Differential pulse anodic stripping voltammetry with a hanging mercury drop electrode (HMDE) was applied to the determination of trace amounts of Zn, Pb and Bi in high purity aluminum. High purity aluminum (1.0g) was dissolved in 40ml of acid mixture (90ml H₂SO₄, 200ml HCl, 200ml HNO₃ and 500ml water). The solution was heated until white H₂SO₄ fume is liberated. After cooled, the solution was diluted to 200ml. An aliquot of 50ml was diluted to 100ml and used for the determination of Zn and Pb. The electrolysis was carried out for 150s at -1.20V vs. Ag/AgCl and the anodic stripping curves were recorded under scan rate of 30mV s^-1, pulse repetition of 0.1s, pulse amplitude of 50mV. The stripping peak current of Zn and Pb appeared at 1.01V and 0.40V vs. Ag/AgCl, respectively. After adding 10ml of 12M HCl to 50ml of the solution, the solution was diluted to 100ml, and used for the determination of Bi. The electrolysis was carried out for 150s at -0.18V vs. Ag/AgCl and the anodic stripping curves were recorded under scan rate of 10mV s^-1, pulse repetition of 0.1s and pulse amplitude of 10mV. The stripping peak current of Bi appeared at -0.09V vs. Ag/AgCl. The lower limits of determination were 0.5ppm for Zn and 0.1ppm for Pb and Bi. The elements ordinarily contained in high purity aluminum did not interfere the determination. The time required was about one to two h.

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Microgram quantities of phosphate ions are quantitatively collected with zinc oxide powder {diam. 5μm, (20100)mg} from 50ml each of water, artificial seawater, and heavy metal nitrate solutions. This simple and rapid technique of separation has been successfully applied to the spectrophotometric determination of traces of arsenic and phosphorus in lead metal. A 4-g sample is dissolved in nitric acid, and arsenic and phosphorus are oxidized with potassium permanganate. To a 1/2 aliquot of the solution, EDTA is added to mask lead, and arsenic and phosphorus are collected with zinc oxide powder, which is then filtered off and dissolved in hydrochloric acid. Ammonium molybdate and hydrazinium sulfate are added, and the absorbance (A_As+P) of the resulting heteropoly molybdenum blue due to arsenic and phosphorus is measured at 830nm. The same procedure is carried out on the other 1/2 aliquot, except that arsenic is completely removed by evaporation with hydrobromic acid after the collection of arsenic and phosphorus. Phosphorus is determined from the absorbance (A_P) on the latter aliquot, and arsenicdetermined from the difference (A_As+P-A_P).The limit of determination is as low as 0.02ppm in lead, and the time required for an analysis is about 2h.

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Zirconium (IV)-loaded cation exchange resin column enables us to collect the low-level fluoride ion (micromolar concentration range) in aqueous samples, such as rain water, tap water and other natural water samples. The collected fluorides can be easily eluted with 2M aqueous sodium hydroxide, and determined with ion-selective electrode after the addition of total ionic strength adjusting buffer (TISAB) The yields are (95±5)% for submillimolar fluoride containing water samples. The interferences by chloride and nitrate ions are neglibible even if their concentrations are around 1M. Millimolar amounts of sulfate and phosphate ions cause only slight negative interferences. Only aluminum(III) causes severe interference because the adsorption behavior of aluminum on the resin column is quite similar to that of the fluoride ion. Submillimolar aluminum (III) can be masked by the addition of CyDTA or citrates into TISAB. As a typical example, the fluoride in Tama river water (Oyakawa-bashi, Dec. 1978) was (0.018±0.002)ppm by this method {(0.02±0.01)ppm by customary method}.

