Second-order phase correction of NMR spectra acquired using linear frequency-sweeps

• Published in: Magnetic resonance letters Vol. 2; no. 1; pp. 1 - 8
• Main Authors: Gan, Zhehong, Hung, Ivan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2022; KeAi Communications Co. Ltd
• Subjects: 35Cl; Absorptive; Adiabatic; Broadband; CHIRP; CPMG; Dispersive; Frequency sweep; Line shape; Noise; Second-order phase; Spin-echo; Wideline; WURST; Line shape; Absorptive; WURST; Broadband; Noise; Adiabatic; Second-order phase; Spin-echo; CHIRP; CPMG; Frequency sweep; Wideline; 35Cl; Dispersive
• ISSN: 2772-5162; 2772-5162
• DOI: 10.1016/j.mrl.2021.100026

NMR spectra acquired with experiments using frequency-sweeps such as the wide-band uniform-rate smooth truncation (WURST) spin-echo and Carr-Purcell-Meiboom-Gill (CPMG) sequences cannot be absorptively phased by using only conventional zeroth- and first-order phase correction. Implementation of phase correction up to the second-order is described for obtaining absorptive spectra, which have more desirable line shapes and noise properties than magnitude spectra. The relationship of the second-order phase to the parameters of frequency sweeps is derived. The second-order phasing in the frequency-domain is equivalent to a point spread in the time-domain signal. The application of second-order phase correction is demonstrated with a wideline 35Cl CPMG spikelet spectrum. - Second-order phase correction yields absorptive spectra acquired using frequency sweeps as illustrated by 35Cl WURST/CPMG spectra.- The relation between second-order phasing and frequency sweep parameters is derived.- Second-order phasing is equivalent to a point spread in the time-domain. [Display omitted]