quantification of δ-, γ- and α-tocopherol in tomatoes using an improved liquid-dispersive solid-phase extraction combined with ultrahigh pressure liquid chromatography

Tomato (solanum lycopersicum l.) consumption has been correlated with a lower incidence of cardiovascular diseases and cancer. this protective effect has been ascribed to different bioactive compounds present in this fruit. therefore, to gain insights on the potential of s. lycopersicum l. as bioactive food, a fast and sensitive methodology, based on liquid–liquid extraction (lle), dispersive solid phase extraction (dspe) followed by ultrahigh pressure liquid chromatography (uhplc-flr) analysis, was developed and validated to quantify δ-, γ- and α-tocopherol in tomatoes. upon the optimization of different parameters, a fast extraction and separation, and simultaneously, increased resolution and sensitivity was attained. the methodology was validated, retrieving better analytical performance than most methods reported so far. this included good linearity, (r 2 > 0.99) and precision (<6.4%), high recoveries (>79.5%) and improved limits of detection and quantification (lods of 2.15, 5.52 and 1.67 ng/ml and loqs of 7.18, 18.40 and 5.58 ng/ml, for δ- γ- and α-tocopherol, respectively). these limits are about 1000 times lower than those reported in literature. furthermore, as far we are aware, this is the first time δ-tocopherol presence in tomato is fully characterized and quantified. the methodology was applied to different tomato varieties, ripening stages and fruit sections, revealing high levels of δ-tocopherol that increase along fruit ripening, while the α-tocopherol follows the inverse trend. moreover, δ-tocopherol is almost fully concentrated in the seeds and skin of ripe tomato. finally, orac and dpph assays revealed that the selected tocopherols contribute to approximately half of tomato total antioxidant capacity.