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Volume 27, Issue 7
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Yasuyuki HOSHIKA1978 Volume 27 Issue 7 Pages 381-386
Published: July 05, 1978
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSThe gas chromatographic determination of the traces of n-, iso-butyric and n-, iso-valeric acids in air at ppb level was performed using a precolumn. The chromatographic conditions were as follows: main analytical column packing, 0.3% FFAP +0.3% H3PO4 on Carbopack B (60/80 mesh) ; column size, 1.5 m × 3 mm i. d., glass; column temperature, 200°C; carrier gas, nitrogen flow rate, 65 ml/min. The four fatty acids were separated within 8 min without tailing. The precolumn packing, 0.3% SP-1000 + 0.3% H3PO4 on Carbopack B (60/80 mesh) ; column size, 18 cm × 4 mm i.d., glass. The trapping was operated at room temperature (about 20°C) and the temperature was elevated to 200°C in 24 s. The acids were detected with a flame ionization detector (FID). The coefficient of variation of the retention times and the peaks areas (as the counts of digital integrator) of (91000) ng of the four fatty acids in this method were less than 3.8% and 9.7%, respectively. The linear relationship was obtained between the peak areas and the amounts of four fatty acids over the range (24000 ) ng. The minimal detectable quantity of the four lower fatty acids was about 0.5 ng. The present method was applied to the determination of known concentrations {about (1113) ppb} of the four lower fatty acids in 10 m3 odor free room. The coefficient of variation of the determination was less than 11%.View full abstractDownload PDF (1072K) -
Yoshimi SASAKI1978 Volume 27 Issue 7 Pages 386-390
Published: July 05, 1978
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSDetermination of total strong chelating agents in water and waste water was performed. The method consisted of the dissolution of equivalent copper (II) oxide with the chelating agents to be determined and the subsequent spectrophotometry of dissolved copper (II) with sodium diethyldithiocarbamate (NaDDTC). A sample solution containing strong chelating agents (less than 2 × 10-6 mol), 3 cm3 of 0.05 mol dm-3 CuSO4 and 2 cm3 of saturated NaCl were put into a beaker. After the pH was adjusted to 10.0 ± 0.2 with 0.2 mol dm-3 Na2CO3, the solution was evaporated to about 40 cm3. To obtain a good coagulation of the precipitate, 2 cm3 of 0.05 mol dm-3 KAI (SO4)2 was added. After cooling the sample was transferred into a 50 cm3 measuring flask and diluted with water. After centrifuged for 30 min, 25 cm3 of the supernatant was taken into a separating funnel which contained 2 cm3 of 0.05 mol dm-3 NaDDTC and 10.0 cm3 of CCl4. Then the mixture was shaken for 10 min and the absorbance of the CCl4 phase was measured at 436 nm. Usual foreign cations and anions did not interfere.View full abstractDownload PDF (777K) -
Masayoshi KIYOKAWA, Akira KAWASE1978 Volume 27 Issue 7 Pages 391-395
Published: July 05, 1978
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSThe compounds, 1-(5-nitro-2-pyridylazo)-, 1-(2-quinolylazo)-, 1-(2-benzothiazolylazo)-, 1-(2-benzox-azolylazo)-9-phenanthols were synthesized as reagents for the determination of small amounts of metals and their metal complexing properties were studied. The influence of the heterocyclic azo groups on the analyticl properties of the reagents were studied. The sensitivity of the reagents for the metal ions was found to be higher than that of parent compound 1-(2-pyridylazo)-2-naphthol. Extension of the π-system of the molecule should lead to sensitive reactions. The effect of nitro group in 5-position of the pyridine ring on sensitivity was large. The acid dissociation constants of the reagents and the formation constants of 1 : 1 chelates in aqueous dioxane were determined spectrophotometrically. Replacement of pyridine ring by benzothiazole or benzoxazole resulted in a decrease in pKa2 values of the reagents. The effect of these groups on the acidity of the hydroxyl group was practically the same and the nitro group in 5-position of the pyridine ring had a great effect on the basicity of N atom of the pyridine. The higher acidity of these reagents was accompanied by decrease in metal chelate stabilities, but proton displacement constants of 1-(2-benzoxazolylazo)-9-phenanthol (BOAP) chelates were larger than those of the other reagents, so that the pH values at which BOAP formed metal chelates were 1 to 3 units higher. The distribution behavior of the reagents and their chelates formed were studied. The composition of the extractable copper chelates was found to be neutral 1 : 2 chelates. An analytical advantage of these reagents was lower aqueous solubilities and higher distribution constants of the chelates.View full abstractDownload PDF (922K) -
