BUNSEKI KAGAKU Abstracts

Vol. 53 No. 12

December, 2004

Accounts

Development of marine environmental observation platform deployed on ferryboats, and observation of marine pollution with hazardous chemicals in coastal region of Japan

Masayuki Kunugi¹, Kazuo Fujimori², Takeshi Nakano² and Akira Harashima¹

(Received 9 August 2004, Accepted 22 October 2004)

We developed a continuous-extraction system for sampling of hazardous chemicals in seawater, suitable for mounting on a merchant vessel. By mounting this system in the ferry "Kurosiwo" which navigated between Osaka Port and Naha New Port from December 1996 to Februry 1998, and the ferry "Sunflower Ivory" which navigated the Seto Inland Sea from December 1998 to March 2000, we observed the concentrations of hazardous chemicals in seawater and confirmed the usefulness of the system. Using these observations, we analyzed the dynamics of hazardous chemical pollution in seawater. From these results, it is clear that frequent observations are indispensable to gain a grasp of the dynamics of marine pollution by hazardous chemicals. By observing their concentraions at various times and locations, it was possible to estimate the dominant origins of HCHs and chlordanes.

Keywords : hazardous chemicals; POPs; HCHs; VOS; spatial distribution.

Precise measurements of the atmospheric O₂/N₂ ratio by gas chromatographic method

Yasunori Tohjima¹

(Received 26 July 2004, Accepted 22 October 2004)

A gas chromatographic method for measuring the changes in the atmospheric O₂/N₂ ratio was developed. An aliquot of air sample was injected into a column filled with molecular sieve 5 A with H2 carrier gas, and the separated O₂+Ar and N₂ peaks were detected by a thermal conductivity detector (TCD). The change in the (O₂+Ar)/N₂ ratio, which was the value actually measured, was easily converted to the change in the O₂/N₂ ratio without any significant error, because the variation in the atmospheric Ar/N₂ ratio is negligible. Air samples were collected in 2 l or 2.5 l glass flasks at a pressure of about 0.2 MPa (0.1 MPa above ambient pressure). To improve the precision statistically, alternate analyses of the sample and reference gas were repeated fourteen times. The reproducibility for the flask samples was about 5 per meg (about 1.1 ppm O₂ in air). O₂/N₂ measurements of the gravimetric mixtures of pure O₂ and N₂ indicated that the response of the gas chromatographic system is almost linear within 2%. The reference scale for the O₂/N₂ determination was based on the air derived from high-pressure cylinders that showed no systematic changes in the O₂/N₂ ratio. Results from samples collected in the urban area (Tsukuba) and in the forest canopy (Tomakomai) showed clear diurnal O₂/N₂ variations. The O₂/N₂ ratios for samples collected at Hateruma Island from 1997 to 2003 showed clear seasonality and decreasing trend.

Keywords : atmospheric oxygen; gas chromatography; carbon cycle; O₂/N₂ ratio; monitoring.

Research Papers

Source identification of polychlorinated naphthalenes, dioxins and related compounds in pine needles from Tokyo Bay, Japan and Poland

Nobuyasu Hanari¹, Anna Orlikowska², Ilona Bochentin², Barbara Wyrzykowska², Jerzy Falandysz², Yuichi Horii¹, Sachi Taniyasu¹, Tsuyoshi Okazawa¹ and Nobuyoshi Yamashita¹

(Received 23 July 2004, Accepted 2 September 2004)