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A method for the preconcentration of trace amounts of mercury (II) and methyl mercury (II) in water by batch method utilizing activated carbon (AC) and determination of mercury enriched on AC by Zeeman effect atomic absorption method were studied. After adding fixed amounts of AC (Darco G-60, bellow 225 mesh) and hydrochloric acid to a sample solution, and then the mixture was shaken for 70min. The AC and sample solution was separated by suction filtration with membrane filter (1μ). The AC separated on membrane filter was dried at 60°C for 30min. The mercury enriched on AC was determined by Hitachi Zeeman effect mercury analyzer 501. Effect of pH, the amounts of AC, shaking time, concentration of NaCl and foreign substances on the recovery of mercury were examined. The best resultwas obtained under the following conditions. To a 500ml of sample solution containing more than 0.002μg of meecury, 50mg Of AC and 5ml of lN hydrochloric acid was added, the mixture was shaken for 70min. Under the optimum condition, the recovery of mercury (II) and methyl mercury (II) was 96% or better. The recovery of mercury (II) decreased in the present of more than 0.2M NaCl, but improved by the addition of sodium iodide to a sample solution.Interference from foreign substance such as K⁺, Ca²⁺, Mg²⁺, Fe³⁺, Mn²⁺, Zn²⁺, Ni²⁺, Co²⁺, Cu²⁺, Cr⁶⁺, Pb²⁺, Pd²⁺, NH⁺₄, Br^-, I^-, IO^-₃, NO^-₂, SO^2-₄, sulfide ion, ABS, glucose, L-glutamic acid and humic acid were not so serious but Au³⁺ and S₂O^2-₃ was interfered with the recovery of mercury (II). The proposed method and flameless atomic absorption method was compared with the determination of mercury (II) and methyl mercury (II) at ppb lebel in the sample solution such as water, river water, 3% NaCl water and sea water. The recovery was (92.3±10)% for the proposed method and (95±9)% for the flameless atomic absorption method respectively. The detection limit of mercury was 0.5ng on 10mg of AC when the signal to noise ratio was 2.

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The standardization of chromium (III) solution was investigated by potentiometric titration with an iron (II) standard solution involving the prior oxidation of chromium (III) to chromium (VI) with the lead dioxide suspension. The proposed procedure is as follows: 10ml of 5×10^-2M lead tetraacetate in glacial acetic acid solution was added dropwise to about 120ml of distilled water. After lead tetra acetate was sufficiently hydrolyzed, the pH of the suspension was adjusted to about 12 by adding 10M sodium hydroxide solution. 15.00ml of (0.52.0)×10^-2M chromium (III) solution was added to the suspension, and the mixture was shaken occasionally for 5min at (7090)°C to complete the quantitative oxidation of chromium (III) to chromium (VI). This mixture was made acidic by adding concentrated hydrochloric acid until a clear solution was obtained as a result of the reduction of excess lead dioxide, and boiled for 15min to remove chlorine, which was produced by the reaction between excess lead dioxide and hydrochloric acid. Then, dichromate produced was titrated with the standard solution of ammonium iron (II) sulfate by potentiometry using platinum electrode and SCE. (5×10^-32×10^-2)M chromium (III) solution, {amounts of chromium taken; (416)mg} could be determined within the relative error of ±0.3% and within the coefficient of variation of 0.2%. This method is useful for the standardization of chromium (III) solution, because it can be made rapidly (within 30min for the prior oxidation) without laborious filtration of excess lead dioxide and gives accurate results.

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Atomic absorption spectrophotometry of aluminum could not attain high sensitivity when air-acetylene flame was used. The present experiment revealedthat sensitivity is increased by adding nitrogen compounds to the sample. The investigation was made on the enhancing effect to adding of various nitrogen compounds to the sample. Organic amines had the best sensitivity enhancing effect and enhancing effect of aliphatic amines was better than that of aromatic amines. The effect of tertiary amines were better than that of primary amines. The sensitivity increased about 4times as large as that of aqueous solution when a sample was dissolved in dimethylformamide. Particularly, sensitivity was increased about 10times by addition of triethanolamine (about 0.3mol/l in a sample solution) as compared with the case of no addition and it was found that by addition of nitrogen compounds, determination of aluminum in the order to several 10ppm to several 100ppm is possible.

