Online ISSN : 1348-3315
Print ISSN : 1342-8284
ISSN-L : 1342-8284
Advance online publication
Displaying 1-4 of 4 articles from this issue
  • Chisato MIZUTANI, Shinya KITAGAWA, Yoshinori IIGUNI, Hajime OHTANI
    Article type: research-article
    Article ID: 2022.013
    Published: October 06, 2022
    Advance online publication: October 06, 2022

    Nonaqueous capillary zone electrophoresis (NACZE) utilizing cationic reagents as an electrophoresis promoter has the potential for separating water-insoluble synthetic polymers and that with tetrahydrofuran based electrophoretic media containing cationic reagents has been reported. In this study, NACZE using hexafluoroisopropanol (HFIP)-based media was developed for separating polyesters and polyamides, which were insoluble in tetrahydrofuran. Nonaqueous media of HFIP containing 400 mM cetyltrimethylammonium chloride (CTAC) and 50 mM trihexyl(tetradecyl)phosphonium chloride (P66614Cl) were used, and it was found that hydrophobic P66614 cation enhanced the electrophoresis of both polyesters and polyamides compared with cetyltrimethylammonium cation. The media containing CTAC resulted in partially separated poly(ethylene terephthalate)/poly(hexamethylene terephthalate) and poly(ethylene terephthalate)/poly(ethylene naphthalate), but P66614Cl failed to separate them. By contrast, nylon 6I and nylon 6/6I were separated with the P66614Cl media, whereas they were co-eluted in the media with CTAC.

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  • Hsin-Miao TSAI, Chin-Ling HSIEH, Chiharu ISHII, Takeyuki AKITA, Masash ...
    Article type: research-article
    Article ID: 2022.011
    Published: October 04, 2022
    Advance online publication: October 04, 2022

    For the simultaneous determination of lactate (LA), 2-hydroxybutyrate (2HB), 3-hydroxybutyrate (3HB) and malate (MA) enantiomers, a new separation technique in a two-dimensional high-performance liquid chromatography (2D-HPLC) system following the fluorescence derivatization with 4-nitro-7-piperazino-2,1,3-benzoxadiazole has been developed. The 2D-HPLC was composed of the reversed-phase (1D) and enantioselective (2D) separations. In the first dimension, the target hydroxy acids were separated as their D plus L mixtures on a Singularity RP18 column (1.0 mm i.d. x 250 mm), and the enantiomers were separated in the second dimension using a polysaccharide-based chiral stationary phase, Chiralpak IG (2.0 mm i.d. x 250 mm). By using the Chiralpak IG column, the LA, 2HB, 3HB and MA enantiomers were separated with resolution values of 3.47,3.63, 6.81 and 3.72, respectively. The developed 2D-HPLC system was applied to human plasma, and trace levels of D-LA and L-3HB in addition to their major antipodes were determined. The acquired %D of LA (the percentage of D-LA over total LA) and %L of 3HB (the percentage of L-3HB over total 3HB) were 1.0 and 2.7, respectively. For 2HB, only the L-form was detected, while the MA enantiomers were not found in the human plasma.

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  • Wataru HOBO, Akihiro JO, Sae KOYAGI, Shoujiro OGAWA, Shoichi NISHIMOTO ...
    Article type: research-article
    Article ID: 2022.010
    Published: October 03, 2022
    Advance online publication: October 03, 2022

    Liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) has the great ability to accurately and precisely quantify various biomolecules, but there is a concern about its analysis time, especially during the analysis of a high number of samples. Sample-multiplexing in the same injection is a promising strategy for reducing the total analysis time. This strategy can be accomplished by derivatization of multiple samples with multiple isotopologous reagents. In this study, a sample-triplex LC/ESI-MS/MS assay was developed for quantifying the urinary hexanoylglycine (HG), a diagnostic marker of medium-chain acyl-coenzyme A dehydrogenase deficiency, in three different samples within a single run. For this purpose, the 1-[(4-diethylaminophenyl)carbonyl]piperazine (DEAPPZ) isotopologues (2H0-, 2H3- and 2H6-forms) were synthesized. When compared to the non-derivatization method, which analyzed one sample in each run, the analysis time after the sample pretreatment was reduced to 55% (390 min → 210 min) for 30 samples in the sample-triplex method, which also had an acceptable precision (intra- and inter-assay precisions; ≤ 5.9% and ≤ 9.1%, respectively) and accuracy (91.7–97.1%). Thus, the sample-triplex strategy using the DEAPPZ isotopologues could successfully reduce the analysis time in the urinary HG quantification.

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  • Takako HAYASHI, Kenji HAMASE
    Article type: research-article
    Article ID: 2022.005
    Published: July 20, 2022
    Advance online publication: July 20, 2022

    A simultaneous determination method for seven β2-agonists (clenbuterol, ractopamine, zilpaterol, cimaterol, isoxsuprine, salbutamol and terbutaline) was developed using liquid chromatography tandem mass spectrometry (LC-MS/MS) to evaluate their residual status in livestock products commercially available in Japan. The livestock sample was homogenized with ethyl acetate under alkaline conditions and degreased with n-hexane. The target β2-agonists were then purified by dispersive solid-phase extraction with C18 particles. For the LC separation, a semi-micro scale column packed with an octadecylsilica (ODS) stationary phase was employed, and gradient elution was performed for 10 min using aqueous acetonitrile containing ammonium acetate as the mobile phase solvent, where the target compounds were eluted within 5-8 min. The developed method was validated using pig muscle, a processed pork food, cattle muscle and a processed beef food, and the obtained trueness values were 60.1-103.5%. The obtained relative standard deviation (RSD) values were 1.26-8.94% (repeatability) and 1.93-10.55% (intermediate precision). In some of the imported livestock products, small but clear peaks of ractopamine were detected by the developed LC-MS/MS method, and the presence of ractopamine was further confirmed by an LC-MS/MS/MS analysis with higher selectivity.

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