Various types of contamination can occur during bulk sampling, including:
- Cross-contamination: This happens when residues from previous samples contaminate the current bulk material. This can be a problem, especially if different types of bulk material are handled with the same equipment.
- Foreign matter contamination: This refers to contaminants that come from the environment, such as dust, dirt or other materials that can enter the bulk material.
- Equipment contamination: This can occur when the sampling equipment itself contaminates the bulk material, for example by abrasion of parts of the equipment or by chemicals migrating from the equipment to the bulk material.
There are several measures that can be taken to prevent these types of contamination:
- Equipment cleaning and maintenance: Sampling equipment should be cleaned and maintained regularly to remove residues and ensure that it is working properly.
- Use of suitable materials: The equipment should be made of materials that do not react with the bulk material or pass into the bulk material. Stainless steel is a commonly used material due to its chemical inertness and robustness.
- Control of environmental conditions: Depending on the type of bulk material and the environment in which sampling is carried out, it may be necessary to take measures to control environmental conditions, such as reducing dust exposure or ensuring that sampling is carried out in a clean environment.
- Use of appropriate sampling techniques: Sampling should be carried out in such a way as to minimize the risk of contamination. This could be achieved, for example, through the use of closed or automated sampling systems.
- Personnel training: The personnel responsible for sampling should be adequately trained to minimize the risk of contamination. This could include making sure they are following the right procedures, using the equipment properly, and understanding how to avoid contamination.