Qinhan Jin, Wenjun Yang, Feng Liang, Hanqi Zhang, Aimin Yu, Yanbo Cao, Jianguang Zhou and Bing Xu
The development of an alternative excitation source, the microwave plasma torch (MPT) is historically reviewed. The unique features and shortcomings of the MPT as an excitation source for AES are outlined. To overcome the relatively severe matrix effects, desolvation, flow injection, on-line preseparation and preconcentration as well as on-line standard additions techniques have been adopted. An oxygen-sheathed Ar-MPT has been developed to alleviate the interferences caused by the strong nitrogen-related emission bands and this has also been shown to be valuable in reducing noise levels as well as improving the excitation capability. Some possible future developments are envisioned.