工作场所空气中钡及其可溶性化合物的涂镧热解石墨管-石墨炉原子吸收测定法

Determination of barium in air of workplace by graphite furnace atomic absorption with lanthanumcoated pyrolytic graphite tube

目的建立涂镧热解石墨管-石墨炉原子吸收法测定工作场所空气中钡含量的方法。方法采用微孔滤膜采集工作场所空气中的钡,滤膜使用消化液(浓硝酸:高氯酸为9:1)于220℃进行消化,以硝酸镁为基体改进剂,采用涂镧热解石墨管-石墨炉原子吸收法测定工作场所空气中钡的含量。结果工作场所空气中钡及其可溶性化合物的测定范围为0~500μg/L,相关系数r=0.997,检出限15.52μg/L,加标回收率为97.8%~101.9%,最低检测浓度0.002 mg/m^3(以采集75 L空气样品计),相对标准偏差小于5.0%。结论该方法简便、准确、经济,能够满足职业卫生现场检测的要求,适用于基层单位对工作场所空气中钡的监测。

[ Objective ] To establish a novel method for the determination of barium in workplace air by graphite furnace atomic absorption spectrometry, with lanthanum-coated pyrolytic graphite tube.[Methods] The sample of workplace air was acquired by microporous membrane, and was digested by concentrated nitric acid and perchlorie acid as digestion （the proportion was 9：1） at 220 ℃. The pyrolytic graphite tube was coated with lanthanum, which was used to determine the level of barium in the air of workplace with magnesium nitrate as matrix modifiers. [ Results ] The measurement range f the method was 0-500μg/L, r=0.997. The detection limit was 15.52 μg/L, and the recovery of standard addition was 97.8%-101.9%. The minimum detectable concentration was 0.002 mg/m3 when the sampling volume was 75 L, and the relative standard deviation was less than 5.0%. [Conclusion] This method is simple, accurate and economic, which can meet the requirements of occupational field monitoring. Thus, it is suitable for the determination of barium in workplace air in the basic organizations.