A new low-power microwave plasma source using microstrip technology for atomic emission spectrometry

A new low-power, compact microwave-induced plasma source for applications i n atomic emission spectrometry at atmospheric pressure using microstrip tec hnology is described. The gas channel of about 1 mm(2) is integrated in a f used silica dielectric wafer. The microstrip transmission lines are fabrica ted by sputtering and electro-plating. For example, a unit operates at an i nput power of 15 W with an argon gas flow of about 500 ml min(-1) at atmosp heric pressure. Rotational (OH) and excitation (Fe) temperatures of 650 K a nd 8000 K, respectively, were measured at these conditions. The emitted rad iation can be taken up by an optical fibre positioned in the plasma-gas cha nnel thus enabling an axial observation and coupling to a miniaturized spec trometer. The first devices showed an operation time of at least several hu ndred hours. Further investigations will lead to even smaller dimensions an d lower power consumption and open the way for integrated microwave plasma sources with low detection limits as integrable parts of miniaturized total analytical systems applications.