Study of solvent synergism for the selective extraction. IITaitiro FUJINAGA, Toshitaka HORI, Yoshihiro KANADA1978 Volume 27 Issue 7 Pages 395-399
Published: July 05, 1978
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSThe authors have already reported a study on phase separation of three component systems composed of 1-butanol-water-cyclohexane and methyl isobutyl ketone-water-cyclohexane. In the present work, partition behaviors of heteropoly molybdic acids of phosphate and silicate have been investigated using these mixed solvents. As it was found that cyclohexane, the synergistic solvent, properly decreases the dielectric constant of the executive solvent of 1-butanol and methyl isobutyl ketone, the stepwise extraction of the respective heteropoly molybdic acid could be achieved in the appropriate conditions: in the presence of (4045)% cyclohexane. Cyclohexane functions not only to improve the phase separation of these three component systems, but also to increase the partition coefficient of an objective solute and/or to decrease the partition coefficient of interfering solutes. These facts mean that cyclohexane acts as a synergistic solvent in the present solvent extraction. In conclusion, such three component systems studied by the aid of phase diagrams could be effectively applied for a variety of extraction analyses.View full abstractDownload PDF (931K) -
Ryota SHINOHARA, Teiji HORI, Minoru KOGA1978 Volume 27 Issue 7 Pages 400-405
Published: July 05, 1978
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSTrace analyses of terphenyl isomers in water and sediment by mass fragmentography were studied. The isomers in water samples were extracted with n-hexane and the average recovery was approximately 95%. For sediment samples, a continuous extractor was used and the extraction for 4 h was enough to get a good recovery. Silica-gel column chromatography was applied to remove interferences. In this procedure the first n-hexane fraction (16 ml) was discarded and then terphenyls were eluted in a fraction of n-hexane: benzene mixture (20% benzene in n-hexane, 20 ml). Nano grams of terphenyl isomers were sufficiently separated on 3% OV-17 as a liquid phase in GC-FID system. For determination of pico grams of terphenyls by mass fragmentography, mixed columns of 1% OV-101/0.1% Bentone 34 and 2% OV-101/1% BMBT were used. Detection limits of terphenyls in a water sample were 0.007, 0.025 and 0.05 ppb for o-, m- and p-isomer, respectively. Those for a sediment sample were 0.14, 0.5 and 1.0 ppb, respectively. Water and sediment samples taken in the Kitakyushu district were analyzed. No terphenyl isomers were detected in water samples, while, 0.8 to 390 of o-isomer, 1.1 to 210 of m-isomer, and 1.7 to 180 ppb of p-isomer were found in sediment samples.View full abstractDownload PDF (965K) -
Kenjiro HAYASHI, Hisako DOUKAN, Atsuo YAMAMOTO1978 Volume 27 Issue 7 Pages 405-409
Published: July 05, 1978
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESS1-Pyrrolidinecarbodithioate ion (hereinafter abbreviated to pdtc) forms a sparingly soluble precipitate with copper (II) ion. This precipitate was dissolved in water in the presence of nonionic surfactant such as Triton X-100 (alkylphenolpolyoxyethylene ether) and gave an absorption maximum at 440 nm. This color development was applied to the spectrophotometric microdetermination of copper (II). The recommended procedure for the determination of copper (II) with pdtc is as follows: Take into a 25 cm3 measuring cylinder with ground stopper an aliquot of sample solution containing less than 95.3 μg of copper (II). Add 4 cm3 of 1.25× 10-1 mol dm-3 EDTA solution, and 1 cm3 of 1 mol dm-3 acetate buffer (final pH of the solution adjust to 4.76.1). Adjust the solution to 16 cm3 with water. Add 2 cm3 of 10.0 (v/v) % Triton X-100 solution and 2 cm3 