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    悬浮液进样-石墨炉原子吸收光谱法测定巴戟天中痕量铅和镉

    GF-AAS Determination of Trace Amounts of Lead and Cadmium in Morinda Officinalis with Direct Suspension Sample Introduction

    • 摘要: 取经烘干粉碎并通过0.074 mm网筛的巴戟天样品0.050 0 g,加入琼脂溶液10.0 mL(其中含磷酸二氢铵0.1 g,作为基体改进剂),超声振荡5 min,制成样品的悬浮液,直接进样,采用石墨炉原子吸收光谱法测定其中铅和镉的含量。设置铅和镉的灰化温度分别为850℃和800℃。结果表明:铅和镉的质量浓度在一定范围内与其吸光度呈线性关系,铅和镉的检出限(3s×V/b)分别为2.17×10-9mg和3.4×10-10mg。按照标准加入法进行加标回收试验,铅和镉的回收率分别在98.8%~103%和98.3%~104%之间。精密度试验表明铅和镉的测定值的相对标准偏差(n=7)分别为2.7%和1.2%。

       

      Abstract: 0.050 0 g of the dried and powdered morinda officinalis sample (passed through 0.074 mm sample sieve) was taken and dispended in 10.0 mL of agar solution (containing 0.1 g of NH4H2PO4 as matrix modifier) with an ultrasonotor for 5 min, to make a suspension of the sample which was introduced into the instrument for GF-AAS determination of lead and cadmium. Ashing temperatures for lead and cadmium were set at 850℃ and 800℃, respectively. As shown by the results, linear relationships between values of absorbance and mass concentration of lead and cadmium were found in definite ranges, with detection limits (3s×V/b) of 2.17×10-9mg and 3.4×10-10mg respectively. Test for recovery was made by standard addition method, giving results in the range of 98.8%-103% and 98.3%-104%, respectively. Values of RSDs (n=7) were found 2.7% (for Pb) and 1.2% (for Cd).

       

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