手性液相色谱法直接定量乳粉中RRR-α-生育酚

Direct quantification of RRR-α-tocopherol in milk powder by chiral liquid chromatography

目的建立手性液相色谱法直接测定乳粉中RRR-α-生育酚的检测方法。方法样品经氢氧化钾皂化,石油醚-异丙醚萃取。经小粒径纤维素衍生物型手性柱Daicel Chiralcel OD-3 (2.1 mm×150 mm, 3μm)直接分离,采用无水乙醇-正己烷(5:995, V:V)(A)和三乙胺-正己烷(5:995, V:V)(B)(A:B=10:90)作为流动相进行等度洗脱,流速为0.2 mL/min,柱温30℃,检测波长为294 nm,外标法定量。结果 RRR-α-生育酚和其他α-生育酚异构体的分离度大于1.2。在0.5~50μg/mL范围内线性关系良好,相关系数大于0.999,检出限为0.20 mg/100 g,定量限为0.60 mg/100 g,加标回收率为95.0%~109.4%,相对标准偏差为2.7%。结论该方法快速、准确、灵敏,适合测定乳粉中RRR-α-生育酚的含量。

Objective To establish a method for directly determining RRR-α-tocopherol in milk powder by chiral liquid chromatography. Methods The samples were saponified with potassium hydroxide and extracted with petroleum ether-isopropyl ether. DAICEL Chiralcel OD-3(2.1 mm×150 mm, 3 μm) was directly separated on a small particle size cellulose derivative chiral column, and isocratic elution was performed using absolute ethanol-n-hexane(5:995, V:V)(A) and triethylamine-n-hexane(5:995, V:V)(B)(A:B=10:90) as the mobile phases, with the flow rate of 0.2 mL/min, the column temperature of 30 ℃, the detection wavelength of 294 nm, and the quantification by external standard method. Results The resolutions of RRR-α-tocopherol and other α-tocopherol isomers were greater than 1.2. The linearities were good within the range of 0.5-50 μg/mL, with the correlation coefficient greater than 0.999. The limit of detection was 0.20 mg/100 g, and the limit of quantitation was 0.60 mg/100 g. The recoveries after standard addition were 95.0%-109.4%, and the relative standard deviation was 2.7%. Conclusion This method is rapid, accurate and sensitive, and is suitable for the determination of RRR-α-tocopherol in milk powder.