The data base of kinetic parameters of electrode reactions and the utility programs for computer retrieval of electrochemical data are prepared as a researchers' file of electrochemical data by the application of the real time data analysis system (RETDAS) which is constructed with a minicomputer. The data base and the utilities for computer retrieval of electrochemical date are formed on a 1.2 M word disc cartridge. In order to apply for an on-line acquisition, evaluation and simulation of electrochemical data and for other available use, the data base is formed as an ASCII file. On-line text editor which is character-oriented is made, and used most frequently to update and to modify the data base in preparation for a new data base. The utility programs for computer retrieval of kinetic parameters of electrode reactions (CORKIPER) are mostly written in FORTRAN IV, and therefore their application to other laboratory computer systerms is possible.

View full abstract

A simple and rapid analysis of benzo(a) pyrene (BaP) in coal tar and pitch was studied. Caol tar and pitch were dissolved in benzene. BaP in the solution was directly separated by a one-dimensional dual band thin-layer chromatography. The BaP spot on the thin-layer was scraped off into a small centrifugal-tube. After adding 5 ml of dimethyl sulfoxide (DMSO) into the tube, ultra sonic extraction was carried out for 10 minutes in order to dissolve BaP completely. The extracted DMSO solution was centrifuged for 5 minutes. BaP in the supernanant was identified by comparison of its fluorescence and excitation spectra with those of standard BaP solution and was determined spectrofluorometrically by means of narrow base line method.
This analytical method has the following advantages over the conventional methods : (i) Spotting process of solution in the present chromatography is easy and not time-consuming and made a quantitative determination possible, because large volume of sample solution (200μl) can be applied to easily. (ii) The extraction procedure of BaP is simplified by the use of DMSO as extracting solvent because of its high dissolving power. (iii) An accurate determination of BaP is easily obtainable because narrow base line method can eliminate the interference of the other polynucler aromatic hydrocarbons mixed in BaP which was scraped off together with a part of its neighbouring spots in order to recover BaP completely.
The method was applied to the determination of BaP in coal tars (6 samples) and pitches (9 samples). The observed concentrations ranged from 5890 to 11800 ppm in the coal tar samples and from 8580 to 16500 ppm in the pitch samples.

View full abstract

The microwave plasma detector is highly specific and much more sensitive than most current detectors for arsenic. But when this detector is used for the determination of arsine, the presence of large amounts of hydrogen makes the discharge unstable. Therefore, the arsine evolved from the sample was separated from hydrogen by gas chromatography. An air-dried soil sample (0.1 g) was decomposed with 3 ml of nitric acid and 4 ml of sulfuric acid (1+1), and the solution was evaporated to (0.51) ml at 200°C. After cooling, the residue was centrifuged, the supernatant liquid transferred to a 10-ml volumetric flask, and 1 ml of 20% potassium iodide, 2 ml of 20% tin (II) chloride and water (to the mark) were added. A 1 ml aliquot was taken with a syringe and introduced into a 15 ml reaction vessel containing 0.5 g of zinc {(0.51)mm diam.} through a silicone rubber stopper. The reaction was allowed by agitating the mixture with a magnetic stirrer until the gauge pressure reached 0.5 atm, and the evolved gas was swept by an argon flow (45 ml/min) into a column (0.3 φ×250 cm) containing PEG 6000/C-22 {(80100) mesh}. The As 228.8 nm line intensity was monitored and the peak height measured for the determination. The lower limit of detection was 0.2 ppm of arsenic in soil and the relative standard deviation was 3% for 10 ppm. The time required for a determination was 1 hr.

