科研之友
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摘要
Microwave-induced combustion (MIC) was applied for analyte volatilization from soil and subsequent determination of As, Cd and Pb by inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP-OES), and Hg by cold vapor generation inductively coupled plasma mass spectrometry (CVG-ICP-MS). Soil samples (up to 300 mg) were mixed with microcrystalline cellulose, pressed as pellets and combusted in closed quartz vessels pressurized with 20 bar O-2. Analytes were volatilized from soil during combustion and quantitatively absorbed in a suitable solution: nitric acid (1, 2, 4 or 6 mol L-1) or a solution of nitric (2 mol L-1) and hydrochloric (1, 2 or 4 mol L-1) acids. Accuracy was evaluated using certified reference materials of soil (NIST 2709, San Joaquin Soil) and sediment (SUD-1, Sudbury sediment for trace elements). Agreement with certified values was better than 95% (t-test, 95% confidence level) for all analytes when 6 mL of a solution of 2 mol L-1 HNO3 and 2 mol L-1 HCl was used with a reflux step of 5 min. The limit of detection was 0.010, 0.002, 0.009 and 0.012 mu g g(-1) for As, Cd, Hg and Pb, respectively using ICP-MS determination. A clear advantage of the proposed method over classical approaches is that only diluted solution is used. Moreover, a complete separation of the analytes from matrix is achieved minimizing potential interferences in ICP-MS or ICP-OES determination. Up to eight samples can be digested in a single run of only 25 min, resulting in a solution suitable for the determination of all analytes by both techniques.
- 出版日期2013-8-1