Pine needles are considered to be a very suitable biomatrix for monitoring long-term ambient air concentrations of such atmospheric pollutants as semivolatile and persistent lipophilic compounds. Pine needles were analyzed for polychlorinated naphthalenes (PCNs) and dioxin-like compounds to provide initial evidence on their occurrence in ambient air and any potential connection to possible sources of pollution around Tokyo Bay, Japan and at industrial sites in Poland. The concentrations of PCNs in pine needles around Tokyo Bay and at sites in Poland varied between 250 to 2100 pg/g, wet weight and 520 to 920 pg/g, respectively. Tri- and tetra-CNs were dominating constituents (54 to 83%) of PCNs quantified in pine needles from Tokyo Bay and Poland. Octa-CN was a characteristic congener in analysed Polish samples, because the level of this congener from Poland was obviously higher than that from Tokyo Bay. Wet weight normalized concentrations of 2,3,7,8-substituted PCDDs/Fs and planar PCBs in pine needles from Tokyo Bay were 27 to 110 pg/g and 110 to 420 pg/g, respectively; however, those from Poland were 37 to 125 pg/g and 990 to 1700 pg/g, respectively. Octa-CDD/F were also the predominant congeners, and the planar PCB concentration was significantly greater in samples from Poland. The results of this study suggest the presence of different pollutant sources between Tokyo Bay and industrial sites in Poland. Pine needles should be useful for not only a long-term indicator of ambient air pollution, but also for evaluations of the local, regional and national distributions of lipophilic air pollutants.

Keywords : polychlorinated naphthalenes; dioxins and related compounds; double column-HPLC system; pine needles.

Distribution of chemical elements and chemical states of sulfur on kosa particles fallen in Asian industrialized cities

Teruo Tanabe¹, Yo'ichi Tanaka¹, Daisaku Tanaka¹, Yuji Taniguchi¹, Masatoshi Toyoda¹, Jun Kawai¹, Hideshi Ishii¹, Chenlin Riu¹, Yibulayin Yilixiati¹, Shinjiro Hayakawa², Yoshinori Kitajima³ and Yasuko Terada⁴

(Received 7 July 2004, Accepted 16 September 2004)

Sand particles of Taklamakan Desert, China loess sample CJ-1 prepared by NIES and kosa particles that had fallen in the cities of Harbin and Shenyang were characterized in terms of the distribution of contained elements by the “synchrotron EDX” method at SPring-8, in addition to the familiar SEM-EDX method. To examine the chemical valence state of sulfur on these particles, the X-ray absorption spectra were measured at the KEK-PF in Tsukuba. The kosa particles of Harbin and Shenyang were contaminated with sulfur, chlorine, phosphor or titanium, although the major components of silicon, aluminum and iron were similar to the reference samples of Taklamakan desert and CJ-1. All of the kosa particles in which sulfur or chlorine were detected contained calcium. A comparison of synchrotron- and electron-excited spectra revealed that heavy metals of Cr, Mn, Fe, Ni are very sensitively detectable in synchrotron radiation, in contrast to the fact that EPMA seems to have a superiority in the detection of light elements: Mg, Al, Si. Sulfur on the particles of Harbin or Shenyang is mainly in the form of the 6⁺valence; the 4⁺valence state of sulfur was also found on a sample of Shenyang. Sulfur of the 6⁺valence state was weakly detected in the sand of Taklamakan desert maybe in the adsorbed form on the surface of particles.

Keywords : characterization of kosa particles; synchrotron radiation; XRF; EDX; SEM.

Analysis of the historical trend of heavy metal-pollution recorded in the pond sediment core at Oki Islands on the Japan Sea coast

Hideo Yamazaki¹, Shusaku Yoshikawa² and Shinya Inano²

(Received 23 July 2004, Accepted 17 September 2004)

The historical trend of heavy-metal pollution recorded in core sediment collected from a small pond in Dougo of Oki Islands, Shimane Prefecture, was deciphered. The pollutant carried through the atmosphere seems to have accumulated in the pond sediment, because Oki Islands are separated from the source of industrial pollution. A core sample of 107 cm length was obtained, and sedimentation age of the deepest part was estimated to be 1880's by using a ²¹⁰Pb method. The vertical distribution of the ¹³⁷Cs concentration in this core agreed well with the historical trend of its global fallout. The contamination of mercury for the sediment started in the 1920's, and the anthropogenic flux at the water-sediment interface was 10~12 ng cm^-2 yr^-1 in the 1960's. The flux has become almost constant by the present. On the other hand, the contamination of lead started in the 1930's, and the flux in the water-sediment interface has increased by the present. The anthropogenic flux of lead in the present sediment surface reaches 5000 ng cm^-2 yr^-1. The abnormal load of mercury for the sediment was recognized in the 1900's. Further, the spiking load was also found for lead in the 1920's. The cause of these anomalies in contaminations was uncertain if it was by human activity or by some natural phenomenon. The anthropogenic inventories of mercury and lead in this pond sediment were estimated to be 0.71 µg cm^-2 and 190 µg cm^-2, respectively. For the past 60 years, the average values of the anthropogenic fluxes from the atmosphere of mercury and lead in Dougo Island were also estimated to be 4.3 and 1100 ng cm^-2 yr^-1, respectively. From the result, concerning the environment of Oki Islands, the possibility of receiving the effect from the continent of China and the Korean Peninsula strongly than from the Kei-Hanshin industrial area in Western Japan was indicated.

