Quantitative 1H NMR and high-sensitivity ICP-MS based integrated analytical approach for eri-flaxseed oil blend: Implications for antioxidant and cytotoxic effects on L6 cell lines.

BACKGROUND: Reliable quantification of edible oil blends remains an analytical challenge that cannot be adequately resolved using a single conventional technique. Therefore, integrated analytical approaches were employed, including highly sensitive ICP-MS and 1H NMR spectroscopy to provide a deeper understanding of changes associated with their constitutional interactions.

RESULTS: Quantitative 1H NMR analysis based on proton peak integration revealed allylic (3.06 ± 0.02), acyl-chain methylene (2.00 ± 0.01), and bis-allylic (1.55 ± 0.01) integral values for EFBO, corresponding to 76.50 % total unsaturated fatty acids and 23.50 % saturated fatty acids. Microwave-assisted acid digestion coupled with ICP-MS quantified 17 elements, with Mn, Fe, Co, Ni, and Zn below detection limits. The analytical method exhibited excellent performance, with spike recoveries of 98.21-102.03 %, LOD ranging from 0.007 to 41.14 ppb, LOQ ranging from 0.023 to 136.99 ppb and R2 of 0.984 to 0.998. Estimated daily intake calculations based on 10 g/day EFBO consumption indicated that the detected trace elements contributed <0.01 % of the recommended daily intake, while heavy metals, including Pb and Al, remained well below Codex permissible limits. Spectrophotometric antioxidant assays (DPPH and ABTS) showed that EFBO had the lowest IC50 values of 74.28 ± 3.67 μg/mL and 51.23 ± 3.09 μg/mL, respectively, among the tested oils. Cytotoxicity assessment by MTT assay reported an IC50 of 48.3 ± 0.1 μg/mL, with >90 % cell viability at lower concentrations.

SIGNIFICANCE: This coherent analytical approach enables robust compositional authentication, quality evaluation, safety monitoring, and the correlation of chemical composition with the biological activity of blended edible oils.