Vol. 5 0, No. 2
February, 2 0 0 1
Hideyuki Matsunaga*
*Tohoku National Industrial Research Institute, 4-2-1, Nigatake, Miyagino-ku, Sendai 983-8551
(Received 12 May 2000)The history of studies on the recognition, separation and concentration of metal ions with chelating resins or chelating reagent impregnated resins (RIR) has been briefly surveyed with 195 references. Both types of chelating resins have been extensively studied in order to develop highly effective separation and detection methods for various metal ions. In this review, the preparation and adsorption mechanisms are mainly summarized. Especially, a method called "Molecular Imprinting" has recently been developed to make new types of chelating resins having high selectivity for specific metal ions. It is shown that chelating resins synthesized based on this idea have high selectivity for imprinted metal ions. The adsorption of metal ions with RIR has attracted considerable attention since it was introduced, because of its advantage of easy preparation. Adsorption mechanisms have recently been studied for various types of RIR. It has been suggested that different preparation methods for RIR give different adsorption mechanisms. Thus, information on the physical state of the reagent impregnated in the resin particles should also be very important to prepare efficient RIR. The separation and concentration of metal ions with these solid materials are expected to be highlighted in the 21st century, since they can provide simple and clean separation technologies that cause few environmental problems.
Keyword : chelating resin; chelating reagent impregnated resin; metal ions; recognition; separation and concentration.
Izumi Ishikawa*,** and Taichi Sato*,***
*Faculty of Engineering, Shizuoka University, 3-5-1, Jyohoku, Hamamatsu-shi, Shizuoka 432-8561
**Present, 1-5-1, Kiba, Koto-ku, Tokyo 135-8512
***Present, Department of Materials and Metallurgical Engineering, Queen's University, Kingston, Ontario K7L 3N6, Canada
The solvent extraction of mercury(II) from nitric acid and hydrochloric acid solutions by dihexyl sulphide (DHS, R2S) in benzene has been investigated under different conditions. The organic extracts were examined by infrared and Raman spectroscopies. As a result, the following equilibrium equations are proposed for the extraction of mercury(II) by DHS: from nitric acid solutions, Hg(NO3)2(a)+mHNO3(a)+2R2S(o)
(R2S)2Hg(NO3)2(HNO3)m(o), where m=0 and 1 are satisfied at [HNO3] < 4 mol dm-3 and 4 mol dm-3, respectively, in which (a) and (o) represent the aqueous and organic phases, respectively. The equilibrium equation, Hg (NO3)2(a)+mHNO3(a)+R2S(o)R2S·Hg(NO3)2(HNO3)m(o), is expected at a higher loading of mercury; from hydrochloric acid solutions, HgCl2(a)+2R2S(o)(R2S)2HgCl2(o), and when mercury loading increases, HgCl2(a)+R2S(o)R2S·HgCl2(o).
Keywords : solvent extraction; equilibrium equation; dihexyl sulphide; mercury(II).
Shingo Saito, Wen-zhe Xu, Hitoshi Hoshino* and Takao Yotsuyanagi*,**
*Department of Applied Chemistry, Graduate School of Engineering, Tohoku University, Aoba-ku, Sendai 980-8579
**Present address: Miyagi National College of Technology, 48, Nodayama, Shiote Medeshima, Natori-shi, Miyagi 981-1239
A sensitive and selective determination of closed-shell rare earth metal ions (La3+, Lu3+, and Y3+) has been demonstrated using a pre-column chelating reagent {8-amino-2-[(2-amino-5-methylphenoxy)methyl]-6-methoxyquinoline-N,N,N',N'-tetraacetatic acid (Quin2)}, in reversed-phase HPLC. Although the resolution is still unsatisfactory in this HPLC system, rare- earth metal chelates with this octadentate aromatic polyaminocarboxylate can be detected. This result suggests that these chelates are unexpectedly inert for the dissociation process during elution. The order of elution is quite different from that of the conventional ion-exchange mode separation. Middle-lanthanide ion-Quin2 chelates were most rapidly eluted, followed by the heavy ones; the light ones were the most strongly retained. Since ligand-centered fluorescence was observed for only La3+, Lu3+, Y3+, and Gd3+-Quin2 chelates, and other rare earth metal ion chelates were sufficiently quenched through a paramagnetic deactivation process, these four metal ions were selectively detected by fluorimetric detection (λex=335 nm, λem=500 nm). The detection limits of La3+, Lu3+, and Y3+ were 2.2, 4.0, and 1.9 ppb, respectively, on a 3σ basis. No interference from each 10-fold excess of other rare-earth metal ions was observed. The success of this HPLC system for rare- earth ions is derived from the combined properties of the Quin2 chelates in terms of inertness, chromatographic retention and fluorescence detection.
