Título:	Development and validation of a time domain NMR relaxometric method for rapid screening of soybean oil adulteration in copaiba oil-resin.
Autoria:	MARINHO, M. O. VITOLANO, L. E. S. SANTOS, Y. F. OLIVEIRA, A. J. G. XAVIER, L. A. COSTA, L. A. M. A. COLNAGO, L. A. MACHADO, M. B.
Afiliação:	UNIVERSIDADE FEDERAL DO AMAZONAS, MANAUS, AM, BRAZIL UNIVERSIDADE DE S˜ AO PAULO, S˜ AO CARLOS, SP, BRAZIL UNIVERSIDADE DE SAO PAULO, SAO CARLOS, SP, BRAZIL UNIVERSIDADE FEDERAL DE SAO CARLOS, SP, BRAZIL UNIVERSIDADE FEDERAL DE RORAIMA, RR, BRAZIL UNIVERSIDADE FEDERAL DE RORAIMA, RR, BRAZIL LUIZ ALBERTO COLNAGO, CNPDIA UNIVERSIDADE FEDERAL DO AMAZONAS, MANAUS, AM, BRAZIL.
Ano de publicação:	2026
Referência:	Journal of Pharmaceutical and Biomedical Analysi, v. 280, 117606, 2026.
Páginas:	11 p.
Conteúdo:	Copaiba oil-resin (CO), extracted from trunks of various copaiba species, has several therapeutic and cosmetic properties and is a valuable non-timber forest product that contributes to preservation of the Amazon rainforest. Unfortunately, adulteration of this oil-resin with cheaper vegetable oils such as soybean oil (SO) has been common. In this paper, a method for the fast screening of SO in CO using time-domain NMR (TD NMR) relax ometry was developed and validated. CPMG relaxation measurements were performed by two analysts using two TD NMR instruments from different manufacturers. Strict temperature control, a low number of echoes, and a long echo time were required for adequate repeatability. The first derivative of CPMG decays and the percentage of SO in CO were modeled with partial least squares regression (PLSR). The first derivative of CPMG signal was found to minimize contributions of longer T 2 components and to emphasize those of shorter T 2 components, associated with more viscous components of the CO/SO mixture. As a result, the first derivative increased sensitivity of the method to the SO content. Results obtained with 1 latent variable showed an R²CV > 0.98, RMSECV between 2.9% and 4.7% SO, and LOQ values ranging from 29.3% to 48.3% SO, with an average close to 36% SO, lower than the adulteration level normally above 50%, but unable to monitor low-level contamination. The precision was assessed by repeatability (RMSEP 2.6 ± 0.5% SO) and intermediate precision (RMSEP 4.2 ±1.0% SO). The results agreed with those obtained using established infrared and NMR spectroscopic methods. Therefore, this method shows potential for rapid and non-destructive screening of gross adulteration of CO with SO, as observed in Brazilian markets.
Palavras-chave:	Adulteration CPMG PLSR
ISSN:	0731-7085
Digital Object Identifier:	https://doi.org/10.1016/j.jpba.2026.117606
Tipo do material:	Artigo de periódico
Acesso:	openAccess
Aparece nas coleções:	Artigo em periódico indexado (CNPDIA)