ICP-OES和ICP-MS应用于石膏多元素分析时的样品微波消解方法研究

分别采用HNO3,HNO3/HF和HNO3/HF+H3BO3三种不同消解用酸微波消解石膏样品.用ICP-OES检测石膏中的Al,Ca,Fe,Mg,K,Na,S,Ti,Si和Sr,用ICP-MS检测石膏中的V,Cr,Mn,Zn,Se和Ce.采用GBW03109a,GBW03110和FGD-2作为石膏标准物质.检测值与样品标准值的对比结果表明,使用HNO3/HF+H3BO3样晶消解最完全.建立了用9 mL HNO3和1 mL HF分解0.2 g石膏,再加入10 mL 4%(ρ)的H3BO3中和过量的HF及氟化物沉淀的两步微波加热消解方法.该方法检测3种石膏标准物质时,元素回收率为88%～112%,RSD均小于3%.利用该方法测定了3种实际燃煤电厂脱硫石膏样品中的元素含量.

Study on microwave digestion of gypsum for the determination of multielement by ICP-OES and ICP-MS

Three acids (HNO3, HNO3/HF and HNO3 /HF+ H3BO3) were used to decompose gypsum with microwave digestion system. The contents of 10 mineral elements (Al, Ca, Mg, Fe, K, Na, S, Ti, Si and Sr) in gypsum were determined by inductively coupled plasma-optical emission spectrometry (ICP-OES) while 6 heavy metals (V, Cr, Mn, Zn, Se and Ce) were determined by inductively coupled plasma-mass spectrometry (ICP-MS). GBW03109a, GBW03110 and FGD-2 were used as gypsum standard reference materials. The results showed that two-step microwave digestion with HNO3/HF at 210 degrees C and then adding H3BO3 for the removal of HF and fluorides completely decomposed the gypsums, while this method achieved good recoveries for all elements in the three gypsum standard reference materials. The recovery was from 88% to 112% and the RSD of tests was below 3%. The method was applied to the elemental analysis for flue gas desulfurization gypsums from three coal-fired power plants.