Carotenoids and fat-soluble vitamin standards: E-β-apo-8′-carotenal, α-carotene, 13-Z-β-carotene, cryptoxanthin, lutein, zeaxanthin, astaxanthin, cantaxanthin, β-carotene, 9-Z-β-carotene, retinol, retinol acetate, 25-hydroxycholecalciferol, cholecalciferol and α-tocotrienol were purchased from Sigma-Aldrich (St. Louis, MO, USA). The standard of 5-Z-lycopene was supplied by CaroteNature GmbH (Ostermundigen, Switzerland).
MeOH of LC-MS grade, n-hexane, ethanol and MTBE of HPLC grade, synthetic plasma and butylated hydroxytoluene (BHT) were obtained from Sigma-Aldrich. AMAC and AA of HPLC grade were purchased from Panreac Quimica SA (Barcelona, Spain). Ultrapure water (Milli-Q) was generated by a Millipore system (Millipore, Bedford, MA, USA).
MeOH of LC-MS grade, n-hexane, ethanol and MTBE of HPLC grade, synthetic plasma and butylated hydroxytoluene (BHT) were obtained from Sigma-Aldrich. AMAC and AA of HPLC grade were purchased from Panreac Quimica SA (Barcelona, Spain). Ultrapure water (Milli-Q) was generated by a Millipore system (Millipore, Bedford, MA, USA).