| Based on GB 5009.82—2016 second method and GB/T 26635—2011 two national standard methods, the determination conditions in the two standards were combined and optimized, and the normal phase high performance liquid chromatography(NP-HPLC) detection method for simultaneous determination of α-, β-, γ-, δ-tocopherol and α-, β-, γ-, δ-tocotrienols in edible oil using silica gel column was determined. The results showed that with 90% n-hexane + 10% methyl tert-butyl ether- tetrahydrofuran- methanol mixture(volume ratio 20∶ 1∶ 0.1)as mobile phase, the sample was dissolved by vortex agitation for 10 s, then separated on a silica gel chromatographic column, which had been equilibrated with mobile phase for more than 90 min, finally analyzed by a fluorescence detector. The linear range of eight isomers was 0.2-10 μg/mL with the correlation coefficients above 099, and the detection limit and quantitation limit were 2 mg/kg and 6 mg/kg respectively. The recovery rates of the eight isomers was 70.08%-116.33%, and the relative standard deviation was 114%-9.85%. After optimization, the recovery rate and repeatability of the determination method were improved, and the separation effect was also greatly improved. The method could meet the requirement of simultaneous determination of tocopherol and tocotrienol in edible oil. |