Keywords : pond sediment; heavy metal; pollution; historical trend, flux.

Monitoring of long-distance transportation of pollutants in precipitation in coastal areas facing the Japan Sea, Japan (2000-2001) and the grouping of ions in pollutants by principal component analysis

Toru Ozeki¹, Toshihiro Ihara¹, Toshinobu Okada¹, Ryoei Kikuchi² and Nobuaki Ogawa²

(Received 26 July 2004, Accepted 29 September 2004)

In recent years, various pollutants are being brought from the Asian Continent to the coastal areas facing the Japan Sea, Japan and are causing the acidification of precipitation during the winter. The amounts and compositions of the pollutants vary depending on the areas. In this work, the precipitation samples were collected at nine coastal areas (Fukuoka, Hagi, Yonago, Tottori, Fukui, Ishikawa, Toyama, Kashiwazaki, and Akita) from July 2000 to June 2001; also the regional and seasonal changes of the chemical compositions of the pollutants contained in the precipitation samples were examined so as to understand the influences of long-distance transportation. As a result, the pH values of the precipitation samples collected October to February were low for all sampling locations. The concentrations of Na⁺ion and Cl^- ion, both sea-salt ions, increased in the winter season. The concentrations of nss-Ca²⁺ion, nss-SO₄^2-ion, NO₃^-ion and NH₄⁺ion, on the other hand, increased in March and April. The sea-salt ions and the acidic mixture of sulfuric and ammonium sulfate were transported by seasonal winter monsoons; however, the pollutants increasing in March and April were transported by the spring jet streams. In this study, the chemical data were also examined by principal component analysis and the features of major nine ions contained in the pollutants were extracted.

Keywords : acid precipitation (rain and snow); long-distance transportation; jet stream; northwestern seasonal winds; principal component analysis.

Multielement determination of trace metals in scallop tissue samples

Motoko Tamaru¹, Tomoki Yabutani¹ and Junko Motonaka¹

(Received 26 July 2004, Accepted 24 September 2004)

A multielement determination method for trace elements in scallop tissue samples has been developed by ICP-MS (inductively coupled plasma mass spectrometry) and ICP-AES (inductively coupled plasma atomic emission spectrometry) after microwave assisted acid digestion. A reference material of oyster tissue (SRM 1566b Oyster tissue) was analysed to verify the determination method. Thirty elements (K, Na, Zn, Mg, Ca, Fe, Al, Cu, Mn, Ba, Sr, Cd, Ni, Co, Pb, Y, and rare earth elements) in the reference material could be determined, and the concentrations of elements obtained by this method were in good agreement with their certified and reference values and had good precision within RSD 4% except for Ni and Pb. This method was applied to analyse concentrations of elements in a scallop tissue sample. Cadmium, Zn, Cu, Al, and Fe in the scallop tissue sample were contained at 69.0, 148, 19.0, 415, and 221 µg g^-1 level, respectively. In particular, the bioaccumulation factors of Cd, which were estimated between the concentration in scallop tissue sample and those in shale and seawater, were the highest among 30 elements determined.

Keywords : inductively coupled plasma mass spectrometry; inductively coupled plasma atomic emission spectrometry; microwave assisted acid digestion; trace elements; scallop tissue; certified reference material.

