摘  要：以锂的次灵敏线323.3 nm为分析谱线，采用火焰原子吸收光谱法测定磷酸铁锂中的高含量锂。通过研究酸介质、消电离剂和基体离子对锂测定的影响，以及进行共存离子干扰实验发现：在2%的硝酸介质中方法的灵敏度最佳；在标准溶液中加入基体离子，可以消除基体对锂测定的干扰；常见共存离子不干扰锂的测定。在优化的实验条件下，锂的检测线性范围为4～140 μg·mL-1，检出限（3σ）为2.0 μg·mL-1，对20.0 μg·mL-1的锂标准溶液连续测定11次，其RSD为0.05%。方法简便、快速、准确，检测线性范围广，避免了稀释操作带来的误差，可用于高含量锂的直接测定；方法用于磷酸铁锂样品测定，回收率在94%~103.7%之间，相对标准偏差（n=7）在1.04%~1.16%之间。
关键词：火焰原子吸收光谱法；磷酸铁锂；锂；次灵敏线
中图分类号：O657.31；TQ131.1+1；O614.111；TM930.12   文献标志码：A    文章编号：1674-5124（2013）05-0046-03
Flame atomic absorption spectrophotometric determination of lithium in lithium
ferric phosphate using sub-sensitive spectral line
DENG Xiang1，2
（1. Engineering Research Center in Biomaterials，Sichuan University，Chengdu 610064，China；
2. Sichuan Testing Center for Biomaterials and Medical Devices，Chengdu 610064，China）
Abstract: The high-content of lithium in lithium ferric phosphate was determined by flame atomic absorption spectrophotometry using sub-sensitive spectral line at 323.3 nm. The effects of acid medium， disionizer and matrix ions had been studied. The effects of concomitant ions had been studied too. The results proved that the sensitivity was the best in 2% HNO3 aqueous solution， and the matrix effect could be eliminating with addition of matrix ions in standard solutions. The concomitant ions did not affect the determination of lithium. Under the optimized conditions， the linearity range of lithium was kept from 4 μg·mL-1 to 140 μg·mL-1 and the detection limit（3σ）was 2.0 μg·mL-1. The relative standard deviation （n=11） was 0.05% for 20.0  g·mL-1 lithium. This was a simple， rapid， accurate method with wide linearity range. It could avoid the error produced in the dilution operation， so it could be applied to determine high-content lithium in samples directly. The content of lithium in lithium ferric phosphate was determined by this method， giving values of recovery in the range of 94%-103.7% and RSD （n=7） in the range of 1.04%-1.16%.
Key words: flame atomic absorption spectrophotometry; lithium ferric phosphate; lithium; sub-sensitive spectral line