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A new type of detector involving heat effects in a catalyst bed has been developed and applied to the measurement of nitrogen oxides. This detector is called the reaction-heat detector (RHD) and consists of a catalyst bed of vanadium pentoxide, a bed of aluminum powder as a preheater and a differential type thermocouple with two junctions. One junction of the thermocouple was placed in the center of the catalyst bed and the other in the bed of aluminum powder as a reference. The sample containing NO_x was introduced with a known amounts of ammonia into a constant air stream as a carrier gas. The determination of NO_x was perfomed by measuring the heat of reaction produced by the catalytic reaction between the NO_x and the added ammonia. The optimum conditions for the measurement were as follows: flow rate, 150 ml/min (s.v.=1200^-1); added concentration of NH₃, 1%; catalyst temperature, 325°C. Under such conditions, detector response was proportional to the concentration of NO_x ranging (201200)ppm. The effects of interference gases were examined to apply the RHD to the selective measurement of NO_x in exhaust gas. The RHD seems to be applicable for the measurement of NO_x in exhaust gas unless the gas contains sulfur dioxide of more than 300ppm or high concentration of hydrocarbons. Especially, the detector was well suited for the actual measurement of NO_x in automobile exhaust gas compared with other methods.

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Preliminary studies on the application of flame atomic absorption spectroscopy with an internal standard to the analysis of aqueous solutions containing organic materials were carried out to improve both accuracy and precision in the determination of trace metals. First, ethanol was used as an organic material which caused both enhancement effect, i. e., organic solvent effect and decrease in sensitivity due to an increase in viscosity. Second, glucose, which mainly caused a decrease in sensitivity due to an increase in viscosity, was selected as an another organic material. It was found that the effect of such organic materials on the determination of cadmium, chromium, copper, iron, manganese, lead and zinc was almost automatically corrected by optimizing flame conditions and burner height with use of two-channel atomic absorption spectrophotometer equipped with internal standardization system. Gold was the most suitable as an internal standard element. The trace elements mentioned above were determined with an error of below 4% for up to 20% of ethanol, and below 5% for up to 5% of glucose. In the case of aqueous solutions containing both ethanol and sugar, an error was within 6% at various concentrations where concentration of ethanol was 0 to 20% and that of glucose 0 to 5%. This fact certainly confirms that internal stand ard method in atomic absorption spectroscopy canbe successfully applied to the analysis of aqueous solution containing organic materials instead of standard addition method.

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An extraction-spectrophotornetric method for the determination of vanadium with N-cinnamoyl-N-(2, 3xylyl)hydroxylamine(CXA) was studied. The procedure is a follows: Take an aliquot of a sample solution containing less than 50μg of vanadium in a separatory funnel and add 40μl of 0.3% (w/v) potassium permanganate solution. Allow to stand for 5 min and then add 5 ml of 0.1% (w/v) solution of CXA in carbon tetrachloride. Add hydrochloric acid to aqueous phase to give a final concentration of ca.6 N. Extract vanadiurn(V)-CXA complex into carbon tetrachloride by shaking the mixture for 3 min. Dehydrate the organic layer with anhydrous sodium sulfate and filter this solution through a small was of cotton into a 1 cm cell and measure the absorbance at 525 nm against carbon tetrachloride. Vanadium(V)-CXA complex was extracted quantitatively into carbon tetrachloride from (49) N hydrochloric acid. The apparent extinction coefficient of the complex at 525 nm was estimated to be 6.1×10³l mol^-1cm^-1. Many coexisting elements do not interfere with the determination of vanadium. And perchloric acid up to 3 M does not interfere. The proposed method was applied to the determination of vanadium in high speed and chrome-vanadium steels.

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2-(2-Thiazolylazo)-5-dimethylaminophenol (TAM)and its nickel chelate were dissolved in a micellar solution of Triton X-100. Two wavelengths were chosen such that the difference between absorbances of the micellar solution was maximal: 560 and 480nm. The absorbance difference was constant in the pH range of 6.7 to 8.5. Pyrophosphate, tartrate and N-(dithiocarboxy)-glycine (DTCG) were used for masking copper, cobalt, iron(III), zinc and cadmium. In the presence of the masking agents at pH 8.0 10 min was required for full color development. The procedure is as follows: place a test solution containing up to 5.0μg of nickel in a 25-ml volumetric flask; add 1ml of 0.5M sodium tartrate, 2ml of 0.1 M potassium pyrophosphate, 2ml of ammonia buffer of pH 8.0, 10mg of DTCG and 2ml of TAM solution (TAM 0.01g: Triton X-100 20g: water 80g); dilute to the mark with water; stand for 10 min; measure the difference in absorbance at 560 nm and 480 nm with 1-cm cell in a full-scale range of 00.3. Beer's law was obeyed over the range (0.35.0)μg of nickel. Sandell's sensitivity was 0.70ng cm^-2. The following amounts (mg) of other ions were tolerated in the determination of 2.0μg of nickel: Fe(III) 3.0, V (V) 4.0, Zn 3.0, Mn(II) 1.5, Cd 0.6, Cu(II) 0.005, Co 0.01, Mg 3.0, Ca 2.0. The present method was applied to the determination of nickel in a sample of granodiorite.

