ROTATING-ELECTRODE SYSTEM FOR IMPROVED REPRODUCIBILITY IN SPARK SOURCE-MASS SPECTROMETRY

A modified electrode configuration in a spark source mass spectrometer improves the reproducibility of analytical results. The system consists of vertically mounted cylindrical electrodes facing each other, one of which is rotating. No rotary feedthrough is needed as coupling between a small magnet inside the source and one (driven by a motor) outside allows rotation. Hence the vacuum inside the source can be kept low (less than 10-6 Pa approximately=10-8 Torr). Relative standard deviations do not exceed 6% for highly inhomogeneous powder mixtures. Moreover, higher and more stable transmissions are obtained, while short-circuiting between low-melting point materials is greatly reduced.