Spectrometer Sensitivity Investigations on the Spectrometric Oil Analysis Program.

An investigation was conducted in order to determine the particle detection capabilities of the AE35U-3 rotating disk electrode arcspark emission spectrometer used by the Joint Oil Analysis Program. It was found that the analyses determined with the rotating disk electrode RDE spectrometer were particle-size dependent and that the RDE spectrometer cannot quantitatively analyze particles larger than 5-10 micrometers. The reasons for the low particle detection capabilities were examined and found to be related to particle settling rates which limit the rotating disks capability to transport particles to the source. Particle transport is improved by using viscous matrices, but the source does not possess the energy required to simultaneously vaporize the oil and excite the metal particles present. Therefore, the particle detection capability of the RDE spectrometer is limited by the low particle transport efficiency of its rotating disk and the low energy of its source. In order to improve the particle detection capabilities of the RDE spectrometer, several alternative sample introduction methods were investigated. Of the methods investigated, the ashing techniques offer the most promise for improving the particle detection capabilities of the RDE spectrometer. Author