On-line monitoring method of PCBs by laser ionization dynamic trapping time of flight mass spectrometry

Shinsaku Dobashi¹, Yoshihiro Deguchi², Norihiro Fukuda¹, Masaharu Kira³, Ryuichiro Tanaka⁴, Yoshinori Izawa⁴ and Takahiro Kubota¹

(Received 20 July 2004, Accepted 26 August 2004)

The emissions of organic hazards from environmental protection equipments and other facilities have become a major social issue, and the evaluation of toxicity concentration requires methods having both high precision and high chemical selectivity. LI-IT-TOFMS (laser ionization/ion trap storage/time of flight mass spectrometry) is expected to be a powerful tool for environmental monitoring. This report, discusses real-time LI-IT-TOFMS measurements gaseous 2~4 chlorinated PCBs in order to evaluate the applicability of the environmental monitoring method. With respect to the effect of ion trap storage for PCBs, we found that it was due to the driving RF voltage on the ring electrode in the ion trap. For the ions of PCBs produced by laser irradiation, we observed that it was more efficient to reach the center of the ion trap by using a gated RF voltage rather than by using a continuous RF voltage. We simulated the ion trajectories in the ion trap by using SIMION 7.0. We found that the voltage of the exit end cap electrode affected both the number of ions trapped and the orbit of ions inside of the trap cell. Optimization of this parameter was performed using both simulated and experimental results. The achievable PCB sensitivity for real-time (1 minute) measurements using the LI-IT-TOFMS technique was found to be in the pptV range (<0.01 µg/Nm³) by a comparison with the conventional gas sampling GC/MS method. A satisfactory proportional relationship was confirmed between laser-based and conventional results. In the future we will pursue the method for environmental monitoring.

Keywords : laser; laser ionization; ion trap; dynamic trapping; PCB; on-line analysis.

Detection of explosive-related compounds with a chemiluminescent enzyme immunosensor

Takatoshi Sakai¹, Daikichi Kitahara¹, Akira Torimaru¹ and Kiyoshi Matsumoto¹

(Received 23 July 2004, Accepted 18 October 2004)

For the rapid and sensitive detection of explosive-related compounds, polyclonal antibody was prepared by immunizing 2,4-dinitrophenyl-gly-hemocyanin (from Keyhole Limpet) to the BALB/c mice, and a chemiluminescent enzyme immunosensor was constructed. The detection ranges of 2,4-dinitrotoluene (2,4-DNT) and 2-amino-4,6-dinitrotoluene (2-ADNT) were 10~1000 ng/ml using an immunosensor, whereas those obtained by an enzyme-linked immunosorbent assay (ELISA) were more than 1000 ng/ml. These results indicated that more sensitive (more than 2 order) and more rapid detection could be achieved using an immunosensor. Furthermore, more sensitive detection could be performed by lowering the flow rate on the interaction between antibody and immobilized antigen; 1~100 ng/ml of 2,4-DNT could be detected.

Keywords : antibody; immunosensor; chemiluminescent; 2,4-dinitrotoluene; 2-amino-4,6-dinitrotoluene.

Determination of total nitrogen in seawater by spectrophotometric/PLS regression method in UV region and ion chromatographic method after oxidative digestion with potassium peroxodisulfate in alkaline medium

Gou Hashida¹, Yukio Yokoyama¹ and Hisakuni Sato¹

(Received 23 July 2004, Accepted 9 September 2004)

A spectrophotometric measurement/PLS regression method and an anion chromatographic method for the determination of total nitrogen in seawater and brackish water were investigated. By oxidative digestion of seawater with potassium peroxodisulfate in alkaline borate buffer, nitrogen is oxidized to nitrate ion and bromide ion to bromate in seawater medium. No remaining bromide ion is present in the digested samples, while bromide ion does not fully oxidized to bromate in water not containing high concentration of salts. By using glass test tube with screw cap and aluminum block heater, digestion can be done simply and easily. After digestion, the absorption spectra were measured in the range of 220~260 nm. Calibration standards were prepared by dissolving KNO3 and KBrO3 into simulated seawater without digestion. By spectrophotometric/PLS method, 0.2~5.0 mg-N/l in seawater and brackish water could be determined without the interference from bromide/bromate. By IC method, 0.01~10 mg-N/l could be determined with a DEAE column (weak anion exchange resin, 10 cm length glass column) and 0.2 M-NaCl eluent.

