磷酸氢二铵分离-电感耦合等离子体原子发射光谱法测定钛白粉中痕量铜和钒

针对钛白粉样品中钛基体对电感耦合等离子体原子发射光谱法(ICP-AES)测定痕量铜和钒有干扰,提出了利用磷酸氢二铵[(NH₄)₂HPO₄]沉淀分离钛基体后ICP-AES测定钛白粉产品中痕量铜和钒的方法。对溶样方式、(NH₄)₂HPO₄沉淀钛的条件和ICP-AES的测定条件进行研究,结果表明:对于0.1 g钛白粉样品,在H₂SO₄和(NH₄)₂SO₄介质中,用沸水浴加热3～5 min,可使钛与(NH₄)₂HPO₄形成的Ti(HPO₄)₂沉淀完全,在实验确定的仪器工作条件下以Cu 324.7 mm和V 292.4 nm进行测定,结果稳定。铜和钒的检出限分别为 0.001 μg/mL和0.000 7 μg/mL。应用实验方法对钛白粉实际样品中铜和钒进行测定,相对标准偏差(RSD,n=6)不大于1.2%,加标回收率在90%～117%之间。方法可以用于钛白粉的日常分析。

Determination of trace copper and vanadium in titanium dioxide by inductively coupled plasma atomic emission spectrometry with diammonium hydrogen phosphate separation

The determination of trace copper and vanadium in titanium dioxide sample by inductively coupled plasma atomic emission spectrometry (ICP-AES) was interfered with the titanium matrix. The titanium matrix was precipitated and separated by diammonium hydrogen phosphate [(NH₄)₂HPO₄]. Then, the content of trace copper and vanadium in titanium dioxide sample was determined by ICP-AES. The sample dissolution method, the precipitation conditions of titanium with (NH₄)₂HPO₄ and the determination conditions of ICP-AES were investigated. The results showed that the titanium in 0.1 g of titanium dioxide sample could be fullyreact with (NH₄)₂HPO₄ to form Ti(HPO₄)₂ precipitate in ammonium sulfate and sulfuric acid medium after heating in boiling bath for 3-5 min. The determination results were stable under the selected instrumental conditions with Cu 327.4 nm and V 292.4 nm as analytical spectral line. The detection limit of copper and vanadium was 0.001 μg/mL and 0.000 7 μg/mL, respectively. The proposed method was applied to determination of copper and vanadium in titanium dioxide actual samples. The relative standard deviation (RSD) was not more than 1.2%, and the recoveries were between 90% and 117%. The proposed method was applicable for the routine analysis of titanium dioxide.