Standardized analytical multivariate methods via agnostization of LF-NMR signals – Updating extra virgin olive oil authentication as practical example Jiménez Carvelo, Ana María Arroyo Cerezo, Alejandra Berzaghi, Paolo Christian H., Pérez Beltrán María, Tello Liébana Cuadros Rodríguez, Luis Extra virgin olive oil (EVOO) is a high-value commodity traded worldwide; thus, accurate quality control analyses are essential to ensure its genuineness. In this context, a universal analytical methodology capable of delivering precise, fast and robust quality assessments would be highly beneficial for stakeholders. This study extends the instrument-agnostizing methodology from chromatography to low-frequency field nuclear magnetic resonance spectroscopy (LF-NMR). The proposed approach outlines the required steps to generate instrumentagnostic fingerprints and demonstrates its application through the development of a global multivariate model. For this purpose, 93 edible vegetable oils (76 EVOO and 17 non-olive ones) and 9 vegetable oil blends were analyzed using two different LF-NMR spectrometers operating at 100 MHz and 80 MHz 1H field frequencies. Each LF-NMR signal was subjected to the instrument-agnostizing methodology to obtain harmonized LF-NMR fingerprints. To demonstrate the usefulness of this methodology, principal component analysis was performed to assess the instrument-related variability before and after the instrument-agnostizing methodology. Finally, partial least squares-discriminant analysis models were developed for each dataset of LF-NMR fingerprints and evaluated using four main classification performance metrics (sensitivity, specificity, precision and accuracy). The developed classification model with 100 MHz LF-NMR fingerprints achieved the required values of quality performance metrics in a conformity scenario, showing for external and cross-instrument validation sets a sensitivity of 96 % in both cases, and highlighting a precision of 100 % and 96 %, respectively. The excellent outcome highlights the viability of the instrument-agnostizing methodology, enabling consistent and accurate quality control across laboratories, regardless of the LF-NMR instrument used. 2025-09-02T06:48:27Z 2025-09-02T06:48:27Z 2026 journal article Talanta 297 (2026) 128730 https://hdl.handle.net/10481/105953 https://doi.org/10.1016/j.talanta.2025.128730 eng http://creativecommons.org/licenses/by-nc-nd/4.0/ open access Attribution-NonCommercial-NoDerivatives 4.0 Internacional ELSEVIER