Characterization of fluorophores released from three kinds of lake phytoplankton using gel chromatography and fluorescence spectrophotometry.

Anal Sci. 2008;24(11):1461-7.
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Characterization of fluorophores released from three kinds of lake phytoplankton using gel chromatography and fluorescence spectrophotometry.

Aoki S, Ohara S, Kimura K, Mizuguchi H, Fuse Y, Yamada E.

Department of Chemistry and Material Technology, Kyoto Institute of Technology, Kyoto 606-8585, Japan.Three kinds of phytoplankton were cultivated, and the contribution of dissolved organic matter (DOM) released from the phytoplankton was examined to clarify the cause of organic pollution of Lake Biwa. Microcystis aeruginosa, Staurastrum dorcidentiferum, and Cryptomonas ovata were evaluated with regard to cultivation. A significant peak (M(w): <3000> Microcystis aeruginosa > Staurastrum dorcidentiferum. These results suggest that the increase of the refractory organic matter in Lake Biwa may be attributed to a change of the predominant phytoplankton.

Publication Types:
Research Support, Non-U.S. Gov't

PMID: 18997376 [PubMed - indexed for MEDLINE]

Simultaneous determination of Fe(III) and Fe(II) ions via complexation with salicylic acid and 1,10-phenanthroline in microcolumn ion chromatography.

Anal Sci. 2008;24(11):1487-92.
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Simultaneous determination of Fe(III) and Fe(II) ions via complexation with salicylic acid and 1,10-phenanthroline in microcolumn ion chromatography.

Oktavia B, Lim LW, Takeuchi T.

Department of Chemistry, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.Fe(III) and Fe(II) ions were separated and determined via in-column and post-column reactions with salicylic acid and 1,10-phenanthroline by microcolumn ion chromatography with UV-Vis detection. The separation could be achieved on a silica microcolumn using an aqueous ethanol solution of salicylic acid as eluent. The effluent from the column was then mixed with aqueous ethanol solution of 1,10-phenanthroline and detected at 518 nm. Fe(III) ion was detected as the complex with salicylic acid, whereas Fe(II) ion was detected as the complex with 1,10-phenanthroline. The detection limits with 0.25 microL injection volume at S/N = 3 were 0.21 and 0.10 mg L(-1) for Fe(III) and Fe(II), respectively. Increasing the injection volume of sample, e.g., 5.1 microL, improved the sensitivity; the detection limits at S/N = 3 were 12 and 9.2 microg L(-1) for Fe(III) and Fe(II), respectively. The present system was applied to the determination of iron in a local well water sample.

Publication Types:
Evaluation Studies

PMID: 18997380 [PubMed - indexed for MEDLINE]

Determination of selenomethionine by high-performance liquid chromatography-fluorescence detection coupled with on-line oxidation.

Anal Sci. 2009 Jan;25(1):63-5.
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Determination of selenomethionine by high-performance liquid chromatography-fluorescence detection coupled with on-line oxidation.

Aoyama C, Tsunoda M, Funatsu T.

Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo, Tokyo 113-0033, Japan.A simple and sensitive determination method for selenomethionine (Se-Met) using an HPLC-fluorescence detection system coupled with an on-line electrochemical reactor has been developed. NBD-F (4-fluoro-7-nitro-2,1,3-benzoxadiazole) was used as the fluorescent derivatization reagent for Se-Met. NBD-Se-Met was separated from NBD-derivatives of 22 other amino acids within 35 min. Applying an optimized oxidation potential enhanced the fluorescence intensity of NBD-Se-Met 10-fold. The calibration curve was linear in the range of 300 fmol to 30 pmol with a correlation coefficient of 0.997. Detection limit (S/N = 3) was calculated to be 50 fmol, which is comparable to that of inductively coupled plasma mass spectrometry. This simple and sensitive method should be useful for the determination of Se-Met in physiological samples, such as serum or urine.Publication Types:
Evaluation StudiesPMID: 19139574 [PubMed - indexed for MEDLINE]