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    石墨炉-原子吸收光谱法测定含维生素B12制品中铅量

    GF-AAS Determination of Lead in Preparations of Vitamin B12

    • 摘要: 提出了用石墨炉-原子吸收光谱法测定维生素B12制品(例如含维生素B12的保健食品及饲料等)中铅的含量。样品于压力罐中用硝酸及过氧化氢经在60 ℃~160 ℃范围内阶梯升温消解,所得溶液蒸缩至0.5 mL后,加水定容至10 mL,按选定的仪器工作条件测定其中铅量。采用热解涂层平台石墨管。用阶梯升温方式先后于350 ℃(5 s)和550 ℃(2 s)进行灰化,并选择在1 700 ℃进行原子化。方法的检出限(3S/N)为0.1 ng。在20.0 μg·L-1浓度水平上重复测定8次做回收及精密度试验,测得平均回收率为100.2%,相对标准偏差为0.39%。

       

      Abstract: GF-AAS was applied to the determination of lead in preparations of vitamin B12 (e.g. healthcare food, feed and etc.). The sample was digested with conc. HNO3 and H2O2 in a pressure-vessel and heated in an electric oven with gradual temperature elevation from 60 ℃ to 160 ℃ for definite time-intervals. The solution obtained was evaporated to 0.5 mL and then diluted to 10 mL, which was used for determination of lead under the prescribed working condition of the instrument. Pyrolytic coated platform graphite tube was used and ashing was performed under the mode of gradient temperature elevations at 350 ℃ for 5 s and at 550 ℃ for 2 s. The atomization was carried out at the temperature of 1 700 ℃. Detection limit (3S/N) of the method was found to be 0.1 ng. Recovery and precision was tested at the concentration level of 20.0 μg·L-1 for 8 determinations, giving results of av. recovery of 100.2% and RSD of 0.39%.

       

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