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R9 Laboratory SOP 430
Tissue Preparation and Homogenization
Summary
This method applies to the initial preparation and homogenization of tissue samples such as whole fish, fish fillets, soft organ tissues, and bivalve mollusks. Further preparation procedures are dependent on the request for analysis. Where this method and the instructions contained in the request for analysis conflict, the request for analysis instructions will take precedence.
The purpose of this SOP is to establish the procedures for the safe use of the Hobart bandsaw, Hobart grinder, Waring blender and Buchi mixer. The bandsaw and grinder are used to cut and grind large biological samples such as fish and birds prior to inorganic and organic analyses. The blender and mixer are used to grind smaller biological samples. This SOP applies to all laboratory personnel responsible for the preparation of tissue samples for extraction and digestion.
Fish, shellfish and tissue samples are received, partially thawed (if frozen), ground, and homogenized. The ground and homogenized samples are then ready for inorganic and organic sample preparation. Please see the individual analytical Region 9 Laboratory SOPs for method specific sample preparation.
Tissue samples are disassembled and ground when they are frozen. Samples should be thawed only to the point where it becomes possible to make an incision into the flesh. Large samples are carefully cut into smaller pieces using the bandsaw and are transferred to a pan or beaker until ground. The cut samples are added into the grinder outlet and pushed through using a feed stomper. Smaller tissue samples are added to the blender or mixer and homogenized. After grinding or homogenizing, the samples are transferred to precleaned glass or plastic jars and stored until use. Each piece of equipment is cleaned with soap and water and isopropanol after each use and between samples to prevent cross contamination.