定量核磁共振技术检测食品中硼的含量

Determination of the content of boron in food by quantitative nuclear magnetic resonance technology

目的 开发一种可以快速检测并监控食品中硼含量的定量核磁共振(qNMR)分析方法。方法 在特定进样条件下,11B原子核在特定谱宽范围内的核磁共振信号峰与样品中硼的含量成正比;使用含硼量<0.01×10的天然石英核磁管以消除干扰;向重水中添加三氟化硼乙醚作为内标(δ=0 ppm),以δ=19.38 ppm的信号峰作为硼酸的特征化学位移进行定标、积分、计算;由于硼酸具有较好的水溶性,样品中的硼酸可直接采用去离子水提取的方法得到。结果 该方法线性结果良好:y=507.81x+5 597.4,R~2>0.999 9;检出限和定量限分别为20、60 mg/kg;加标回收率90.3%~102.1%;日间精密度为1.26%~1.61%。结论 该方法前处理简单、测定过程快捷、测定结果准确,具有良好的潜在应用前景。

Objective To develop a method that can quickly determine the absolute content of boron in food by quantitative nuclear magnetic resonance(qNMR)analysis technology.Methods The signal area is directly proportional to the content of boron causing the peak under certain sample-acquired condition. Natural quartz NMR tubes(boron content <0. 01×10-6)was used to eliminate the interference. boron trifluoride etherate was used as an internal standard(δ=0 ppm)in Deuterium Oxide. Signal peak δ=19. 38 ppm was set as the characteristic chemical shift of boric acid to pick peaks,integrate,and perform later mathematical operation. Boric acid was extracted from samples with deionized water since its glorious solvability.Results The linearity and the method repeatability of the method were good:y=507. 81x+5 597. 4,R2>0. 999 9. The LODs and the LOQs were 20 and 60 mg/kg,respectively. The recoveries ranged from 90. 3%to 102. 1%. The precision between days was 1. 26%-1. 61%.Conclusion There are some good potential application prospects as for its simple pretreatment,quick measurement process,and accurate experimental result.