Opinion ID: 1285369
Heading Depth: 1
Heading Rank: 2

Heading: The Electrophoretic Procedure

Text: Serum electrophoresis is a process that separates blood into its component proteins and enzymes [2] by the use of an electric current. A portion of the blood sample is placed on a gelatin-like substance that is mounted on a glass plate. Known blood samples are placed beside the unknown sample. An electric current is passed for a period of time through the samples and gel. The blood proteins assume positive, negative or neutral charges, then move toward the pole of the opposite charge. Because the proteins vary in size, shape, density and charge, they vary in mobility. Thus, they migrate in the electrical field at different speeds and stop migrating at different specific points. The result is that the particular proteins and enzymes are separated into banding patterns. Each banding pattern is distinctive for a particular protein/enzyme. After separation, chemical dyes are applied that react with the proteins/enzymes to make them visible to either the eye or under ultraviolet light. The patterns are then read by a trained analyst and the proteins/enzymes are typed. At the BCA, any necessary control is provided by having another analyst read the results and make an independent determination. A photographic record of the banding is not usually made. If the forensic sample is completely used up in the testing procedure, which may occur with small sample sizes, no retesting will be possible on that particular sample. Two types of testing are done. One type is to test for several proteins at once using a method called the multi-system method. The other type tests for only one protein at a time. Use of the multi-system on PGM can compromise results, not in the sense of mistyping, but in the sense of causing inconclusive results, because the dye paper used to stain a particular protein can soak up PGM molecules.