View full abstract

A sensitive and rapid method has been developed for the determination of picogram quantities of beryllium. Beryllium was converted to its trifluoroacetylacetone (TFA) chelate and separated on a glass column (90cm×3mm i.d.) packed with 0.5% SE-30 on glass beads {(6080) mesh} at 130°C, with argon containing 0.05% TFA vapor as carrier gas. Spectra were excited in the plasma of a low-wattage 2450 MHz electrodeless discharge at atmospheric pressure, and the Be I 234.9 nm line was monitored. To eliminate the high background emission due to argon and chloroform used as solvent, a quartz plate vibrating at 108.8 Hz was mounted behind the entrance slit of a monochromator, and a lock-in amplifier was tuned to twice the frequency of the vibration. The chromatographic peak height was proportional to the beryllium quantity over the range (0.0021) ng, with an error of 5% at 0.1 ng. The lower limit of detection was 0.001 ng of beryllium (0.03 ng with a mechanical disk chopper and a lock-in amplifier, and 0.1 ng with a DC amplifier). The proposed method was applied to the determination of beryllium at the low ppm level in samples of aluminum metal and aluminum-magnesium alloy. A sample {(2040) mg} was dissolved in hydrochloric acid and beryllium was extracted with 2 ml of 0.1 M TFA in chloroform at pH 6.5 in the presence of EDTA to mask aluminum. A 1 μl aliquot of the organic phase was then injected into the gas chromatograph. A determination required (11.5) hrs.

View full abstract

An analytical method of a small amount of dissolved oxygen in deaerated water has been established by measuring the color development between oxygen and indigo calmine. Ordinally the color produced by the reaction of oxygen with reagent is compared with the standard colors by eye. Although very rapid and sensitive, this method is not accurate. This paper describes the results obtained by spectrophotometric studies, and the application to the determination of oxygen dissolved in the feed water of a high pressure boiler or an atomic power plant (BWR).
The analytical procedure is as follows. After taking a sample water in a sampling vessel, a reagent in a buret of the vessel is introduced into the vessel by opening a cock. After developing a clolr, the absorbance was messured with a Hitachi spectrophotometer (model 139) by setting a special cell holder.
The absorption wavelength of the oxidized indigo carmine are 510, 555 and 610 nm. The most suitable wavelength to determine a small amount of oxygen is 555 nm. To prepare a calibration curve, known amounts of oxygen were added by electolyzing the sample water. A linear calibration curve was obtained within a range of less than 80 ppb oxygen. The coefficients of variation were 15.7, 8.1 and 2.4 for 3.5, 13 and 50 ppb oxygen, respectively.
The analytical values obtained from the feed water in a power plant were in good agreement with those obtained by Winkler-amperometry (JIS B 8224).

View full abstract

A new data processor for a gas or liquid chromatograph was developed.
The new instrument consists of an analog to digital converter, a microprocessor, IC memories (8 k words), a cassette tape memory device, and a display panel (Fig. 1).
Programs for data processing (12 kW) and parameters for analysis (16 kW), etc. have been stored in an auxiliary cassette tape with a large memory capacity of 128 k words, and in actual analysis, only the necessary parts of the memories in the cassette tape are automatically stored in the IC memories, and then used for data processings. This method can enlarge the performance and the function of the data processor, saving the programable ROM.
Unresolved peaks on a tail of a main peak are well processed with the tangential skimming method and the perpendicular method, and their repeatability were 0.29 to 0.43%.
Concentration of each component is automatically calculated. Even when the calibration curves of the components do not intersect the origin of the coordinate axes (Fig. 7), concentration of each components can be correctly obtained by automatic calibration of the curves for each components with two standard samples of different concentrations.
Eluted components can be grouped into up to 20 groups as desired, and the concentration for each group can be totaled.
Forty nine components in gasoline were grouped into 7 groups based on the number of carbon atoms and their concentrations were determined.

View full abstract

Rubber membrane dialysis method was applied to the separation of metallic sulfonates in additive concentrates, which are used as detergent-dispersants for preparing lubricating oils. The experiment was carried out using soxhlet extractor equipped with a extracting tube set up a rubber membrane for hygienic use. A 2 g sample of additives is transferred to the bottom of a rubber membrane and petroleum ether (b.p. below 70°C) is circulated through the extracting tube for 10 hours. In the case of lubricating base oils, recoveries of oils were more than 99.8% for neutral oils and about 99.5% for bright stock oils by circulation of petroleum ether for 10 hours. The dialysis residue in the rubber membrane was mixtures of resinous constituents of base oil and small amount of extracts from rubber membrane. This method was examined for the separation of heavily overbased calcium sulfonate, basic sulfonates of calcium, barium, magnesium and calcium sulfonates. Almost metallic sulfonates except calcium sulfonate were separated from diluent oils quantitatively. However, a part of calcium sulfonate was gradually dialyzed with diluent oil. This is caused by the difference of chemical structures between heavily overbased or basic calcium sulfonate and calcium sulphonate, i.e., the difference of miscelle size in solution. It was found that the dialysis technique given above was very useful for the separation of heavily overbased or basic metallic sulfonates in additive concentrates and lubricating oils.

