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Analytical Chemistry in Japan

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Analytical Chemistry".

Deadline for manuscript submissions: closed (31 December 2022) | Viewed by 4304

Special Issue Editor

Special Issue Information

Dear Colleagues,

In Japan, many researchers are working on the topic of analytical chemistry, with outstanding results. In order to collect those new results from the researchers in Japan, a Special Issue entitled “Analytical Chemistry in Japan” is being launched. This Special Issue collects full papers and high-quality review papers in all fields of analytical chemistry. We kindly encourage the colleagues involved in all branches of analytical chemistry to make contributions to this Special Issue.

Prof. Dr. Makoto Tsunoda
Guest Editor

Manuscript Submission Information

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Published Papers (2 papers)

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Research

6 pages, 1345 KiB  
Article
Improvement of an Automated Sample Injection System for Pillar Array Columns to Increase Analytical Reproducibility
by Hiroshi Kuroki, Hirotaka Koyama and Makoto Tsunoda
Molecules 2022, 27(15), 4715; https://doi.org/10.3390/molecules27154715 - 23 Jul 2022
Viewed by 1050
Abstract
In our previous study, we developed an automatic sample injection system for pillar array columns for quantitative analysis. An autosampler was used to maintain a constant sample injection volume. However, the sample was diluted during injection using the autosampler, thus deteriorating the analytical [...] Read more.
In our previous study, we developed an automatic sample injection system for pillar array columns for quantitative analysis. An autosampler was used to maintain a constant sample injection volume. However, the sample was diluted during injection using the autosampler, thus deteriorating the analytical reproducibility. In this study, we have substituted the autosampler with a syringe pump to overcome the abovementioned problem and improve the system. Sample dilution was avoided by filling the entire capillary with the sample at a constant rate. This improved system also increased the analytical reproducibility. In the previous system, the relative standard deviation (RSD) exceeded 17% of the peak height for coumarin dyes. In contrast, the improved system decreased the RSD to the range 1.2–1.8%. The analytical reproducibility was evaluated by using five types of amino acids. The RSD of each peak height was within 3.0%, confirming good reproducibility. These results indicate that the sample injection method developed in this study can be applied to biological sample analyses as a simple quantitative analysis method for pillar array columns. Full article
(This article belongs to the Special Issue Analytical Chemistry in Japan)
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7 pages, 788 KiB  
Article
Quantification of Intracellular Thiols by HPLC-Fluorescence Detection
by Hiroki Yamamoto, Takuya Fujiwara, Takashi Funatsu and Makoto Tsunoda
Molecules 2021, 26(8), 2365; https://doi.org/10.3390/molecules26082365 - 19 Apr 2021
Cited by 5 | Viewed by 2712
Abstract
Biothiols, such as cysteine and glutathione, play important roles in various intracellular reactions represented by the redox equilibrium against oxidative stress. In this study, a method for intracellular thiol quantification using HPLC-fluorescence detection was developed. Thiols were derivatized with a thiol-specific fluorescence derivatization [...] Read more.
Biothiols, such as cysteine and glutathione, play important roles in various intracellular reactions represented by the redox equilibrium against oxidative stress. In this study, a method for intracellular thiol quantification using HPLC-fluorescence detection was developed. Thiols were derivatized with a thiol-specific fluorescence derivatization reagent, viz. ammonium 7-fluoro-2,1,3-benzoxadiazole-4-sulfonate (SBD-F), followed by reversed-phase separation on an InertSustain AQ-C18 column. Six different SBD-thiols (homocysteine, cysteine, cysteinylglycine, γ-glutamylcysteine, glutathione, and N-acetylcysteine as an internal standard) were separated within 30 min using a citric buffer (pH 3.0)/MeOH mobile phase. The calibration curves of all the SBD-thiols had strong linearity (R2 > 0.999). Using this developed method, the thiol concentrations of human chronic myelogenous leukemia K562 cell samples were found to be 5.5–153 pmol/1 × 106 cells. The time-dependent effect of a thiol scavenger, viz. N-ethyl maleimide, on intracellular thiol concentrations was also quantified. This method is useful for elucidating the role of intracellular sulfur metabolism. Full article
(This article belongs to the Special Issue Analytical Chemistry in Japan)
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