A Novel Double Disc Electrode Excitation Method for Oil Elemental Analysis in Rotating Disc Electrode- Optical Emission Spectrometry (RDE-OES)

However, electrode wear impedes sample combustion and spectral stability, causing errors in acquisition and analysis. In this work, we propose and develop a novel arc excitation method with a double disc electrode structure, replacing the conventional upper rod electrode with a disc electrode of the same type as the lower electrode, and the double electrodes rotate simultaneously.

This method minimizes wear and maintains a constant gap, enabling a long-lasting, energy-focused arc and high-intensity, stable spectrum. Our method is validated by analyzing spectral lines of Al, Mg, Cr and Ca. Compared with the conventional method, the results revealed that our smethod can improved calibration robustness, with 2-3 times higher spectral intensity and 1-3 times higher signal-to-noise ratio (SNR) with an 8-10% reduction in the relative standard deviation (RSD) values.