of 1.0 × 10-1 mol dm-3 pdtc solution. Measure the absorbance at 440 nm against water. A linear relationship was obtained within the range of (1.395.3) μg Cu (II) /20 cm3. The molar absorption coefficient at 440 nm was 1.57 × 104. The ions which interfere seriously in this method are Cd (II), Fe (III), Mn (II), Co (II) and CN-. However, at the concentration of 2.5×10-2 mol dm-3 of EDTA, zinc (II) up to 70 mg, iron (III) up to 0.8 mg, cadmium (II) up to 0.1 mg, manganese (II) up to 0.3 mg and cobalt (II) up to 0.03 mg had no interference on the determination of 63.5 μg of copper (II) in 20 cm3. This method does not need solvent extraction and is rapid, and simple. The composition ratio of copper (II) to pdtc in the dissolved yellow colored complex was 1:2 by Yoe-Jones plot and the continuous variation plot. This agreed with the results from gravimetric and solvent extraction analyses. Therefore it is assumed that the precipitate of Cu (pdtc)2 is highly soluble in micelles of Triton X-100 formed in water.View full abstractDownload PDF (814K) -
Tadao SAKAI, Noriko ISHIDA1978 Volume 27 Issue 7 Pages 410-414
Published: July 05, 1978
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSQuaternary ammonium salts, amines and alkaloids have sensitively been determined with tetrabromophenolphthalein ethyl ester (TBPE). Accordingly, amines and alkaloids gave strong interferences on the determination of quaternary ammonium salts. Therefore, as a method which supplement this point, a new spectrophotometry has proposed for the determination of quaternary ammonium salts with 2, 6-dichlorophenolindophenol or picric acid, but these have poor sensitivity compared with TBPE. It is found that only TBPE-R3N series show a reversible thermochromism. That is to say, the red colored species, being molecular addition compounds, decreases with the rising of temperature on measurements. On the other hand, blue colored species do not change. The red species contained in blue species disappears at 60°C. It can be assumed the following equation;
TBPE·H·R3N0 warmed _??_ cooled TBPE·H0+R3N0
(Red) (Yellow) (Non)
Therefore, amines and alkaloids give little interferences on the determination of benzalkonium by thermochromism on measurements. The calibration curve was prepared as follows: (15) ml of a standard benzalkonium solution (2.5 × 10-5 M) is taken in the separatory funnel, and 5 ml of borate(0.1 M)-phosphate (0.2 M) buffer (pH 7.5) and 2 ml of TBPE solution (4 × 10-3) are added. It is diluted to 50 ml with water, and shaken with 10 ml of 1, 2-dichloroethane for 5 min. The extracts are centrifuged to remove droplets of water. The absorbance is measured at 610 nm against a reagent blank. ε at 25°C was 7.5 × 104 mol-1 cm-1 and s at 60°C 7.3 × 104 mol-1 cm-1 l.View full abstractDownload PDF (833K) -
Kanji TSUJII, Kazuo KUGA1978 Volume 27 Issue 7 Pages 415-419
Published: July 05, 1978
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSA new glow discharge chamber is constructed and used as an atom reservoir for atomic absorption spectrometry. The anode of the chamber is positioned at about 0.2 mm from the cathode. After evacuation of the system to about 10-3 Torr by a rotary pump, an operating pressure was maintained by bleeding the high purity Ar. The discharge took place in the abnormal glow region. Cathodic sputtering occurred only on the limited part of the specimen located opposite the cylindrical anode cavity. The following features were observed for a brass specimen (Cu: 59.5%, Zn : 34%): (1) The absorbance of Cu went through a maximum and then decreased with the increase of voltage and current for each Ar pressure; (2) The maximum absorbance increased with the in crease of Ar pressure; (3) The maximum absorbance appeared near the same voltage region for each Ar pressure. However, the maximum shifted to the direction of higher current with the increase of Ar pressure; (4) The sputtering rate measured at 3.3 Torr of Ar increased with the increase of voltage. To assess the performance of the sputtering chamber in practical analysis the relationship between the concentration of Co and absorbance of Co was measured using iron base alloys (The Iron and Steel Institute of Japan). When using this technique in practical analyses dual-wavelength atomic absorption measurements with an appropriate element as an internal standard are desirable.View full abstractDownload PDF (729K) -
