超高效液相色谱－串联质谱法测定大豆分离蛋白中的嘌呤.

[Obiective] To establish a method for the simultaneous measurement of 4 purines in soybean protein isolate (SPI) using UPLC- MS/MS. [Method] Purines in SPI samples were hydrolyzed and extracted with trifluoroacetic acid: formic acid (V: V=1:1), and diluted with water. The 4 purines (guanine, adenine, hypoxanthine and xanthine) were then separated on an Agilent Poroshell 120 EC-C18 column, using 0.002% formic acid aqueous solution and methanol as mobile phases with gradient elution. Subsequently, the target compounds were analyzed with electrospray ionizationsource in positive ion mode under multi-reaction monitoring mode, employing the external standard quantitative method. [Result] Within the concentration range of 1-200 ng/mL, all four purines had good linear relationships, with correlation coefficients (r) exceeding 0.999 1.The limits of quantitation (LOQ) and the limits of detection (LOD) for the four purines were in the range of 0.24- 3.00 mg/kg and 0.08-1.00 mg/kg. The spiked experiments were performed at three concentration levels, and the average recovery rates for the four components ranged from 81.7% to 95.2%, with RSD all less than 8.6% (n=6). [Conclusion] This method is highly operable, simple and fast, with high sensitivity, recovery rate and precision, and can simultaneously detect four purine compounds in soy protein isolate. [ABSTRACT FROM AUTHOR]