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The color reaction product of creatinine with potassium 1, 2-naphthoquinone-4-sulfonate was isolated asdark blue violet prisms with mp 318°C. This compound has the characteristic that its alkaline solution is very unstable to the oxygen gas to decolarize. An equimolar amount of oxygen to the color reaction product dissolved in aqueous sodium hydroxide solution was absorbed and a decomposition product, 2-hydroxy-1, 4-naphtho quinone, was formed. This compound also produced the same product in a strong acidic solution. The structure of the color reaction product was elucidated to be 4-[3'H-1'-methyl-2'-imino-4'-oxo-5'-imidazo lylidene]-1-oxo-2-hydroxy-naphthalene on the basis of its spectral properties.

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An extraction-spectrophotometric method for the determination of antimony(III) with a reagent (BrPADAP) in the title has been presented. To thesample solution containing antimony(III) (125)μg in 2.5N sulfuric acid, were added 0.5ml of 1.2M potassium iodide, and then 2.5N sulfuric acid to make its volume of about 10ml. Antimony in the solutionwas extracted only once with 10ml of 0.002w/w % Br-PADAP benzene solution by shaking the mixturefor 1min. The absorbance of the extract was measured at 610nm referring to its reagent blank, for (2030)min after the extraction. (ε=5.9×10⁴ 1mol^-1 cm^-1)(Antimony in 100ml of the sample solution was also determined by this technique, if the added quantities of potassium iodide and of Br-PADAP were increased.)This method was applied to the determination of antimony in the benzene solution of antimony (III) chloride, and in each acetone solution of some organo antimony(V) compounds.

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An imporved method for the fluorophotometric determination of micro amounts of sulfide ion and 8-hydroxyquinoline were developed by using five halogenofluorescein mercury compounds as the reagents. The fluorescence intensities of silfide ionhalogenofluorescein mercury compounds and 8-hydroxyquinoline-halogenofluorescein mercury compounds were examined. Among them 3, 4, 5, 6-tetrachlorofluorescein mercury compound (T. Cl. Fl. Hg₄) formeda very stable, pink colors with sulfide ion or 8-hydroxyquinoline in the presence of polyvinylpyrolidone, and a marked decrease in the fluorescence intensity of T. Cl. Fl. Hg₄ solution accompanied with the color formation. Consequently, the fluorescence intensity of T. Cl. Fl. Hg₄-sulfide ion or T. Cl. Fl. Hg₄- 8-hydroxyquinoline complex was applied to a sensitive and simple fluorophotometric determination of minute amounts of sulfide ion and 8-hydroxyquinoline. Maximum difference of fluorescence intensity between T. Cl. Fl. Hg₄ solution and T. Cl. Fl. Hg₄-sulfide ion or T. Cl. Fl. Hg₄-8-hydroxyquinoline solution was observed at 550nm, and the fluorescence intensities were constant in the pH range from 6.4 to 7.0 for determination of sulfide ion and from 8.8 to 9.5 for determination of 8-hydroxyquinoline by adjustment, respectively. The calibration curves were linear in the concentration range of 0 to 40μg/10ml for sulfide ion and 0 to 20μg/10ml for 8-hydroxyquinoline, respectively. The effects of diverse ions on the fluorophotometric determination of sulfide ion and 8-hydroxyquinoline were examined. Zinc (II), lead(II), bismuth(III) and copper(II) could be masked by addition of iminodiacetic acid or nitrilotriacetic acid soluiton, but thiocyanate ion, thiosulfate ions and ammonium ion must be avoided. The reaction is quite sensitive, and the procedure is simple.

