamin, urea, uric acid and glucose was examined. Most of them caused no effect on the results. The sensitivity of the proposed method is about 100 times that of the usual colorimetric method using acid dye.

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