Determination of Retinol, -Tocopherol, Lycopene, and -Carotene in Human Plasma Using HPLC with UV-Vis Detection: Application to a Clinical Study
Figure 1
An HPLC chromatogram of retinol (1.00 μmol/L; 0.29 μg/mL), -tocopherol (15.0 μmol/L; 6.46 μg/mL), lycopene (0.020 μmol/L; 0.011 μg/mL), and β-carotene (0.100 μmol/L; 0.054 μg/mL) in standard solution. Peaks: (1) retinol, (2) retinyl acetate, (3) -tocopherol, (4) -tocopheryl acetate, (5) lycopene, and (6) β-carotene. HPLC conditions: an isocratic elution (mobile phase : methanol-ethanol, 75 : 25, v/v); the stationary phase was an analytical column Discovery HS , 150 × 4 mm i.d., 5 μm fitted with a Discovery , 20 × 4 mm i.d., 5 μm guard column; the flow rate was kept constant at 0.8 mL/min, separation ran at 40°C. Retinol together with retinyl acetate was monitored at 325 nm, -tocopherol together with -tocopheryl acetate was monitored at 292 nm, lycopene was monitored at 468 nm, and β-carotene was monitored at 450 nm.