Keywords : total nitrogen in seawater and brackish water; ultravioret absorption spectrum; PLS regression; anion chromatography; peroxodisulfate digestion in borate buffer.

On-site solid phase extraction method for endocrine disrupters

Kumiko Ujiie¹, Rie Hando¹, Kiichi Sato¹, Mitsuru Abo¹ and Akira Okubo¹

(Received 27 July 2004, Accepted 6 October 2004)

A compact, lightweight, and portable solid-phase extraction system without a power supply was designed and constructed for the on-site pretreatment of water samples. First, the recovery rates of endocrine disruptors, such as alkylphenols and bisphenol A from a solid-phase adsorbent, were examined. The recovery rates of each analytes were almost unchanged after one-day storage. We also proposed an on-site addition of a surrogate in water samples. By this procedure it was possible to calculate recovery rates even for on-site extraction. This method was evaluated using water samples from Arakawa River. Because the quantitative value of nonylphenol (mix) by this method was higher than that by the usual method, this pretreatment method is useful and reliable for field analyses.

Keywords : endocrine disrupters; bisphenol A; nonylphenol; solid phase extraction; on-site extraction.

Gamma-ray spectrometry of ²¹⁰Pb in rainwater using preconcentration with iminodiacetate extraction disk

Yuya Koike¹, Jun Sato¹ and Toshihiro Nakamura¹

(Received 23 July 2004, Accepted 7 October 2004)

An analytical method for ²¹⁰Pb in rainwater using a γ-ray spectrometry combined with solid-phase extraction on iminodiacetate extraction disk has been developed. A rainwater sample was adjusted to pH 5.6 with HNO₃ and 1 M CH₃CO₂NH₄, and then passed through an EmporeTM chelating resin disk pretreated by 0.1 M CH₃CO₂NH₄. The chelating resin disk was packed into acrylic containers (38 mmφ) having a window of a thin Mylar film (1 mg cm^-2) for a non-distractive γ-ray measurement. Radioactivity of ²¹⁰Pb was determined by the 46.5 keV γ-ray with an HP-Ge spectrometer. The radioactivity of ²¹⁰Pb in rainwater sample collected on the chelating resin disk ranged from 28 to 54 mBq l^-1, which was a lower level than those observed at several sites along the Japan sea. The present method is more simple and rapid than the conventional method, and is applicable to short-lived ²¹²Pb and cosmogenicaly-produced ⁷Be in environmental water.

Keywords : iminodiacetate extraction disk; radioactivity of ²¹⁰Pb; rainwater; γ-ray spectrometry.

Technical Papers

Determination of total antimony in river water by graphite furnace AAS after coprecipitation with manganese(IV) oxide

Tokuo Shimizu¹, Toshiaki Wada¹ and Nobuo Uehara¹

(Received 23 June 2004, Accepted 25 October 2004)

Miniaturized coprecipitation with hydrous manganese(IV) oxide was studied for the preconcentration of sub µg/l levels of total antimony in river water samples. Manganese(IV) oxide was produced by a reaction of permanganate ion with ethanol in the presence of 0.1 mol/l nitric acid. A nanogram amount of antimony in a 10 ml sample was quantitatively coprecipitated. The precipitate was collected on a 10 mm membrane filter, and then dissolved in 100 µl of nitric acid(1+1) and 150 µl of hydrogen peroxide(1+15). A 40-fold preconcentration factor was obtained by this procedure. The detection limit(3σ) was found to be 0.031 µg/l in the case of 40 µl injection into a graphite furnace. The interference of various metal ions was investigated with a mixture of metal ions at concentrations approximately equal to, or exceeding, those normally found in river water. The mixture of metal ions tested was found not to cause severe interference with the determination of antimony. The proposed method was successfully applied to river water samples.