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An extraction-spectrophotometric method using 2-hydroxy-1-naphthaldoxime (HNA) was developed for the determination of palladium in palladium brazing filler metal. A required amount of the sample (0.1g) was dissolved by heating in 10ml of nitric adid (1+1). The solution was made up to 100ml with water, fromwhich a portion containing up to 100μg of palladium was transferred into a 50-ml separatory funnel. Two milliliters of 0.05 M zephiramine solution and 10ml of 2N sulfuric acid were added, and the solution was diluted to about 20ml with water. It was shaken with 10ml of 0.01M HNA-chloroform solution for 10min. After the organic phase was separated, a little turbidity in the organic phase was removed by centrifugation. The absorbance of the organic phase was measured at 402nm against the reagent blank. Palladium in palladium brazing filler metals colud be determined precisely with high reproducibility.

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Ethyleneglycol is oxidized to formaldehyde and determined colorimetrically by the reaction with either chromotropic acid or 3-methyl-2-benzothiazolinone hydrazone. It was found that the oxidatior of ethyleneglycol with potassium permanganate-sul.furic acid was accelerated by acetaldehyde-ammonia ([CH₃ CH(NH₂)OH]₃). Based on this fact, a procedure for the determination of ethyleneglycol was established To 1.0ml of the test solution containing (1040) of ethyleneglycol, add 0.2ml of 0.05w/v% ace. taldehyde-ammonia solution, 0.1ml of 0.25M sulfuric acid, and 0.1ml of 1.20% potassium permanganate solution. Allow the mixture to stand at room tem. perature for 50min. Add 0.1ml of 20% sodiurr sulfite solution to reduce excessive permanganate and 0.2ml of 2% aqueous chromotropic acid solution Add slowly 4ml of 75% sulfuric acid. Heat the mixture in a boiling water bath for 10min. Upon cooling to room temperature, measure the absorbance at 575nm against the reagent blank. The calibratior curve was linear in a range of (1040)μg ethylenegly. col/ml, the coefficient of variation being 4.2%. Me thanol and glycerol seriously yielded a positive interfer ence.

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Sub-pg levels of carbon monoxide (CO) have been determined by the use of the gas chromatograph equipped with a flame ionization detector and a catalytic reduction unit. This unit for conversion of CO to methane consists of the catalyst tube packed with Shimalite-nickel powder, a thermocouple and an electric heater. The catalytic reduction unit was attached between the separation column and the detector of the gas chromatograph. The specification and optimum operating conditions were as follows: catalyst, Shimalite-Ni, (80100) mseh, 3mm φ×35cm(0.81g); catalyst temperature, (340350)°C; carrier gas, hy drogen, (3040) ml/min. The quantity of 18pg of CO was the determination limit which could be actually determined under these conditions. The calibration curve for CO was linear up to the determination limit and the coefficient of variation for mesurements was within 5% on sub-pg levels of CO.

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Some enantiomers of hydroxyl acid esters, amino acid esters, and amino alcohols have been resolved by gas chromatography on optically active copper complexes of Schiff's bases with good separation factors. For example, DL-lactic acid isopropyl ester was resolved (α=1.16) on a 40m×0. 25mm i. d. open tubular glass capillary column coated with the binuclear copper complex of N-salicyliden-(R)-2-amino-1, 1-bis-(5-tert-butyl-2-octyloxyphenyl)-1-propanol (50 w/w% insilicone OV-101) within 10min at 70°C. The Disomer eluted prior to the L-isomer. These copper complexes which are a valuable catalyzer for the asymmetric synthesis have enabled the direct resolution of lactic acid enantiomers in their ester forms.

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Determination of mercury in the coastal sea water was studied for a flameless atomic absorption spectrometry with the pre-concentration of mercury on metallic gold. The apparatus used was the model "Mercury SP", Rigaku Denki Co. Ltd., which was modified by eliminating the sample heating furnace, oxidation furnace and one of gold columns for mercury collection. The reasons why the modifications were made are: (1) the original apparatus is not suitable for the treatment of a large amount of sample solution, (2) only sea water was analyzed in this study, and (3) a shorter passway of mercury vapor is desirable. The mercury collector made of gold was prepared by the deposition of gold (from tetrachloroaurate) on Chromosorb W by heating the mixture at 100°C for 2h and 600°C for 6h, successively. Sea water was sampled into a 11 glass bottle and then made to 0.5N acidic with sulfuric acid. To a 200ml portion of the sample solution, 0.1g of potassium permanganate was added and heated in a water bath for 1h.After cooling, nitrogen purified by passing the charcoaland gold-beds was bubbled into the solution at the rate of 11/min for 10min. Then added the 10ml of stannous chloride solution, and nitrogen was again passed through the solution at 0.8 1/min for 5min. The generated mercury vapor was expelled off from the gold bed by heating at 550°C with passing nitrogen. Interferences were not seen for 10ppm each of S₂O^2-₃, S^2- and L-cysteine, 100ppm of bromine, and 10ppm of iodine. Interferences caused with a large amount of iodine and bromine were avoided by the increase of addition of stannous chloride solution. The sensitivity of this method was as high as 0.025ng as mercury with standard deviation of 2%. Mercury content in the coastal sea water was 2 to 3 ppt for most samples.

