Mass spectrometric analysis of positive ions extracted from glow discharges is a common experimental procedure most often motivated by basic research considerations. An exception is the fairly recent application of this technique to the elemental analysis of solids. The experimental aspects of mass spectrometric analysis of plasma ions are discussed, and it is concluded that the insertion of an electrostatic deflection energy analyzer between the sampling orifice and the quadrupole mass filter is worthy of serious consideration in many research projects of this type. Several examples of the value of energy analysis are given. A brief discussion of the use of this technique in plasma process development is presented, and it is concluded that mass spectrometric ion sampling is not an obvious first choice in an applied environment but holds considerable promise in a basic research program. © 1989.