Keywords : rare earth metal; reversed-phase HPLC; fluorescence detection; Quin2; metal chelate.
Kiyotoshi Morishige*, Masaki Yoshida**, Yoshiaki Yoshitake***, Mitsuya Matsumori, Kiyoshi Nishiyama and Hidetoshi Gotoh*
*Department of Chemistry, Faculty of Science and Technology, Kinki University, 3-4-1, Kowakae, Higashiosaka-shi, Osaka 577-8502
**Mitsuwa Chemicals Co., Ltd., 1-2-9, Doshomachi, Chuo-ku, Osaka 541-0045
***Kinki University attached Junior High School, 5-1-3, Wakaeshinmachi, Higashiosaka-shi, Osaka 578-0944
As fluorometric reagents for niobium and tantalum and several heavy metal ions, three derivatives of hydrazone {2-pyridinecarboxaldehydepicolinoylhydrazone(hyd·H), 2-acetylpyridinepicolinoylhydrazone(hyd·CH3), 2-benzoylpyridinepicolinoylhydrazone(hyd·C6H5)} were synthesized. The hyd·H was a specific and excellent fluorometric reagent for niobium(V), because the reagent did not react with tantalum(V). However the hyd·CH3 was effective for the fluorometric determination of the total amount of niobium(V) and tantalum(V) in the presence of tartaric acid(4 mg/25 cm3). Further, the fluorometric intensity of hyd·H3-Nb(V) and hyd·CH3-Ta(V) complexes showed an additive property. Because fractional determinations of niobium(V) and tantalum(V) are possible by these reagents, they were used for the rapid and accurate determination of niobium(V) and tantalum(V) in minerals. The relative standard deviation (n=5) of fluorometric measurements was less than 3.7% at 2 µg of niobium(V) for a tantalum determination with hyd·CH3, and 1.9% at 5 µg of niobium(V) for a niobium determination with hyd·H. Two minerals were analyzed. Fergusonite contained 19.8% of Nb2O5 and 5.66% of Ta2O5, and manganotantalite contained 5.12% of Nb2O5 and 50.3% of Ta2O5.
Keywords : fluorometric analysis; derivatives of picolinoylhydrazone; determination of niobium(V) and tantalum(V); mineral.
Satoshi Okita, Yoshiaki Ishii and Sun-Ja Yun*
*The Institute of Basic Environmental Research, Environmental Control Center Co., Ltd., 323-1, Shimo-ongata-machi, Hachiouji-shi, Tokyo 192-0154
(Received 27 September 2000, Accepted 22 November 2000)Carbendazim (MBC) and thiabendazole (TBZ) in environmental water samples were simultaneously determined by a liquid chromatograph/tandem mass spectrometer equipped with an electrospray ionization interface (LC/ESI-MS/MS). A simple and rapid sample pretreatment procedure using solid-phase extraction was developed to minimize the ion-suppression effect and to enrich analyte compounds. Both MBC and TBZ were quantitatively retained on a solid-phase extraction cartridge (Oasis HLB). The cartridge was washed with 3 ml of a 30 vol% methanol solution and then with 3 ml of water, and subsequently dried under a vacuum. MBC and TBZ retained on the cartridge were recovered by elution with 4 ml of ethyl acetate. The eluate was taken to dryness under a nitrogen stream before being re-dissolved in 1 ml of a water/methanol (1:1) solution. The solution was analyzed by LC/ESI-MS/MS. The results of analyses of spiked MBC and TBZ in aqueous solution demonstrate the applicability of the proposed method to environmental aqueous solutions, such as river water and the discharge of sewage treatment plant (DSTP). Detection limits of 0.32 ng/l for MBC and 0.93 ng/l for TBZ in river water, and 5.6 ng/l for MBC and 4.9 ng/l for TBZ in DSTP have been achieved. The results of overall recovery tests showed that the recovery of deuterated MBC-d3, the spiked internal standard, was 85.4%, and that the relative standard deviation (RSD) was 11% . The recoveries of MBC for river water spiked at 5 ng/l and 50 ng/l were 102% and 104%, and for DSTP spiked at 250 ng/l was 106%, respectively, and their RSD ranged from 1.9% to 3.4% . The recoveries and RSD of TBZ ranged from 78.9% to 136%, and from 1.8% to 4.8%, respectively.
