ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Matrix-assisted diffusion-ordered spectroscopy applied to essential oils of two species of Ocimum

Henrique M. Cezar, João Vito B. de Freitas, Alan Diego C. Santos, Nágila M. P. S. Ricardo, and Nilce V. Gramosa

Departamento de Química Orgânica e Inorgânica, Universidade Federal do Ceará - UFC, Fortaleza, Brazil

E-mail: nilce@dqoi.ufc.br

Received: 21 September 2022  Accepted: 2 February 2023

Abstract:

Diffusion-ordered spectroscopy (DOSY) is an NMR method developed for separation of the components in mixtures according to their diffusion coefficients. Compounds of similar diffusion coefficients can be separated by addition of a co-solute or co-solvent to the mixture in a matrix-assisted DOSY experiment (MAD). The aim of this work is to present the diffusion behavior of the main components of essential oils of Ocimum basilicum var. purpurascens and Ocimum gratissimum, as well as, of eugenol derivatives investigated by DOSY, using the surfactant polyoxyethylene(20)-oleyl ether (Brij 78) as matrix. The results showed the effect of solvent, nature of the sample, and surfactant concentration on the resolution of investigated sample spectra. The choice of the solvent played the main role in the separation of resonances. The mixture of DMSO-d₆:D₂O allowed suitable separation of components from the essential oils in proportions of 1:1 and 5:1 to O. basilicum and O. gratissimum, respectively. The diffusion behavior of binary and ternary mixtures of eugenol derivatives was studied in different concentrations of the solutes and Brij 78. In general, the best separation was achieved with Brij 78 at 40 mM in DMSO-d₆:D₂O (1:1).

Graphical abstract

Keywords: Ocimum basilicum; Ocimum gratissimum; Brij 78; MAD; DOSY; Eugenol derivatives

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-023-02715-5

Chemical Papers 77 (6) 3439–3446 (2023)