ISO 20579-3:2021 Surface chemical analysis — Sample handling, preparation and mounting — Part 3: Biomaterials.
6 General requirements and classes of specimens
6.1 General information
General inlormation on specimen handling of solid biomaterials is available in References  to Li±ij. Biomaterials analysis requires special methods to control many of the biological reactions occurring in response to a biomaterial. Functionality, biocompatibility and durability are of concern. Some information for solid surfaces is found in Reference (5. Contamination is a key concern. The degree of cleanliness in particular for biomaterials required by surface-sensitive analytical techniques is much higher than for many other forms of analysisW. Specimens and mounts must never be in contact with the bare hand. Handling of the surface to be analysed should be eliminated or minimized whenever possible. Fingerprints contain mobile species that may contaminate the surface of interest. Hand creams, skin oils and other skin materials are not suitable for high vacuum.
Care should be taken in the handling of biomaterials to ensure that nothing, apart from air or clean inert gases, comes in contact with the surface to be investigated. In particular, avoid contacting the specimen surface with solvents or cleaning solutions, gases such as compressed air or solvent vapours, metals, tissue or other wrapping materials, tape, cloth, tools, packing materials, or the walls of containers. In response to hydrophobic environment compatible components may migrate to the surface of the specimen, thus reducing interfacial energy. Responding to an aqueous environment, the surface may reverse its structure and point polar (hydrophilic) groups outward to interact with the polar water molecules. Many materials can undergo a reversal of surface structure when transferred from air into a water environment. A hydroxylated polymer, such as a pHEMA contact lens, exhibits a surface rich in methyl groups in air, and a surface rich in hydroxyl groups under water. Energy minimization drives this process. For metal alloys, one component tends to dominate the surface, as chromium in stainless steel4. In particular, the use of low-density poly(ethylene) (LDPE) bags, which are known to be contaminated with slip agents, should he avoided. In cases where these precautions are not feasible due to the size of the specimen, some alternative specimen storage and transporting methods are presented in Clause 15. Some approaches to sample handling will apply to all biomaterials and some only to subsets, i.e. liquid specimen.ISO 20579-3 pdf download.