松香中杂质元素的质谱分析

建立测定松香中16个杂质元素含量的分析方法。松香经乙醇溶解稀释后直接采用电感耦合等离子体质谱(ICP-MS)法测定。高浓度乙醇对等离子体所产生的负载以及有机碳不完全燃烧可能会在采样锥和截取锥孔沉积导致信号逐渐降低，通过优化等离子体的射频功率、载气流量以及样品提升量等仪器的操作条件，增加了等离子体中心通道的温度，提高等离子体的电离效率。采用在等离子体中加入低浓度氧气使有机碳充分燃烧，消除了积碳现象，维持了质谱分析信号的稳定。通过仪器调谐和同位素的选择有效地降低了氧化物和双电荷质谱干扰，避开了大量同量异位素干扰以及多原子离子干扰，利用碰撞/反应池(CRC)技术，分别选用氦碰撞模式和氢反应模式，消除了其余质谱干扰，选择内标元素补偿了样品与标准之间的粘度差异来匹配不同基体。结果表明，该方法的检出限在0.002～0.035 μg·g-1之间，实际样品的加标回收率为94.00%～106.00%，相对标准偏差(RSD)≤3.34%。方法采用乙醇溶解松香后直接测定，无需专用的样品前处理设备，具有操作简单、分析速度快、灵敏准确等优点，为松香中杂质元素的质量评价提供了一种新的分析方法。

Determination of Impurity Elements in Rosin with Inductively Coupled Plasma Mass Spectrometry

An analytical method for the content determining of impurity elements in rosin was established.After being dissolved and dilute d in ethanol,the rosin was analyzed directly with inductively coupled plasma ma ss spectrometry (ICP-MS).Some experiment conditions were optimized,such as th e RF power,carrier gas flow,sample amount,and increase the temperature of pla sma center channel,to improve the ionization efficiency.Proper oxygen concentr ation was added in plasma to make sure organic carbon been complete burned,resu lting in carbon deposits eliminate and signal stable.Though equipment turn and isotopes selection can effectively eliminate interferences caused by oxide and d oubly charged ions mass spectrums.A large amount of isobars and polyatomic ion interference were avoided.The collision reaction cell (CRC) technology was used to further eliminate the mass spectra interference,with He collision model and H2 reaction model,respectively.The results showed that detection limits of di fferent impurity elements were within the range from 0.002 to 0.035 μg·g-1,and the recoveries of real added sample were between the range from 94.00% to 106.00%,and relative standard deviation is less than 3.34%.This method enables to detect rosin dissolved in ethanol directly and needs no special sampl e preparation equipment.This simple,fast and accurate approach provides us a n ew analysis method for the quality valuation of impurity elements in rosin.