Takatomi MINAMI, Yoshikazu YAMAMOTO, Shunzo UEDA1978 Volume 27 Issue 7 Pages 419-423
Published: July 05, 1978
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSArsenic(V) reacts with Bismuthiol II to form a light yellow precipitate in hydrochloric acid solution, which is extracted into chloroform. The spectrophotometric determination of As(V) based on this reaction was studied. The recommended procedure is as follows: To a sample solution containing up to 50 μg of As (V), hydrochloric acid and 5 ml of 0.1% reagent solution are added, the whole volume being adjusted to about 30 ml and the HCl concentration to (34) M. The solution is allowed to stand for 10 min at a temperature below 22°C. Then, the precipitate is extracted by shaking for 10 min with 10 ml of chloroform. To remove the excess reagent from the chloroform extract, it is washed twice by shaking for 90 s with 20 ml each of the buffer solution (potassium phosphate/sodium borate, pH 7.5) and the absorbance is measured at 335 nm against the reagent blank. Beer's law was held up to 50 μg-As(V) in 10 ml of chloroform and the molar absorptivity was 1.62×104 l mol-1 cm-1 at 335 nm. Large amounts of Al (III), Cd(II), Co(II), Mn(II), Ni(II), Pb(II), Zn(II) and PO43- do not interfere with the determination of As (V), but Cr(VI), Mo(VI), Pt(IV), Se(IV), Te(IV) and V(V) interfere.View full abstractDownload PDF (834K) -
Masahiro KANAI, Tadashi KIKUCHI, Keiichi FURUYA, Satoshi HAYAKAWA1978 Volume 27 Issue 7 Pages 424-428
Published: July 05, 1978
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSFor the determination of nitrogen in ferrovanadium and ferrotitanium, a vacuum fusion method, two inert gas fusion methods and a modified Kjeldahl method were compared. The effect of Pt, Pt-Ce, Ni and Ni-Ce as bath metal was investigated for vacuum fusion and inert gas fusion methods, and best results were obtained for nitrogen when the ratio of bath metal to sample was 45 in inert gas fusion method with the Pt bath. Kjeldahl method was a modified JIS method involving 40 ml sulfuric acid (1+4) as solvent {Bunseki Kagaku, 19, 1278 (1970)}. In ferrovanadium analysis the highest value of nitrogen was obtained by inert gas fusion method with heat and extraction time for 30 s (Leco TC-36) when platinum was used as a bath metal (A). The determination values of nitrogen with vacuum fusion method with Pt-Ce bath using graphite capsule and with Kjeldahl method (B) were 10% lower than those by (A). Inert gas fusion result by heat and extraction time for 15 s (Leco TC-30) was lower than other methods. In ferrotitanium analysis, nitrogen values of (A) and (B) were in good agreement while other methods gave inferior results to those. A high fusion temperature for certain time duration and a quick heating-up for sample in inert gas fusion method were inferred to give better nitrogen decomposition and extraction from such samples as ferrovanadium and ferrotitanium.View full abstractDownload PDF (1024K) -
Kiyokazu SONODA, Makoto OTOMO, Kazunobu KODAMA1978 Volume 27 Issue 7 Pages 429-434
Published: July 05, 1978
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSPurified Xylenol Orange (XO) and semi-Xylenol Orange (SXO) are tested as metallochromic indicators in the direct EDTA titration of 9 metals and as spectrophotometric reagents for the determination of zirconium and bismuth. The results are also compared with those reported previously with commercial products of XO, which generally contain appreciable amounts of SXO. XO can be used as an excellent indicator for all the metals investigated, except for indium, since it forms intensely colored (reddish-violet or blue violet) complexes with the metals and gives a sharp color transition at the equivalence point of the titration. On the other hand, SXO, which forms pink or pink-red metal complexes, can also be employed as an indicator for zirconium, thorium and bismuth, but rather poor end-points are observed in the titrarion of the other metals. The use of pure XO is therefore preferable in the routine back-titrations with a standard bismuth, lead or zinc solution. In the spectrophotometric determination of zirconium and bismuth with XO, the optimal conditions for the determination and the spectral properties of the complexes formed are considerablly different from those reported previously. It should be noted that, as a spectrophotometric reagent, SXO is much superior to XO in sensitivity, although both reagents can be conveniently used for the determination of these metals.View full abstractDownload PDF (959K) -
