Sample Pretreatment for Optical Emission Spectrometry

Spark marks on sample surface after analysis in Shimadzu PDA-7000

By using the spectrophotometers to determine the chemical composition of alloys, thereby identifying materials such as carbon steel, stainless steel, low alloy steel, cast iron, etc.

There are many factors that affect the determination of the chemical composition of materials such as the metallurgical process, the operation of the analyzer user, etc. The preparation of the surface of the sample is also an important factor in determining the optimum result when applied to the analyzer on the spectrophotometer.

Requirements for sample preparation:

• Samples are taken, shaped using specialized tools and can be cooled during sampling, but not wet during analysis.
• After preparing the surface, if the sample is hot, cool it by placing on a copper substrate and not contacting the surface of the analysis.
• Do not cool the sample after preparing the surface with liquid.
• Do not touch the surface of the analysis with pollution sources: finger, clamp, etc.
• The whole surface must be clean, the surface of the sample and the contact surface of the sample holder must be parallel.
• After preparation of the surface should immediately analyze.

For different materials, sample preparation is a bit different:

• For samples of steel, cast iron ...: using the machine to cut or the mold for shaping and cooling the material after that surface is processed by grinding machine.
• For samples from the zinc - copper - aluminum group: lathes should be used to treat the sample surface before analysis.

The following is an illustration of the process of preparing a sample of common materials:

Diagram of preparation of analytical samples for some common materials 

Source: ETA