异丙醇增感电感耦合等离子体质谱法直接测定土壤和沉积物中硒

提出了沸水浴混合酸法消解,以异丙醇为增感剂,电感耦合等离子体质谱直接测定土壤和沉积物中硒的方法。实验表明2mol/L硝酸-4mol/L盐酸混酸能有效溶出土壤和沉积物中各种形态的硒。相对于1%硝酸基体,4%(V/V)异丙醇基体中硒的ICP-MS响应值提高了12.1倍;而且4%(V/V)异丙醇基体可有效抑制硒的质谱干扰。ICP发射功率和雾化气流速是影响异丙醇在ICP-MS测定过程增敏效应的主要因素。以78硒为测定同位素,方法检出限为0.005mg/kg,实际样品测定精密度均小于5%。用于测定土壤和沉积物国家标准样品并对其消解液进行加标回收实验,结果令人满意。

Direct Determination of Se by Inductively Coupled Plasma Mass Spectrometry with Isopropanol as a Signal Enhancer

A mixed acid digestion in boiling water bath, combined with inductively coupled plasma mass spectrometry for selenium using isopropanol as a signal enhancer was developed. The mixed acid system of 2mol/LHNO₃-4mol/LHCl dissolved effectively all kinds of selenium in the soil and sediment samples. Compared with 1% (v/v) nitric acid matrix, the response value by ICP-MS increased 12.1 times in the 4% (v/v) isopropanol matrix. And the 4% (v/v) isopropanol matrix eliminated obviously the mass spectrometry interference of selenium. ICP forward power and nebulizer gas flow were the two main influence factor for signal enhance effect of isopropanol in ICP-MS. The detected limit of ⁷⁸Se was 0.005mg/kg; the relative standard deviations of environmental samples were below 5%; the determination results of national standard samples of soil and sediment and spiked recovery test were satisfactory.