电热消解-电感耦合等离子体质谱法测定准东煤中15种元素

基于全自动消解仪优化程序,以混合酸体系(硝酸-氢氟酸-高氯酸)消解样品,通过选择合适的待测同位素以及干扰元素校正方程校正质谱干扰,建立了电热消解-电感耦合等离子质谱法(ICP-MS)测定准东煤中铍、钒、锰、钴、镍、铜、锌、钼、镉、钡、铊、铅、银、铬、锑等15种元素的新方法。确定的最佳实验条件如下:采用标准模式测定铅、镍;采用碰撞模式,以氦气流速为3.0mL/min测定铍、锰、钴、铜、锌、钼、镉、钡、铊、铬、锑,以氦气流速为4.0mL/min测定钒、银;以~(187)Re对~(205)Tl、~(208)Pb进行校正,以~(115)In对~9 Be、~(51)V、~(55)Mn、~(59)Co、~(60)Ni、~(63)Cu、~(66)Zn、~(98)Mo、~(111)Cd、~(138)Ba、~(107)Ag、~(52)Cr、~(121)Sb进行校正可消除基体效应和信号漂移现象的影响。15种元素校准曲线的线性相关系数均大于0.999 9,方法检出限在0.005~0.400μg/g之间。采用实验方法对准东五彩湾煤样中15种元素进行测定,所得结果的相对标准偏差(RSD,n=11)为0.4%~3.3%,加标回收率为94%~115%;除镉、铊、银因含量低超出电感耦合等离子体原子发射光谱法(ICP-AES)的检出限外,其他元素的测得结果均与ICPAES基本一致。

Determination of fifteen elements in Zhundong coal by inductively coupled plasma mass spectrometry combined with electric heating digestion

The sample was digested with mixed acid system (nitric acid-hydrofluoric acid-perchloric acid) based on the optimized program of full automatic digestion instrument.The mass spectral interference was corrected by selecting proper isotopes and correction equation of interference elements. Then, a new determination method of 15 elements including beryllium, vanadium, manganese, cobalt, nickel, copper, zinc, molybdenum, cadmium, barium, thallium, lead, silver, chromium and antimony in Zhundong coal was established by inductively coupled plasma mass spectrometry (ICP-MS) combined with electric heating digestion. The obtained optimum experimental conditions were listed as follows: lead and nickel were determined at standard mode;beryllium, manganese, cobalt, copper, zinc, molybdenum, cadmium, barium, thallium, chromium and antimony were determined at collision mode with helium gas flow rate of 3.0 mL/min; vanadium and silver were determined at collision mode with helium gas flow rate of 4.0 mL/min. The influence of matrix effect and signal drift was eliminated when ²⁰⁵Tl and ²⁰⁸Pb were corrected with ¹⁸⁷Re, while ⁹Be, ⁵¹V, ⁵⁵Mn, ⁵⁹Co, ⁶⁰Ni, ⁶³Cu, ⁶⁶Zn, ⁹⁸Mo, ¹¹¹Cd, ¹³⁸Ba, ¹⁰⁷Ag, ⁵²Cr and ¹²¹Sb were corrected with ¹¹⁵In. The linear correlation coefficients of calibration curves of 15 elements were all higher than 0.999 9. The detection limits were between 0.005 μg/g and 0.400 μg/g. The proposed method was applied to the determination of 15 elements in Zhundong Wucaiwan coal sample. The relative standard deviations (RSD, n=11) were between 0.4% and 3.3%, and the recoveries were between 94% and 115%. Except for chromium, thallium and silver whose content was too low to exceed the detection limit of inductively coupled plasma atomic emission spectrometry (ICP-AES), the determination results of other elements were consistent with those obtained by ICP-AES.