View full abstract

In most methods for the determination of trace amounts of iron in non-ferrous metals, prior to the spectrophotometric determination, iron must be separated from the matrix or obstructive metals, and the procedures require some troublesome techniques for separation of iron (III). The author aims to establish a new method involving no tedious separation of iron(III) from other metal ions: ion exchange extraction using aluminum cupferrate in chloroform as extractant.
An aqueous solution of (10100) ml containing less than 100 μg of iron (III), is taken in a separating funnel. The pH of the solution is adjusted to 34 with 1 M acetate buffer, and 10.0 ml of aluminum cupferrate in chloroform is added. After the mixture is shaken for 3 minutes, the chloroform phase is transferred into a 10 mm cell and the absorbance is measured at 400 nm against the reagent blank.
A linear calibration curve was obtained from 10 to 100μg of iron (III) and the molar absorptivity was calculated to bc 4700 at 400 nm. Most cations do not interfere. Vanadium(V) was found to interfere, but it could be avoided by adding 1 ml of 3% hydrogen peroxide. About 10 μg of iron in aqueous solution, and (0.500.001)% of iron in various non-ferrous metals and in heavy metal salts could be successfully determined.
The ion exchange extraction process seems to obey the equation: Fe³⁺ + Al (Cup)₃₍₀₎E_??_Fe (Cup) ₃₍₀₎ + Al³⁺, and the equilibrium constant(log E) was calculated to be 13.4 from the extraction coefficients of aluminum and iron (III) with cupferron-chloroform.

View full abstract

A selective method was described for the determination of trace amounts of copper. It consists of the ion exchange extraction of copper with aluminum cupferrate in chloroform, and the ligand exchange with sodium diethyldithiocarbamate as a colorimetric reagent.
An aqueous solution of (10100) ml containing copper(II), less than 40 μg, is taken in a separating funnel. The pH of the solution is adjusted to 45 with 2 ml of 1 M acetate buffer, and 10.0 ml of 0.01 M aluminum cupferrate in chloroform is added. After the mixture is shaken for 2 minutes, the chloroform phase is transferred to another separating funnel. Ten ml of 0.04% sodium diethyldithiocarbamate solution and 10 ml of 0.1 M ammonium salt buffer of pH 9.5 are added and shaken for 30 seconds. The chloroform phase is transferred into a 10 mm cell and the absorbance is measured at 436 nm against the reagent blank.
Under the optimum condition, a linear relation between the absorbance and the amount of copper in sample solution was observed in the range 2 to 40 μg and the molar absorptivity was calculated to be 1.32×10⁴ at 436 nm. Most cations do not interfere. Iron(III) and vanadium(V) were found to interfere but the interference could be avoided by adding potassium fluoride to iron(III) and hydrogen peroxide to vanadium(V) in the sample solution.
As small as 10 μg of copper in a sample solution and 0.007% of copper in heavy metal salt could be determined without separation of copper.

View full abstract

A simple and rapid spectrometric determination of micro amounts of palladium using 4-(2-pyridylazo)-resorcinol(PAR) and EDTA was described. It has been known that Pd(II) reacts with PAR to form four kinds of stable 1 : 1 chelates, one of them was green at pH below 4 and the others were red at pH above 4. The water soluble red complex at pH 10.311 had an absorption maximum at 520 nm in 0.01 M EDTA. EDTA (0.1 M) the pH of which was adjusted at 10.5 with sodium hydroxide had rather strong buffer action, and 5 ml of the solution was used to the test solution before the addition of 0.5 ml of 0.1% PAR per 50 ml of each solution to be measured; i.e. by the use of the EDTA solution, not only a masking of diverse ions also a buffer action at pH 10.5 had been achieved. It was necessary to warm the test solution after addition of PAR, because in the presence of some elements such as V or As, the formation of Pd-PAR chelates was very slow and gave low values for palladium contents. Beer's law was confirmed over the range of 0100 μg Pd(II) in 50 ml and sensitivity which gave the absorbance of 0.001 was 0.0043 μg Pd(II)/cm². In the above method, when a large amount of diverse ions such as cobalt(II) or iron(II) etc. are present, the solvent extraction separation was employed. To the sample solution, 2 ml of 0.1 M EDTA, 0.5 ml of PAR and 5 ml of 0.1 M NaH₂PO₄ were added. The solution was adjusted to pH 2 with 0.1 M H₃PO₄ and was warmed in a water bath at 80 °C for 10 min. and was cooled.
The green chelate formed was extracted twice by 5 ml each of the methylisobutyl-ketone (MIBK) and this chelate in organic phase was back-extracted rapidly into an aqueous alkaline solution. Five ml of 0.1 M EDTA (pH 10.5) could be used for this alkaline solution and then the aqueous phase was separated after back-extraction and was diluted to 50 ml with water to provide the solution for measurement. The calibration curve almost agreed with that obtained when the extraction separation had not been employed.