Keywords : total antimony; miniaturized coprecipitation method; manganese(IV) oxide; river water; graphite furnace AAS.

Ion-exclusion chromatography of silicate ion in sea and river water samples by an ion-exchange enhancement of conductivity detection

Masanobu Mori¹, Kazuhiko Tanaka^1,2, Hiroshi Taoda¹, Mikaru Ikedo^1,2 and Wenzhi Hu³

(Received 13 July 2004, Accepted 19 October 2004)

Ion-exclusion chromatography with an ion-exchange enhancement of conductivity was developed for the selective and sensitive determination of silicate ion. The separation of silicate ion from anions of strong acids was achieved by the ion-exclusion effect on a separation column packed with a weakly acidic cation-exchange resin in the H⁺-form by elution with water. Two different ion-exchange resin columns were inserted between the separation column and the conductivity detector in order to improve the sensitivity of silicate ion. The first enhancement column, a strongly acidic cation-exchange resin in the K⁺-form, could be converted from silicic acid to potassium silicate. Subsequently, the second enhancement column, a strongly basic anion-exchange resin in the OH^--form, could be converted to potassium hydroxide having high conductivity response. The detection sensitivity of silicate ion using two conductivity enhancement columns could be ca. 20 times greater than that using the separation column alone at an eluent flow rate of 1 ml/min. The detection limit (S/N=3) was 0.02 ppm as H₃SiO₄^- at 0.5 ml/min. The calibration graph was linear in the range of 0.05~50 ppm. This method could be successfully applied to the determination of the silicate ion in several sea and river water samples.

Keywords : river water; seawater; silicate ion; ion-exclusion chromatography; enhancement; conductivity detection.

Development of a rapid evaluation system for fresh-water quality

Tomoji Yoshida¹ and Sanae Ikeda¹

(Received 22 July 2004, Accepted 18 October 2004)

This paper describes a rapid evaluation system for fresh-water quality. In general, a Stiff diagram and a Trilinear diagram are used for a water quality evaluation, such as ground water. These methods can represent the characteristics of water, but it is difficult to make a diagram and to understand its chemical meaning. The proposed system is able to automatically calculate the necessary values for drawing a diagram from the dissolved ion concentration obtained by ion chromatography, after evaluating the reliability of the measured values. The characteristics of water quality can be instantaneously shown without any complicated process. Moreover, a rapid evaluation system that uses COD, pH, NH₄⁺ and hardness values is presented for the water quality, which enables intuitional indication by a graphical chart.

Keywords : rapid evaluation system for fresh-water quality; Stiff diagram; Trilinear diagram.

Monitoring of inorganic ions in xylem sap of Konara (Quercus serrata Murray) by ion exchange

Masahiro Matsuzuka¹, Kohei Ueki¹, Mika Ima¹ and Takeshi Hamada¹

(Received 23 July 2004, Accepted 19 October 2004)

Much physiological information on trees has been provided to be basically available for understanding their rolls in forested ecosystems, such as being stressed by probable continuous acidification. With xylem sap, though its flow characteristics have been well examined diurnally and seasonally by measuring the flow rate, its chemistry has been left unprovided with sufficient information on a continuous change in the composition and/or amounts of dissolved species, as understood to be probably due to a lack of in vivo observations. Here, with a Konara stand, a method for the examination of xylem sap chemistry comprising continuous collection of ionic species with use of ion-exchange fibers and determination of species adsorbed is proposed. Application of the method gave the tollowing results: (1) Ionic species collected by the ion exchange fibers were effectively desorbed to be determined. (2) Major ions in the xylem sap were potassium and calcium to change from 70 to 93% and from 13 to 4%, respectively, reflecting an air temperature rise and a radiation change from early spring to summer. Thus, though some difficulties are left to be solved, the present method is potentially applicable for monitoring the chemistry of xylem and/or phloem saps in trees.

Keywords : acidification stress; tree physiology; long term monitoring; ion exchange fibers; xylem sap chemistry.

