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Kotani A, Ishikawa H, Shii T, Kuroda M, Mimaki Y, Machida K, Yamamoto K, Hakamata H. Determination of oxalic acid in herbal medicines by semi-micro hydrophilic interaction liquid chromatography coupled with electrochemical detection. ANAL SCI 2023; 39:441-446. [PMID: 36639558 DOI: 10.1007/s44211-022-00245-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 12/13/2022] [Indexed: 01/15/2023]
Abstract
In this study, the determination of oxalic acid in herbal medicines was performed by using a hydrophilic interaction liquid chromatography coupled with electrochemical detection (HILIC-ECD) method. A semi-micro column packed with amide-silica particles and an acetonitrile-30 mM phosphate buffer (pH 6.8) mixture (65:35, v/v) were used as the stationary and mobile phases, respectively, in the HILIC-ECD. A potential of + 1.1 V vs. Ag/AgCl was applied to a glassy carbon working electrode. The ratio of the peak height of oxalic acid to that of the internal standard (synephrine) was proportional to the concentration of 0.45 μg L-1 to 1.8 mg L-1 with a correlation coefficient of 0.999. The detection limit (signal-to-noise ratio, S/N = 3) of oxalic acid was 0.17 μg L-1. By the HILIC-ECD, the oxalic acid content in crude drugs and Kampo medicine extract granules (Zingiberis Rhizoma Processum, Pinelliae Tuber, Sho-seiryu-to, Hange-shashin-to, etc.) were determined with less than 2.9% relative standard deviation (RSD, n = 6), and their recoveries were more than 88.7% with less than 3.3% RSD (n = 6). In conclusion, we demonstrated that the HILIC-ECD performed measurements that were quite selective, accurate, and precise for the determination of oxalic acid in herbal medicines.
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Affiliation(s)
- Akira Kotani
- Department of Analytical Chemistry, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, 192-0392, Japan.
| | - Hisanobu Ishikawa
- Department of Analytical Chemistry, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, 192-0392, Japan
| | - Takashi Shii
- Department of Medicinal Pharmacognosy, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, 192-0392, Japan
- Department of Pharmacy, Kitasato University Hospital, 1-15-1, Kitazato, Minami-Ku, Sagamihara, Kanagawa, 252-0375, Japan
| | - Minpei Kuroda
- Department of Medicinal Pharmacognosy, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, 192-0392, Japan
| | - Yoshihiro Mimaki
- Department of Medicinal Pharmacognosy, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, 192-0392, Japan
| | - Koichi Machida
- Department of Analytical Chemistry, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, 192-0392, Japan
| | - Kazuhiro Yamamoto
- Department of Analytical Chemistry, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, 192-0392, Japan
| | - Hideki Hakamata
- Department of Analytical Chemistry, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, 192-0392, Japan
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Taraji M, Haddad PR, Amos RIJ, Talebi M, Szucs R, Dolan JW, Pohl CA. Chemometric-assisted method development in hydrophilic interaction liquid chromatography: A review. Anal Chim Acta 2017; 1000:20-40. [PMID: 29289311 DOI: 10.1016/j.aca.2017.09.041] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 09/22/2017] [Accepted: 09/24/2017] [Indexed: 02/09/2023]
Abstract
With an enormous growth in the application of hydrophilic interaction liquid chromatography (HILIC), there has also been significant progress in HILIC method development. HILIC is a chromatographic method that utilises hydro-organic mobile phases with a high organic content, and a hydrophilic stationary phase. It has been applied predominantly in the determination of small polar compounds. Theoretical studies in computer-aided modelling tools, most importantly the predictive, quantitative structure retention relationship (QSRR) modelling methods, have attracted the attention of researchers and these approaches greatly assist the method development process. This review focuses on the application of computer-aided modelling tools in understanding the retention mechanism, the classification of HILIC stationary phases, prediction of retention times in HILIC systems, optimisation of chromatographic conditions, and description of the interaction effects of the chromatographic factors in HILIC separations. Additionally, what has been achieved in the potential application of QSRR methodology in combination with experimental design philosophy in the optimisation of chromatographic separation conditions in the HILIC method development process is communicated. Developing robust predictive QSRR models will undoubtedly facilitate more application of this chromatographic mode in a broader variety of research areas, significantly minimising cost and time of the experimental work.
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Affiliation(s)
- Maryam Taraji
- Australian Centre for Research on Separation Science (ACROSS), School of Physical Sciences-Chemistry, University of Tasmania, Private Bag 75, Hobart 7001, Australia
| | - Paul R Haddad
- Australian Centre for Research on Separation Science (ACROSS), School of Physical Sciences-Chemistry, University of Tasmania, Private Bag 75, Hobart 7001, Australia.
| | - Ruth I J Amos
- Australian Centre for Research on Separation Science (ACROSS), School of Physical Sciences-Chemistry, University of Tasmania, Private Bag 75, Hobart 7001, Australia
| | - Mohammad Talebi
- Australian Centre for Research on Separation Science (ACROSS), School of Physical Sciences-Chemistry, University of Tasmania, Private Bag 75, Hobart 7001, Australia
| | - Roman Szucs
- Pfizer Global Research and Development, CT13 9NJ, Sandwich, UK
| | - John W Dolan
- LC Resources, 1795 NW Wallace Rd., McMinnville, OR 97128, USA
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