A Sustainable TD‑NMR Protocol for the Quantitative Analysis of Triacylglycerols in Copaíba Oil‑Resin: Development and Validation

The present study has developed and validated a sustainable, low‑cost TD‑NMR method for the identification and quantification of triacylglycerols (TAGs) in Copaifera spp. Oleo-resin. The adulteration of this Amazonian commodity with TAGs is an increasingly prevalent issue, driven by the absence of standard protocols for the oil-resin handling and storage, and by insufficient quality control measures.¹ Although conventional techniques such as HPLC and GC are widely effective, they are comparatively expensive and produce hazardous chemical waste. Previously, we developed and validated a high-resolution ¹H NMR method to quantify TAGs and mineral‑oil adulterants.² Notably, 75 % of commercial samples were adulterated with soybean‑derived triacylglycerols or mineral oil. Overall, 1H NMR demonstrated efficacy in detecting adulteration of copaíba oil-resin by both TAGs and mineral oil; however, that method incurs high costs and demands specialized personnel. Accordingly, this study aimed to develop and validate a TD-NMR analytical protocol capable of quantifying TAG adulterants in copaíba oil-resin. The TD‑NMR results exhibited reasonable linearity (R² > 0.99) and consistent performance across calibration and validation trials. Comparative studies with near‑ and mid‑infrared spectroscopy (NIR and MIR) confirmed that the method meets established recovery criteria for oil mixtures. Analysis of both authentic and commercial samples revealed substantial chemical variability, manifested in viscosity differences that directly influence TAG quantification. Despite an adequate linear range, 64% of commercial samples showed adulteration levels exceeding 50 %, underscoring challenges in analyzing matrices with diverse physicochemical properties. Validation at UFAM and EMBRAPA‑Instrumentação laboratories demonstrated the method’s applicability. However, the proposed method showed a false-positive rate of 7%, indicating the need for complementary strategies, such as the standard‑addition technique. In conclusion, these findings establish TD‑NMR as an alternative for the quality control and authentication of copaiba oil-resin, offering an alternative approach for adulteration detection and a means by which enhanced reliability in the commercialization of this valuable natural resource may be established.