Furthermore, this specific

peak is not symmetrical and not well resolved. These data confirm the efficiency of the specified flow and composition gradients of the mobile phase to separate carotenes and tocopherols. Previous studies performed by Rodrigues et al. (2010) and Costa et al. (2010) were not able to quantify tocotrienols, nor distinguish β- and γ-tocopherols. Samples with standard concentrations of α-, β-, γ- and δ-tocopherols in hexane ranging from 2.50 to 37.50 mg L−1 and samples of β-carotene in hexane Bcl2 inhibitor ranging from 0.05 to 10.00 mg L−1 were used to construct the calibration curves. Results for the six different sequences of tocopherols standard samples performed in triplicate on different days using the fluorescence detector are shown in Table 1. The relationship between tocopherol concentrations and the peak areas was described by the linear regression equations, and in all equations x is the tocopherol homologue concentration in mg L−1 and y is the chromatogram peak area divided by 1 × 105. All R2 obtained were higher than 0.9810. At the upper limit of quantification (i.e. 37.50 mg L−1) the percentage deviation and the inter-run variability values were less

than 4.10%, an appropriate value according to the literature ( Marin et al., 2007, Shah Selleckchem GSK2118436 et al., 2000 and USDHHS, 2001). For all the other tocopherol concentrations, excluding the LOQ (2.5 mg L−1), the percent deviation and the inter run variability values were less than 13.30%. Data of the same six sequences of tocopherol standard samples run in triplicate on different days, obtained using the PDA detector set at 292 nm, are also shown in Table 1. The relationship between each tocopherol concentration and peak area (divided by 1 × 105) was described by linear

regressions in the same way as for the fluorescence detector. All R2 values obtained were higher than 0.9970. At the upper limit of quantification (i.e. 37.50 mg L−1) the percent deviation and the inter-run variability values were less than 4.60%. For all the other concentrations of tocopherols, excluding the LOQ (2.5 mg L−1), the percent deviation and the inter run variability values were Protein kinase N1 also less than 13.50%. Data of the six different sequences of β-carotene standard samples performed in triplicate on different days, using the PDA detector set at 455 nm, are show in Table 2. R2 value was higher than 0.9940. At the upper limit of quantification (i.e. 10.00 mg L−1) the percent deviation and the inter-run variability values were less than 2.00%. For all the other concentrations of β-carotene, excluding the LOQ (0.10 mg L−1), the percent deviation and the inter run variability values were less than 11.10%. Reproducibility of the method was evaluated by analysing replicates of tocopherol quality control samples at concentrations of 5.00 (LOQ), 15.00 and 35.