Shoji HIRAI, Shogo SUZUKI, Makoto OKAMOTO1978 Volume 27 Issue 7 Pages 435-440
Published: July 05, 1978
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSThe method for the rapid, precise and routine determination of selenium in biological materials was investigated by means of instrumental neutron activation analysis using the short lived 77mSe (T1/2= 17.5 s). The each sample was irradiated for 10 s in a pneumatic system at Musashi Institute of Technology Research Reactor in a thermal neutron flux, 1×1012n cm-2 s-1. After about 30 s from the end of the irradiation, gamma-rays were counted for 30 s using a 15% relative efficiency Ge (Li) detector, of resolution 2.0 keV at 1332 keV, which was coupled with a multichannel analyzer to accumulate 01000 keV gamma-rays in the 02000 channels. The reproducibility in the irradiation and the measurement was (45)% as the coefficient of variation. Under the various conditions of cooling time, counting time and selenium contents, the spectra analysis program for the decay and dead time correction was examined and found to be reliable for our purpose. Selenium in NBS Bovine Liver was nondestructively determined by the present method, and selenium content was found to be (1.07±0.11) μg/g {NBS certified value: (1.1±0.1) μg/g}. Selenium in mouse organs and fish was also determined precisely within about two min. It can be concluded that the present method allows us to carry out the determination of selenium in biological meterials precisely as a rapid routine work.View full abstractDownload PDF (1008K) -
Kazuo KUGA, Kanji TUJII1978 Volume 27 Issue 7 Pages 441-443
Published: July 05, 1978
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSTrace amount of rare earth and alkaline earth elements was determined by graphite furnace atomic absorption spectrometry using the pyrolytic graphite coated tube. The apparatus used was a Hitachi atomic absorption spectrometer (Model 308) equipped with a Perkin Elmer graphite furnace atomizer (Model 2000). The pyrolytic-graphite-coated tubes were made in argon atmosphere containing (210) % volume of methane by heating the conventional tube (lengh; 53 mm, internal diameter 8.5 mm, external diameter; 10.5 mm) up to 2200°C for (210) min. The tube was applied to the determination of rare earth and alkaline earth elements by graphite furnace atomic absorption spectrometry. The sensitivity for Er, Eu, Gd, Ho, La, Pr, Sm, Tb, Y, Yb, Ba, Sr and Ca increased (2.56) fold by using the pyrolytic-graphite-coated tube.View full abstractDownload PDF (438K) -
Tadao SAKAI1978 Volume 27 Issue 7 Pages 444-447
Published: July 05, 1978
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSThis paper deals with an extraction-spectrophotometric method for the determination of berberine in pharmaceuticals with picric acid (PCA). As shown in the previous paper, TBPE (tetrabromophenolphthalein ethyl ester) method has no selectivity because of the reaction with many onium compounds, in spite of having high sensitivity and stability. Therefore, DCIP (2, 6-dichlorophenolindophenol) method has been proposed on supplement of TBPE method for the depression of interferences of trace amounts of amines. However, DCIP has weak points on stability and effect of reagent concentration. On the other hand, this proposed method using PCA is excellent with respect to interferences, pH range and stability. Therefore, PCA method can supplement the former methods on various factors. The procedure is as follows; Phosphate buffer solution (pH 8) 5 ml, PCA solution (4×10-3 M) 2 ml and berberine standard solution (5×10-5 M) (15) ml are poured into a separatory funnel. After diluting the mixture to 50 ml with water, 10 ml of 1, 2-dichloroethane is added. After the solution is shaked for 3 min, the organic phase is centrifuged to remove droplets of water. The absorbance of the extracts is measured at 360 nm, using a reagent blank or water as a reference. Various inorganic or organic anions and cations do not interfere. However, only acrinol interfered slightly. Consequently, this method can be applied to the determination of berberine in pharmaceuticals containing many additions. The molar absorptivity is 4.0×104 mol-1 cm-1 l. The extracted species is presumed to be a 1:1 ion-pair compound between berberine and PCA.View full abstractDownload PDF (750K) -