Keywords : carbendazim; thiabendazole; LC/ESI-MS/MS; river water; discharge of sewage treatment plant.
Tokuo Shimizu, Takami Motegi, Makiko Nakano*, Hiroshi Kawagauchi*,** and Nobuo Uehara*
*Department of Applied Chemistry, Faculty of Engineering, Utsunomiya University, 7-1-2, Yoto, Utsunomiya-shi, Tochigi 321-8585
**Present address: Corporate R&D Center, Mitsui Mining & Smelting Co., Ltd., 1333-2, Haraichi, Ageo-shi, Saitama 362-0021
An effective separation and preconcentration method has been developed for the fractional determination of vanadium(IV) and vanadium(V) in water samples. The proposed method is based on the solvent extraction of vanadium(V) with 1-butanol (BuOH) and vanadium(IV) with 8-mercaptoquinoline (thiooxine); a preconcentration factor of 50 times is obtainable using 25 ml of a sample. A water sample was filtered through a 0.45 µm membrane filter immediately after sampling. For the determination of vanadium(IV), an aliquot of the filtered sample was subjected to the separation of vanadium(V) immediately after an adjustment of the pH to 4 with nitric acid. For determining the total vanadium, the remainder of the filtered sample was preserved by acidification to pH 1 with nitric acid. Vanadium(V) was separated into benzene by extraction with BuOH. After phase separation, dissolved BuOH in the aqueous phase was removed by evaporation in a hot water bath. The resulting solution or the acidified sample solution was subjected to the preconcentration of vanadium(IV) or total vanadium after adjusting the pH to 5.5. Both vanadium(IV) and vanadium(V) were extracted with thiooxine into chloroform, and subsequently back-extracted into 0.4 ml of a nitric acid solution. The back-extracted solution, containing 200 µg/ml of nickel as a matrix modifier, was suitable for the determination of vanadium by graphite-furnace AAS. The vanadium(V) concentration was obtained by subtracting the vanadium(IV) concentration from the total vanadium concentration. The proposed method was applied to river water samples.
Keywords : vanadium(IV) and vanadium(V); solvent extraction; 1-butanol; 8-mercaptoquinoline; graphite-furnace AAS.
Mitsuyoshi Watanabe*
*Materials Research Laboratory, Technical Center, NGK Insulators, Ltd., 2-56, Suda-cho, Mizuho-ku, Nagoya 467-8530
(Received 26 July 2000, Accepted 1 November 2000)Boron carbide is one of the most difficult fine ceramics to be decomposed. However, it was easily dissolved in nitric acid without any residue after its degradation by alkaline solution using the pressurized vessel. A 0.25 g of sample was taken in a platinum crucible, followed by adding 1 ml of 50 m/v% sodium hydroxide. The crucible was inserted into a sealed vessel and heated at 250°C for 16 h. After cooling, 10 ml of 60% nitric acid was added carefully, and heated again under the same conditions above. The contents of the crucible was transferred to a 250 ml measuring flask, and diluted to the mark with water. Boron in the clear sample solution was determind by mannitol/alkali titration. The analytical results by the proposed method were accurate and quite reproducible compared with those by a conventional alkali fusion.
