ISO 20579-3:2021 pdf download – Surface chemical analysis — Sample handling, preparation and mounting — Part 3: Biomaterials.
6.3 Packaging If a sample is placed in a package for shipping or storage prior to surface analysis it is critical to know whether the packaging material can induce surface contamination. Plain paper in contact with most biomaterials will transfer atoms or molecules to the surface. Many plastics are processed with silicone oils or other additives that can be transferred to the specimen surface [4] . Ideally, specimens should be transported to the analyst in a container that does not come into direct contact with the surface of interest. A small vacuum desiccator is preferred. When this is not possible, clean packaging materials should be used. Examples of clean containers include Piranha-cleaned glass vials, UHV foil or tissue and specific polystyrene Petri dishes. The surface cleanliness of the container should be verified prior to use. Compare Clause 8. In some cases, it may be necessary to take a representative sample from the specimen. Selection of a smaller sample from a larger specimen should be done after considering the information being sought because in homogeneities are often present. It is recommended that this choice be made in consultation with an experienced analyst. Specific care should be taken to avoid contaminating the surface of interest during the cutting procedure (for more details see ASTM E1829 – 14 and ASTM E1078 – 14). These general principles are applicable to all materials. There are properties that are specific to specific classes of materials. Compared with metals, ceramics, glasses and carbons, organic and polymeric materials are more easily damaged by surface analysis methods. Polymeric systems also exhibit greater surface molecular mobility than inorganic systems. Surfaces of inorganic materials are contaminated more rapidly than polymeric materials because of their higher surface energy. Electrically conductive metals and carbons are often easier to characterise than insulators using electron, X-ray or ion interactive methods [1] .