ANALYTICAL CHARACTERISTICS OF A HELIUM HYDROGEN CAPACITIVELY COUPLED MICROWAVE PLASMA

Excitation temperatures and rotational temperatures have been determin ed in a helium/hydrogen plasma as a function of the concentration of h ydrogen in the plasma gas. The helium/hydrogen plasma was then evaluat ed in terms of matrix effects of Na+ and PO43- on Ca atomic emission s ignals. Little interference by Na+ on Ca atomic emission signals was o bserved while there was no suppression of Ca atomic signals by PO43- a t PO43- concentrations below 100 ppm. Above this concentration, some s uppression of the Ca signal was observed. Limits of detection determin ed in this work were comparable to the limits of detection by other wo rkers by capacitively coupled plasmas using molecular gases as the pla sma gas.