Mechanism of Interference Effects by Matrix Element and Elimination of the Effect in ICP Mass Spectrometry

电感耦合等离子体质谱中伴随元素的影响可分为非光谱干扰和光谱干扰。仪器类型的不同会影响NS干扰的程度。这种干扰的机制并不一定很清楚。为了阐明减小干扰效应的机理，我们研究了不同基质元素引起的NS干扰，测量了NS干扰随等离子体操作条件的变化，证实了信号抑制效应(SSE)的质量依赖性。这可能是由于在取样器后面的超音速膨胀中分析物离子与基质离子的碰撞造成的。离子透镜元件的SSE随电压的变化可以用离子光学中空间电荷效应的变化来解释。由于基质元素的电离势越低，SSE越大，等离子体中电离平衡的移动是不能忽略的。S的…更多的SE不能用单一的机制来解释，而是几种机制的组合来解释。每种机制的贡献程度被认为取决于所使用的仪器类型和运行条件。实验还发现，选择合适的操作条件，虽然灵敏度有所降低，但可以减小基质效应。电离平衡的漂移可用内标法进行校正。引入的基质元素的绝对量与基质效应的程度有关，因此样品溶液的稀释有利于减小基质效应，与基质元素的双电荷离子和氧离子的重叠也很严重。等离子体电势是用探针测量的，因为这些离子的强度受电势的影响。双电荷离子随着电势的增加而增加。火炬的静电屏蔽显著降低了双电荷离子的电势和强度。较少

The effects of concomitant elements in ICP-MS can be classified into non-spectroscopic (NS) and spectroscopic interferences. The degree of NS interference is affected by the difference in types of instrument. The mechanism of the interference is not necessarily clear. In order to elucidate the mechanism to reduce the interference effect, we investigated NS interference caused by various matrix elements and the variation of NS interference with changing operating conditions of plasma was measured.Mass dependency of signal suppression effect (SSE) was confirmed in this work. This may be caused by the collision of analyte ions with matrix ions in the supersonic expansions behind the sampler. The variation of SSE with varying voltage of ion lens element may be explained by the change in the space charge effect in the ion optics. The shift of ionization equilibria in the plasma cannot be neglected because the lower is the ionization potential of the matrix element, the larger the SSE. The S … More SE cannot be explained by a single mechanism but by a combination of several mechanisms. The extent of the contribution of each mechanism is considered to depend on the type of instrument employed and the operating conditions. It was also found that matrix effect can be decreased by using an appropriate operating condition, though the sensitivity decreases. The shift of ionization equilibria can be corrected with the internal standard method. Absolute quantity of matrix element introduced is concerned with the degree of matrix effect, therefore the dilution of the sample solution is useful for the reduction of the matrix effect.The overlap with doubly charged and oxide ions of a matrix element is also severe. The plasma potential was measured with a probe, because the intensity of these ions is affected by the potential. The doubly charged ions increased with the increase in the potential. The electrostatic shielding of the torch significantly reduces the potential and the intensity of doubly charged ions. Less