Phosphorus-31 nuclear magnetic resonance (31P NMR) for quantitative measurements of phospholipids derived from natural products: Effect of analysis conditions. (May 2021)

• Record Type: Journal Article
• Authors: Ahmmed, Mirja Kaizer; Carne, Alan; Stewart, Ian; Tian, Hong (Sabrina); Bekhit, Alaa El-Din Ahmed
• Is Part Of: Lebensmittel-Wissenschaft + Technologie =. Volume 142(2021)
• Publication Date: 2021-05
• Subjects: Krill -- Soybean lecithin -- Egg yolk -- Sodium cholate -- pH effect -- ETHEX; Food industry and trade -- Periodicals; Food -- Composition -- Periodicals; Microbiology -- Periodicals; Nutrition -- Periodicals; 664.005
• DOI: 10.1016/j.lwt.2021.110991
• Languages: English
• ISSNs: 0023-6438

Abstract

Abstract: In the present study the running conditions (sample pH, scan number, relaxation delay and NMR solvent) for the quantification of phospholipids by 31 P NMR using commercial pure standards were optimised. A mixture of pure standards was run at different pH (7.3, 7.8, 9.5 and 12), scan numbers (64, 128, 192 and 512), relaxation delay times (1s, 2s, 3.5s and 10s) and NMR solvents (D2 O/EDTA/sodium cholate or CDCl3 /CD3 OD/EDTA) to achieve this goal. Best 31 P NMR conditions were found to be pH 7.3, a scan number of 192 and a relaxation delay of 3.5s, which were used for the quantification of natural samples (Krill oil, soybean lecithin and egg phospholipid) in D2 O/EDTA/sodium cholate or CDCl3 /CD3 OD/EDTA. Phospholipids and lysophospholipids were highly resolved and detected in D2 O/EDTA/sodium cholate compared to CDCl3 /CD3 OD/EDTA. A number of phospholipids (lysophoshatidylglycerol-2, LPG-2; lysophosphatidylethanolamine, LPE; N-acyl phosphatidylethanolamine, APE) were not detected in CDCl3 /CD3 OD/EDTA, but they were detected in D2 O/EDTA/sodium cholate. Therefore, it is concluded that D2 O/EDTA/sodium cholate is a better detection solvent for 31 P NMR quantification of phospholipids extracted from natural sources. Highlights: 31 P NMR running conditions were optimised for phospholipid analysis. Phospholipids were hydrolysed under alkaline conditions. Soybean lecithin, krill oil and egg phospholipids were analysed in two NMR solvents. D2 O provided better detection and quantification of phospholipids than CDCl3 .