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本文报道利用自制的徐镧石墨管,以(NH_4)_2-EDTA为基体改进剂,在以氘灯为背景校正光源的国产仪器上测定乳粉中痕量铬。研究确定了测定乳粉中铬的最佳条件。样品基体干扰消除较完全,石墨管的记忆效应小,使用寿命长,灵敏度是普通石墨管的两倍。9次测定给出相对标准偏差为3.9%。测定结果与二苯碳酸二肼比色法和火焰原子吸收法相比较无显著差异。
This paper reports the determination of trace chromium in milk powder by using homemade lanthanum graphite tube and (NH 4) 2-EDTA as matrix modifier on domestic instruments with deuterium lamp as background correction light source. The study determined the best conditions for determination of chromium in milk powder. Sample matrix interference to eliminate more completely, graphite tube memory effect is small, long life, twice the sensitivity of ordinary graphite tube. Nine determinations gave a relative standard deviation of 3.9%. The results were not significantly different from the diphenyl carbonate dihydrazine colorimetric method and flame atomic absorption spectrometry.