Hiroshi Uchihara

Microscopic analysis of chromium accumulation in the bronchi and lung of chromate workers.

It is known that chromium is an inhaled carcinogen and an important risk factor in the development of lung carcinoma.

Direct solid sampling system for electrothermal vaporization and its application to the determination of chlorine in nanopowder samples by inductively coupled plasma optical emission spectroscopy

An electrothermal vaporization (ETV) system using a tungsten boat furnace (TBF) sample cuvette was designed for the direct determination of chlorine in metallic nanopowders and fine powder samples with detection by inductively coupled plasma optical emission spectroscopy (ICP-OES). A portion of a powder or particle sample was placed into a small tungsten sample cuvette and weighed accurately. A modifier solution of aqueous or alcoholic potassium hydroxide was added to it. Then, the cuvette was positioned on the TBF incorporated into the ETV apparatus. The analyte was vaporized and introduced into the ICP optical emission spectrometer with a carrier gas stream of argon and hydrogen. The metal samples were analyzed by using an external calibration curve prepared from aqueous standard solutions. Few chemical species including analyte and some chlorine-free species were introduced into the ICP, because the analyte has been separated from the matrix before introduction. Under such dry plasma conditions, the energy of plasma discharge was focused on the excitation of chlorine atoms, and as a result, lower detection limits were achieved. A detection limit of 170 ng g(-1) of chlorine in solid metal samples was established when 60 mg sample was used. The relative standard deviation for 16 replicate measurements obtained with 100 ng chlorine was 8.7%. Approximately 30 batches could be vaporized per hour. The analytical results for various nanopowders (iron (III) oxide, copper, silver, and gold) and metallic fine powder samples (silver and gold) are described.

Determination of Trace Chlorine in Fine Ceramics by ICP-AES Using Tungsten Boat Furnace Vaporizer and Exchangeable Sample Cuvette System as a Direct Solid Sampler

A new approach to simple solid sample digestion, subsequent vaporization, and introduction into an inductively coupled plasma was developed for the direct determination of chlorine in fine ceramic materials by atomic emission spectrometry. To each small sample cuvette made of tungsten, a powder sample was placed and weighed accurately. Following an addition of modifier solution, the cuvette was positioned on the tungsten boat furnace incorporated an electrothermal vaporizer. Then, the analyte in the sample cuvette was vaporized and introduced into the plasma; the major components of ceramic being retained. The solid ceramic samples were analyzed by using an external calibration curve prepared with the aqueous standard solutions. The detection limit of chlorine was estimated to be 0.71 ng, which corresponds to 59 ng g−1 of the chlorine concentration in solid ceramic materials. The relative standard deviation was calculated to be 3.2%. The analytical results in various ceramic materials are described.

Direct solid sampling conductive heating vaporisation system for the determination of sulfur in steel without chemical treatment by inductively coupled plasma atomic emission spectrometry (ICP-AES)

A vaporiser based on a drop-in-crucible is described. Sample is allowed to drop into a heated crucible (2000 °C) which makes it vaporise; it is subsequently introduced into an ICP. Since metallic tin present in the crucible acts as a chemical modifier, the sample is immediately fused with the tin to make an alloy of low melting point. During the melting process, the analyte sulfur reacts with the carbon from the inside wall of the crucible and is released as sulfide.

Direct determination of bismuth in steel samples by magnetic drop-in electrothermal vaporization inductively coupled plasma atomic emission spectrometry.

YASUAKI OKAMOTO, KEISUKE YAMAMOTO, HIROKO KATAOKA, SATOSHI TSUKAHARA, TERUFUMI FUJIWARA,* HIROSHI UCHIHARA, MASAHIKO IKEDA, BUNJI HASHIMOTO, and KAZUAKI WAGATSUMA Department of Chemistry, Graduate School of Science, Hiroshima University, Kagamiyama, Higashihiroshima 739-8526, Japan; Horiba Analytical Application Center, Miyanohigashi, Kisshoin, Minami-Ku, Kyoto 601-8510, Japan; Institute for Materials Research, Tohoku University, Katahira, Aoba-Ku, Sendai, 980-8577, Japan

Pinpoint condensation technique using perfluorated polymer film for the identification of tetrahydrocannabinol by microscope/FTIR.

The pinpoint condensation technique using perfluorated polymer film was applied to the identification of tetrahydrocannabinol (THC), the primary psychoactive constituent of marijuana. Rapid solvent elimination for condensation of THC into a small single residual at room temperature was performed by solvent evaporation on perfluorated polymer film, and the residual was measured by the microscope/FTIR technique. This sample condensation method provided high sensitivity for IR analysis. The detection limit was at the subnanogram level, and the sensitivity was nearly equal to that of gas chromatography using a mass spectrometer.

Determination of Trace Amout of Non-ionic Suface Active Reagent by HPLC with Micro-FTIR using Pin-point Condensation Technique

ODSを分離カラムとしアセトニトリルを溶離液としてPOE系非イオン界面活性剤を分離した。POEアルキルエーテルはRI検出器で100ppm, POEアルキルフェニルエーテルはUV検出器で5ppmが限界であった。溶出液をフッ素樹脂コーティングした鏡面金属板に滴下すると, 溶媒の蒸発に伴い約2分後には局所に集中しその液滴の外径は滴下直後と比較し1/100程度に集中濃縮される。この残渣を顕微FTIRで反射測定すると赤外スペクトルが得られる。アセトニトリル中の不純物はHPLCポンプの直後にODSカラムを設置することで減少し, 1ppmのPOEアルキルエーテルとPOEフェニルエーテルとの判定が可能となった。