Basic accuracy of a 1D NOESY with presaturation method using standard solutions of amino and maleic acids.

Autor: Saito N; Center for Environmental Standards and Measurement, Health and Environmental Risk Division, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan. saito-naoki@nies.go.jp.
Jazyk: angličtina
Zdroj: Analytical and bioanalytical chemistry [Anal Bioanal Chem] 2024 Nov; Vol. 416 (26), pp. 5721-5731. Date of Electronic Publication: 2024 Aug 23.
DOI: 10.1007/s00216-024-05491-7
Abstrakt: 1D NOESY with presaturation (NOESY-presat) is the most popular water suppression method. When D 2 O solutions of L-phenylalanine or L-valine were measured using NOESY, the absolute concentration biases increased with longer mixing and evolution times, reaching a maximum of 54% with respect to the preparation values. At mixing and evolution times of 0 ms and 0 µs, respectively, the absolute concentration biases were reduced to less than 3%. The remaining biases were caused by the off-resonance effect, which was prevented by setting the frequency offset to an intermediate value between the analyte and internal standard 3-(trimethylsilyl)-1-propanesulfonic acid-d 6 (DSS-d 6 ) signals. Nevertheless, NOESY-presat gave maximum absolute biases of 26% and 11% for glycine and maleic acid concentrations, respectively, in three H 2 O/D 2 O (90/10 vol%) solutions. The proposed NOESY-dual-presat method reduced the absolute biases to below 4%. However, water suppression was insufficient but was improved by setting the frequency offset to the same as the presaturation offset with the H 2 O signal, although the absolute biases rose to 5 to 13%. Quantitative analyses using NOESY-presat and NOESY-dual-presat require careful consideration of the off-resonance effect.
(© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.)
Databáze: MEDLINE
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