View full abstract

Porous alumina (Poramina^®), a column packing material which was developed by the authors and reported previously, was used for gel permeation chromatography of water soluble polymers. HETP values of about 20 microns were obtained on the columns packed with 9 micron Poramina particles. GPC calibration curves of polystyrene and dextran standard samples were given. The two materials gave approximately parallel curves over the molecular weight range from 1 × 10⁴ to 1.5 × 10⁵, but the upper exclusion limit was 2.5 × 10⁵ Daltons for dextran while that was 3 × 10⁶ for polystyrene. The difference was due to the increased elution volume of dextran, which may be explained by the interaction between dextran and the alumina. Chromatograms of several water soluble polymers were also shown. Poramina columns had good resolving power for potassium polystyrene sulfonate. Molecular weight of three potassium polystyrene sulfonate samples obtained by calibrating the elution volume against that of polystyrene standard samples gave good agreement with the values estimated by the viscosity measurement. However, for polyacrylamide, correct molecular weight distribution could not be obtained because of the interaction between the polymer and the alumina. Studies on the mechanism of the interaction between polymers and the alumina will be necessary to make Poramina columns universally applicable to various water soluble polymers.

View full abstract

A trace amount of chromium(VI) was extracted as diethyldithiocarbamate from (1001000) ml of sea water into (1030) ml of methyl-iso-butyl ketone, and determined by atomic absorption spectrophotometry with an acetylene-air flame or a graphite furnace.
Various analytical parameters for the measurements of chromium by the flame and the flameless methods were examined. When the extraction was carried out at pH 4, the interference of coexisting chromium(III) was eliminated. The optimum concentration of sodium diethyldithiocarbamate in the aqueous phase was found to be 2.0×10^-3 M for the extraction of 500 ppb of chromium(VI). Calibration curves were linear and the sensitivities were 0.4 ppb of chromium (VI) for 1% absorption using the flame method and 0.02 ppb using the flameless method when 1000 ml of aqueous and 30 ml of organic layers were used. No serious interference was observed when 1.0 ppb of chromium(VI) was determined in the presence of 10 ppb of Sr(II), Cu(II), Pb(II), Zn(II), Cd(II), Hg(II), Ni(II), As(III), Mn(II), Co(II), Be(II), Al(III), Fe(III), Mo(VI).
The proposed method was applied to the determination of chromium(VI) in artificial sea water and several actual sea water samples. When known amounts of chromium (VI) was added to the sea water samples, the chromium(VI) was recovered satisfactorily.

View full abstract

Five collaborative analyses of two samples of magnesia-chrome refractory were carried out by thirteen analysts. The following is the procedure they recommend. Fuse 0.5 g of the powdered sample (about 200 mesh) with 2 g of boric acid and 3 g of anhydrous sodium carbonate in a platinum crucible. Cool, dissolve in warm water and add 40 ml of perchloric acid. Evaporate until white fume appears. Boil gently, and add several drops of hydrochloric acid intermittently and then two portions of 0.1 g dried sodium chloride, until the supernatant liquid becomes clear, to remove the chromium completely. Cool, dilute with warm water and filter through No. 5B filter. Evaporate the filtrate again to fumes to recover the silica, and dilute it with water to 250 ml. Pipet a 25 ml aliquot, add a slight excess of 0.1 M EDTA, adjust the pH to 3.5, boil for several min and back-titrate with a standard copper(II) solution at hot against PAN to obtain the amount of aluminum and iron(III) oxides. Determine the latter in another aliquot by Zimmermann-Reinhardt method after addition of a small amount of hydrochloric acid. For determination of calcium and magnesium oxides, remove the hydroxides after precipitation with ammonia water from a 100 ml aliquot, evaporate the filtrate to about 70 ml and add sodium hydroxide to make pH 12.312.5. Add 5 g of sodium carbonate and 10 ml of ethanol, and dilute to 100 ml. After filtration, dissolve the precipitate in dilute hydrochloric acid and adjust the volume to 250 ml. Determine calcium by the atomic absorption spectrometry or EDTA titration, and the sum of calcium and magnesium by EDTA titration. Because a large excess of magnesium is usually present, the pH readjustment method or the addition of a slightly defficient amount of EDTA before the titration is needed. Chromium is determined with a separate sample by the ordinary redox titration.

