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Igarashi T, Aursand M, Sacchi R, Paolillo L, Nonaka M, Wada Y, Arata Y, Bildsoe H, Falcigno L, Fauhl C, Guillou C, Halvorsen J, Honma E, Ijuuin Y, Kushida K, Martin GJ, Miyake Y, Optum OI, Oshima Y, Remaud G, Retif M, Robins R, Satake M, Shimidzu N, Tsuchiya F, Watanabe K, Watanuki C. Determination of Docosahexaenoic Acid and n-3 Fatty Acids in Refined Fish Oils by H-NMR Spectroscopy: IUPAC Interlaboratory Study. J AOAC Int 2019. [DOI: 10.1093/jaoac/85.6.1341] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
A high-resolution proton nuclear magnetic resonance (NMR) method for determining the concentration (mg/g) of docosahexaenoic acid (DHA), the molar proportion (mol%) of DHA, and the molar proportion of total n-3 fatty acids in fish oils was validated by an IUPAC interlaboratory study (the Commission VI-6 on Oils, Fats, and Derivatives WG 3/98). Thirteen laboratories from 5 countries tested 6 pairs of blind duplicate fish oils: a refined tuna oil, 2 extracted tuna oils, an extracted bonito oil, an extracted salmon oil, and an extracted sardine oil ranging from 9 to 30 mol% DHA and from 20 to 35 mol% n-3 fatty acids. Before 1D-proton NMR measurements with 300–500 MHz instruments, oil samples were weighed and diluted with deuterochloroform solution containing ethylene glycol dimethyl ether as internal standard. To achieve precise performance, a detailed procedure for signal area measurement was described in the protocol, and all participants were instructed about the critical importance of following the protocol. Statistical performances with invalid and outlier data removed were as follows: repeatability relative standard deviations (RSDr) ranged from 0.91 to 2.62% and reproducibility relative standard deviation (RSDR) ranged from 1.73 to 4.27% for DHA concentration (mg/g); RSDr ranged from 0.39 to 2.06%, and RSDR ranged from 0.59 to 3.46% for mol% DHA; RSDr ranged from 0.23 to 0.90% and RSDR ranged from 0.85 to 2.01% for mol% total n-3 fatty acids. The method is expected to be recommended by IUPAC.
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Affiliation(s)
- Tomoji Igarashi
- Japan Marine Oil Association, 32-7 Motoyoyogi-cho, Shibuya-ku, 151-0062, Tokyo, Japan; Japan Food Research Laboratories, Tama Laboratory, 6-11-10 Nagayama, Tama-shi, 206-0025, Tokyo, Japan
| | - Marit Aursand
- SINTEF, Division of Applied Chemistry, Fisheries and Aquaculture, N-7034, Trondheim, Norway
| | - Raffaele Sacchi
- University of Naples Federico II, Department of Food Science, Parco Gussone, 80055 Portici, Italy
| | - Livio Paolillo
- University of Naples Federico II, Department of Chemistry, via Mezzocannone 4, 80134 Naples, Italy
| | - Michio Nonaka
- Japan Marine Oil Association, 32-7 Motoyoyogi-cho, Shibuya-ku, 151-0062, Tokyo, Japan
| | - Y Wada
- Tokyo University of Fisheries, Department of Food Science and Technology, 4-5-7 Konan, Minato-ku, 108-8477, Tokyo, Japan
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Vosegaard T, Hald E, Langer V, Skov HJ, Daugaard P, Bildsoe H, Jakobsen HJ. Improved hardware and software for single-crystal NMR spectroscopy. J Magn Reson 1998; 135:126-132. [PMID: 9799686 DOI: 10.1006/jmre.1998.1551] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Design of state-of-the-art instrumentation and software for acquisition and analysis of single-crystal NMR spectra is presented. The design involves highly accurate rotation of a goniometer, and the acquisition of all the spectra for each rotation axis is automatically controlled by the host computer of the spectrometer using a homebuilt interface between the computer and the single-crystal probe. Moreover, a software package (ASICS) for fast and routine assignment/analysis of complex single-crystal spectra has been developed. Employing this equipment, the acquisition and complete analysis of single-crystal NMR spectra may be performed in about the same time as required for powder methods (spinning or static). The hardware and software are compared to recent alternative approaches within single-crystal NMR. Finally, it has been observed that single-crystal NMR techniques may provide the desired data for samples where powder methods fail.
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Affiliation(s)
- T Vosegaard
- Department of Chemistry, University of Aarhus, Aarhus C, DK-8000, Denmark
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