Synergistic extraction of cadmium (II) in the presence of zinc (II) with thiothenoyltrifluoroacetoneHideo AKAIWA, Hiroshi KAWAMOTO, Yukihiko TSUTSUMI1978 Volume 27 Issue 7 Pages 447-449
Published: July 05, 1978
Released on J-STAGE: February 16, 2010
JOURNAL FREE ACCESSThe selectivity in the synergistic extraction of cadmium (II) and zinc (II) with a mixture of thio-thenoyltrifluoroacetone (STTA) and a pyridine base was surveyed. The degree of synergistic effect of a pyridine base in the extraction of cadmium (II) was more remarkable than in the case of zinc (II). As a result, preferential extraction of cadmium (II) could. be performed. In order to attain the complete separation of cadmium (II) from zinc (II), we employed 2, 2'-dipyridyl (dipy), which might act as an additive in cadmium (II) extraction due to possible formation of an adduct Cd (STTA)2(dipy) and at the same time, this reagent is expected to work as a masking agent for zinc (II). The procedure for the separation is as follows: Twenty ml of an aqueous solution. containing 0.1 M sodium chloride (pH=3.6) is equilibrated with an equal volume of 1×10-3 M STTA and 0.1 M 2, 2'-dipyridyl in 1, 2-dichloroethane by shaking the mixture for 10 min. Only cadmium (II) is selectively extracted into the organic phase.View full abstractDownload PDF (495K) -
Hideo AKAIWA, Hiroshi KAWAMOTO, Toshikazu TAKENOUCHI1978 Volume 27 Issue 7 Pages 449-452
Published: July 05, 1978
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSThe procedure for the determination of cadmium (II) in the presence of large amounts of zinc (II) is as follows: Take a sample solution containing 0100 μg of cadmium (II) in a separatory funnel. After the addition of 10 ml of 10% thiourea solution and 5 ml of 20% potassium iodide solution, adjust the pH to 5.8 by adding 5 ml of 5% urotropine solution. The resulting volume should be ca. 50 ml. Add 20.0 ml of 5% Capriquat in chloroform, and then shake the mixture for 3 min. Transfer the organic phase to another separatory funnel, and repeat the extraction with 20.0 ml of the Capriquat solution. Wash the aqueous phase with 10.0 ml of pure chloroform. Combine the extracts and backextract zinc (II) twice with 20 ml of 10% potassium nitrate solution, then add 5 ml of 0.1% 1-(2-pyridylazo)-2-naphthol in methanol, 10 ml of 10% ammonium nitrate solution and allow the phases to separate. Measure the absorbance of the organic phase at 555 nm against a reagent blank. The calibration curve was linear over the concentration range of 0100μg cadmium (II) /50 ml, the Sandell sensitivity being 0.0044 μg/cm2. The effect of diverse ions was also investigated. Almost all metal ions did not interfere with the determination. The present method was applied to the determination of trace amount of cadmium in high purity metallic zinc.View full abstractDownload PDF (691K) -
Kohei SHIMOKAWA, Hideaki TAKADA, Norito WATANABE1978 Volume 27 Issue 7 Pages 452-454
Published: July 05, 1978
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSThe method of entrainment distillation with water was applied to the analysis of bottom sediments for PCB. The apparatus for volatile oil determination was slightly modified to prevent the following troubles, that is, foaming and bumping of the sample solution and evaporation of the extracting solvent during distillation of PCB from a sediment sample. Analytical results obtained by this method were in good correlation with those by the solvent extraction method but the former gave somewhat higher results than the later. Moreover, reproducibility of the distillation method was better than that of the solvent extraction method, the coefficient of variation being 6.5% and 8.2%, respectively.View full abstractDownload PDF (598K) -
Toru NOZAKI, Kiyoshi TAKEUCHI, Tadamichi YAMAUCHI, Takeshi NOMURA1978 Volume 27 Issue 7 Pages 454-457
Published: July 05, 1978