Keywords : boron in boron carbide; stepwise decomposition; pressurized vessel; mannitol/alkali titration.
Junichi Shida and Shigemitsu Umeki*
*Department of Chemistry and Chemical Engineering, Faculty of Engineering, Yamagata University, 4-3-16, Jonan, Yonezawa-shi, Yamagata 992-8510
(Received 7 September 2000, Accepted 6 November 2000)A sensitive method based on preconcentraion on a membrane filter with an anion-exchange resin suspension (ARS) has been developed for the determination of Sb(III) in water samples by graphite furnace atomic absorption spectrometry (GF-AAS). Sb(III) (0.02~0.2) µg, in 20~500 ml of a sample solution, was retained as a Pyrocatechol Violet (PV) complex anion on a resin at pH 7; the resulting resin was filtered through a membrane filter. A portion of the resin with the membrane filter (3 mm in diameter) was inserted into a cuvette, and the absorbance of Sb was measured at 217.6 nm. The relative standard deviation for five measurements at 0.1 µg of Sb(III) was 5%. The detection limit was 5.4 ng of Sb(III) in 500 ml {10.8 ngSb(III) l-1} of the water samples. EDTA was used as a masking agent to remove any interference of Sr(II), Fe(II), Fe(III), Pd(II), Cu(II), Al(III) and Ga(III). The proposed method has been applied to the determination of Sb(III) in river water.
Keywords : antimony(III); Pyrocatechol Violet; anion-exchange resin suspension; graphite-furnace AAS; river-water.
Masako Ishikawa, Shinji Yoshioka* and Atsumu Hirabayashi**
*Techno-reserch Laboratory, Hitachi Sience Systems Co., Ltd., 882, Ichige, Hitachinaka-shi, Ibaraki 312-8504
**Central Reserch Laboratory, Hitachi Co., Ltd., 1-280 Higashi-koigakubo, Kokubunji-shi, Tokyo 185-8601
A liquid chromatography/sonic spray ionization mass spectrometry (LC/SSI-MS) in conjunction with solid-disk extraction has been developed to assay dymron in river-water samples. The mean recovery of dymron from pure water at a concentration of 0.01 mg/l was 89%, and the limit of detection was 50 pg (S/N=3). The repeatability of ion intensity with a concentration of 1 mg/l was 2.9% RSD (n=5). The positive ionization produced a typical [M+H]+ molecula-related ion of dymron(m/z=269). The extracts from river-water samples included interfering substances. Our result shows MS/MS product ion was detected at a m/z of 151 both dymron and extract from river-water samples, thus suggesting that river-water samples contained dymron.
Keywords : sonic spray ionization; agrochemicals; river-water; LC/MS; dymron.
Kazuhiko Oinuma, Ryuzi Mutoh and Chikakiyo Nagata*
*Department of Industrial Chemistry, Faculty of Engineering, Shibaura Institute of Technology, 3-9-14, Shibaura, Minato-ku, Tokyo 108-8548
(Received 1 September 2000, Accepted 29 November 2000)The 1H- and 13C-NMR spectra of trimethyl(1-indenyl)silane(IV) and dimethylbis(1-indenyl)silane(IV) compounds were measured. Assignments of the chemical shifts for 1H and 13C in those compounds were obtained by means of hydrogen-hydrogen nuclear Overhauser effect spectroscopy(H-H NOESY), hydrogen-hydrogen correlation spectroscopy(H-H COSY) and carbon-hydrogen correlation spectroscopy(C-H COSY). The methyl proton and carbon signals for two stereoisomers(R,R and R,S) in the dimethylbis(1-indenyl)silane(IV) compound were separated into three signals, with a relative signal intensity of 1:2:1; the other protons and carbons were split, except for H1, H5, C5, C9, into two signals. These results considered that the signal splits were caused by a magnetic nonequivalent in the two stereoisomers.
Keywords : methyl(1-indenyl)silane compounds; 1H and 13C NMR chemical shifts.
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