View full abstract

Monoguanylmelamine was separated from its related compounds on a cation exchange column (AG-50WX 4 in Na-form, 8 φ×300 mm) by stepwise elution with Sorensen's buffer solution (pH 10.210.4 and pH 11.611.8) at the flow rate of 1.5 ml/min and the column temperature 30°C. The interfering compounds such as melamine, acetoguanamine, acetoguanide, ammeline, acetoguanamide and cyanomelamine were completely removed from the column by (100150) ml of the first buffer solution (pH 10.4) and then, monoguanylmelamine was eluted by (5070) ml of the second buffer solution (pH 11.611.8) without interference of diguanylmelamine. Quantitative determination of monoguanylmelamine was performed by calibrating the peak area of chromatogram monitored by the absorbance at 255 nm. Monoguanylmelamine could be determined down to 5μg by the proposed method.

View full abstract

One of the present authors reported that the patterns of absorption spectra of heavier rare earth-chlorophosphonazo III chelates changed from α- to β-type and that of the lighter rare earth chelates did not change with an increase of the mole ratio of each rare earth to the chelating agent. Since the mole ratio of rare earth to the chelating agent in the α-type chelate was known to be 1 : 1, the mole ratio method was applied to estimate the purity of the chelating agent by using of the standard solutions of lighter rare earths (La³⁺, Nd³⁺, and Gd³⁺) and magnesium. The results show that the purity is about 76%. The result of the determination of phosphorus in the chelating agent used shows 85% as the purity. The continuous variation plots were carried out on the assumption that the purity was 65, 76, and 85%. The maximum peak of the absorbance, in the case of 76%, is observed at mole fraction [La³⁺] /([La³⁺] [chelating agent]) of 0.5. The purity of the chelating agent was estimated by determining phosphorus in the precipitate because the solutions of the heavier rare earth (Tm³⁺, Yb³⁺, and Lu³⁺) chelates gave the β-type spectrum and the chelating agent was completely precipitated from the solutions in the presence of an excess amount of rare earths. The result shows the purity of about 76% and this value agrees well with that of the mole ratio and continuous variation methods.

View full abstract

A combined method of ion-exchange separation and spectrophotometry was described for determination of copper, gold and palladium in dental alloys. The sample of about 50 mg was taken and treated with a few ml of nitric acid and then aqua regia and diluted. The silver chloride precipitated was filtered off, and the filtrate was diluted to a definite volume to give ca. 0.2 M in hydrochloric acid. One ml aliquot was taken and mixed with 19 ml of acetic acid and transferred to a column (φ 1×6 cm) of one gram of weakly basic anion exchanger diethylaminoethyl cellulose in the chloride form.
Au(III) and Pd(II) were retained on the column, while Cu(II) was easily removed from the column with 60 ml of acetic acid-0.5 M hydrochloric acid (9:1). Subsequently, Au(III) was eluted from the column with 50 ml of acetic acid-2 M hydrochloric acid (9:1) and finally Pd(II) was recovered by elution with 50 ml of acetone-6 M hydrochloric acid (9:1). An aliquot of each effluent was taken and the metal ion was determined spectrophotometrically by use of diethyldithiocarbamate for copper, rhodamine B for gold and p-nitrosodiphenylamine for palladium, respectively.
The proposed method is reasonably simple and can be applied successfully to the determination of copper, gold and palladium in a variety of dental alloys.

View full abstract