Li Qi, Zhou Tian, Gu Guoxian
Key Laboratory of Industrial Biotechnology, Ministry of Education, Southern Yangtze University, Wuxi 214036, China.
Se Pu. 2007 Jul;25(4):532-5.
An analytical method for four isomerized a-acids in beer was developed using solid phase extraction (SPE) coupled with high performance liquid chromatography (HPLC). The method for solid phase extraction was systematically optimized. The optimal conditions were determined as follows: 2 mL of acidic methanol as eluting solvent through a Sep-Pak C18 cartridge and the pH value of beer was adjusted to 2.5. Under these conditions, the recoveries of four isomerized a-acids for spiked standards (n=10) were 90.6%-96.4% and the relative standard deviations (RSDs) were generally less than 4%. The detection limits for iso-alpha-acid, rho-iso-alpha-acid, tetrahydro-iso-alpha-acid and hexahydro-iso-alpha-acid were 0.14 mg/L, 0.36 mg/L, 0.33 mg/L and 0.53 mg/L, respectively. The method is sensitive, accurate and suitable for the analysis of isomerized alpha-acids in beer.
建立了一种采用固相萃取（SPE）与高效液相色谱（HPLC）联用分析啤酒中四种异构化α-酸的方法。对固相萃取方法进行了系统优化。确定的最佳条件如下：通过Sep-Pak C18柱，以2 mL酸性甲醇作为洗脱溶剂，并将啤酒的pH值调至2.5。在此条件下，加标标准品（n=10）中四种异构化α-酸的回收率为90.6%-96.4%，相对标准偏差（RSD）一般小于4%。异α-酸、ρ-异α-酸、四氢异α-酸和六氢异α-酸的检出限分别为0.14 mg/L、0.36 mg/L、0.33 mg/L和0.53 mg/L。该方法灵敏、准确，适用于啤酒中异构化α-酸的分析。
