Separation of inorganic anions on reversed-phase C18 columns with a phosphomolybdate mobile phase

Tomoko Kemmei; Azusa Yudo; Shuji Kodama; Atsushi Yamamoto; Yoshinori Inoue; Shigehiro Kagaya; Kazuichi Hayakawa

doi:10.1016/j.chroma.2024.464843

Separation of inorganic anions on reversed-phase C18 columns with a phosphomolybdate mobile phase

J Chromatogr A. 2024 May 10:1722:464843. doi: 10.1016/j.chroma.2024.464843. Epub 2024 Mar 29.

Authors

Tomoko Kemmei¹, Azusa Yudo², Shuji Kodama³, Atsushi Yamamoto⁴, Yoshinori Inoue⁵, Shigehiro Kagaya⁶, Kazuichi Hayakawa⁷

Affiliations

¹ Toyama Institute of Health, 17-1 Nakataikoyama, Imizu 939-0363, Japan; Department of Environmental Applied Chemistry, Faculty of Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan. Electronic address: tomoko.kenmei01@pref.toyama.lg.jp.
² Toyama Institute of Health, 17-1 Nakataikoyama, Imizu 939-0363, Japan; Department of Environmental Applied Chemistry, Faculty of Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan.
³ Department of Chemistry, School of Science, Tokai University, 4-1-1 Kitakaname, Hiratsuka 259-1292, Japan.
⁴ Department of Biological Chemistry, College of Bioscience and Biotechnology, Chubu University, 1200 Matsumoto-cho, Kasugai 487-8501, Japan.
⁵ Department of Environmental Applied Chemistry, Faculty of Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan; Department of Applied Chemistry, Faculty of Engineering, Aichi Institute of Technology, 1247 Yachigusa, Yakusa-cho, Toyota 470-0392, Japan.
⁶ Department of Environmental Applied Chemistry, Faculty of Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan.
⁷ Institute of Nature and Environmental Technology, Kanazawa University, O24 Wakemachi, Nomi 923-1224, Japan.

PMID: 38574599
DOI: 10.1016/j.chroma.2024.464843

Abstract

Reversed-phase high performance liquid chromatography (RP-HPLC) is the most widely used chromatographic method. In addition to hydrophobic interactions, additional interactions such as electrostatic interactions may participate in the retention behaviour of an analyte. This makes it possible to use RP-HPLC for many types of analyte. We describe a simple method for separating inorganic anions on a C18 column, in which retention of inorganic anions is almost entirely due to electrostatic interactions. This leads to rapid separations as well as higher theoretical plate numbers. We used 2 mM phosphoric acid containing a low concentration of disodium molybdate as the mobile phase, which allows UV detection of non-UV-absorbing anions. With this method, we determined eight inorganic anions including several non-UV-absorbing anions photometrically at 220 nm. The detection limits of the examined eight inorganic anions calculated at a signal-to-noise ratio of 3 were between 0.3 and 10 μM. The detector response was linear over three orders of magnitude of inorganic anion concentration. The proposed RP-HPLC/UV method was successfully applied to determine inorganic anions in some water samples.

Keywords: Inorganic anions; Phosphomolybdate; Reversed-phase liquid chromatography; Ultraviolet detection.

MeSH terms

Anions* / chemistry
Chromatography, High Pressure Liquid / methods
Chromatography, Reverse-Phase* / methods
Limit of Detection
Molybdenum* / chemistry
Phosphoric Acids* / chemistry

Substances

Anions
Molybdenum
Phosphoric Acids
phosphomolybdic acid
phosphoric acid