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSTwo component separations involving titanium (IV), zirconium (IV) iron (III), aluminum (III), gallium (III), indium (III), copper(II) and zinc (II) were carried out by using a column (i. d. 0.9 cm, height 10 cm) of Amberlite IR-120 {(60100) mesh} in the hydrogen form. 5 × 10-5 mol each of metallic element was loaded on to the top of the column. After washing the column the eluant was passed down the column at a flow rate of 0.5 cm3 min-1, and the metal in each fraction (10 cm3) of the effluent was determined chelatometrically after decomposition of the oxalato complex and excess oxalic acid with ammonium peroxodisulfate. Complete separations were achieved of titanium from aluminum, titanium from copper, zirconium from aluminum, iron from aluminum with 0.05 M oxalic acid-0.4 M hydrochloric acid, gallium from indium with 0.05 M oxalic acid-0.2 M hydrochloric acid, indium from zinc with 0.05 M oxalic acid-0.6 M hydrochloric acid, zirconium from titanium with 0.02 M oxalic acid-0. 12 M hydrochloric acid, zirconium from copper with 0.01 M oxalic acid-0.02 M hydrochloric acid, and zirconium from iron with 0.005 M oxalic acid-0.01 M hydrochloric acid.View full abstractDownload PDF (620K) -
Eiji UCHINO, Shigeki KONISHI, Masakichi NISHIMURA1978 Volume 27 Issue 7 Pages 457-459
Published: July 05, 1978
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSThe total blank in reagents used for mercury determination is sometimes higher than the content of mercury in a sample. Methods for determination of mercury blanks and reducing the mercury contents in the reagents used frequently for digestion of biological materials and natural waters are presented. To determine the mercury blank in reagents, following method was used. Appropriate amounts of H2SO4 and SnCl2 solutions were added to pure water in a flask, and the mercury in the solution was expelled by bubbling nitrogen gas. A certain amount of a reagent solution of which mercury concentration was to be determined was added, and the mercury vaporized by bubbling nitrogen gas was collected on silver powder. The silver was heated and the released mercury was determined by atomic absorption spectro-photometry. The following methods were used to reduce mercury concentration in the reagents. To a 100 ml solution of H2SO4, HCl, NH2OH·HCl, NaCl or water, 5 g of Unicellex chelating resin was added. To a 100 ml solution of H2SO4 or NH2OH·HCl, 5 g of charcoal (200 mesh) was added. The solutions were shaken for 30 or 60 min, or allowed to stand for one day with occasional shaking. In the case of using the resin, the supernatant was used, and in the case of charcoal the solution was centrifuged. A small amount of sodium oxalate was added to a permanganate solution, followed by boiling for 2 h and filtration through a Millipore filter (0.45 μm). Nitrogen gas was passed through a SnCl2 solution. Sub-boiling distillation method was adopted for HNO3. Generally, the mercury concentrations in the reagents were reduced by one order of magnitude.View full abstractDownload PDF (458K) -
Katsumi YAMAMOTO, Yuichi TAKANO1978 Volume 27 Issue 7 Pages 460-461
Published: July 05, 1978
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSWe found that the reactivity of chromium (III) with complexing agents was accelerated when the oxidation state of chromium (III) was turned to change to (IV) or (V) in the presence of hydrogen peroxide. Consequentry, we applied the finding to the reaction of chromium (III) and 4-(2-pyridylazo)-resorcinol (PAR) to obtain more sensitive and simple method for the determination of chromium (III). A given quantity of chromium (III), 2 ml of 5.00 × 10-3 M PAR, 2 ml of 2 M acetic acid-sodium acetate buffer solution, and 3 ml of 1 M hydrogen peroxide were pipetted into a 100 ml Erlenmeyer flask fitted with a plug. The final volume was brought to 50 ml by the addition of redistilled water. The solution was warmed for 20 min at 40°C in a thermostatically-controlled water bath. After cooling to room temperature, a portion of the solution was then transferred into a cell. The measurements of absorbance were made at 530 nm. The calibration curve was obtained by the above procedure for the concentration range of (0.100.52) μg ml-1 of chromium (III). The molar absorptivity at 530 nm was calculated to be 5.1 × 104 1 mol-1 cm-1. The method is very sensitive and simple.View full abstractDownload PDF (321K)
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