Right place at the right time is a common phrase in US culture. The right preparation and positioning of a test sample can make or break analysis results. Let’s explore proper sample grinding and positioning for OES metal analysis in Spark Mode using high purity argon gas.
Samples must be ground to a flat, even surface using a stationary belt sander and an aluminum oxide belt. The lines should be evenly spaced and moving in a parallel direction. Swirl marks and cross-hatching from a wire wheel, grinding stone, roloc disc or carbide bit will produce an uneven surface leading to inaccurate results.
The image above illustrates samples with a correctly ground surface. The surface is level and the scratches run in a uniform pattern producing an excellent surface for analyzing metal. On the next post, we will look at a proper technique for analyzing pipe and tubing in spark mode.