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Three different ashing methods were tested for determination of mercury in biological and environmental samples in order to find out which gives the most accurate deta with the least procedural complication. The methods studied were: (A) dry ashing by combustion of samples in a quartz tube coupled with concentration by the gold-amalgamation, (B) acid-decomposition by a mixture of H₂SO₄/HNO₃ on a water bath for 3h, and (C) the bomb method with acid in a teflon vessel at 150°C. The best ashing conditions were investigated for the samples of fish meat, dried fish powder, and dried leaves. The wet ashing of the fat in fish samples by the mehthod (B) was incomplete although the mercury contents in the final solutions were found in good agreement with those obtained by the bomb method with which the fat could be completely decomposed at 150°C. The leaf samples were ashed to a clear solution by the bomb method when a mixture of H₂SO₄/HNO₃ and HF were used, and with this method a good reproducibility of data were observed. The three methods were also compared by ashing the four kinds of the marine environmental samples prepared by International Atomic Energy Agency (Monaco), and found. that there was no significant difference in the observed data which were also in good agreement with the ones reported by IAEA as the results of the International Intercalibration Experiments on trace element measurements (19761978).

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In this paper is described on the characterization of the trace odorants in air by gas chromatography using two preconcentration methods, namely, the cold trapping with liquid oxygen and the adsorption trapping with the porous polymer beads (such as Tenax-GC) at room temperature. The odorants (147 odorants) were classified into the following eight groups, i.e., Group (I): Sulfur compounds; Group (II): Lower aliphatic amines; Group (III): Carbonyl compounds; Group(IV): Hydrocarbons; Group(V): Lower aliphatic mono alcohols; Group (VI): Phenols; Group (VII): Lower fatty acids; Group(VIII): Indoles. The conditions for the systematic gas chromatography of the eight odorant groups in air are listed in Table 1. The concentration volumes, detection limits, the time required for analysis (including the sampling time) and the accuracy of the present method for the analyses of the eight odorant groups were as follows: the concentration volumes, (150) 1; the detection limits, about (0.052) ppb; the time required, less than about 40 min; the accuracy (in the coefficient of variation), less than about 10%. A new unit pOU is also proposed for the characterization of the eight odorant groups in some fetid air. The quantity pOU is defined by the following equation: pOU=Σlog(C₁, ppb/R.Th.V.₁, ppb+C₂, ppb/R.Th.V.₂, ppb+……+C_n, ppb/R.Th.V._n, ppb) where C₁, C₂……C_n are the detected concentrations (in ppb) of the respective odorant group; R. Th. V.₁, R. Th. V.₂ …… R. Th. V._n are the corresponding odor perception threshold values (in ppb) of the detected odorant group, respectively. The calculated pOU values of the eight odorant groups {Group (I) to Group (VIII)} were plotted on a circular chart. The present method was applied to the characterization of the eight odorant groups detected for the cigarette smoke odor in the 10m³ stainless steel odor-free room. The results of the detected concentrations, the pOU values of the eight odorant groups are listed in Table 2, and a circular odor chart for the cigarette smoke odor is illustrated in Fig. 10. As shown in Table 2 and in Fig. 10, it is found that the odorant group (I) contributes most to the perception of the characteristic cigarette smoke odor since the pOU value of the odorant group (I) is 1.51 which is the largest of the eight odorant groups. As the pOU values of the odor components, acetaldehyde and 3-methylindole are large the odorant groups (III) and (VIII) can also be considered to be the main odor groups, while the contribution of the odorant groups (II) and (VI) is only appreciable, and that of the odorant groups (IV), (V) and (VII) very little.

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