Notes

Liquid-chromatographic determination of halogenated bisphenols based on intramolecular excimer-forming fluorescence derivatization

Shigekatsu Tsunetomo¹, Hideyuki Yoshida¹, Kenichiro Todoroki¹, Tadashi Hayama^1,2, Hitoshi Nohta¹, Hiroaki Kuroki³ and Masatoshi Yamaguchi¹

(Received 20 July 2004, Accepted 19 October 2004)

A selective determination method for halogenated bisphenols containing tetrabromobisphenol A has been developed. This method is based on an intramolecular excimer-forming fluorescence derivatization with a pyrene reagent, 4-(1-pyrene)butanoyl chloride (PBC), followed by reversed-phase chromatography (LC). Bisphenols, containing two phenolic hydroxyl groups in a molecule, were converted to the corresponding dipyrene-labeled derivatives by a reaction with PBC. These derivatives afforded intramolecular excimer fluorescence (440~540 nm), which could be clearly discriminated from the normal fluorescence (360~420 nm) emitted from PBC and monopyrene-labeled derivatives. The PBC derivatives could be separated by reversed-phase LC on an ODS column with isocratic elution using aqueous 99% (v/v) acetonitrile as a mobile phase. The detection limits (signal-to-noise ratio=3) for halogenated bisphenols were femto-mole levels for a 5 µl injection.

Keywords : halogenated bisphenol; tetrabromobisphenol A; liquid chromatography; excimer fluorescence; 4-(1-pyrene)butanoyl chloride; human serum.

Analytical Reports

Separation and detection limit of chiral amino acids in multiple components by analytical techniques

Yoshinori Takano¹, Katsumi Marumo¹, Kensei Kobayashi² and Jun-ichi Takahashi³

(Received 14 June 2004, Accepted 22 October 2004)

The separation of hydrolyzed chiral amino acids in multiple components, such as high-molecular-weight interstellar type complex organics, was verified to compare with meteoritic amino acids. Reversed-phase high-performance liquid chromatography (RP-HPLC) gave±0.34% (n=7) regarding the standard deviation(s) of enantiomeric excesses (%D-%L) of D, L-alanine in a hydrolyzed fraction of complex organics. The chiral separation of D, L-alanine by the RP-HPLC method might be more convenient than gas chromatograph combined with the mass spectrometry (GC/MS) method in asymmetric synthesis verification. Possible pathways for the asymmetric synthesis of amino acid precursors (not asymmetric photolysis of monomer amino acids) were considered in terms of the detection limit of statistically significant enantiomeric excesses.

Keywords : chiral separation; asymmetric synthesis; meteorite; complex organics.

Ash contents of foodstuff samples in environmental radioactivity analysis

Shinji Oikawa¹, Hiroshi Ohta¹, Kazuhiko Hayano¹ and Nobuhiro Nonaka¹

(Received 23 July 2004, Accepted 10 September 2004)

Statistical data of the ash content in various environmental samples obtained from an environmental radioactivity survey project commissioned by the Japanese government of Science and Technology Agency (at present Ministry of Education, Culture, Sports, Sciences and Technology) during the past 10 years are expressed for establishing a standard of ash content in environmental samples based on radioactivity analysis. The ash content for some kinds of environmental samples such as dietary food, milk, Japanese radish, spinach, fish, green tea and potato was reviewed in the light of statistical and stochastic viewpoints. For all of the samples reviewed in this paper, the coefficient of variation varied from 4.7% for milk to 36.3% for cabagge. Dietary food and milk samples were reviewed more than 1900 and 1400 samples, respectively. Especially, ash content of dietary food depended mainly on the dietary culture reflected on the period. However it showed an almost invariant distribution within 18.7% of coefficient of variation during the past 10 years. Pretreatment of environmental samples especially ashing processes are important from the viewpoint on environmental radioactivity analysis, which is one of the especial fields in analytical chemistry. Statistical reviewed data obtained in this paper may be useful for sample preparation.

Keywords : environmental radioactivity; foodstuff sample; ash content; statistical review; analytical chemistry.

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