Mini, micro, and high-efficiency torches for the ICP - toys or tools?

Because the inductively-coupled plasma (ICP) is expensive both to purchase and to continue in operation, many workers have sought to reduce both the radiofrequency power and coolant argon ordinarily required to sustain the discharge. In one approach, the ICP has been reduced in size, in the hope that its analytical strengths could be retained but the power and argon required for it reduced. In the second approach, the torch used to support the discharge has been modified extensively. The final and most recent approach utilises alternative torch cooling schemes using, for example, water or high air flows as a coolant. In this paper, these alternative approaches will be reviewed and assessed in terms of their practicability and analytical capability. Prospects for future torch modification and low-flow, low-power ICP instrumentation will be considered and discussed.