电感耦合等离子体质谱法测定磷酸铁锂中杂质元素

用微波消解技术,以混合酸(盐酸-硝酸-硫酸-双氧水)消解磷酸铁锂样品,建立了电感耦合等离子体质谱法(ICP-MS)测定磷酸铁锂中钠、镁、铝、钙、钛、铬、锰、钴、镍、铜、锌、铅等12种微量杂质元素的分析方法。确定了最佳实验条件如下:采用普通模式测定元素铅,氦碰撞模式测定钠、镁、铝、钛、铬、锰、钴、镍、铜、锌,氢气反应模式测定钙;碰撞气He气流速为5.6 mL/min,反应气H₂的流速为6.2 mL/min;钠、镁、铝、钙、钛采用钪为内标进行基体校正,铬、锰、钴、镍、铜、锌采用铱进行校正,铅采用铋进行校正。方法检出限在4.5～28.9 ng/L之间。采用实验方法对磷酸铁锂实际样品中各元素进行测定,结果的相对标准偏差(RSD,n=11)在0.6%～1.9%之间,加标回收率为94%～107%。方法测得结果与电感耦合等离子体原子发射光谱法(ICP-AES)进行对比分析,结果基本一致。

Determination of impurity elements in lithium iron phosphate by inductively coupled plasma mass spectrometry

After the sample was digested with mixed acid(hydrochloric acid-nitric acid-sulfuric acid-hydrogen peroxide), an inductively coupled plasma mass spectrometry (ICP-MS) was developed for the determination of sodium, magnesium, aluminum, calcium, titanium, chromium, manganese, cobalt, nickel, copper, zinc and lead in lithium iron phosphate with microwave digestion. The maximum experiment condition was as follows: lead was determined by normal mode; sodium, magnesium, aluminum, titanium, chromium, manganese, cobalt, nickel, copper, zinc were determined by collision gas hellum; calcium was determined by reaction gas hydrogen mode; the flow rate of collision gas hellum was 5.6 mL/min; the flow rate of reaction gas hydrogen was 6.2 mL/min; sodium, magnesium, aluminum, calcium, titanium were corrected with scandium as internal standard; chromium, manganese, cobalt, nickel, copper, zinc were corrected with yttrium as internal standard; lead was corrected with bismuth as internal standard. The detection limit of method was 4.5-28.9 ng/L. This proposed method was applied to determine elements in lithium iron phosphate actual samples with relative standard deviation(RSD, n=11) was 0.6%-1.9% and recoveries of 94%-107%. The results were consist with those obtained by inductively coupled plasma atomic emission spectrometry (ICP-AES).