“双电弧”是一种简便的利用分馏来提高矿物试样中易挥发元素光谱分析灵敏度的方法。自从它由Shaw等提出以后,已有好几篇述及应用双电弧的论文发表。从电学上看,这些双电弧不过是两个串联着的普通连续直流或交流电弧,它们有着如下的主要缺点:(1)激发电弧和加热电弧是串联的,在电学上可以直接互相影响。(2)激发电弧是个连续电弧,再现性差;“激发温度”不高,不利于“难激发元素”的 “Double Arc” is a simple and easy method to use fractional distillation to improve the sensitivity of spectral analysis of volatile elements in mineral samples. Since it was proposed by Shaw et al., Several papers describing the application of double arcs have been published. Electrically, these double arcs are but two ordinary continuous DC or AC arcs connected in series. They have the following major disadvantages: (1) The excitation and heating arcs are connected in series and can directly influence each other electrically. (2) excitation arc is a continuous arc, poor reproducibility; “excitation temperature” is not high, is not conducive to “difficult to stimulate elements”